424B5

424B5 1 d300116d424b5.htm 424B5 424B5

As Filed Pursuant to Rule 424(b)(5)
Registration No. 333-283179

PROSPECTUS SUPPLEMENT

(To Prospectus Dated November 19, 2024)

LOGO

35,190,292 Shares of Common Stock

Pre-Funded Warrants to Purchase 17,787,033 Shares of Common Stock

Warrants to Purchase 52,977,325 Shares of Common Stock

We are offering (i) 35,190,292 shares of our common stock, pre-funded warrants to purchase 17,787,033 shares of our common stock, or the pre-funded warrants, and (ii) accompanying warrants, or the purchase warrants, to purchase up to an aggregate of 52,977,325 shares of our common stock (and the shares of common stock issuable from time to time upon exercise of each of the purchase warrants and pre-funded warrants), pursuant to this prospectus supplement and the accompanying prospectus. The common stock and pre-funded warrants will be sold in combination with an accompanying purchase warrant to purchase one share of common stock issued for each share of common stock or pre-funded warrant sold. The shares of our common stock (or the pre-funded warrants) and purchase warrants are immediately separable and will be issued separately. The purchase warrants will be exercisable six months from the date of issuance and will expire five and a half years from the date of issuance. The purchase warrants will have an exercise price of $0.4719 per whole share of our common stock, subject to adjustment as described elsewhere in this prospectus supplement. The pre-funded warrants will be exercisable immediately and are exercisable for one share of our common stock. The purchase price of each pre-funded warrant is equal to the combined purchase price at which a share of our common stock and the accompanying purchase warrant is sold in this offering, minus $0.01, and the exercise price of each pre-funded warrant is $0.01 per share of our common stock.

Our common stock is traded on The Nasdaq Capital Market under the symbol “SGMO.” On February 2, 2026, the last reported sale price of our common stock was $0.57 per share. There is no established public trading market for the purchase warrants or the pre-funded warrants, and we do not expect a market to develop. In addition, we do not intend to apply for listing of the purchase warrants or the pre-funded warrants on any securities exchange or recognized trading system.

Investing in our securities involves a high degree of risk. Before making an investment decision, please read the information in “Risk Factors” beginning on page S-5 of this prospectus supplement and in our Annual Report on Form 10-K for the year ended December 31, 2024 and our Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, which are incorporated by reference into this prospectus supplement and the accompanying prospectus.


	Per Share and Accompanying Purchase Warrant		Per Pre- Funded Warrant and Accompanying Purchase Warrant		Total
Public offering price	$	0.4719	$	0.4619	$	24,822,129.34
Underwriting discounts and commissions(1)	$	0.0283	$	0.0277	$	1,488,586.08
Proceeds, before expenses, to us	$	0.4436	$	0.4342	$	23,333,543.26

(1)	See “Underwriting” for a description of the compensation payable to the underwriters.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The underwriters expect to deliver the securities to the investor on or about February 4, 2026.



Cantor		Wells Fargo Securities

Prospectus supplement dated February 3, 2026.

TABLE OF CONTENTS

PROSPECTUS SUPPLEMENT


ABOUT THIS PROSPECTUS SUPPLEMENT			S-ii
PROSPECTUS SUPPLEMENT SUMMARY			S-1
RISK FACTORS			S-5
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS			S-11
USE OF PROCEEDS			S-13
DILUTION			S-14
DESCRIPTION OF SECURITIES WE ARE OFFERING			S-16
MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS			S-20
UNDERWRITING			S-28
LEGAL MATTERS			S-39
EXPERTS			S-39
WHERE YOU CAN FIND MORE INFORMATION			S-39
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE			S-40

PROSPECTUS


ABOUT THIS PROSPECTUS			ii
PROSPECTUS SUMMARY			1
RISK FACTORS			5
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS			6
USE OF PROCEEDS			8
DESCRIPTION OF CAPITAL STOCK			9
DESCRIPTION OF DEBT SECURITIES			14
DESCRIPTION OF WARRANTS			21
LEGAL OWNERSHIP OF SECURITIES			23
PLAN OF DISTRIBUTION			27
LEGAL MATTERS			29
EXPERTS			29
WHERE YOU CAN FIND MORE INFORMATION			29
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE			30

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ABOUT THIS PROSPECTUS SUPPLEMENT

This prospectus supplement and the accompanying prospectus relate to the offering of our securities. Before buying any of the securities that we are offering, we urge you to carefully read this prospectus supplement and the accompanying prospectus, together with the information incorporated by reference as described in the section titled “Incorporation of Certain Information by Reference” in this prospectus supplement and the accompanying prospectus and the information in any free writing prospectus that we may authorize for use in connection with this offering. These documents contain important information that you should consider when making your investment decision.

This document is in two parts. The first part is this prospectus supplement, which describes the terms of this offering of our securities and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference into this prospectus supplement and the accompanying prospectus. The second part, the accompanying prospectus dated November 19, 2024, including the documents incorporated by reference therein, provides more general information. Generally, when we refer to this prospectus, we are referring to both parts of this document combined. To the extent there is a conflict between the information contained in this prospectus supplement, on the one hand, and the information contained in the accompanying prospectus or in any document incorporated by reference that was filed with the Securities and Exchange Commission, or the SEC, before the date of this prospectus supplement, on the other hand, you should rely on the information in this prospectus supplement. If any statement in one of these documents is inconsistent with a statement in another document having a later date—for example, a document incorporated by reference in the accompanying prospectus—the statement in the document having the later date modifies or supersedes the earlier statement.

We have not authorized anyone to provide you with information different than or inconsistent with the information contained in or incorporated by reference into this prospectus supplement, the accompanying prospectus or in any free writing prospectus that we have authorized for use in connection with this offering. We take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We are not making an offer to sell our securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus supplement, the accompanying prospectus, the documents incorporated by reference into this prospectus supplement and the accompanying prospectus, and in any free writing prospectus that we have authorized for use in connection with this offering, is accurate only as of the date of those respective documents, regardless of the time of delivery of those respective documents. Our business, financial condition, results of operations and prospects may have changed since those dates. You should read this prospectus supplement, the accompanying prospectus, the documents incorporated by reference into this prospectus supplement and the accompanying prospectus, and any free writing prospectus that we have authorized for use in connection with this offering, in their entirety before making an investment decision regarding the securities we are offering. You should also read and consider the information in the documents to which we have referred you to in the section of this prospectus supplement entitled “Where You Can Find More Information” and “Incorporation of Certain Information by Reference.”

Except as otherwise indicated herein or as the context otherwise requires, references in this prospectus supplement, the accompanying prospectus and the information incorporated by reference herein and therein to “Sangamo,” “the company,” “we,” “us,” “our” and similar references refer to Sangamo Therapeutics, Inc., a Delaware corporation, and its subsidiaries on a consolidated basis.

This prospectus supplement, the accompanying prospectus, and the information incorporated herein and therein by reference include trademarks, trade names and service marks owned by us or other companies. SANGAMO is a registered trademark in Australia, Canada, the European Union and the United Kingdom. SANGAMO THERAPEUTICS and SANGAMO THERAPEUTICS Design are registered trademarks in Australia, Canada, the European Union, Japan, the United Kingdom, and the United States. The trademarks UNIVERSAL GENE RECOGNITION, UNIVERSAL GENETOOLS and ZFP THERAPEUTIC are registered in

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Canada. An intent-to-use application is pending regarding the trademark GEXREV in the United States. All other trademarks or trade names referred to in this prospectus supplement are the property of their respective owners. We do not intend our use or display of other companies’ trademarks or trade names to imply a relationship with, or endorsement or sponsorship of us by, any other companies or products.

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PROSPECTUS SUPPLEMENT SUMMARY

This summary highlights certain information about us, this offering and selected information contained elsewhere in or incorporated by reference into this prospectus supplement and the accompanying prospectus. This summary is not complete and does not contain all of the information that you should consider before deciding whether to invest in our securities. For a more complete understanding of our company and this offering, we encourage you to read and consider carefully this entire prospectus supplement and the accompanying prospectus, the information incorporated by reference herein and therein and the information included in any free writing prospectus that we have authorized for use in connection with this offering, including the factors described in “Risk Factors” beginning on page S-5 of this prospectus supplement and in our Annual Report on Form 10-K for the year ended December 31, 2024 and our Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, which are incorporated by reference into this prospectus supplement and the accompanying prospectus, our consolidated financial statements and the related notes and other documents incorporated by reference into this prospectus supplement and the accompanying prospectus.

Overview

We are a genomic medicine company dedicated to translating ground-breaking science into medicines that transform the lives of patients and families afflicted with serious neurological diseases who do not have adequate or any treatment options. We believe our zinc finger epigenetic regulators are ideally suited to potentially address devastating neurological disorders and our capsid discovery platform can expand delivery beyond currently available intrathecal delivery capsids, including in the central nervous system.

Our Core Neurology Programs

Our neurology development is focused on two innovative areas: (i) development of epigenetic regulation therapies to treat serious neurological diseases and (ii) development of novel engineered adeno-associated virus, or AAV, capsids to deliver our therapies to the intended neurological targets.

Initial indications for our wholly owned preclinical programs include small fiber neuropathy, or SFN, a type of chronic neuropathic pain, and prion disease. Following clearance in November 2024 of the investigational new drug application, or IND, from the U.S. Food and Drug Administration, or FDA, for ST-503, an investigational epigenetic regulator for the treatment of intractable pain due to SFN, the first four clinical sites for the Phase 1/2 STAND study have been activated and we have begun patient enrollment and recruitment. We also are preparing a clinical trial authorisation, or CTA, for our product candidate to treat prion disease.

In addition, we are party to collaboration and license arrangements pursuant to which our collaborators are developing preclinical product candidates in indications such as tauopathies, amyotrophic lateral sclerosis and Huntington’s disease. These partners include Genentech, Inc., a member of the Roche Group, or Genentech, Alexion Pharmaceuticals, Inc. and Takeda Pharmaceutical Company Limited.

We also are developing novel engineered AAV capsids enhanced for delivery to neurological targets and have identified a proprietary engineered neurotropic AAV capsid variant, STAC-BBB, that has demonstrated an ability to cross the blood-brain barrier in nonhuman primates and mediated robust transduction, transgene expression, and targeted epigenetic repression throughout the brain and spinal cord after intravenous administration. We believe this novel capsid has the potential to unlock multiple wholly owned neurology epigenetic regulation programs, and is the subject of multiple out-license agreements, including with Genentech and Astellas Gene Therapies, Inc., or Astellas, and Eli Lilly and Company, or Lilly.

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Other Clinical Programs

Isaralgagene civaparvovec

Isaralgagene civaparvovec, also known as ST-920, our wholly owned gene therapy product candidate for the treatment of Fabry disease, has been evaluated in our registrational Phase 1/2 STAAR clinical study, which is now complete. In October 20025, the FDA reiterated its October 2024 agreement that data from the Phase 1/2 STAAR study can serve as the primary basis for approval under the Accelerated Approval Program, using estimated glomerular filtration rate, or eGFR, slope at 52 weeks across all patients as an intermediate clinical endpoint. In this regard, in December 2025, we initiated a rolling submission of a Biologics Licensing Application, or BLA, to the FDA seeking accelerated approval of isaralgagene civaparvovec. Rolling submission allows for completed modules of the BLA to be submitted and reviewed by the FDA on an ongoing basis rather than waiting for the entire BLA to be submitted at once. We are currently in early-stage business development discussions with respect to a potential commercialization agreement for isaralgagene civaparvovec.

Giroctocogene fitelparvovec

Giroctocogene fitelparvovec, also known as SB-525, is a gene therapy product candidate for the treatment of moderately severe to severe hemophilia A that we co-developed with and previously licensed to Pfizer Inc., or Pfizer. In December 2024, Pfizer notified us of its termination of our collaboration for convenience, effective April 21, 2025. We have completed the transition of the program back to Sangamo, and we currently are in early-stage business development discussions with respect to a potential collaboration partner for giroctocogene fitelparvovec.

Preliminary Financial Information

Based upon preliminary estimates and information available to us as of the date of this prospectus supplement, we estimate that we had approximately $20.9 million in cash and cash equivalents as of December 31, 2025. We have not yet completed our financial close process for the quarter and year ended December 31, 2025. This estimate of our cash and cash equivalents as of December 31, 2025 is preliminary, unaudited and is subject to change upon completion of our financial statement closing procedures and the audit of our consolidated financial statements.

Our independent registered public accounting firm, Ernst & Young LLP, has not audited, reviewed, compiled, or applied agreed-upon procedures with respect to the foregoing preliminary financial data. Accordingly, Ernst & Young LLP does not express an opinion or any other form of assurance with respect thereto. It is possible that we or Ernst & Young LLP may identify items that require us to make adjustments to the financial information set forth above. Our audited consolidated financial statements for the year ended December 31, 2025 are scheduled to be completed subsequent to the completion of this offering. Accordingly, undue reliance should not be placed on this preliminary estimate.

Company Information

We were incorporated in June 1995 in the state of Delaware and in January 2017, we changed our name from “Sangamo BioSciences, Inc.” to “Sangamo Therapeutics, Inc.” Our principal executive offices are located at 501 Canal Blvd., Richmond, California 94804. Our telephone number is (510) 970-6000. Our website is www.sangamo.com. Information found on, or accessible through, our website is not a part of, and is not incorporated into, this prospectus supplement or the accompanying prospectus, and you should not consider it part of this prospectus supplement or the accompanying prospectus. Our website address is included in this prospectus supplement as an inactive textual reference only.

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The Offering

Common stock offered by us

35,190,292 shares.

Pre-funded warrants offered by us

Pre-funded warrants to purchase up to 17,787,033 shares of our common stock. Each pre-funded warrant will have an initial exercise price per share of $0.01, subject to certain adjustments. The purchase price of each pre-funded warrant is equal to the price at which a share of our common stock and accompanying purchase warrant is being sold in this offering, minus $0.01. The pre-funded warrants are exercisable immediately and may be exercised at any time until all of the pre-funded warrants are exercised in full. For more information, see the section titled “Description of Securities We Are Offering—Pre-Funded Warrants” on page S-16 of this prospectus supplement. This prospectus supplement also relates to the offering of the shares of our common stock issuable upon exercise of the pre-funded warrants.

Purchase warrants offered by us

Purchase warrants to purchase up 52,977,325 shares of our common stock. Each purchase warrant will have an initial exercise price per share of $0.4719, subject to certain adjustments, will become exercisable six months from the date of issuance, and will expire five and a half years from the date of issuance. For more information, see the section titled “Description of Securities We Are Offering—Purchase Warrants” on page S-16 of this prospectus supplement. This prospectus supplement also relates to the offering of the shares of our common stock issuable upon exercise of the purchase warrants.

Warrant repricing transaction

Concurrent with the closing of this offering, we have agreed to reduce the exercise price of 23,809,523 outstanding common stock warrants issued on March 26, 2024 and held by the investor in this offering, or the Repriced Warrants, from $1.00 per share to $0.4719 per share, the exercise price of the purchase warrants issued in this offering. The Repriced Warrants will become exercisable six months after the closing of this offering, and will expire five and a half years after the closing of this offering.

Common stock to be outstanding immediately after this offering

357,199,331 shares (assuming none of the purchase warrants or the pre-funded warrants issued in this offering are exercised).

Use of proceeds

We estimate that net proceeds from this offering, excluding the proceeds, if any, from the exercise of the purchase warrants or the pre-funded warrants offered hereby, will be approximately $22.9 million, after deducting the underwriting discounts and commissions and estimated offering expenses payable by us.

We intend to use the net proceeds from this offering, together with our cash and cash equivalents, for working capital and general corporate purposes. See “Use of Proceeds” for additional information.

Risk factors

Investing in our securities involves a high degree of risk. Before making an investment decision, please read the information contained

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in and incorporated by reference in this prospectus supplement and the accompanying prospectus under the section titled “Risk Factors” beginning on page S-5 of this prospectus supplement.

Nasdaq listing for our common stock

Our common stock is listed on the Nasdaq Capital Market under the symbol “SGMO.” There is no established public trading market for the purchase warrants or the pre-funded warrants and we do not expect a market to develop. In addition, we do not intend to apply for listing of the purchase warrants or the pre-funded warrants on any securities exchange or recognized trading system.

The number of shares of our common stock to be outstanding immediately after this offering as shown above is based on 322,009,039 shares of our common stock outstanding as of September 30, 2025. This number excludes:

•

15,697,986 shares of our common stock issuable upon the exercise of outstanding stock options as of September 30, 2025 with a weighted-average exercise price of $4.602 per share;

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15,605,557 shares of our common stock issuable upon the exercise of outstanding stock options granted after September 30, 2025 with a weighted-average exercise price of $4.5024 per share;

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6,947,690 shares of our common stock issuable upon the vesting and settlement of outstanding restricted stock units, or RSUs, as of September 30, 2025 with a weighted-average grant date fair value of $0.8594 per share;

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4,582,499 shares of our common stock issuable upon the exercise of outstanding RSUs granted after September 30, 2025 with a weighted-average grant date fair value of $0.9617 per share;

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28,571,428 shares of common stock issuable upon the exercise of outstanding warrants as of September 30, 2025 with an exercise price of $1.00 per share (before giving effect to the amendment of the Repriced Warrants);

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46,633,393 shares of common stock issuable upon the exercise of outstanding warrants as of September 30, 2025 with an exercise price of $0.75 per share;

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22,672,591 shares of our common stock available for issuance or future grant under our Amended and Restated 2018 Equity Incentive Plan, or EIP, as of September 30, 2025;

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1,647,826 shares of our common stock available for issuance under our 2020 Employee Stock Purchase Plan, or ESPP, as of September 30, 2025; and

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32,250,609 shares of our common stock sold since September 30, 2025 under an “at the market” equity offering program that we entered into pursuant to our Open Market Sale Agreement, dated August 5, 2020, as amended, with Jefferies LLC, as agent, or the Sales Agreement, for aggregate net proceeds of approximately $17.0 million, and up to approximately $131.2 million of shares of our common stock remaining to be sold under the Sales Agreement as of the date of this prospectus supplement.

Unless otherwise indicated, all information in this prospectus supplement assumes:

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no exercise of outstanding options or warrants to purchase our common stock;

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no vesting and settlement of outstanding RSUs;

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no issuance of shares available, or that may become available, for future issuance under our equity compensation plans; and

•

no exercise of the purchase warrants or the pre-funded warrants offered in this offering.

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RISK FACTORS

Investing in our securities involves a high degree of risk. Before deciding whether to invest in our securities, you should consider carefully the risks and uncertainties described below and discussed under the section titled “Risk Factors” contained in our Annual Report on Form 10-K for the year ended December 31, 2024 and our Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, which are incorporated by reference into this prospectus supplement and the accompanying prospectus, together with the other information in this prospectus supplement, the accompanying prospectus, the information and documents incorporated by reference and any free writing prospectus prepared by or on behalf of us or to which we have referred you. If any of these risks actually occur, our business, financial condition, results of operations or prospects could be seriously harmed. This could cause the trading price of our common stock to decline, resulting in a loss of all or part of your investment. Please also carefully read the section titled “Special Note Regarding Forward-Looking Statements.”

Risks Related to this Offering and the Securities Offered Hereby

There is currently substantial doubt about our ability to continue to operate as a going concern, which substantial doubt will not be alleviated with the net proceeds of this offering. We will continue to need substantial additional funding following this offering to continue to operate as a going concern. If adequate funds are not available to us on a timely basis, or at all, we will be required to take additional actions to address our liquidity needs, including additional cost reduction measures such as further reducing operating expenses, including through workforce reductions, and delaying, reducing the scope of, discontinuing or altering our research and development activities, which would have a material adverse effect on our business and prospects.

We have incurred significant operating losses and negative operating cash flows since inception and have not achieved profitability. In addition, our current financial position raises substantial doubt about our ability to continue to operate as a going concern, which substantial doubt will not be alleviated with the net proceeds of this offering. Based on our current operating plan, we believe our existing cash and cash equivalents, together with the estimated net proceeds from this offering, will be adequate to fund our planned operations only into the beginning of the third quarter of 2026. This estimate regarding our cash resources is based on assumptions that are inherently uncertain, and actual results could differ materially from those estimates. In this regard, we could use our available capital resources sooner than we currently expect and changing circumstances, some of which may be beyond our control, could cause us to consume capital significantly faster than we currently anticipate. Accordingly, our ability to continue to operate as a going concern will remain dependent upon our ability to raise substantial additional capital following this offering to fund our operations and support our research and development endeavors, including to progress our core neurology programs as described in this prospectus supplement and the accompanying prospectus.

Subject to the lock-up agreement we entered into in connection with this offering as described under “Underwriting,” we will continue to actively seek additional capital following this offering, including through public or private equity or debt financing, or other sources, such as strategic collaborations and other direct investments in our programs. The substantial additional capital needed to support our operations and to continue to operate as a going concern may not be available on acceptable terms or at all. In particular, the perception of our ability to continue to operate as a going concern has made and will continue to make it more difficult to obtain additional financing for the continuation of our operations, particularly in light of currently challenging macroeconomic and market conditions. Further, we have been and may continue to be unable to attract substantial new investments as a result of the speculative nature of our newly reprioritized core neurology preclinical programs and the absence of partners to progress our more advanced clinical-stage programs. In this regard, our ability to fund our operations beyond the third quarter of 2026 and to advance the development of our technologies and product candidates will remain wholly dependent on our ability to secure collaboration partners for our more advanced clinical-stage programs or to otherwise enter into value-maximizing transactions for those

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programs. If we are not able to secure collaborators for, or to otherwise enter into value-maximizing transactions for, these more advanced clinical-stage programs, we will not be able to secure sufficient capital following this offering to continue to operate as a going concern and to advance the development of our technologies and product candidates. In particular, despite an extensive, long-term process to secure commercialization partners for our Fabry disease and hemophilia A programs, we are currently only in the early stages of discussions with potential counterparties in respect of potential business development transactions for our Fabry disease and hemophilia A programs. There can be no assurance that such current or potential future discussions will meaningfully advance at all or ultimately result in value-maximizing transactions, and if we are unable to execute one or more such transactions for our more advanced clinical-stage programs in the near-term, particularly our Fabry disease program, we will be unable to raise the substantial additional capital needed to support our operations and to continue to operate as a going concern. If adequate funds are not available to us on a timely basis, or at all, we will be required to take significant additional actions to address our liquidity needs, including substantial additional cost reduction measures such as further reducing operating expenses and further delaying, reducing the scope of, altering or discontinuing entirely our research and development activities. In this regard, we are actively considering a variety of significant cost-cutting measures designed to preserve our cash resources and the value of our assets including, among others, additional reductions in our workforce. If we are unable to consummate one or more transactions to provide for, or enable, the substantial additional funding needed to operate our business, our business and prospects would be materially and adversely affected, and we may be required to cease operations entirely, liquidate all or a portion of our assets, and/or seek protection under the U.S. Bankruptcy Code, and you may lose all or part of your investment. We have explored, and will continue to explore, whether filing for bankruptcy protection is in the best interest of Sangamo and our stakeholders.

Moreover, we have historically relied in part on collaboration partners to provide funding for and otherwise advance our preclinical and clinical programs. However, in June 2023, our collaboration agreements with Biogen and Novartis terminated, our collaboration agreement with Kite expired pursuant to its terms in April 2024, and in December 2024, Pfizer notified us of its termination for convenience, effective April 21, 2025, of its collaboration agreement with us. Further, while we may identify new collaboration partners who can progress some of the programs that were the subject of these collaborations, as well as our Fabry disease program, STAC-BBB capsid and modular integrase platform, we have not yet been, and may never be, successful in doing so in a timely manner, or on acceptable terms or at all, and we may otherwise fail to raise sufficient additional capital in order to progress these and our other programs ourselves, in which case, we will not receive any return on our investments in these programs. Although we have received an aggregate of $88.0 million in upfront license fees and/or milestone payments and are eligible to earn future licensed target fees and development and commercial milestone payments in connection with our license agreements with Genentech, Astellas and Lilly, we may never receive any further payments under any of these agreements. In any event, we need substantial additional funding in order to advance our core neurology programs, including to make planned regulatory submissions and commence planned clinical trials as described in this prospectus supplement and the accompanying prospectus, as well as our Fabry disease and hemophilia A programs, capsid engineering efforts and modular integrase platform, and to otherwise execute on our current operating plan.

If we raise additional capital following this offering through public or private equity offerings, including sales pursuant to our at-the-market offering program with Jefferies LLC, your ownership interest will be diluted, and such dilution may be substantial given our current stock price decline. In addition, the terms of any new equity securities we may issue following this offering may have a preference over, and include rights superior to, our common stock. If we raise additional capital through royalty financings or other collaborations, strategic alliances or licensing arrangements with third parties, we may need to relinquish certain valuable rights to our product candidates, technologies, future revenue streams or research programs or grant licenses on terms that may not be favorable. If we raise additional capital through debt financing, we may be subject to specified financial covenants or covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or pursuing certain transactions, any of which could restrict our ability to commercialize our product candidates or operate our business.

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In addition, as we focus our efforts on proprietary human therapeutics, we will need to seek regulatory approvals of our product candidates from the FDA or other comparable foreign regulatory authorities, a process that could cost in excess of hundreds of millions of dollars per product. We may experience difficulties in accessing the capital markets due to external factors beyond our control, such as volatility in the equity markets for emerging biotechnology companies and general economic and market conditions both in the United States and abroad. In particular, our ability to raise the substantial additional capital we need in order to fund our business may be adversely impacted by global economic conditions and disruptions to and volatility in the credit and financial markets in the United States and worldwide, such as has been experienced recently. We cannot be certain that we will be able to obtain the substantial additional capital that we need to support our operations and to continue to operate as a going concern following this offering. Our failure to obtain adequate funding in the near term will adversely affect our ability to continue to operate as a going concern and our ability to develop our technology and products candidates, and we may be required to cease operations.

We currently do not meet, and may not regain compliance with, the listing standards of the Nasdaq Capital Market, or Nasdaq, and as a result our common stock may be delisted. Delisting could adversely affect the liquidity of our common stock and the market price of our common stock could decrease, and our ability to obtain sufficient additional capital to fund our operations and to continue to operate as a going concern would be substantially impaired.

Our common stock is currently listed on the Nasdaq Capital Market, which has minimum requirements that a company must meet in order to remain listed. These requirements include maintaining a minimum closing bid price of $1.00 per share, which closing bid price cannot fall below $1.00 per share for a period of more than 30 consecutive trading days, or the Bid Price Requirement. On April 30, 2025, we received a deficiency notice from the Listing Qualifications Staff, or the Staff, of Nasdaq notifying us that, for the prior 30 consecutive business days, the bid price of our common stock had closed below $1.00 per share, thereby failing to satisfy the bid price requirement set forth in the continued listing requirements of Nasdaq Listing Rule 5550(a)(2), or the Minimum Bid Price Requirement. On October 29, 2025, we received a letter, or the Extension Notice, from Nasdaq advising that we were granted a 180-day extension, or until April 27, 2026, to regain compliance with the Minimum Bid Price Requirement. If at any time prior to April 27, 2026, the bid price of our common stock closes at $1.00 per share or more for a minimum of 10 consecutive trading days, we will regain compliance with the Minimum Bid Price Requirement. The Extension Notice has no immediate effect on the listing of our common stock on The Nasdaq Capital Market and does not affect our reporting requirements with the SEC.

We intend to cure the Minimum Bid Price Requirement by April 27, 2026, however if we do not regain compliance with the Minimum Bid Price Requirement during this period, we expect that Nasdaq will provide written notification to us that our common stock will be delisted. At that time, we may appeal the delisting determination to a hearings panel pursuant to the procedures set forth in the applicable Nasdaq listing rules. However, there can be no assurance that, if we do appeal the delisting determination by Nasdaq to the hearings panel, that such appeal would be successful. There can be no assurance that we will regain compliance with the Minimum Bid Price Requirement during the additional 180-day compliance period or maintain compliance with any other Nasdaq listing requirement.

A reverse stock split may allow us to meet the Minimum Bid Price Requirement, but we cannot assure you that a reverse stock split will be approved by our stockholders or that any reverse stock split, if implemented, will be sufficient to enable us to maintain our Nasdaq listing. Additionally, if a reverse stock split is implemented, there can be no assurance that the market price per new share of our common stock following the reverse stock split will remain unchanged or will increase in proportion to the reduction in the number of old shares of our common stock outstanding before the reverse stock split. The liquidity of the shares of our common stock may be affected adversely by any reverse stock split given the reduced number of shares of our common stock that will be outstanding following such reverse stock split. Furthermore, following any reverse stock split, the resulting market price of our common stock may not attract new investors and may not satisfy the investing requirements of those investors.

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In the event that our common stock is delisted from Nasdaq as a result of our failure to regain compliance with the Minimum Bid Price Requirement, as a result of Nasdaq not granting us an extension or the panel not granting us a favorable decision or due to our failure to continue to comply with any other requirement for continued listing on Nasdaq, trading of our common stock could be conducted in the over-the-counter market or on an electronic bulletin board established for unlisted securities such as the Pink Sheets or the OTC Bulletin Board, but there can be no assurance that our common stock will be eligible for trading on such alternative exchange or market.

Additionally, if our common stock is delisted from Nasdaq, the liquidity of our common stock would be adversely affected, the market price of our common stock could decrease, our ability to obtain sufficient additional capital to fund our operations and to continue to operate as a going concern would be substantially impaired and transactions in our common stock could lose federal preemption of state securities laws. Furthermore, there could also be a further reduction in our coverage by securities analysts and the news media and broker-dealers may be deterred from making a market in or otherwise seeking or generating interest in our common stock, which could cause the price of our common stock to decline further. Moreover, delisting may also negatively affect our collaborators’, vendors’, suppliers’ and employees’ confidence in us and employee morale.

The trading price of our common stock has been, and is likely to continue to be, highly volatile and could be subject to wide fluctuations in response to various factors, some of which are beyond our control.

The trading price of our common stock has been, and is likely to continue to be, be volatile and subject to wide fluctuations in response to various factors, some of which are beyond our control. As a result of fluctuations in the price of our common stock, you may be unable to sell your shares at or above the price you paid for them. The market price of our common stock is likely to continue to be volatile and subject to significant price and volume fluctuations in response to market, industry and other factors, including the risk factors described in this prospectus supplement and discussed under the section titled “Risk Factors” contained in our Annual Report on Form 10-K for the year ended December 31, 2024 and our Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, which are incorporated by reference into this prospectus supplement and the accompanying prospectus. In the near term, we expect the market price of our common stock will be dependent on our ability to complete the rolling BLA submission for, and achieve FDA approval of, isaralgagene civaparvovec and to alleviate the substantial doubt about our ability to continue to operate as a going concern. The market price of our common stock may also be dependent upon the valuations and recommendations of the analysts who cover our business. If the results of our business and our efforts to raise the additional capital that we need to fund our operations do not meet these analysts’ forecasts, the expectations of investors or the financial guidance we provide to investors in any period, the market price of our common stock could decline, perhaps significantly.

In addition, the stock markets in general, and the markets for biotechnology stocks in particular, have experienced significant volatility that has often been unrelated to the operating performance of particular companies. These broad market fluctuations may adversely affect the trading price of our common stock and, consequently, adversely affect the price at which you could sell the shares that you purchase in this offering. In the past, following periods of volatility in the market or significant price declines, securities class-action litigation has often been instituted against companies. Such litigation, if instituted against us, could result in substantial costs and diversion of management’s attention and resources, which could materially and adversely affect our business, financial condition, results of operations and growth prospects.

If you purchase securities in this offering, you will suffer immediate dilution of your investment.

The combined offering price per share (or pre-funded warrant) and accompanying purchase warrant in this offering is higher than the net tangible book value per share of our common stock. Therefore, if you purchase securities in this offering, you will pay a combined offering price per share (or pre-funded warrant) and accompanying purchase warrant that substantially exceeds our net tangible book value per share after this

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offering. To the extent outstanding options or warrants are exercised or RSUs are settled, you will incur further dilution. Our net tangible book value as of September 30, 2025 was $6.2 million, or $0.02 per share. After giving effect to this offering at the combined offering price of $0.4719 per share and accompanying purchase warrant, and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us (but excluding the shares of common stock to be issued and the proceeds received, if any, from exercises of the purchase warrants or pre-funded warrants offered hereby), you will experience immediate dilution of $0.39 per share, representing the difference between our as adjusted net tangible book value per share as of September 30, 2025 after giving effect to this offering (but without giving effect to the exercise of the purchase warrants or pre-funded warrants offered hereby) and the combined offering price. If the holders of the purchase warrants exercise the warrants in full, our as adjusted net tangible book value per share after this offering would be $0.13, representing an immediate increase in as adjusted net tangible book value per share of $0.11 to existing stockholders and immediate dilution in as adjusted net tangible book value per share of $0.34 to the new investor purchasing securities in this offering. See the section of this prospectus supplement titled “Dilution” for a more detailed discussion of the dilution you will incur if you purchase securities in this offering.

You may experience future dilution as a result of future equity offerings.

In order to raise the substantial additional capital we need for the continuation of our operations, we expect to in the future offer additional shares of our common stock or other securities convertible into or exchangeable for our shares of our common stock, including pursuant to the Sales Agreement. We cannot assure you that we will be able to sell shares or other securities in any other offering at a price per share that is equal to or greater than the price per share paid by the investors in this offering, and investors purchasing shares or other securities in the future could have rights superior to existing stockholders. The price per share at which we sell additional shares of our common stock or other securities convertible into or exchangeable for our shares of our common stock in future transactions may be higher or lower than the price per share you may pay in this offering.

Our management has broad discretion in the use of our cash and cash equivalents, including the proceeds we receive in this offering, and might not use them effectively.

Our management has broad discretion to use our cash and cash equivalents, including the net proceeds we receive in this offering, to fund our operations and could spend these funds in ways that do not improve our results of operations or enhance the value of our common stock, and you will not have the opportunity as part of your investment decision to assess whether the net proceeds are being used appropriately. The failure by our management to apply these funds effectively could harm our business and cause the price of our common stock to decline, perhaps significantly.

We do not intend to pay dividends on our common stock so any returns will be limited to the value of our stock.

We have never declared or paid any cash dividends on our common stock. We currently anticipate that we will retain future earnings for the development, operation and expansion of our business and do not anticipate declaring or paying any cash dividends for the foreseeable future. Any return to stockholders will therefore be limited to the appreciation of their stock.

There is no public market for the purchase warrants or the pre-funded warrants being offered by us in this offering.

There is no established public trading market for the purchase warrants or the pre-funded warrants being sold in this offering, and we do not expect a market to develop. In addition, we do not intend to apply to list the purchase warrants or the pre-funded warrants on any securities exchange or recognized trading system. Without an active market, the liquidity of the purchase warrants or the pre-funded warrants will be limited.

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The purchase warrants are speculative in nature. You may not be able to recover your investment in the purchase warrants, and the purchase warrants may expire worthless.

The purchase warrants do not confer any rights of our common stock ownership on their holders, such as voting rights, but rather merely represent the right to acquire shares of our common stock at a fixed price for a limited period of time. Specifically, commencing six months after the date of issuance, holders of purchase warrants may exercise their right to acquire the underlying common stock and pay an exercise price per share equal to $0.4719, subject to certain adjustments, and the purchase warrants will expire five and a half years after the date of issuance. Moreover, following this offering, the market value of the purchase warrants, if any, is uncertain and there can be no assurance that the market value of the purchase warrants will equal or exceed their imputed offering price. In addition, there can be no assurance that the market price of our common stock will equal or exceed the exercise price of the purchase warrants for a sustained period of time or at all, and, consequently, it may not ever be profitable for holders of the purchase warrants to exercise the purchase warrants.

Holders of the purchase warrants or the pre-funded warrants will have no rights as common stockholders until they acquire our common stock.

Until you acquire shares of our common stock upon exercise of the purchase warrants or the pre-funded warrants, you will have no rights with respect to our common stock issuable upon exercise of the purchase warrants or the pre-funded warrants, including the right to receive dividend payments, vote or respond to tender offers. Upon exercise of your purchase warrants or pre-funded warrants, you will be entitled to exercise the rights of a common stockholder only as to matters for which the record date occurs after the exercise date.

We will not receive any meaningful amount of additional funds upon the exercise of the pre-funded warrants.

Each pre-funded warrant will be exercisable until it is fully exercised and by means of payment of the nominal cash purchase price upon exercise or by means of a “cashless exercise” according to a formula set forth in the pre-funded warrant. Accordingly, we will not receive any meaningful additional funds upon the exercise of the pre-funded warrants.

If we do not maintain a current and effective registration statement relating to the shares of our common stock issuable upon exercise of the purchase warrants or pre-funded warrants at the time that holders wish to exercise such purchase warrants or pre-funded warrants, they will only be able to exercise them on a “cashless basis” provided that an exemption from registration is available. As a result, the number of shares of our common stock that holders will receive upon exercise of the purchase warrants or pre-funded warrants will be fewer than it would have been had such holder exercised such purchase warrants or pre-funded warrants for cash, and holders may be limited in their ability to immediately sell shares upon exercise subject to volume or other securities law limitations. Further, if an exemption from registration is not available, holders would not be able to exercise on a cashless basis and would only be able to exercise their purchase warrants or pre-funded warrants for cash if a current and effective registration statement relating to the shares of our common stock issuable upon exercise of the purchase warrants or pre-funded warrants is available.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement, the accompanying prospectus, the documents we have filed with the SEC that are incorporated by reference and any free writing prospectus that we have authorized for use in connection with this offering contain “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. These statements relate to our future events, including our anticipated operations, research, development, manufacturing and commercialization activities, clinical trials, operating results and financial condition. These forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performances or achievements expressed or implied by the forward-looking statements. Forward-looking statements may include, but are not limited to, statements about:

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our estimates regarding the sufficiency of our cash resources and our expenses, capital requirements and need for substantial additional financing, and our ability to obtain the substantial additional financing that we need to support our operations and to continue to operate as a going concern following this offering;

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our ability to establish and maintain collaborations and strategic partnerships and realize the expected benefits of such arrangements, including in particular our ability to secure a commercialization partner for our Fabry disease program and to enter into new collaborations with respect to our STAC-BBB capsid, epigenetic regulation capabilities and hemophilia A program;

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our projected operating and financial performance;

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our plans for advancing our development programs and the plans of any collaboration partners for advancing partnered programs;

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anticipated research and development of product candidates and potential commercialization of any resulting approved products;

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the initiation, scope, rate of progress, enrollment, dosing, anticipated results and timing of our preclinical studies and clinical trials and those of our collaborators or strategic partners;

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the therapeutic and commercial potential of our product candidates, including the durability of therapeutic effects;

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the therapeutic and commercial potential of technologies used by us in our product candidates, including our gene therapy and gene editing technologies, zinc finger, or ZF, technology platform, and zinc finger transcriptional regulators, or ZF-transcriptional regulators, which include zinc finger repressors, or ZFRs;

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anticipated revenues from existing and new collaborations and the timing thereof;

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our and our collaborators’ anticipated plans and timelines in conducting our ongoing and potential future clinical trials and presenting clinical data from such clinical trials, and the anticipated advancement of our product candidates to late-stage development;

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our ability to realize the expected benefits of our license agreements with Genentech, Astellas and Lilly, the potential for these licensees to complete clinical development, regulatory interactions, manufacturing and global commercialization of any resulting products, and the potential for us to receive milestone payments and/or additional fees and royalties from these licensees;

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potential IND and CTA submissions and potential acceptance thereof by the FDA and regulatory authorities outside the United States;

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the potential for isaralgagene civaparvovec to obtain Accelerated Approval from the FDA, including the adequacy of data generated in the Phase 1/2 STAAR study to support any such approval, and our

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expectations concerning the availability of additional data to support the rolling BLA submission for isaralgagene civaparvovec and the anticipated timing of potentially completing such submission;

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our estimates regarding the impact of the macroeconomic and geopolitical environment on our business and operations and the business and operations of our collaborators, including preclinical studies, clinical trials and manufacturing, and our ability to manage such impacts;

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our research and development and other expenses;

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our ability to obtain adequate preclinical and clinical supplies of our product candidates from current and potential new suppliers and manufacturers;

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our ability, and the ability of our collaborators and strategic partners, to obtain and maintain regulatory approvals for product candidates and the timing and costs associated with obtaining regulatory approvals;

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our ability to comply with, and the impact of, regulatory requirements, obligations and restrictions on our business and operations;

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our ability to protect our intellectual property and operate our business without infringing upon the intellectual property rights of others, including our ability to obtain and maintain rights to the technologies required to develop and commercialize our product candidates;

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competitive developments, including the impact on our competitive position of rival products and product candidates and our ability to meet such competition;

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our operational and legal risks;

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our plans, objectives, expectations and intentions and any other statements that are not historical facts; and

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the anticipated use of our existing capital resources and the net proceeds from this offering.

In some cases, you can identify forward-looking statements by use of future dates or by terms such as: “anticipates,” “believes,” “continues,” “could,” “estimates,” “expects,” “intends,” “may,” “plans,” “seeks,” “should,” “will” and similar expressions intended to identify forward-looking statements. These statements reflect our current views with respect to future events, are based on assumptions and are subject to risks and uncertainties. Given these risks and uncertainties, you should not place undue reliance on these forward-looking statements. We discuss many of these risks in greater detail in “Risk Factors” beginning on page S-5 of this prospectus supplement and under the section titled “Risk Factors” contained in our Annual Report on Form 10-K for the year ended December 31, 2024 and our Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, which are incorporated by reference into this prospectus supplement and the accompanying prospectus. Also, these forward-looking statements represent our estimates and assumptions only as of the date of the document containing the applicable statement. Unless required by law, we undertake no obligation to update or revise any forward-looking statements to reflect new information or future events or developments. Thus, you should not assume that our silence over time means that actual events are bearing out as expressed or implied in such forward-looking statements. You should carefully read this prospectus supplement, the accompanying prospectus and the documents incorporated herein and therein by reference as described in the section titled “Incorporation of Certain Information by Reference” in this prospectus supplement completely and with the understanding that our actual future results may be materially different from what we expect. We qualify all of the forward-looking statements in the foregoing documents by these cautionary statements.

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USE OF PROCEEDS

We estimate that the net proceeds from the sale of the 35,190,292 shares of common stock, pre-funded warrants to purchase 17,787,033 shares of common stock and accompanying purchase warrants that we are offering, excluding the proceeds, if any, from the exercise of the purchase warrants or the pre-funded warrants offered hereby, will be approximately $22.9 million, based on the combined offering price of $0.4719 per share of common stock (or pre-funded warrants at the combined offering price less $0.01) and accompanying purchase warrant to purchase one share of common stock, and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us. This estimate excludes the proceeds, if any, from the exercise of the purchase warrants and the pre-funded warrants sold in this offering.

We intend to use the net proceeds from this offering, together with our cash and cash equivalents, for working capital and general corporate purposes.

Our management has broad discretion to use our cash and cash equivalents, including the net proceeds we receive in this offering, to fund our operations and the investor will be relying upon the judgment of our management regarding the application of these proceeds. The failure by our management to apply these funds effectively could harm our business and cause the price of our common stock to decline, perhaps significantly.

Based on our current operating plan, we estimate that our cash and cash equivalents as of December 31, 2025, together with the $2.0 million generated through our at-the-market offering program since December 31, 2025, and the anticipated net proceeds of this offering will be sufficient to meet our liquidity requirements only into the beginning of the third quarter of 2026. This estimate regarding our cash resources is based on assumptions that are inherently uncertain, and actual results could differ materially from those estimates. In this regard, we could use our available capital resources sooner than we currently expect and changing circumstances, some of which may be beyond our control, could cause us to consume capital significantly faster than we currently anticipate.

If all of the purchase warrants sold in this offering were to be exercised in cash at an exercise price per share equal to $0.4719, we would receive additional proceeds of approximately $25.0 million. We cannot predict when or if the purchase warrants will be exercised. In addition, we will receive only $0.01 per share upon exercise of any pre-funded warrants.

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DILUTION

Our net tangible book value as of September 30, 2025 was $6.2 million, or $0.02 per share. Net tangible book value is total assets minus the sum of liabilities and intangible assets. Net tangible book value per share is net tangible book value divided by the total number of shares of our common stock outstanding as of September 30, 2025.

Dilution in net tangible book value per share represents the difference between the amount per share paid by purchasers of our common stock in this offering, and the as adjusted net tangible book value per share of our common stock immediately after completion of this offering.

After giving effect to the sale of (i) 35,190,292 shares of our common stock and accompanying purchase warrants to purchase an additional 35,190,292 shares of our common stock in this offering at the combined offering price of $0.4719 per share and (ii) pre-funded warrants to purchase 17,787,033 shares of our common stock and accompanying purchase warrants to purchase an additional 17,787,033 shares of our common stock in this offering at the combined offering price minus $0.01 (excluding, in each case, the shares of common stock to be issued and the proceeds received, if any, from exercises of the pre-funded warrants and the purchase warrants, as applicable), and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us, our as adjusted net tangible book value as of September 30, 2025 would have been approximately $29.14 million, or $0.08 per share. This represents an immediate increase in the net tangible book value of $0.06 per share to existing stockholders and immediate dilution in net tangible book value of $0.39 per share to the investor purchasing securities in this offering.

The following table illustrates this dilution on a per share basis to the new investor participating in this offering:


Public offering price per share			$	0.4719
Historical net tangible book value per share as of September 30, 2025	$	0.02
Increase in net tangible book value per share attributable to this offering		0.06
As adjusted net tangible book value per share as of September 30, 2025, after giving effect to this offering		0.08
Dilution per share to investor purchasing common stock in this offering			$	0.39

The investor who purchases common stock upon the exercise of the purchase warrants or the pre-funded warrants offered hereby may experience dilution depending on our net tangible book value at the time of exercise.

The foregoing discussion and table (other than historical net tangible book value) are based on 322,009,039 shares of our common stock outstanding as of September 30, 2025. This number excludes the shares of common stock issuable upon exercise of the purchase warrants and the pre-funded warrants offered hereby, and also excludes the following:

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15,697,986 shares of our common stock issuable upon the exercise of outstanding stock options as of September 30, 2025 with a weighted-average exercise price of $4.602 per share;

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15,605,557 shares of our common stock issuable upon the exercise of outstanding stock options granted after September 30, 2025 with a weighted-average exercise price of $4.5024 per share;

•

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•

4,582,499 shares of our common stock issuable upon the exercise of outstanding RSUs granted after September 30, 2025 with a weighted-average grant date fair value of $0.9617 per share;

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46,633,393 shares of common stock issuable upon the exercise of outstanding warrants as of September 30, 2025 with an exercise price of $0.75 per share;

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22,672,591 shares of our common stock available for issuance or future grant under our EIP as of September 30, 2025;

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1,647,826 shares of our common stock available for issuance under our ESPP as of September 30, 2025; and

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32,250,609 shares of our common stock sold since September 30, 2025 under an “at the market” equity offering program that we entered into pursuant to the Sales Agreement for aggregate net proceeds of approximately $17.0 million, and up to approximately $131.2 million of shares of our common stock remaining to be sold under the Sales Agreement as of the date of this prospectus supplement.

After giving effect to the sale of (i) 35,190,292 shares of our common stock and accompanying purchase warrants to purchase an additional 35,190,292 shares of our common stock in this offering at the combined offering price of $0.4719 per share and (ii) pre-funded warrants to purchase 17,787,033 shares of our common stock and accompanying purchase warrants to purchase an additional 17,787,033 shares of our common stock in this offering at the combined offering price minus $0.01 (including, in each case, the shares of common stock to be issued and the proceeds received, if any, from exercises of the pre-funded warrants and the purchase warrants, as applicable), and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us, our as adjusted net tangible book value per share as of September 30, 2025 would have been approximately $0.13, representing an immediate increase in as adjusted net tangible book value per share of $0.11 to existing stockholders and immediate dilution in as adjusted net tangible book value per share of $0.34 to the investor purchasing securities in this offering.

To the extent that outstanding options, warrants and RSUs are exercised or settle, as applicable, or other shares issued, the investor purchasing our securities in this offering may experience further dilution. In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to the investor in this offering.

We have not yet determined whether the purchase warrants or the pre-funded warrants will be classified and accounted for as liabilities or as stockholders’ equity.

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DESCRIPTION OF SECURITIES WE ARE OFFERING

We are offering 35,190,292 shares of our common stock, pre-funded warrants to purchase 17,787,033 shares of our common stock, or the pre-funded warrants, and accompanying warrants to purchase an additional 52,977,325 shares of our common stock, or the purchase warrants. The common stock (or pre-funded warrants) and the purchase warrants will be sold together. Each share of our common stock (or pre-funded warrant) will be sold with a purchase warrant to purchase one share of our common stock. The shares of our common stock (or pre-funded warrants) and the accompanying purchase warrants are immediately separable and will be issued separately. The shares of our common stock issuable from time to time upon exercise of the purchase warrants and the pre-funded warrants, if any, are also being offered pursuant to this offering.

Common Stock

Our restated certificate of incorporation authorizes us to issue 960,000,000 shares of our common stock, par value $0.01 per share, and 5,000,000 shares of preferred stock, par value $0.01 per share. Shares of our common stock are the only security of the Company registered pursuant to Section 12 of the Exchange Act. The holders of our common stock are entitled to one vote per share on all matters to be voted on by the stockholders. Stockholders have no cumulative voting rights. Subject to the preferences of any outstanding shares of preferred stock, the holders of our common stock are entitled to receive ratably any dividends our board of directors declares out of funds legally available for the payment of dividends. If we are liquidated, dissolved or wound up, the holders of our common stock are entitled to share pro rata all assets remaining after payment of liabilities and liquidation preferences of any outstanding shares of preferred stock. Holders of our common stock have no preemptive rights or rights to convert their common stock into any other securities. There are no redemption or sinking fund provisions applicable to the common stock.

For more information, see “Description of Capital Stock” in Exhibit 4.1 to our Annual Report on Form 10-K for the year ended December 31, 2024, which Exhibit 4.1 is incorporated by reference into this prospectus supplement and the accompanying prospectus.

Our common stock is listed on the Nasdaq Capital Market under the symbol “SGMO.” The transfer agent and registrar for our common stock is Computershare, Inc.

Pre-Funded Warrants

The material terms and provisions of the pre-funded warrants being issued in this offering are summarized below. The following description is subject to, and qualified in its entirety by, the form of pre-funded warrant which will be filed as an exhibit to a Current Report on Form 8-K to be filed by us with the SEC in connection with this offering. You should review the form of pre-funded warrant for a complete description of the terms and conditions applicable to the pre-funded warrants. See “Where You Can Find More Information” on page S-39 of this prospectus supplement.

Exercisability. The pre-funded warrants will be immediately exercisable, at the option of each holder, in whole or in part, by delivering to us a duly executed exercise notice and by payment in full in immediately available funds for the number of shares of our common stock purchased upon such exercise. However, if a registration statement registering the issuance of the shares of our common stock underlying a pre-funded warrant held by holder under the Securities Act is not effective or available for the issuance of such shares to such holder at the time of exercise, the holder may only exercise the pre-funded warrant through a “cashless exercise,” in which case, the holder would receive upon such exercise, the net number of shares of our common stock determined according to the formula set forth in the pre-funded warrant. Apart from the limited circumstance where such a registration statement is not then effective or available, the exercise price must be paid by the holder in cash in immediately available funds.

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Exercise Limitations. A holder (together with its affiliates and other attribution parties) may not exercise any portion of a pre-funded warrant to the extent that immediately prior to or after giving effect to such exercise the holder would own more than 9.99% (at the election of the holder prior to the issuance of the warrant) of our outstanding common stock immediately after exercise, which percentage may be changed at the holder’s election to a higher or lower percentage not in excess of 19.99% (if exceeding such percentage would result in a change of control under Nasdaq Listing Rule 5635(b) or any successor rule) upon 61 days’ notice to us subject to the terms of the pre-funded warrants.

Exercise Price. Each pre-funded warrant offered hereby has an initial exercise price per share equal to $0.01. The pre-funded warrants are immediately exercisable and may be exercised at any time until the pre-funded warrants are exercised in full. The exercise price and number of shares of our common stock issuable upon exercise is subject to adjustment in the event of stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events affecting our common stock.

Transferability. Subject to compliance with any applicable securities laws, the pre-funded warrants are separately tradeable immediately after issuance at the option of the holders and may be transferred at the option of the holders.

No Listing. There is no established public trading market for the pre-funded warrants and we do not expect a market to develop. In addition, we do not intend to apply for listing of the pre-funded warrants on any securities exchange or recognized trading system, including Nasdaq. Without an active market, the liquidity of the pre-funded warrants will be limited.

Fundamental Transactions. In the event of a fundamental transaction, as described in the pre-funded warrants and generally including any reorganization, recapitalization or reclassification of our common stock, the sale, transfer or other disposition of all or substantially all of our properties or assets, our consolidation or merger with or into another person, the acquisition of more than 50% of our outstanding common stock, or any person or group becoming the beneficial owner of more than 50% of the voting power represented by our outstanding common stock, the pre-funded warrants shall automatically be deemed to be exercised in full in a cashless exercise effective immediately prior to the consummation of such fundamental transaction, without regard to any limitations on exercise contained in the pre-funded warrants.

Rights as a Stockholder. Except for the right to participate in certain dividends and distributions and as otherwise provided in the pre-funded warrant or by virtue of a holder’s ownership of shares of our common stock, the holders of the pre-funded warrants do not have the rights or privileges of holders of our common stock, including any voting rights, until they exercise their pre-funded warrants.

Warrant Agent. We are acting as warrant agent for the pre-funded warrants.

Purchase Warrants

The material terms and provisions of the purchase warrants being issued in this offering are summarized below. The following description is subject to, and qualified in its entirety by, the form of purchase warrant which will be filed as an exhibit to a Current Report on Form 8-K to be filed by us with the SEC in connection with this offering. You should review the form of purchase warrant for a complete description of the terms and conditions applicable to the purchase warrants. See “Where You Can Find More Information” on page S-39 of this prospectus supplement.

General. Each purchaser of a share of our common stock or pre-funded warrant will receive a purchase warrant to purchase one share of our common stock.

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Exercisability. The purchase warrants will be exercisable six months from the date of issuance and will expire five and a half years from the date of issuance. The purchase warrants will be exercisable, at the option of each holder, in whole or in part by delivering to us or the warrant agent a duly executed exercise notice and by payment in full in immediately available funds for the number of shares of our common stock purchased upon such exercise. However, if a registration statement registering the issuance of the shares of our common stock underlying a purchase warrant held by holder under the Securities Act is not effective or available for the issuance of such shares to such holder at the time of exercise, the holder may only exercise the purchase warrant through a “cashless exercise,” in which case, the holder would receive upon such exercise, the net number of shares of our common stock determined according to the formula set forth in the purchase warrant. Apart from the limited circumstance where such a registration statement is not then effective or available, the exercise price must be paid by the holder in cash in immediately available funds.

Exercise Limitations. A holder (together with its affiliates and other attribution parties) may not exercise any portion of a purchase warrant to the extent that immediately prior to or after giving effect to such exercise the holder would own more than 4.99% of our outstanding common stock immediately after exercise, which percentage may be changed at the holder’s election to a higher or lower percentage not in excess of 19.99% (if exceeding such percentage would result in a change of control under Nasdaq Listing Rule 5635(b) or any successor rule) upon 61 days’ notice to us subject to the terms of the purchase warrants.

Exercise Price. The initial per share exercise price of the purchase warrants is $0.4719. The exercise price is subject to adjustment in the event of stock combinations, subdivisions or similar events affecting our common stock.

Transferability. Subject to compliance with any applicable securities laws, the purchase warrants are separately tradeable immediately after issuance at the option of the holders and may be transferred at the option of the holders.

No Listing. There is no established public trading market for the purchase warrants and we do not expect a market to develop. In addition, we do not intend to apply for listing of the purchase warrants on any securities exchange or recognized trading system, including Nasdaq. Without an active market, the liquidity of the purchase warrants will be limited.

Fundamental Transactions. In the event of a fundamental transaction, as described in the purchase warrants and generally including any reorganization, recapitalization or reclassification of our common stock, the sale, transfer or other disposition of all or substantially all of our properties or assets, our consolidation or merger with or into another person, the acquisition of more than 50% of our outstanding common stock, or any person or group becoming the beneficial owner of more than 50% of the voting power represented by our outstanding common stock, the holders of the purchase warrants will be entitled to receive upon exercise of the purchase warrants the kind and amount of securities, cash or other property that the holders would have received had they exercised the purchase warrants immediately prior to such fundamental transaction. Notwithstanding the foregoing, as more fully described in the purchase warrant, in the event of certain fundamental transactions, the holders of the purchase warrants will be entitled to receive consideration in an amount equal to the Black Scholes value of the purchase warrants.

Rights as a Stockholder. Except for the right to participate in certain dividends and distributions and as otherwise provided in the purchase warrant or by virtue of a holder’s ownership of shares of our common stock, the holders of the purchase warrants do not have the rights or privileges of holders of our common stock, including any voting rights, until they exercise their purchase warrants.

Warrant Repricing Transaction

In a concurrent private transaction, we have agreed to reduce the exercise price of the Repriced Warrants from $1.00 per share to $0.4719 per share (the exercise price of the purchase warrants offered in this offering).

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The Repriced Warrants will become exercisable six months from the closing date of this offering. In connection with the reduction in exercise price, the Company has additionally agreed to extend the expiration date of the Repriced Warrants to be five and a half years from the closing of this offering. Other than as described herein, the terms of the Repriced Warrants remain the same and unchanged.

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MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS

The following is a general discussion of the material United States, or U.S., federal income tax considerations of the purchase, ownership and disposition of shares of our common stock issued pursuant to this offering, or the Shares, the purchase, exercise, disposition and lapse of warrants to purchase shares of our common stock pursuant to this offering, or the purchase warrants, the purchase, ownership and disposition of pre-funded warrants to purchase shares of our common stock issued pursuant to this offering, or the pre-funded warrants, and the ownership and disposition of shares of our common stock issuable upon exercise of the purchase warrants or the pre-funded warrants, or the warrant shares. The Shares, the purchase warrants, the warrant shares and the pre-funded warrants are collectively referred to herein as our “securities.” All prospective holders of our securities should consult their tax advisors with respect to the U.S. federal, state, local and non-U.S. tax consequences of the purchase, ownership and disposition of our securities.

This discussion is not a complete analysis of all potential U.S. federal income tax consequences relating to the purchase, ownership and disposition of our securities. This discussion is based on current provisions of the U.S. Internal Revenue Code of 1986, as amended, which we refer to as the Code, existing U.S. Treasury Regulations promulgated thereunder, published administrative pronouncements and rulings of the U.S. Internal Revenue Service, which we refer to as the IRS, and judicial decisions, all as in effect as of the date of this offering. These authorities are subject to change and to differing interpretation, possibly with retroactive effect. Any change or differing interpretation could alter the tax consequences to holders described in this discussion. There can be no assurance that a court or the IRS will not challenge one or more of the tax consequences described herein, and we have not obtained, nor do we intend to obtain, a ruling with respect to the U.S. federal income tax consequences to a holder of the purchase, ownership or disposition of our securities.

We assume in this discussion that a holder holds our securities as a “capital asset” within the meaning of Section 1221 of the Code (generally, property held for investment). This discussion does not address all aspects of U.S. federal income taxation that may be relevant to a particular holder in light of that holder’s individual circumstances, nor does it address any alternative minimum, Medicare contribution, estate or gift tax consequences, or any aspects of U.S. state, local or non-U.S. taxes or any other U.S. federal tax laws. This discussion also does not address consequences relevant to holders subject to special tax rules, such as holders that own or have owned, or are deemed to own or have owned, more than 5% of our capital stock (except to the extent specifically set forth below), corporations that accumulate earnings to avoid U.S. federal income tax, tax-exempt organizations, governmental organizations, banks, financial institutions, investment funds, insurance companies, brokers, dealers or traders in securities, commodities or currencies, regulated investment companies or real estate investment trusts, persons that have a “functional currency” other than the U.S. dollar, tax-qualified retirement plans, “qualified foreign pension funds” as defined in Section 897(l)(2) of the Code and entities all of the interests of which are held by qualified foreign pension funds, holders who hold or receive our securities pursuant to the exercise of employee stock options or otherwise as compensation, holders holding our securities as part of a hedge, wash, straddle or other risk reduction strategy, conversion transaction or other integrated investment, holders deemed to sell our securities under the constructive sale provisions of the Code, holders subject to special tax accounting rules under Section 451(b) of the Code, controlled foreign corporations, passive foreign investment companies and certain former U.S. citizens or long-term residents.

In addition, this discussion does not address the tax treatment of partnerships (or entities or arrangements that are treated as partnerships or disregarded entities for U.S. federal income tax purposes) or persons that hold our securities through such partnerships. If a partnership, including any entity or arrangement treated as a partnership for U.S. federal income tax purposes, holds our securities, the U.S. federal income tax treatment of a partner in such partnership will generally depend upon the status of the partner and the activities of the partnership. Such partners and partnerships should consult their tax advisors regarding the tax consequences of the purchase, ownership and disposition of our securities.

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Treatment of Pre-Funded Warrants

Although it is not entirely free from doubt, we believe a pre-funded warrant should be treated as a Share for U.S. federal income tax purposes and a holder of pre-funded warrants should generally be taxed in the same manner as a holder of Shares, as described below. Accordingly, no gain or loss should be recognized upon the exercise of a pre-funded warrant and, upon exercise, the holding period of a pre-funded warrant should carry over to the Share received. Similarly, the tax basis of the pre-funded warrant should carry over to the Share received upon exercise, increased by the exercise price of $0.01 per share. However, our characterization is not binding on the IRS, and the IRS may treat the pre-funded warrants as warrants to acquire our Shares. If so, the amount and character of your gain with respect to an investment in our pre-funded warrants could change. Accordingly, each holder should consult his, her or its own tax advisor regarding the risks associated with the acquisition of pre-funded warrants pursuant to this offering (including potential alternative characterizations). The balance of this discussion generally assumes that the characterization described above is respected for U.S. federal income tax purposes.

Allocation of Purchase Price

Each purchaser of Shares or pre-funded warrants must allocate its purchase price for such Shares, pre-funded warrants, or purchase warrants between each Share, pre-funded warrant, or purchase warrant, as applicable, based on the respective relative fair market values of each at the time of issuance. This allocation of the purchase price will establish the holder’s initial tax basis for U.S. federal income tax purposes for each Share, pre-funded warrant and purchase warrant. A holder’s allocation of the purchase price among the Shares, pre-funded warrants and purchase warrants is not binding on the IRS or the courts, and no assurance can be given that the IRS or the courts will agree with a holder’s allocation. Each holder should consult its own tax advisor regarding the allocation of the purchase price among the Shares, pre-funded warrants and purchase warrants.

Tax Considerations Applicable to U.S. Holders

Definition of U.S. Holder

In general, a “U.S. holder” means a beneficial owner of our securities (other than a partnership or an entity or arrangement treated as a partnership for U.S. federal income tax purposes) that is, for U.S. federal income tax purposes:

•

an individual who is a citizen or resident of the United States;

•

a corporation, or an entity treated as a corporation for U.S. federal income tax purposes, created or organized in the United States or under the laws of the United States or of any state thereof or the District of Columbia;

•

an estate, the income of which is subject to U.S. federal income tax regardless of its source; or

•

a trust if (a) a U.S. court can exercise primary supervision over the trust’s administration and one or more U.S. persons have the authority to control all of the trust’s substantial decisions or (b) the trust has a valid election in effect under applicable U.S. Treasury Regulations to be treated as a U.S. person.

Exercise of Purchase Warrants

A U.S. holder generally will not recognize gain or loss on the exercise of a purchase warrant and the related receipt of warrant shares (unless cash is received in lieu of the issuance of a fractional warrant share). A U.S. holder’s initial tax basis in a warrant share will be equal to the sum of (a) such U.S. holder’s tax basis in the purchase warrant plus (b) the exercise price paid by such U.S. holder on the exercise of such purchase warrant. A U.S. holder’s holding period in a warrant share received on the exercise of a purchase warrant generally should begin on the day after the date that such purchase warrant is exercised by such U.S. holder.

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In certain circumstances, the purchase warrants may be exercised on a cashless basis. The U.S. federal income tax treatment of an exercise of a warrant on a cashless basis is not clear, and could differ from the consequences described above. It is possible that a cashless exercise could be a taxable event. U.S. holders are urged to consult their tax advisors as to the consequences of an exercise of a purchase warrant on a cashless basis, including with respect to their holding period and tax basis in the warrant share.

Distributions on the Shares or the Warrant Shares

We do not anticipate declaring or paying any future distributions. However, if we do make distributions on the Shares or the warrant shares, such distributions will constitute dividends to the extent paid from our current or accumulated earnings and profits, as determined under U.S. federal income tax principles, and will be includible in your income as ordinary income when received. However, with respect to dividends received by individuals, such dividends are generally taxed at the lower applicable long-term capital gains rates, provided certain holding period and other requirements are satisfied. If a distribution exceeds our current and accumulated earnings and profits, the excess will be treated as a tax-free return of the U.S. holder’s investment, up to such U.S. holder’s adjusted tax basis in the Shares or the warrant shares, as applicable. Any remaining excess will be treated as capital gain from the sale or exchange of such Shares or warrant shares, subject to the tax treatment described in “-Sale or Other Taxable Disposition of the Shares, Pre-Funded Warrants, Purchase Warrants or Warrant Shares.”

Sale or Other Taxable Disposition of the Shares, Pre-Funded Warrants, Purchase Warrants or Warrant Shares

Upon the sale, exchange or other taxable disposition of the Shares, pre-funded warrants (other than by exercise), purchase warrants (other than by exercise) or warrant shares, a U.S. holder will generally recognize capital gain or loss equal to the difference between the amount of cash and the fair market value of any property received upon the sale, exchange or other taxable disposition and such U.S. holder’s adjusted tax basis in the Shares, pre-funded warrants, purchase warrants or warrant shares. This capital gain or loss will be long-term capital gain or loss if the U.S. holder’s holding period in such Shares, pre-funded warrants, purchase warrants or warrant shares is more than one year at the time of the sale, exchange or other taxable disposition. Long-term capital gains recognized by certain non-corporate U.S. holders, including individuals, generally will be subject to reduced rates of U.S. federal income tax. The deductibility of capital losses is subject to certain limitations.

Lapse of Pre-Funded Warrants and Purchase Warrants

Upon the lapse or expiration of a pre-funded warrant or a purchase warrant, a U.S. holder will recognize a loss in an amount equal to such U.S. holder’s tax basis in the pre-funded warrant or the purchase warrant. Any such loss generally will be a capital loss and will be long-term capital loss if the pre-funded warrant or the purchase warrant is held for more than one year. Deductions for capital losses are subject to limitations.

Certain Adjustments to the Pre-Funded Warrants and Purchase Warrants

The terms of each pre-funded warrant and purchase warrant provide for an adjustment to the number of warrant shares for which the pre-funded warrant or purchase warrant may be exercised and/or to the exercise price of the pre-funded warrant or purchase warrant in certain events. An adjustment to the exercise price of a pre-funded warrant or purchase warrant may be treated as a constructive distribution to a U.S. holder of the pre-funded warrants or purchase warrants depending on the circumstances of such adjustment if, and to the extent that, such adjustment has the effect of increasing such U.S. holder’s proportionate interest in our “earnings and profits” or assets, depending on the circumstances of such adjustment. In addition, the failure to provide for such an adjustment (or to adequately adjust) may also result in a deemed distribution to U.S. holders of the pre-funded warrants or purchase warrants or Shares. Any such constructive distribution may be taxable whether or not there is an actual distribution of cash or other property. However, adjustments to the exercise price of pre-funded

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warrants or purchase warrants made pursuant to a bona fide reasonable adjustment formula that has the effect of preventing dilution of the interest of the holders thereof generally should not be considered to result in a constructive distribution. Generally, such deemed distributions will be taxable in the same manner as an actual distribution as described in “-Distributions on the Shares or the Warrant Shares,” except that it is unclear whether such deemed distributions would be eligible for the reduced tax rate applicable to certain dividends paid to non-corporate holders or the dividend-received deduction applicable to certain dividends paid to corporate holders. Generally, a U.S. holder’s tax basis in the underlying stock will be increased to the extent any such constructive distribution is treated as a dividend. Proposed U.S. Treasury Regulations address the amount of, timing of, and withholding obligations in respect to, constructive distributions made to holders of convertible securities such as the pre-funded warrants or purchase warrants. These proposed regulations are effective for constructive distributions made on or after the date of finalization, but may generally be relied upon as to certain matters for constructive distributions that occur prior to such date. U.S. holders should consult their own tax advisors regarding the application of such regulations and other tax considerations relating to the possibility of constructive distributions.

Backup Withholding and Information Reporting

A U.S. holder may be subject to information reporting and backup withholding when such holder receives payments on our securities (including constructive dividends) or receives proceeds from the sale or other taxable disposition of our securities. Certain U.S. holders are exempt from backup withholding, including C corporations and certain tax-exempt organizations. A U.S. holder will be subject to backup withholding if such holder is not otherwise exempt and such holder:

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fails to furnish the holder’s taxpayer identification number, which for an individual is ordinarily his or her social security number;

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furnishes an incorrect taxpayer identification number;

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is notified by the IRS that the holder previously failed to properly report payments of interest or dividends; or

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fails to certify under penalties of perjury that the holder has furnished a correct taxpayer identification number and that the IRS has not notified the holder that the holder is subject to backup withholding.

Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against a U.S. holder’s U.S. federal income tax liability, provided the required information is timely furnished to the IRS. U.S. holders should consult their tax advisors regarding their qualification for an exemption from backup withholding and the procedures for obtaining such an exemption.

Tax Considerations Applicable to Non-U.S. Holders

Definition of non-U.S. Holder

For purposes of this discussion, a “non-U.S. holder” is a beneficial owner of our securities that is neither a U.S. holder nor a partnership or an entity or arrangement treated as a partnership for U.S. federal income tax purposes.

Exercise of Purchase Warrants

A non-U.S. holder generally will not recognize gain or loss on the exercise of a purchase warrant and the related receipt of warrant shares (unless cash is received in lieu of the issuance of a fractional warrant share and certain other conditions are present, as discussed under “-Gain on Sale, Exchange or Other Taxable Disposition of Our Securities”). See “-Tax Considerations Applicable to U.S. Holders-Exercise of Purchase Warrants.”

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However, if a cashless exercise of purchase warrants results in a taxable exchange, as described in “-Tax Considerations Applicable to U.S. Holders-Exercise of Purchase Warrants,” the rules described in “Gain on Sale, Exchange or Other Taxable Disposition of Our Securities” would apply.

Lapse of Purchase Warrants

If a non-U.S. holder allows a purchase warrant to expire unexercised, such non-U.S. holder will recognize a capital loss in an amount equal to such holder’s tax basis in the purchase warrant. See “-Tax Considerations Applicable to U.S. Holders-Lapse of Warrants.”

Certain Adjustments to the Pre-Funded Warrants and Purchase Warrants

See the discussion of the rules applicable to constructive distributions on a pre-funded warrant or purchase warrant in “-Tax Considerations Applicable to U.S. Holders-Certain Adjustments to the Warrants.” If an adjustment to the number of warrant shares that will be issued on the exercise of the Warrants, or an adjustment to the exercise price of the pre-funded warrants or purchase warrants, results in a constructive distribution, as described in “-Tax Considerations Applicable to U.S. Holders-Certain Adjustments to the Pre-Funded Warrants and Purchase Warrants,” the rules described in “-Distributions on the Shares or the Warrant Shares” would apply. U.S. federal income tax required to be withheld on any portion of such constructive distribution that is treated as a dividend (as described in “-Distributions on the Shares or the Warrant Shares”) may be withheld from warrant shares, sales proceeds subsequently paid or credited, or other amounts payable or distributable to a non-U.S. holder.

Distributions on the Shares or the Warrant Shares

We do not anticipate declaring or paying any future distributions. However, if we make distributions on the Shares or the warrant shares such distributions will constitute dividends to the extent paid from our current or accumulated earnings and profits, as determined under U.S. federal income tax principles. If a distribution exceeds our current and accumulated earnings and profits, the excess will be treated as a tax-free return of the non-U.S. holder’s investment, up to such non-U.S. holder’s adjusted tax basis in the Shares or the warrant shares, as applicable. Any remaining excess will be treated as capital gain from the sale or exchange of such Shares or warrant shares, subject to the tax treatment described in “-Gain on Sale, Exchange or Other Taxable Disposition of Our Securities” below.

Dividends paid to a non-U.S. holder will generally be subject to withholding of U.S. federal income tax at a 30% rate of the gross amount of the dividend or such lower rate as may be specified by an applicable income tax treaty between the United States and such non-U.S. holder’s country of residence for purposes of such treaty.

Dividends that are treated as effectively connected with a trade or business conducted by a non-U.S. holder within the United States and, if an applicable income tax treaty so provides, that are attributable to a permanent establishment or a fixed base maintained by the non-U.S. holder within the United States, are generally exempt from the 30% withholding tax if the non-U.S. holder satisfies applicable certification and disclosure requirements. However, such U.S. effectively connected income, net of specified deductions and credits, is taxed at the same U.S. federal income tax rates applicable to U.S. persons (as defined in the Code). Any U.S. effectively connected income received by a non-U.S. holder that is a corporation may also, under certain circumstances, be subject to an additional “branch profits tax” at a 30% rate or such lower rate as may be specified by an applicable income tax treaty between the United States and such non-U.S. holder’s country of residence for purposes of such treaty.

To claim a reduction or exemption from withholding, a non-U.S. holder generally will be required to provide (a) a properly executed IRS Form W-8BEN or IRS Form W-8BEN-E (or successor form) and satisfy applicable certification and other requirements to claim the benefit of an applicable income tax treaty between

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the United States and such non-U.S. holder’s country of residence, or (b) a properly executed IRS Form W-8ECI stating that dividends are not subject to withholding because they are effectively connected with such non-U.S. holder’s conduct of a trade or business within the United States. Non-U.S. holders are urged to consult their tax advisors regarding their entitlement to benefits under a relevant income tax treaty.

A non-U.S. holder that is eligible for a reduced rate of U.S. withholding tax under an income tax treaty may obtain a refund or credit of any excess amounts withheld by timely filing an appropriate claim for refund with the IRS.

Distributions will also be subject to the discussion in “-Backup Withholding and Information Reporting” and “-Foreign Accounts.”

Gain on Sale, Exchange or Other Taxable Disposition of Our Securities

Subject to the discussion in “-Backup Withholding and Information Reporting” and “-Foreign Accounts,” in general, a non-U.S. holder will not be subject to any U.S. federal income tax on any gain realized upon such non-U.S. holder’s sale, exchange or other taxable disposition of our securities unless:

•

the gain is effectively connected with a U.S. trade or business of the non-U.S. holder and, if an applicable income tax treaty so provides, is attributable to a permanent establishment or a fixed base maintained in the United States by such non-U.S. holder, in which case the non-U.S. holder generally will be taxed at the U.S. federal income tax rates applicable to U.S. persons (as defined in the Code) and, if the non-U.S. holder is a foreign corporation, the branch profits tax described in “-Distributions on the Shares or the Warrant Shares” also may apply;

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the non-U.S. holder is a nonresident alien individual who is present in the United States for 183 days or more in the taxable year of the disposition and certain other conditions are met, in which case the non-U.S. holder will be subject to a 30% U.S. federal income tax (or such lower rate as may be specified by an applicable income tax treaty) on the net gain derived from the disposition, which may be offset by U.S. source capital losses of the non-U.S. holder, if any (even though the individual is not considered a resident of the United States); or

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we are, or have been, at any time during the five-year period preceding such disposition (or the non-U.S. holder’s holding period, if shorter) a “U.S. real property holding corporation” in which case such non-U.S. holder generally will be taxed on its net gain derived from the disposition as effectively connected income taxable at the U.S. federal income tax rates applicable to U.S. persons (as defined in the Code); however, the branch profits tax described above will not apply to a U.S. holder that is a foreign corporation. Generally, a corporation is a U.S. real property holding corporation if the fair market value of its U.S. real property interests equals or exceeds 50% of the sum of the fair market value of its worldwide real property interests plus its other assets used or held for use in a trade or business. Although there can be no assurance, we do not believe that we are, or have been, a U.S. real property holding corporation, or that we are likely to become one in the future. Even if we are or become a U.S. real property holding corporation, provided that our common stock is regularly traded, as defined by applicable U.S. Treasury Regulations, on an established securities market, the Shares will be treated as a U.S. real property interest only with respect to a non-U.S. holder that holds more than 5% of our outstanding common stock, directly or indirectly, actually or constructively, during the shorter of the 5-year period ending on the date of the disposition or the period that the non-U.S. holder held the Shares or warrant shares, as applicable. There can be no assurance that our common stock will continue to qualify as regularly traded on an established securities market. Disposition by a non-U.S. holder of purchase warrants (that are not expected to be regularly traded on an established securities market) may also be eligible for an exemption from withholding even if we are treated as a U.S. real property holding corporation, if on the date such purchase warrants were acquired by such non-U.S. holder such holdings had a fair market value no greater than the fair market value on that date of 5% of

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our regularly-traded common stock, provided that, if a non-U.S. holder holding our not-regularly-traded purchase warrants subsequently acquires additional purchase warrants, then such interests would be aggregated and valued as of the date of the subsequent acquisition to apply this 5% limitation.

Backup Withholding and Information Reporting

We must report annually to the IRS and to each non-U.S. holder the gross amount of the dividends on our securities paid to such non-U.S. holder and the tax withheld, if any, with respect to such dividends. Non-U.S. holders will have to comply with specific certification procedures to establish that the holder is not a U.S. person (as defined in the Code) in order to avoid backup withholding at the applicable rate with respect to any dividends on our securities. A non-U.S. holder generally will not be subject to U.S. backup withholding with respect to payments of dividends on our securities if it certifies its non-U.S. status by providing a valid IRS Form W-8BEN or IRS Form W-8BEN-E (or successor form) or IRS Form W-8ECI, or otherwise establishes an exemption; provided we do not have actual knowledge or reason to know such non-U.S. holder is a U.S. person, as defined in the Code. Dividends paid to non-U.S. holders subject to the U.S. withholding tax, as described in “-Distributions on the Shares or the Warrant Shares” generally will be exempt from U.S. backup withholding.

Information reporting and backup withholding will generally apply to the proceeds of a disposition of our securities by a non-U.S. holder effected by or through the U.S. office of any broker, U.S. or foreign, unless the holder certifies its status as a non-U.S. holder and satisfies certain other requirements, or otherwise establishes an exemption. Generally, information reporting and backup withholding will not apply to a payment of disposition proceeds to a non-U.S. holder where the transaction is effected outside the United States through a non-U.S. office of a broker. However, for information reporting purposes, dispositions effected through a non-U.S. office of a broker with substantial U.S. ownership or operations generally will be treated in a manner similar to dispositions effected through a U.S. office of a broker. Non-U.S. holders should consult their tax advisors regarding the application of the information reporting and backup withholding rules to them.

Copies of information returns may be made available to the tax authorities of the country in which the non-U.S. holder resides or is established under the provisions of a specific treaty or agreement.

Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules from a payment to a non-U.S. holder may be allowed as a credit against the non-U.S. holder’s U.S. federal income tax liability, if any, and may entitle such holder to a refund, provided that the required information is timely furnished to the IRS.

Foreign Accounts

The Code generally imposes a U.S. federal withholding tax of 30% on dividends and, subject to the discussion below regarding proposed regulations issued by the U.S. Treasury Department, the gross proceeds of a disposition of our securities paid to a “foreign financial institution” (as defined in the Code), unless such institution enters into an agreement with the U.S. government to, among other things, withhold on certain payments and to collect and provide to the U.S. tax authorities substantial information regarding accounts held by certain “specific United States persons” or “United States owned foreign entities” (each as defined in the Code), or otherwise qualifies for an exemption from these rules. A U.S. federal withholding tax of 30% also applies to dividends and, subject to the discussion below regarding proposed regulations issued by the U.S. Treasury Department, will apply to the gross proceeds of a disposition of our securities paid to a “non-financial foreign entity” (as defined in the Code), unless such entity provides the withholding agent with either a certification that it does not have any “substantial United States owners” (as defined in the Code), provides information regarding each substantial United States owners of the entity, or otherwise qualifies for an exemption from these rules. Under certain circumstances, a non-U.S. holder might be eligible for refunds or credits of such taxes. An intergovernmental agreement between the United States and an applicable foreign country may modify the requirements described in this paragraph.

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The withholding provisions described above currently apply to dividends paid on our securities. The U.S. Treasury Department released proposed regulations which, if finalized in their present form, would eliminate the U.S. federal withholding tax of 30% applicable to the gross proceeds of a sale or other disposition of our securities. In its preamble to such proposed regulations, the U.S. Treasury Department stated that taxpayers may generally rely on the proposed regulations until final regulations are issued.

EACH PROSPECTIVE INVESTOR SHOULD CONSULT ITS TAX ADVISOR REGARDING THE PARTICULAR U.S. FEDERAL, STATE AND LOCAL AND NON-U.S. TAX CONSEQUENCES OF PURCHASING, HOLDING AND DISPOSING OF OUR SECURITIES, INCLUDING THE CONSEQUENCES OF ANY PROPOSED CHANGE IN APPLICABLE LAWS.

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UNDERWRITING

Cantor Fitzgerald & Co. and Wells Fargo Securities, LLC are acting as representatives of each of the underwriters named below. Subject to the terms and conditions set forth in the underwriting agreement by and among us and the underwriters, we have agreed to sell to the underwriters, and each of the underwriters has agreed, severally and not jointly, to purchase from us, the shares of common stock and accompanying warrants and pre-funded warrants and accompanying warrants shown opposite its name below:


Underwriter	Number of Shares		Number of Pre-Funded Warrants		Number of Accompanying Warrants(1)
Cantor Fitzgerald & Co.		20,332,951		10,277,348		30,610,299
Wells Fargo Securities, LLC.		14,857,341		7,509,685		22,367,026

Total		35,190,292		17,787,033		52,977,325

(1)	Each accompanying warrant is exercisable for one share of common stock.

The underwriting agreement provides that the obligations of the several underwriters are subject to certain conditions precedent such as the receipt by the underwriters of officers’ certificates and legal opinions and approval of certain legal matters by their counsel. The underwriting agreement provides that the underwriters will purchase all of the securities if any of them are purchased. We have agreed to indemnify the underwriters and certain of their controlling persons against certain liabilities, including liabilities under the Securities Act, and to contribute to payments that the underwriters may be required to make in respect of those liabilities.

The underwriters are offering the securities subject to their acceptance of the securities from us and subject to prior sale. The underwriters reserve the right to withdraw, cancel or modify offers to the public and to reject orders in whole or in part. In addition, the underwriters have advised us that they do not intend to confirm sales to any account over which they exercise discretionary authority.

Commission and Expenses

The underwriters have advised us that they propose to offer the securities to the public at the offering price set forth on the cover page of this prospectus supplement and to certain dealers, which may include the underwriters, at that price less a concession not in excess of $0.0170 per share of common stock and accompanying warrant or pre-funded warrant and accompanying warrant. After the initial offering, the underwriters may change the offering price and other selling terms.

The following table shows the combined offering price, the underwriting discounts and commissions that we are to pay the underwriters and the proceeds, before expenses, to us in connection with this offering.


	Per Share and Accompanying Warrant		Per Pre-Funded Warrant and Accompanying Warrant		Total
Combined offering price	$	0.4719	$	0.4619	$	24,822,129.34
Underwriting discounts and commissions	$	0.0283	$	0.0277	$	1,488,586,08
Proceeds to us, before expenses	$	0.4436	$	0.4342	$	23,333,543.26

We estimate expenses payable by us in connection with this offering, other than the underwriting discounts and commissions referred to above, will be approximately $440,000. We have also agreed to reimburse the underwriters for up to $10,000 of certain of their counsels’ fees and expenses, which reimbursed fee is deemed underwriting compensation for this offering by FINRA.

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Listing

Our common stock is listed on Nasdaq Capital Market under the trading symbol “SGMO.” We do not intend to list the pre-funded warrants or the warrants on Nasdaq, any other national securities exchange or any other nationally recognized trading system.

No Sales of Similar Securities

We, our officers and our directors have agreed, subject to certain specified exceptions, not to directly or indirectly, for a period of 30 days after the date of this prospectus supplement (the “Lock-Up Period”), (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, or otherwise transfer or dispose of, directly or indirectly, any shares of common stock or any securities convertible into or exercisable or exchangeable for common stock (including without limitation, common stock or such other securities which may be deemed to be beneficially owned now or hereafter by the lock-up signatory in accordance with the rules and regulations of the SEC (such shares or securities, the “Beneficially Owned Shares”) and securities which may be issued upon exercise of a stock option or warrant), (2) engage in any hedging or other transaction or arrangement (including, without limitation, any short sale or the purchase or sale of, or entry into, any put or call option, or combination thereof, forward, swap or any other derivative transaction or instrument, however described or defined) which is designed to or which reasonably could be expected to lead to or result in a sale, loan, pledge or other disposition (whether by the lock-up signatory or someone other than the lock-up signatory), or transfer of any of the economic consequences of ownership, in whole or in part, directly or indirectly, of any Beneficially Owned Shares, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of common stock or such other securities, in cash or otherwise (any such sale, loan, pledge or other disposition, or transfer of economic consequences, a “Transfer”), (3) make any demand for or exercise any right with respect to the registration of any shares of common stock or any security convertible into or exercisable or exchangeable for common stock, or (4) otherwise publicly announce any intention to engage in or cause any action, activity, transaction or arrangement described in clause (1), (2) or (3) above, in each case other than:

(a)

any sale or transfer of shares of common stock at least 30 days after the date of the final prospectus supplement relating to the public offering, provided that the closing price per share of the common stock equals or exceeds 120% of the purchase price (as adjusted for share sub-divisions, share capitalizations, reorganizations, recapitalizations and the like) for any 5 trading days within a 10-trading day period commencing at least 30 days after the date of the final prospectus supplement relating to the public offering;

(b)

transfers of Beneficially Owned Shares, common stock or securities convertible into or exercisable or exchangeable for common stock (i) as a bona fide gift or gifts, (ii) to any trust for the direct or indirect benefit of the lock-up signatory or the immediate family of the lock-up signatory, (iii) to any affiliate of the lock-up signatory or (iv) by will or intestacy to the lock-up signatory’s legal representative, heir or legatee;

(c)

the acquisition or exercise of any stock option issued pursuant to our existing stock option plan, including any exercise effected by the delivery of shares of common stock held by the lock-up signatory;

(d)

any conversion of restricted stock units into shares of common stock as provided in the applicable restricted stock unit issuance agreement;

(e)

any transfer of shares of common stock to us in connection with the lock-up signatory’s tax withholding obligation upon issuance of such shares pursuant to the applicable restricted stock unit issuance agreement;

(f)

pursuant to a sale or an offer to purchase 100% of the outstanding common stock, whether pursuant to a merger, tender offer or otherwise, to a third party or group of third parties resulting in a change of

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control and approved by our board of directors, provided that, in the event that such a change of control is not completed, the lock-up signatory’s shares shall remain subject to the restrictions contained in the lock-up agreement and title to the lock-up signatory’s shares shall remain with the lock-up signatory; or

(g)

the establishment of a trading plan pursuant to Rule 10b5-1 under the Exchange Act for the transfer of common stock, provided that such plan does not provide for the transfer and sale of common stock during the Lock-Up Period, and provided further that, except as required by applicable securities laws, no public announcement of the establishment or existence of such plan, and no filing with the SEC or any other regulatory authority in respect thereof or for transactions thereunder or contemplated thereby, by the lock-up signatory, us or any other person, shall be required, and no announcement or filing shall be made voluntarily by the lock-up signatory, us or any other person prior to the expiration of the Lock-Up Period.

In the case of any transfer or distribution pursuant to clause (a) above, each donee or distributee or transferee shall execute and deliver to the underwriters a lock-up agreement for the balance of the Lock-Up Period in the form of this paragraph and, pursuant to clauses (a)(ii) through (iv) above, no filing by any party (donor, donee, distributor, distributee, transferor or transferee) under the Exchange Act, or other public announcement reporting a reduction in the beneficial ownership shall be required or shall be made voluntarily in connection with such transfer or distribution. In the case of any transfer or distribution pursuant to clause (a)(i) above, it shall be a condition to such transfer that no public filing, report or announcement shall be voluntarily made and if any filing under Section 16(a) of the Exchange Act, or other public filing, report or announcement reporting a reduction in beneficial ownership of shares of common stock in connection with such transfer or distribution shall be legally required during the Lock-Up Period, such filing, report or announcement shall clearly indicate in the footnotes thereto the nature and conditions of such transfer. For the avoidance of doubt, any shares of common stock received by the lock-up signatory upon the exercise of a stock option or conversion of restricted stock units as described in foregoing clauses (c) and (d) shall be subject to the restrictions under the lock-up agreement.

The underwriters may, in their sole discretion and at any time or from time to time before the termination of the Lock-Up Period release all or any portion of the securities subject to lock-up agreements.

Market Making, Stabilization and Other Transactions

The underwriters may make a market in the common stock as permitted by applicable laws and regulations. However, the underwriters are not obligated to do so, and the underwriters may discontinue any market-making activities at any time without notice in their sole discretion. Accordingly, no assurance can be given as to the liquidity of the trading market for the common stock, that you will be able to sell any of the common stock held by you at a particular time or that the prices that you receive when you sell will be favorable.

The underwriters have advised us that it, pursuant to Regulation M under the Securities Exchange Act of 1934, as amended, may engage in short sale transactions, stabilizing transactions, syndicate covering transactions or the imposition of penalty bids in connection with this offering. These activities may have the effect of stabilizing or maintaining the market price of the common stock at a level above that which might otherwise prevail in the open market. Establishing short sales positions may involve either “covered” short sales or “naked” short sales.

“Covered” short sales are sales made in an amount not greater than the number of shares of our common stock the underwriter is required to purchase in this offering. The underwriters may close out any covered short position by purchasing shares of our common stock in the open market.

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“Naked” short sales are sales in excess of the number of shares of our common stock the underwriter is required to purchase in this offering. The underwriters must close out any naked short position by purchasing shares in the open market. A naked short position is more likely to be created if the underwriters are concerned that there may be downward pressure on the price of the shares of our common stock in the open market after pricing that could adversely affect the investor purchasing in this offering.

A stabilizing bid is a bid for the purchase of shares of common stock on behalf of the underwriters for the purpose of fixing or maintaining the price of the common stock. A syndicate covering transaction is the bid for or the purchase of shares of common stock on behalf of the underwriters to reduce a short position incurred by the underwriters in connection with the offering. Similar to other purchase transactions, the underwriters’ purchases to cover the syndicate short sales may have the effect of raising or maintaining the market price of our common stock or preventing or retarding a decline in the market price of our common stock. As a result, the price of our common stock may be higher than the price that might otherwise exist in the open market. A penalty bid is an arrangement permitting the underwriters to reclaim the selling concession otherwise accruing to a syndicate member in connection with the offering if the common stock originally sold by such syndicate member are purchased in a syndicate covering transaction and therefore have not been effectively placed by such syndicate member.

Neither we, nor any of the underwriters make any representation or prediction as to the direction or magnitude of any effect that the transactions described above may have on the price of our common stock. The underwriters are not obligated to engage in these activities and, if commenced, may end any of these activities at any time. These transactions may be effected on the Nasdaq in the over-the-counter market or otherwise.

Passive Market Making

The underwriters may also engage in passive market making transactions in our common stock on the Nasdaq in accordance with Rule 103 of Regulation M during a period before the commencement of offers or sales of shares of our common stock in this offering and extending through the completion of distribution. A passive market maker must display its bid at a price not in excess of the highest independent bid of that security. However, if all independent bids are lowered below the passive market maker’s bid, that bid must then be lowered when specified purchase limits are exceeded. Passive market making may cause the price of our common stock to be higher than the price that otherwise would exist in the open market in the absence of those transactions. The underwriters are not required to engage in passive market making and, if commenced, may end passive market making activities at any time.

Electronic Distribution

A prospectus in electronic format may be made available by e-mail or on the web sites or through online services maintained by one or more of the underwriters, selling group members (if any) or their affiliates. The underwriters may agree with us to allocate a specific number of securities for sale to online brokerage account holders. Any such allocation for online distributions will be made by the underwriters on the same basis as other allocations.

Other Activities and Relationships

The underwriters and certain of their respective affiliates are full service financial institutions engaged in a wide range of activities for their own accounts and the accounts of customers, which may include, among other things, corporate finance, mergers and acquisitions, merchant banking, equity and fixed income sales, trading and research, derivatives, foreign exchange, futures, asset management, custody, clearance and securities lending. The underwriters and certain of their affiliates have, from time to time, performed, and may in the future perform, various investment banking and financial advisory services for us and our affiliates, for which they received or will receive customary fees and expenses.

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In addition, in the ordinary course of its business, the underwriters and their respective affiliates may, directly or indirectly, hold long or short positions, trade and otherwise conduct such activities in or with respect to debt or equity securities and/or bank debt of, and/or derivative products. Such investment and securities activities may involve our securities and instruments. The underwriters and their respective affiliates may also make investment recommendations or publish or express independent research views in respect of such securities or instruments and may at any time hold, or recommend to clients that they acquire, long or short positions in such securities and instruments.

Stamp Taxes

If you purchase securities offered in this prospectus supplement, you may be required to pay stamp taxes and other charges under the laws and practices of the country of purchase, in addition to the offering price listed on the cover page of this prospectus supplement.

Notice to Investors

Canada

This prospectus supplement constitutes an “exempt offering document” as defined in and for the purposes of applicable Canadian securities laws. No prospectus has been filed with any securities commission or similar regulatory authority in Canada in connection with the offer and sale of the securities. No securities commission or similar regulatory authority in Canada has reviewed or in any way passed upon this prospectus supplement or on the merits of the securities and any representation to the contrary is an offence.

Canadian investors are advised that this prospectus supplement has been prepared in reliance on section 3A.3 of National Instrument 33-105 Underwriting Conflicts (“NI 33-105”). Pursuant to section 3A.3 of NI 33-105, this prospectus supplement is exempt from the requirement that the issuer and the underwriter(s) provide investors with certain conflicts of interest disclosure pertaining to “connected issuer” and/or “related issuer” relationships that may exist between the issuer and the underwriter(s) as would otherwise be required pursuant to subsection 2.1(1) of NI 33-105.

Resale Restrictions

The offer and sale of the securities in Canada is being made on a private placement basis only and is exempt from the requirement that the issuer prepares and files a prospectus under applicable Canadian securities laws. Any resale of the securities acquired by a Canadian investor in this offering must be made in accordance with applicable Canadian securities laws, which may vary depending on the relevant jurisdiction, and which may require resales to be made in accordance with Canadian prospectus requirements, pursuant to a statutory exemption from the prospectus requirements, in a transaction exempt from the prospectus requirements or otherwise under a discretionary exemption from the prospectus requirements granted by the applicable local Canadian securities regulatory authority. These resale restrictions may under certain circumstances apply to resales of the securities outside of Canada.

Representations of Purchasers

Each Canadian investor who purchases the securities will be deemed to have represented to the issuer and the underwriter(s) that the investor (i) is purchasing the securities as principal, or is deemed to be purchasing as principal in accordance with applicable Canadian securities laws, for investment only and not with a view to resale or redistribution; (ii) is an “accredited investor” as such term is defined in section 1.1 of National Instrument 45-106 Prospectus Exemptions (“NI 45-106”) or, in Ontario, as such term is defined in section 73.3(1) of the Securities Act (Ontario); and (iii) is a “permitted client” as such term is defined in section 1.1 of National Instrument 31-103 Registration Requirements, Exemptions and Ongoing Registrant Obligations.

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Taxation and Eligibility for Investment

Any discussion of taxation and related matters contained in this prospectus supplement does not purport to be a comprehensive description of all of the tax considerations that may be relevant to a Canadian investor when deciding to purchase the securities and, in particular, does not address any Canadian tax considerations. No representation or warranty is hereby made as to the tax consequences to a resident, or deemed resident, of Canada of an investment in the securities or with respect to the eligibility of the securities for investment by such investor under relevant Canadian federal and provincial legislation and regulations.

Rights of Action for Damages or Rescission

Securities legislation in certain of the Canadian jurisdictions provides certain purchasers of securities pursuant to an offering memorandum (such as this prospectus supplement), including where the distribution involves an “eligible foreign security” as such term is defined in Ontario Securities Commission Rule 45-501 Ontario Prospectus and Registration Exemptions and in Multilateral Instrument 45-107 Listing Representation and Statutory Rights of Action Disclosure Exemptions, as applicable, with a remedy for damages or rescission, or both, in addition to any other rights they may have at law, where the offering memorandum, or other offering document that constitutes an offering memorandum, and any amendment thereto, contains a “misrepresentation” as defined under applicable Canadian securities laws. These remedies, or notice with respect to these remedies, must be exercised or delivered, as the case may be, by the purchaser within the time limits prescribed under, and are subject to limitations and defences under, applicable Canadian securities legislation. In addition, these remedies are in addition to and without derogation from any other right or remedy available at law to the investor.

Language of Documents

Upon receipt of this document, each Canadian investor hereby confirms that it has expressly requested that all documents evidencing or relating in any way to the sale of the securities described herein (including for greater certainty any purchase confirmation or any notice) be drawn up in the English language only. Par la réception de ce document, chaque investisseur Canadien confirme par les présentes qu’il a expressément exigé que tous les documents faisant foi ou se rapportant de quelque manière que ce soit à la vente des valeurs mobilières décrites aux présentes (incluant, pour plus de certitude, toute confirmation d’achat ou tout avis) soient rédigés en anglais seulement.

Australia

This document does not constitute a prospectus, product disclosure statement or other disclosure document under the Australia’s Corporations Act 2001 (Cth) (the “Corporations Act”) of Australia. This document has not been lodged with the Australian Securities & Investments Commission and is only directed to the categories of exempt persons set out below. Accordingly, if you receive this document in Australia:

You confirm and warrant that you are either:

•

a “sophisticated investor” under section 708(8)(a) or (b) of the Corporations Act;

•

a “sophisticated investor” under section 708(8)(c) or (d) of the Corporations Act and that you have provided an accountant’s certificate to the company which complies with the requirements of section 708(8)(c)(i) or (ii) of the Corporations Act and related regulations before the offer has been made; or

•

a “professional investor” within the meaning of section 708(11)(a) or (b) of the Corporations Act.

To the extent that you are unable to confirm or warrant that you are an exempt sophisticated investor or professional investor under the Corporations Act any offer made to you under this document is void and incapable of acceptance.

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You warrant and agree that you will not offer any of the shares issued to you pursuant to this document for resale in Australia within 12 months of those securities being issued unless any such resale offer is exempt from the requirement to issue a disclosure document under section 708 of the Corporations Act.

European Economic Area

In relation to each member state of the European Economic Area (each a “Member State”), no securities have been offered or will be offered pursuant to the offer described herein in that Member State prior to the publication of a prospectus in relation to the securities which has been approved by the competent authority in that Member State or, where appropriate, approved in another Member State and notified to the competent authority in that Member State, all in accordance with the Prospectus Regulation, except that the securities may be offered to the public in that Member State at any time:

(i) to any legal entity which is a qualified investor as defined under Article 2 of the Prospectus Regulation;

(ii) to fewer than 150 natural or legal persons (other than qualified investors as defined under Article 2 of the Prospectus Regulation), subject to obtaining the prior consent of the underwriters for any such offer; or

(iii) in any other circumstances falling within Article 1(4) of the Prospectus Regulation,

provided that no such offer of securities shall require the issuer or any underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Regulation or supplement a prospectus pursuant to Article 23 of the Prospectus Regulation.

Each person in a Member State who acquires any securities in the offer or to whom any offer is made will be deemed to have represented, acknowledged and agreed to and with the issuer and the underwriters that it is a qualified investor within the meaning of the Prospectus Regulation.

In the case of any securities being offered to a financial intermediary as that term is used in Article 5(1) of the Prospectus Regulation, each such financial intermediary will be deemed to have represented, acknowledged and agreed to and with the issuer and the underwriters that the securities acquired by it in the offer have not been acquired on a non-discretionary basis on behalf of, nor have they been acquired with a view to their offer or resale to, persons in circumstances which may give rise to an offer to the public other than their offer or resale in a Member State to qualified investors, in circumstances in which the prior consent of the underwriters has been obtained to each such proposed offer or resale. Neither the issuer nor the underwriters have authorised, nor do they authorise, the making of any offer of securities through any financial intermediary, other than offers made by the underwriters which constitute the final placement of securities contemplated in this document.

The issuer and the underwriters and their affiliates will rely upon the truth and accuracy of the foregoing representations, acknowledgements and agreements.

For the purposes of this provision, the expression an “offer to the public” in relation to any securities in any Member State means the communication in any form and by any means of sufficient information on the terms of the offer and any securities to be offered so as to enable an investor to decide to purchase, or subscribe for, any securities and the expression “Prospectus Regulation” means Regulation (EU) 2017/1129.

In Member States, this document is being distributed only to, and is directed only at, persons who are “qualified investors” within the meaning of Article 2(e) of the Prospectus Regulation (“Qualified Investors”). This document must not be acted on or relied on in any Member State by persons who are not Qualified Investors. Any investment or investment activity to which this document relates is available in any Member State only to Qualified Investors and will be engaged in only with such persons.

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Hong Kong

No securities have been, may be or will be offered or sold in Hong Kong, by means of any document, other than to persons whose ordinary business is to buy or sell shares or debentures, whether as principal or agent; or to “professional investors” as defined in the Securities and Futures Ordinance (Cap. 571) of Hong Kong (the “SFO”) and any rules made thereunder; or in other circumstances which do not result in the document being a “prospectus” as defined in the Companies (Winding UP and Miscellaneous Provisions) Ordinance (Cap. 32) of Hong Kong (the “C(WUMP)O”), or which do not constitute an offer to the public within the meaning of the C(WUMP)O. No document, invitation or advertisement relating to the securities has been issued or may be issued or will be issued or may be in the possession of any person for the purpose of issue (in each case whether in Hong Kong or elsewhere), which is directed at, or the contents of which are likely to be accessed or read by, the public of Hong Kong (except if permitted under the securities laws of Hong Kong) other than with respect to securities which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” as defined in the SFO and any rules made thereunder.

This document has not been and will not be registered with the Registrar of Companies in Hong Kong. Accordingly, this document may not be issued, circulated or distributed in Hong Kong, and the securities may not be offered for subscription to members of the public in Hong Kong. Each person acquiring the securities will be required, and is deemed by the acquisition of the securities, to confirm that he is aware of the restriction on offers of the securities described in this document and the relevant offering documents and that he is not acquiring, and has not been offered any securities in circumstances that contravene any such restrictions.

Japan

The offering has not been and will not be registered under the Financial Instruments and Exchange Act of Japan (Act No. 25 of 1948 of Japan, as amended) (the “FIEA”), and the Initial Purchaser will not offer or sell any securities, directly or indirectly, in Japan or to, or for the benefit of, any resident of Japan (which term as used herein means, unless otherwise provided herein, any person resident in Japan, including any corporation or other entity organized under the laws of Japan), or to others for re-offering or resale, directly or indirectly, in Japan or to a resident of Japan, except pursuant to an exemption from the registration requirements of, and otherwise in compliance with, the FIEA and any other applicable laws, regulations and ministerial guidelines of Japan.

Singapore

This document has not been and will not be lodged or registered with the Monetary Authority of Singapore. Accordingly, this document and any other document or material in connection with the offer or sale, or the invitation for subscription or purchase of the securities may not be issued, circulated or distributed, nor may the securities be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to any person in Singapore other than (i) to an institutional investor under Section 274 of the Securities and Futures Act, Chapter 289 of Singapore (the “SFA”), (ii) to a relevant person as defined under Section 275(2) of the SFA, or any person pursuant to Section 275(1A) of the SFA, and in accordance with the conditions, specified in Section 275 of the SFA and where (where applicable) Regulation 3 of the Securities and Futures (Classes of Investors) Regulations 2018 , or (iii) otherwise pursuant to, and in accordance with the conditions of any other applicable provision of the SFA. In the event that you are not an investor falling within any of the categories set out above, please return this document immediately. You may not forward or circulate this document to any other person in Singapore.

No offer is made to you with a view to the securities being subsequently offered for sale to any other party. There are on-sale restrictions that may be applicable to investors who acquire securities. As such, investors are advised to acquaint themselves with the provisions of the SFA relating to resale restrictions and comply accordingly.

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Where the securities are subscribed or purchased under Section 275 of the SFA by a relevant person which is:

•

a corporation (which is not an accredited investor as defined under Section 4A of the SFA) the sole business of which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor; or

•

a trust (where the trustee is not an accredited investor) whose sole purpose is to hold investments and each beneficiary is an accredited investor,

securities or securities-based derivatives contracts (each term as defined in Section 2(1) of the SFA) of that corporation or the beneficiaries’ rights and interest (howsoever described) in that trust shall not be transferable within six months after that corporation or that trust has acquired the securities under Section 275 of the SFA except:

•

to an institutional investor under Section 274 of the SFA or to a relevant person defined in Section 275(2) of the SFA, or to any person pursuant to an offer referred to in Section 275(1A) or Section 276(4)(i)(B) of the SFA;

•

where no consideration is given for the transfer;

•

where the transfer is by operation of law;

•

as specified in Section 276(7) of the SFA; or

•

as specified in Regulation 37A of the Securities and Futures (Offers of Investments) (Securities and Securities-based Derivatives Contracts) Regulations 2018 of Singapore.

Switzerland

The securities may not be publicly offered in Switzerland and will not be listed on the SIX Swiss Exchange, or SIX, or on any other stock exchange or regulated trading facility in Switzerland. This document has been prepared without regard to the disclosure standards for issuance prospectuses under art. 652a or art. 1156 of the Swiss Code of Obligations or the disclosure standards for listing prospectuses under art. 27 ff. of the SIX Listing Rules or the listing rules of any other stock exchange or regulated trading facility in Switzerland. Neither this document nor any other offering or marketing material relating to the securities or the offering may be publicly distributed or otherwise made publicly available in Switzerland.

Neither this document nor any other offering or marketing material relating to the offering, the issuer or the securities have been or will be filed with or approved by any Swiss regulatory authority. In particular, this document will not be filed with, and the offer of securities will not be supervised by, the Swiss Financial Market Supervisory Authority FINMA, or FINMA, and the offer of securities has not been and will not be authorized under the Swiss Federal Act on Collective Investment Schemes, or CISA. The investor protection afforded to acquirers of interests in collective investment schemes under the CISA does not extend to acquirers of securities.

Israel

This document does not constitute a prospectus under the Israeli Securities Law, 5728-1968, or the Securities Law, and has not been filed with or approved by the Israel Securities Authority. In the State of Israel, this document is being distributed only to, and is directed only at, and any offer of the shares is directed only at, investors listed in the first addendum, or the Addendum, to the Israeli Securities Law, consisting primarily of joint investment in trust funds, provident funds, insurance companies, banks, portfolio managers, investment advisors, members of the Tel Aviv Stock Exchange, underwriters, venture capital funds, entities with equity in excess of NIS 50 million and “qualified individuals”, each as defined in the Addendum (as it may be amended from time to time), collectively referred to as qualified investors (in each case purchasing for their own account

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or, where permitted under the Addendum, for the accounts of their clients who are investors listed in the Addendum). Qualified investors will be required to submit written confirmation that they fall within the scope of the Addendum, are aware of the meaning of same and agree to it.

United Kingdom

In relation to the United Kingdom, no securities have been offered or will be offered pursuant to the offer described herein to the public in the United Kingdom prior to the publication of a prospectus in relation to the securities which has been approved by the UK Financial Conduct Authority, except that the securities may be offered to the public in the United Kingdom at any time:

(i) to any legal entity which is a qualified investor as defined under Article 2 of the UK Prospectus Regulation;

(ii) to fewer than 150 natural or legal persons (other than qualified investors as defined under Article 2 of the UK Prospectus Regulation), subject to obtaining the prior consent of the underwriters for any such offer; or

(iii) in any other circumstances falling within Section 86 of the Financial Services and Markets Act 2000 (as amended) (the “FSMA”),

provided that no such offer of the securities shall require the issuer or any underwriter to publish a prospectus pursuant to Section 85 of the FSMA or supplement a prospectus pursuant to Article 23 of the UK Prospectus Regulation.

Each person in the United Kingdom who acquires any securities in the offer or to whom any offer is made will be deemed to have represented, acknowledged and agreed to and with the issuer and the underwriters that it is a qualified investor within the meaning of the UK Prospectus Regulation.

In the case of any securities being offered to a financial intermediary as that term is used in Article 5(1) of the UK Prospectus Regulation, each such financial intermediary will be deemed to have represented, acknowledged and agreed to and with the issuer and the underwriters that the securities acquired by it in the offer have not been acquired on a non-discretionary basis on behalf of, nor have they been acquired with a view to their offer or resale to, persons in circumstances which may give rise to an offer to the public other than their offer or resale in the United Kingdom to qualified investors, in circumstances in which the prior consent of the underwriters has been obtained to each such proposed offer or resale. Neither the issuer nor the underwriters have authorised, nor do they authorise, the making of any offer of securities through any financial intermediary, other than offers made by the underwriters which constitute the final placement of securities contemplated in this document.

The issuer and the underwriters and their affiliates will rely upon the truth and accuracy of the foregoing representations, acknowledgements and agreements.

For the purposes of this provision, the expression an “offer to the public” in relation to the securities in the United Kingdom means the communication in any form and by any means of sufficient information on the terms of the offer and any securities to be offered so as to enable an investor to decide to purchase or subscribe for any securities and the expression “UK Prospectus Regulation” means Regulation (EU) 2017/1129 as it forms part of United Kingdom law by virtue of the European Union (Withdrawal) Act 2018.

In the United Kingdom, this document is being distributed only to, and is directed only at, persons who are “qualified investors” within the meaning of Article 2(e) of the UK Prospectus Regulation who are also: (i) persons who fall within the definition of “investment professionals” in Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the “Order”); (ii) persons falling within

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Article 49(2) of the Order; or (iii) persons to whom it may otherwise lawfully be communicated (all such persons together being referred to as “relevant persons”). This document must not be acted on or relied on in the United Kingdom by persons who are not relevant persons. Any investment or investment activity to which this document relates is available in the United Kingdom only to relevant persons and will be engaged in only with such persons.

Any invitation or inducement to engage in investment activity (within the meaning of Section 21 of the FSMA) may only be communicated or caused to be communicated in connection with the issue or sale of the securities in circumstances in which Section 21(1) of the FSMA does not apply. All applicable provisions of the FSMA and the Order must be complied with in respect of anything done by any person in relation to the securities in, from or otherwise involving the United Kingdom.

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LEGAL MATTERS

Cooley LLP, San Francisco, California, will pass upon the validity of the securities offered by this prospectus supplement and the accompanying prospectus. White & Case LLP, New York, New York is acting as counsel for the underwriters in connection with this offering.

EXPERTS

Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2024, and the effectiveness of our internal control over financial reporting as of December 31, 2024, as set forth in their reports (which contains an explanatory paragraph describing conditions that raise substantial doubt about the Company’s ability to continue as a going concern as described in Note 1 to the consolidated financial statements), which are incorporated by reference in this prospectus supplement and elsewhere in the registration statement. Our financial statements are incorporated by reference in reliance on Ernst & Young LLP’s reports, given on their authority as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

This prospectus supplement and the accompanying prospectus are part of a registration statement on Form S-3 we filed with the SEC under the Securities Act and do not contain all the information set forth or incorporated by reference in the registration statement. Whenever a reference is made in this prospectus supplement or the accompanying prospectus to any of our contracts, agreements or other documents, the reference may not be complete and you should refer to the exhibits that are a part of the registration statement or the exhibits to the reports or other documents incorporated by reference into this prospectus supplement and the accompanying prospectus for a copy of such contract, agreement or other document. Because we are subject to the information and reporting requirements of the Exchange Act, we file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the Internet at the SEC’s website at www.sec.gov. Copies of certain information filed by us with the SEC are also available on our website at www.sangamo.com. Our website is not a part of this prospectus supplement and is not incorporated by reference in this prospectus supplement.

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INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” information from other documents that we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus supplement and the accompanying prospectus. Information in this prospectus supplement supersedes information incorporated by reference that we filed with the SEC prior to the date of this prospectus supplement, while information that we file later with the SEC will automatically update and supersede the information in this prospectus supplement and the accompanying prospectus. We incorporate by reference the documents listed below and any future filings (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items unless such Form 8-K expressly provides to the contrary) we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this prospectus supplement and prior to the termination of the offering of the common stock covered by this prospectus supplement (Commission File No. 000-30171). Any statements in any such future filings will automatically be deemed to modify and supersede any information in any document we previously filed with the SEC that is incorporated or deemed to be incorporated herein by reference to the extent that statements in the later filed document modify or replace such earlier statements:

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our Annual Report on Form 10-K for the year ended December 31, 2024, which was filed with the SEC on March 17, 2025;

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our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2025, which was filed with the SEC on May 12, 2025; June 30, 2025, which was filed with the SEC on August 7, 2025; and September 30, 2025, which was filed with the SEC on November 6, 2025;

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our Current Reports on Form 8-K, which were filed with the SEC on May 6, 2025; May 13, 2025; June 16, 2025; June 24, 2025; September 4, 2025; September 11, 2025; September 30, 2025; October 29, 2025; and February 3, 2026.

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the information specifically incorporated by reference into our Annual Report on Form 10-K for the year ended December 31, 2024 from our definitive proxy statement relating to our 2025 annual meeting of stockholders held on June 12, 2025, filed with the SEC on April 30, 2025; and

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the description of our common stock in our registration statement on Form 8-A, which was filed with the SEC on March 31, 2000, including all amendments and reports filed for the purpose of updating such description, including Exhibit 4.1 of our Annual Report on Form 10-K for the year ended December 31, 2024.

We will furnish without charge to each person, including any beneficial owner, to whom a prospectus is delivered, upon written or oral request, a copy of any or all of the documents incorporated by reference, including exhibits to these documents. Any such request may be made by writing or telephoning us at the following address or phone number:

Sangamo Therapeutics, Inc.

501 Canal Blvd.

Richmond, California 94804

(510) 970-6000

Attention: Investor Relations

S-40

Prospectus

$500,000,000

LOGO

Common Stock

Preferred Stock

Debt Securities

Warrants

From time to time, we may offer and sell up to a maximum aggregate offering price of $500,000,000 of any combination of the securities described in this prospectus, either individually or in combination with other securities. We may also offer common stock or preferred stock upon conversion of debt securities, common stock upon conversion of preferred stock, or common stock, preferred stock or debt securities upon the exercise of warrants.

Each time we sell securities pursuant to this prospectus, we will provide the specific terms of these offerings and securities in one or more supplements to this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as the documents incorporated by reference, before buying any of the securities being offered.

Our common stock is listed on The Nasdaq Capital Market under the trading symbol “SGMO.” On November 11, 2024, the last reported sale price of our common stock was $2.70 per share. The applicable prospectus supplement will contain information, where applicable, as to other listings, if any, on The Nasdaq Capital Market or other securities exchange of the securities covered by the applicable prospectus supplement.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and in any free writing prospectuses we have authorized for use in connection with a specific offering, and under similar headings in the documents that are incorporated by reference into this prospectus.

This prospectus may not be used to consummate a sale of securities unless accompanied by a prospectus supplement.

The securities may be sold directly to investors, through agents designated from time to time or to or through underwriters or dealers, on a continuous or delayed basis. For additional information on the methods of sale, you should refer to the section titled “Plan of Distribution” in this prospectus. If any agents, underwriters or dealers are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such agents, underwriters or dealers and any applicable fees, commissions, discounts and over-allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is November 19, 2024.

TABLE OF CONTENTS


ABOUT THIS PROSPECTUS			ii
PROSPECTUS SUMMARY			1
RISK FACTORS			5
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS			6
USE OF PROCEEDS			8
DESCRIPTION OF CAPITAL STOCK			9
DESCRIPTION OF DEBT SECURITIES			14
DESCRIPTION OF WARRANTS			21
LEGAL OWNERSHIP OF SECURITIES			23
PLAN OF DISTRIBUTION			27
LEGAL MATTERS			29
EXPERTS			29
WHERE YOU CAN FIND MORE INFORMATION			29
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE			30

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process. Under this shelf registration process, we may offer and sell shares of our common stock and preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or in combination with other securities, in one or more offerings up to a total aggregate offering price of $500,000,000. This prospectus provides you with a general description of the securities we may offer.

Each time we offer securities under this prospectus, we will provide a prospectus supplement that will contain more specific information about the terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change any of the information contained in this prospectus or in the documents that we have incorporated by reference into this prospectus. We urge you to read carefully this prospectus, any applicable prospectus supplement and any free writing prospectuses we have authorized for use in connection with a specific offering, together with the information incorporated herein by reference as described under the section titled “Incorporation of Certain Information by Reference,” before buying any of the securities being offered.

This prospectus may not be used to consummate a sale of securities unless it is accompanied by a prospectus supplement.

You should rely only on the information contained in, or incorporated by reference into, this prospectus and the applicable prospectus supplement, along with the information contained in any free writing prospectuses we have authorized for use in connection with a specific offering. We have not authorized anyone to provide you with different or additional information. This prospectus is an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so.

The information appearing in this prospectus, any applicable prospectus supplement and any related free writing prospectus is accurate only as of the date on the front of the document and any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus, the applicable prospectus supplement or any related free writing prospectus, or any sale of a security. Our business, financial condition, results of operations and prospects may have changed since those dates.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described under the section titled “Where You Can Find More Information.”

Unless the context indicates otherwise, as used in this prospectus, the terms “Sangamo,” “we,” “us” and “our” refer to Sangamo Therapeutics, Inc., a Delaware corporation, and its subsidiaries on a consolidated basis. BETTER THERAPEUTICS BY DESIGN is our registered trademark in the United States and the United Kingdom, and SANGAMO is our registered trademark in Australia, Canada, the European Union and the United Kingdom. SANGAMO THERAPEUTICS and SANGAMO THERAPEUTICS & Design are our registered trademarks in Australia, Canada, the European Union, Japan and the United Kingdom; they have been allowed, but are not yet registered, in the United States. Our trademarks UNIVERSAL GENE RECOGNITION, UNIVERSAL GENETOOLS and ZFP THERAPEUTIC are registered in Canada. All other trademarks or trade names referred to in this prospectus and any prospectus supplement are the property of their respective owners. We do not intend our use or display of other companies’ trademarks or trade names to imply a relationship with, or endorsement or sponsorship of us by, any other companies or products.

PROSPECTUS SUMMARY

This summary highlights selected information contained elsewhere in this prospectus or incorporated by reference in this prospectus, and does not contain all of the information that you need to consider in making your investment decision. You should carefully read the entire prospectus, the applicable prospectus supplement and any related free writing prospectus, including the risks of investing in our securities discussed under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus. You should also carefully read the information incorporated by reference into this prospectus, including our consolidated financial statements, and the exhibits to the registration statement of which this prospectus is a part.

Sangamo Therapeutics, Inc.

We are a genomic medicine company committed to translating ground-breaking science into medicines that transform the lives of patients and families afflicted with serious neurological diseases. We believe our zinc finger, or ZF, epigenetic regulators are ideally suited to potentially address devastating neurology disorders and our capsid engineering platform has demonstrated the ability to expand delivery beyond currently available intrathecal delivery capsids, including in the central nervous system, or CNS, in preclinical studies.

Our neurology preclinical development is focused on two innovative areas aligned with our strategic transformation: (i) development of epigenetic regulation therapies to treat serious neurological diseases and (ii) development of novel engineered adeno-associated virus, or AAV, capsids to deliver our therapies to the intended neurological targets. We also continue to advance development of novel engineered AAV capsids enhanced for delivery to neurological targets and have identified a proprietary engineered neurotropic AAV capsid variant that demonstrated an ability to cross the blood-brain barrier in nonhuman primates and mediated robust transduction, transgene expression and targeted epigenetic repression throughout the brain and spinal cord after intravenous administration.

We are a leader in the research and development of zinc finger proteins, or ZFPs, which are abundantly occurring human proteins that have evolved to regulate the genome through interactions with DNA and regulatory proteins. Our strategy is to translate our differentiated and versatile ZF technology platform to create product candidates with best- or first-in-class clinical potential. We believe that the versatility and flexibility of our technology platforms enable us to design therapeutic approaches to resolve the underlying genetic or cellular causes of disease, using whichever technology is best suited to deliver that treatment.

In addition to the ZF platform, we are developing integrases as a tool for targeted integration of therapeutic transgenes into the somatic human genome. The goal of this program is to develop a platform that allows for highly efficient gene integration without cutting the human genome or depending on any native cellular DNA repair machinery.

We were incorporated in June 1995 in the state of Delaware and in January 2017, we changed our name from “Sangamo BioSciences, Inc.” to “Sangamo Therapeutics, Inc.” Our principal executive offices are located at 501 Canal Blvd., Richmond, California 94804. Our telephone number is (510) 970-6000. Our website is www.sangamo.com. Information found on, or accessible through, our website is not a part of, and is not incorporated into, this prospectus, and you should not consider it part of this prospectus. Our website address is included in this prospectus as an inactive textual reference only.

Description of Securities

We may offer shares of our common stock and preferred stock, various series of debt securities and/or warrants to purchase any of such securities, up to a total aggregate offering price of $500,000,000, either individually or in

combination with other securities, from time to time under this prospectus, together with the applicable prospectus supplement and any related free writing prospectus, at prices and on terms to be determined by market conditions at the time of any offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

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designation or classification;

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aggregate principal amount or aggregate offering price;

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maturity date, if applicable;

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original issue discount, if any;

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rates and times of payment of interest or dividends, if any;

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redemption, conversion, exercise, exchange or sinking fund terms, if any;

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ranking;

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restrictive covenants, if any;

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voting or other rights, if any;

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conversion or exchange prices or rates, if any, and, if applicable, any provisions for changes to or adjustments in the conversion or exchange prices or rates and in the securities or other property receivable upon conversion or exchange; and

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material or special U.S. federal income tax considerations, if any.

The applicable prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change any of the information contained in this prospectus or in the documents we have incorporated by reference.

We may sell the securities directly to investors or to or through agents, underwriters or dealers. If we do offer securities to or through agents or underwriters, we will include in the applicable prospectus supplement:

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the names of those agents or underwriters;

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applicable fees, discounts and commissions to be paid to them;

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details regarding over-allotment or other options, if any; and

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the net proceeds to us.

Common Stock. We may issue shares of our common stock from time to time. The holders of common stock are entitled to one vote per share on all matters to be voted on by the stockholders. Subject to the preferences of any outstanding shares of preferred stock, the holders of common stock are entitled to receive ratably any dividends our board of directors declares out of funds legally available for the payment of dividends. If we are liquidated, dissolved or wound up, the holders of common stock are entitled to share pro rata all assets remaining after payment of liabilities and liquidation preferences of any outstanding shares of preferred stock. Holders of common stock have no preemptive rights or rights to convert their common stock into any other securities. There are no redemption or sinking fund provisions applicable to the common stock. In this prospectus, we have summarized certain general features of the common stock under the section titled “Description of Capital Stock—Common Stock.” We urge you, however, to read the applicable prospectus supplement (and any related free writing prospectus that we may authorize to be provided to you) related to any common stock being offered.

Preferred Stock. We may issue shares of our preferred stock from time to time, in one or more series. Under our restated certificate of incorporation, as amended, our board of directors has the authority to designate up to 5,000,000 shares of preferred stock in one or more series and determine or alter the designation, rights, preferences, privileges and restrictions granted to or imposed upon any series of preferred stock, any or all of which may be greater than the rights of the common stock. If we sell any new series of preferred stock under this prospectus and any applicable prospectus supplement, our board of directors will determine the rights, preferences and privileges of the preferred stock being offered, as well as the qualifications, limitations or restrictions thereof, including dividend rights, conversion rights, voting rights, preemptive rights, terms of redemption or repurchase, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of any series. Preferred stock may be convertible into our common stock or other securities of ours, or may be exchangeable for debt securities. Conversion may be mandatory or at the holder’s option and would be at prescribed conversion rates. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of the certificate of designation that describes the terms of the series of preferred stock being offered before the issuance of the related series of preferred stock. In this prospectus, we have summarized certain general features of the preferred stock under the section titled “Description of Capital Stock—Preferred Stock.” We urge you, however, to read the applicable prospectus supplement (and any related free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

Debt Securities. We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. Convertible or exchangeable debt securities will be convertible into or exchangeable for our common stock or our other securities. Conversion or exchange may be mandatory or optional (at our option or the holders’ option) and would be at prescribed conversion or exchange prices.

The debt securities will be issued under an indenture that we will enter into with a national banking association or other eligible party, as trustee. In this prospectus, we have summarized certain general features of the debt securities under the section titled “Description of Debt Securities.” We urge you, however, to read the applicable prospectus supplement (and any related free writing prospectus that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indenture and any supplemental indentures that contain the terms of the debt securities. We have filed the form of indenture as an exhibit to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

Warrants. We may issue warrants for the purchase of common stock, preferred stock and/or debt securities in one or more series. We may issue warrants independently or in combination with common stock, preferred stock and/or debt securities offered by any prospectus supplement. In this prospectus, we have summarized certain general features of the warrants under the section titled “Description of Warrants.” We urge you, however, to read the applicable prospectus supplement (and any related free writing prospectus that we may authorize to be provided to you) related to the particular series of warrants being offered, as well as the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that contain the terms of the warrants. We have filed the forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants that we may offer as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, and any supplemental agreements, before the issuance of such warrants.

Warrants may be issued under a warrant agreement that we enter into with a warrant agent. We will indicate the name and address of the warrant agent, if any, in the applicable prospectus supplement relating to a particular series of warrants.

Use of Proceeds

Except as described in any applicable prospectus supplement or in any free writing prospectuses we have authorized for use in connection with a specific offering, we intend to use the net proceeds from the sale of the securities under this prospectus for working capital and other general corporate purposes, which may include funding research and development, general and administrative activities and capital expenditures. See the section titled “Use of Proceeds” on page 7 of this prospectus.

Nasdaq Capital Market Listing

Our common stock is listed on The Nasdaq Capital Market under the symbol “SGMO.”

RISK FACTORS

Investing in our securities involves a high degree of risk. Before deciding whether to invest in our securities, you should consider carefully the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and described under the section titled “Risk Factors” contained in our most recent annual report on Form 10-K and in our most recent quarterly report on Form 10-Q, as well as any amendments thereto reflected in subsequent filings with the SEC, which are incorporated by reference into this prospectus in their entirety, together with other information in this prospectus, the documents incorporated by reference herein and any free writing prospectus that we may authorize for use in connection with a specific offering. The risks described in these documents are not the only ones we face, but those that we consider to be material. There may be other unknown or unpredictable economic, business, competitive, regulatory or other factors that could have material adverse effects on our future results. Past financial performance may not be a reliable indicator of future performance, and historical trends should not be used to anticipate results or trends in future periods. If any of these risks actually occurs, our business, financial condition, results of operations or cash flow could be seriously harmed. This could cause the trading price of our securities to decline, resulting in a loss of all or part of your investment. Please also carefully read the section titled “Special Note Regarding Forward-Looking Statements.”

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and any accompanying prospectus supplement, as well as the documents incorporated by reference in this prospectus or any accompanying prospectus supplement, contain “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. These statements relate to our future events, including our anticipated operations, research, development, manufacturing and commercialization activities, clinical trials, operating results and financial condition. These forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performances or achievements expressed or implied by the forward-looking statements. Forward-looking statements may include, but are not limited to, statements about:

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our estimates regarding the sufficiency of our cash resources and our expenses, capital requirements and need for substantial additional financing, and our ability to obtain additional financing, including the impact of business development and clinical advancements on our cash runway;

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our ability to continue to operate as a going concern;

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our projected operating and financial performance;

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our plans for advancing our development programs and the plans of our collaboration partners for advancing our partnered programs, and the expected charges and cost savings associated with our restructurings and facility closures;

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anticipated research and development of product candidates and potential commercialization of any resulting approved products;

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the initiation, scope, rate of progress, enrollment, dosing, anticipated results and timing of our preclinical studies and clinical trials and those of our collaborators or strategic partners;

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the therapeutic and commercial potential of our product candidates, including the durability of therapeutic effects;

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the therapeutic and commercial potential of technologies used by us in our product candidates, including our gene therapy and gene editing technologies, ZF technology platform and ZF transcriptional regulators, which include ZF repressors;

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our ability to realize the expected benefits of the global epigenetic regulation and capsid delivery license agreement with Genentech, a member of the Roche group, the potential for Genentech to complete clinical development, regulatory interactions, manufacturing and global commercialization of any resulting products, and the potential for us to receive milestone payments and royalties from Genentech;

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anticipated investigational new drug and clinical trial application submissions and potential acceptance thereof by the U.S. Food and Drug Administration, or FDA, and regulatory authorities outside the United States;

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the potential for isaralgagene civaparvovec to qualify for the FDA’s Accelerated Approval program, including the adequacy of data generated in the Phase 1/2 STAAR study to support any such approval; expectations concerning the availability of additional data to support a potential Biologics License Application submission for isaralgagene civaparvovec and the timing of such submission;

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our ability to establish and maintain collaborations and strategic partnerships and realize the expected benefits of such arrangements, including our ability to find a collaboration partner for our Fabry disease program and to engage in additional transactions with respect to our STAC-BBB capsid delivery program and epigenetic regulation capabilities, and Pfizer’s continued advancements of the giroctocogene fitelparvovec program, including the potential for Pfizer to complete clinical

development, regulatory interactions, manufacturing and global commercialization of any resulting products;

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anticipated revenues from existing and new collaborations and the timing thereof;

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our estimates regarding the impact of the macroeconomic environment on our business and operations and the business and operations of our collaborators, including preclinical studies, clinical trials and manufacturing, and our ability to manage such impacts;

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our research and development and other expenses;

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our ability to obtain adequate preclinical and clinical supplies of our product candidates from current and potential new suppliers and manufacturers;

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our ability to comply with, and the impact of, regulatory requirements, obligations and restrictions on our business and operations;

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competitive developments, including the impact on our competitive position of rival products and product candidates and our ability to meet such competition;

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our operational and legal risks;

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our plans, objectives, expectations and intentions and any other statements that are not historical facts; and

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our intended use of the net proceeds from offerings of our securities under this prospectus.

In some cases, you can identify forward-looking statements by use of future dates or by terms such as: “aim,” “anticipates,” “assume,” “believes,” “continues,” “could,” “estimates,” “expects,” “forecast,” “goal,” “guidance,” “intends,” “likely,” “may,” “objective,” “ongoing,” “plans,” “project,” “seeks,” “should,” “target,” “will” and similar expressions intended to identify forward-looking statements. These statements reflect our current views with respect to future events, are based on assumptions and are subject to risks and uncertainties. Given these assumptions, risks and uncertainties, you should not place undue reliance on these forward-looking statements. We cannot guarantee that any forward-looking statement will be realized. We discuss in greater detail, and incorporate by reference into this prospectus in their entirety, many of these risks and uncertainties under the heading “Risk Factors” contained in the applicable prospectus supplement, in any free writing prospectus we may authorize for use in connection with a specific offering, and in our most recent annual report on Form 10-K and in our most recent quarterly report on Form 10-Q, as well as any amendments thereto reflected in subsequent filings with the SEC. Also, these forward-looking statements represent our estimates and assumptions only as of the date of the document containing the applicable statement. Unless required by law, we undertake no obligation to update or revise any forward-looking statements to reflect new information or future events or developments. Thus, you should not assume that our silence over time means that actual events are bearing out as expressed or implied in such forward-looking statements. You should read this prospectus, the applicable prospectus supplement, together with the documents we have filed with the SEC that are incorporated by reference and any free writing prospectus we have authorized for use in connection with a specific offering completely and with the understanding that our actual future results may be materially different from what we expect. We qualify all of the forward-looking statements in the foregoing documents by these cautionary statements.

USE OF PROCEEDS

Except as described in any applicable prospectus supplement or in any free writing prospectuses we have authorized for use in connection with a specific offering, we intend to use the net proceeds from the sale of the securities under this prospectus for working capital and other general corporate purposes, which may include funding research and development, general and administrative activities and capital expenditures. We will set forth in the applicable prospectus supplement our intended use for the net proceeds received from the sale of any securities. Pending the use of the net proceeds, we intend to invest the net proceeds in short-term, investment-grade, interest-bearing securities.

DESCRIPTION OF CAPITAL STOCK

As of the date of this prospectus, our restated certificate of incorporation, as amended, or the Restated Certificate, authorizes us to issue 960,000,000 shares of common stock, par value $0.01 per share, and 5,000,000 shares of preferred stock, par value $0.01 per share.

The following summary description of our capital stock is based on the provisions of the Restated Certificate, our fifth amended and restated bylaws, or the Bylaws, and the applicable provisions of the General Corporation Law of the State of Delaware, or DGCL. This information may not be complete in all respects and is qualified entirely by reference to the provisions of the Restated Certificate, the Bylaws and the DGCL. For information on how to obtain copies of the Restated Certificate and our Bylaws, which are exhibits to the registration statement of which this prospectus forms a part, see the section titled “Where You Can Find More Information.”

Common Stock

The holders of common stock are entitled to one vote per share on all matters to be voted on by the stockholders. Stockholders have no cumulative voting rights. Subject to the preferences of any outstanding shares of preferred stock, the holders of common stock are entitled to receive ratably any dividends our board of directors declares out of funds legally available for the payment of dividends. If we are liquidated, dissolved or wound up, the holders of common stock are entitled to share pro rata all assets remaining after payment of liabilities and liquidation preferences of any outstanding shares of preferred stock. Holders of common stock have no preemptive rights or rights to convert their common stock into any other securities. There are no redemption or sinking fund provisions applicable to the common stock. When we issue shares of common stock under this prospectus, the shares will be fully paid and nonassessable.

Additional shares of authorized common stock may be issued, as authorized by our board of directors from time to time, without stockholder approval, except as may be required by applicable stock exchange requirements.

Preferred Stock

Pursuant to the Restated Certificate, our board of directors has the authority, without further action by the stockholders, to issue shares of preferred stock in one or more series. Our board of directors also has the authority to determine or alter the designation, rights, preferences, privileges and restrictions granted to or imposed upon any unissued series of preferred stock, any or all of which may be greater than the rights of the common stock. Our board of directors, without stockholder approval, may issue preferred stock with voting, conversion or other rights that are superior to the voting and other rights of the holders of common stock. The issuance of preferred stock may have the effect of delaying, deferring or preventing a change of control of Sangamo without further action by the stockholders, and may have the effect of delaying or preventing changes in management of Sangamo. In addition, the issuance of preferred stock may have the effect of decreasing the market price of the common stock and may adversely affect the voting power of holders of common stock and reduce the likelihood that common stockholders will receive dividend payments and payments upon liquidation.

Our board of directors will determine the rights, preferences, privileges and restrictions of the preferred stock of each series that we sell under this prospectus and applicable prospectus supplements in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of the certificate of designation that describes the terms of the series of preferred stock that we are offering before the issuance of the related series of preferred stock. This description will include:

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the title and stated value;

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the number of shares we are offering;

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the liquidation preference per share;

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the purchase price per share;

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the dividend rate per share, dividend period and payment dates and method of calculation for dividends;

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whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;

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our right, if any, to defer payment of dividends and the maximum length of any such deferral period;

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the procedures for any auction and remarketing, if any;

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the provisions for a sinking fund, if any;

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the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;

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any listing of the preferred stock on any securities exchange or market;

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whether the preferred stock will be convertible into our common stock or other securities of ours, including warrants, and, if applicable, the conversion period, the conversion price, or how it will be calculated, and under what circumstances it may be adjusted;

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whether the preferred stock will be exchangeable for debt securities, and, if applicable, the exchange period, the exchange price, or how it will be calculated, and under what circumstances it may be adjusted;

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voting rights, if any, of the preferred stock;

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preemption rights, if any;

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restrictions on transfer, sale or other assignment, if any;

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a discussion of any material or special United States federal income tax considerations applicable to the preferred stock;

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the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;

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any limitations on issuances of any class or series of preferred stock ranking senior to or on a parity with the series of preferred stock being issued as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and

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any other specific terms, rights, preferences, privileges, qualifications or restrictions of the preferred stock.

When we issue shares of preferred stock under this prospectus, the shares will be fully paid and nonassessable.

Unless we specify otherwise in the applicable prospectus supplement, the preferred stock will rank, with respect to dividends and upon our liquidation, dissolution or winding up:

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senior to all classes or series of our common stock and to all of our equity securities ranking junior to the preferred stock;

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on a parity with all of our equity securities the terms of which specifically provide that the equity securities rank on a parity with the preferred stock; and

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junior to all of our equity securities the terms of which specifically provide that the equity securities rank senior to the preferred stock.

The term “equity securities” does not include convertible debt securities.

The DGCL provides that the holders of preferred stock will have the right to vote separately as a class on any proposal involving fundamental changes in the rights of holders of that preferred stock. This right is in addition to any voting rights that may be provided for in the applicable certificate of designation.

Antitakeover Effects of Provisions of our Restated Certificate, Bylaws and Delaware Law

Our Restated Certificate and Bylaws

As noted above, our board of directors, without stockholder approval, has the authority under our Restated Certificate to issue preferred stock with rights superior to the rights of the holders of common stock. As a result, the issuance of preferred stock may have the effect of delaying, deferring or preventing a change of control of Sangamo without further action by the stockholders and may adversely affect the voting and other rights of the holders of common stock. Our Restated Certificate also requires that any action required or permitted to be taken by our stockholders must be effected at a duly called annual or special meeting of the stockholders and may not be effected by a consent in writing. Further, our Restated Certificate provides that a special meeting of the stockholders may be called only by our board of directors.

In addition to the provisions noted above, our Bylaws further establish advance notice procedures with respect to stockholder proposals and nomination of candidates for election as directors other than nominations made by or at the direction of the board of directors or a committee of the board of directors. Although our stockholders may amend, repeal or alter our Bylaws by a vote of at least a majority of the outstanding shares of our capital stock entitled to vote, our board of directors may also unilaterally adopt, repeal, alter, amend and rescind our Bylaws by a vote of at least a majority of the board of directors. Finally, our board of directors has the ability to elect a director to fill a vacancy created by the expansion of the board of directors or due to the resignation or departure of an existing board member.

These provisions may have the effect of delaying, deferring or preventing a change in control and may also delay or prevent changes in management of Sangamo, which could have an adverse effect on the market price of our stock. These and other provisions are intended to enhance the likelihood of continued stability in the composition of our board of directors and to discourage certain types of transactions that may involve an actual or threatened change of control. However, such provisions could have the effect of discouraging others from making tender offers for our shares and, as a consequence, such provisions also may inhibit fluctuations in the market price of our shares that could result from actual or rumored takeover attempts.

Section 203 of the General Corporation Law of the State of Delaware

We are subject to Section 203 of the DGCL, which regulates acquisitions of some Delaware corporations. In general, Section 203 prohibits, with some exceptions, a publicly held Delaware corporation such as us from engaging in a “business combination” with an “interested stockholder” for a period of three years following the time that the stockholder became an interested stockholder, unless:

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prior to the time the stockholder became an interested stockholder, the board of directors of the corporation approved either the business combination or the transaction which resulted in the stockholder becoming an interested stockholder;

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upon consummation of the transaction which resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding for purposes of determining the number of shares outstanding (but not the outstanding voting stock owned by the interested stockholder) those shares owned by (a) persons who are directors and also officers and (b) employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or

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at or subsequent to the time the stockholder became an interested stockholder, the business combination is approved by the board of directors and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least 66 2/3% of the outstanding voting stock which is not owned by the interested stockholder.

Section 203 of the DGCL generally defines a “business combination” to include any of the following:

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any merger or consolidation involving the corporation and the interested stockholder;

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any sale, lease, exchange, mortgage, transfer, pledge or other disposition involving the interested stockholder (in one transaction or a series of transactions) of assets of the corporation having an aggregate market value equal to 10% or more of the aggregate market value of either all of the assets of the corporation or its outstanding stock;

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subject to exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder;

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subject to exceptions, any transaction involving the corporation that has the effect, directly or indirectly, of increasing the proportionate share of the stock or any class or series of the corporation beneficially owned by the interested stockholder; and

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the receipt by the interested stockholder of the benefit, directly or indirectly (except proportionately as a stockholder of such corporation), of any loans, advances, guarantees, pledges or other financial benefits, other than certain benefits set forth in Section 203, provided by or through the corporation.

In general, Section 203 defines an “interested stockholder” as an entity or person who, together with the person’s affiliates and associates, beneficially owns, or within three years prior to the time of determination of interested stockholder status did own, 15% or more of the outstanding voting stock of the corporation.

Section 203 of the DGCL could depress our stock price and delay, discourage or prohibit transactions not approved in advance by our board of directors, such as takeover attempts that might otherwise involve the payment to our stockholders of a premium over the market price of our common stock.

Forum Selection Bylaw

Unless we consent in writing to the selection of an alternative forum, the sole and exclusive forum for (1) any derivative action or proceeding brought on behalf of Sangamo, (2) any action asserting a claim of breach of a fiduciary duty owed by any director, officer or other employee or stockholder of Sangamo to Sangamo or to our stockholders, (3) any action asserting a claim arising pursuant to any provision of the DGCL, the Restated Certificate, the Bylaws or as to which the DGCL confers jurisdiction on the Court of Chancery of the State of Delaware, or (4) any action asserting a claim governed by the internal affairs doctrine shall, to the fullest extent permitted by law, be the Court of Chancery of the State of Delaware or, if such court does not have subject matter jurisdiction thereof, the federal district court of the State of Delaware. However, this provision does not apply to actions arising under the Securities Act or the Exchange Act or any claim for which the federal courts have exclusive jurisdiction.

Unless we consent in writing to the selection of an alternative forum, to the fullest extent permitted by law, the federal district courts of the United States of America shall be the exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act.

Any person or entity purchasing or otherwise acquiring any interest in shares of capital stock of Sangamo is deemed to have notice of and consented to the forum selection provisions of the Bylaws.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare, Inc. Its address is 250 Royall Street, Canton, MA 02021 and its telephone number is (781) 575-3951. The transfer agent for any series of preferred stock that we may offer under this prospectus will be named and described in the applicable prospectus supplement for that series.

Listing on The Nasdaq Capital Market

Our common stock is listed on The Nasdaq Capital Market under the symbol “SGMO.”

DESCRIPTION OF DEBT SECURITIES

We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any debt securities that we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indenture, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

We will issue the debt securities under the indenture that we will enter into with the trustee named in the indenture. The indenture will be qualified under the Trust Indenture Act of 1939, as amended, or the Trust Indenture Act. We have filed the form of indenture as an exhibit to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

The following summary of material provisions of the debt securities and the indenture is subject to, and qualified in its entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus, as well as the complete indenture that contains the terms of the debt securities.

General

The indenture does not limit the amount of debt securities that we may issue. It provides that we may issue debt securities up to the principal amount that we may authorize and may be in any currency or currency unit that we may designate. Except for the limitations on consolidation, merger and sale of all or substantially all of our assets contained in the indenture, the terms of the indenture do not contain any covenants or other provisions designed to give holders of any debt securities protection against changes in our operations, financial condition or transactions involving us.

We may issue the debt securities issued under the indenture as “discount securities,” which means they may be sold at a discount below their stated principal amount. These debt securities, as well as other debt securities that are not issued at a discount, may be issued with “original issue discount,” or OID, for U.S. federal income tax purposes because of interest payment and other characteristics or terms of the debt securities. Material U.S. federal income tax considerations applicable to debt securities issued with OID will be described in more detail in any applicable prospectus supplement.

We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:

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the title of the series of debt securities;

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any limit upon the aggregate principal amount that may be issued;

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the maturity date or dates;

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the form of the debt securities of the series;

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the applicability of any guarantees;

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whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

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whether the debt securities rank as senior debt, senior subordinated debt, subordinated debt or any combination thereof, and the terms of any subordination;

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if the price (expressed as a percentage of the aggregate principal amount thereof) at which such debt securities will be issued is a price other than the principal amount thereof, the portion of the principal amount thereof payable upon declaration of acceleration of the maturity thereof, or if applicable, the portion of the principal amount of such debt securities that is convertible into another security or the method by which any such portion shall be determined;

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the interest rate or rates, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

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our right, if any, to defer payment of interest and the maximum length of any such deferral period;

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if applicable, the date or dates after which, or the period or periods during which, and the price or prices at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;

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the date or dates, if any, on which, and the price or prices at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder’s option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

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the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;

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any and all terms, if applicable, relating to any auction or remarketing of the debt securities of that series and any security for our obligations with respect to such debt securities and any other terms which may be advisable in connection with the marketing of debt securities of that series;

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whether the debt securities of the series shall be issued in whole or in part in the form of a global security or securities; the terms and conditions, if any, upon which such global security or securities may be exchanged in whole or in part for other individual securities; and the depositary for such global security or securities;

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if applicable, the provisions relating to conversion or exchange of any debt securities of the series and the terms and conditions upon which such debt securities will be so convertible or exchangeable, including the conversion or exchange price, as applicable, or how it will be calculated and may be adjusted, any mandatory or optional (at our option or the holders’ option) conversion or exchange features, the applicable conversion or exchange period and the manner of settlement for any conversion or exchange;

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if other than the full principal amount thereof, the portion of the principal amount of debt securities of the series which shall be payable upon declaration of acceleration of the maturity thereof;

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additions to or changes in the covenants applicable to the particular debt securities being issued, including, among others, the consolidation, merger or sale covenant;

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additions to or changes in the events of default with respect to the securities and any change in the right of the trustee or the holders to declare the principal, premium, if any, and interest, if any, with respect to such securities to be due and payable;

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additions to or changes in or deletions of the provisions relating to covenant defeasance and legal defeasance;

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additions to or changes in the provisions relating to satisfaction and discharge of the indenture;

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additions to or changes in the provisions relating to the modification of the indenture both with and without the consent of holders of debt securities issued under the indenture;

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the currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars;

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whether interest will be payable in cash or additional debt securities at our or the holders’ option and the terms and conditions upon which the election may be made;

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the terms and conditions, if any, upon which we will pay amounts in addition to the stated interest, premium, if any and principal amounts of the debt securities of the series to any holder that is not a “United States person” for federal tax purposes;

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any restrictions on transfer, sale or assignment of the debt securities of the series; and

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any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, any other additions or changes in the provisions of the indenture, and any terms that may be required by us or advisable under applicable laws or regulations.

Conversion or Exchange Rights

We will set forth in the applicable prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to settlement upon conversion or exchange and whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.

Consolidation, Merger or Sale

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indenture will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of our assets as an entirety or substantially as an entirety. However, any successor to or acquirer of such assets (other than a subsidiary of ours) must assume all of our obligations under the indenture or the debt securities, as appropriate.

Events of Default under the Indenture

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indenture with respect to any series of debt securities that we may issue:

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if we fail to pay any installment of interest on any series of debt securities, as and when the same shall become due and payable, and such default continues for a period of 90 days; provided, however, that a valid extension of an interest payment period by us in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of interest for this purpose;

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if we fail to pay the principal of, or premium, if any, on any series of debt securities as and when the same shall become due and payable whether at maturity, upon redemption, by declaration or otherwise, or in any payment required by any sinking or analogous fund established with respect to such series; provided, however, that a valid extension of the maturity of such debt securities in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of principal or premium, if any;

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if we fail to observe or perform any other covenant or agreement contained in the debt securities or the indenture, other than a covenant specifically relating to another series of debt securities, and our failure continues for 90 days after we receive written notice of such failure, requiring the same to be remedied and stating that such is a notice of default thereunder, from the trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series; and

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if specified events of bankruptcy, insolvency or reorganization occur.

If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the trustee or the holders of at least 25% in aggregate principal

amount of the outstanding debt securities of that series, by notice to us in writing, and to the trustee if notice is given by such holders, may declare the unpaid principal of, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the principal amount of and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the trustee or any holder.

The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.

Subject to the terms of the indenture, if an event of default under an indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to the debt securities of that series, provided that:

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the direction so given by the holder is not in conflict with any law or the applicable indenture; and

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subject to its duties under the Trust Indenture Act, the trustee need not take any action that might involve it in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.

A holder of the debt securities of any series will have the right to institute a proceeding under the indenture or to appoint a receiver or trustee, or to seek other remedies only if:

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the holder has given written notice to the trustee of a continuing event of default with respect to that series;

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the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made written request, such holders have offered to the trustee indemnity satisfactory to it against the costs, expenses and liabilities to be incurred by the trustee in compliance with the request; and

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the trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series other conflicting directions within 90 days after the notice, request and offer.

These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities.

We will periodically file statements with the trustee regarding our compliance with specified covenants in the indenture.

Modification of Indenture; Waiver

We and the trustee may change an indenture without the consent of any holders with respect to specific matters:

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to cure any ambiguity, defect or inconsistency in the indenture or in the debt securities of any series;

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to comply with the provisions described under the section titled “—Consolidation, Merger or Sale;”

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to provide for uncertificated debt securities in addition to or in place of certificated debt securities;

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to add to our covenants, restrictions, conditions or provisions such new covenants, restrictions, conditions or provisions for the benefit of the holders of all or any series of debt securities, to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default or to surrender any right or power conferred upon us in the indenture;

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to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms, or purposes of issue, authentication and delivery of debt securities, as set forth in the indenture;

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to make any change that does not adversely affect the interests of any holder of debt securities of any series in any material respect;

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to provide for the issuance of and establish the form and terms and conditions of the debt securities of any series as provided under the section titled “—General” to establish the form of any certifications required to be furnished pursuant to the terms of the indenture or any series of debt securities, or to add to the rights of the holders of any series of debt securities;

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to evidence and provide for the acceptance of appointment under any indenture by a successor trustee; or

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to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust Indenture Act.

In addition, under the indenture, the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, we and the trustee may make the following changes only with the consent of each holder of any outstanding debt securities affected:

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extending the fixed maturity of any debt securities of any series;

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reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any premium payable upon the redemption of any series of any debt securities; or

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reducing the percentage of debt securities, the holders of which are required to consent to any amendment, supplement, modification or waiver.

Discharge

Each indenture provides that we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:

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provide for payment;

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replace stolen, lost or mutilated debt securities of the series;

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pay principal of and premium and interest on any debt securities of the series;

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maintain paying agencies;

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hold monies for payment in trust;

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recover excess money held by the trustee;

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compensate and indemnify the trustee; and

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appoint any successor trustee.

In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, any premium, if any, and interest on, the debt securities of the series on the dates payments are due.

Form, Exchange and Transfer

We will issue the debt securities of each series only in fully registered form without coupons and, unless we provide otherwise in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indenture provides that we may issue debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company, or DTC, or another depositary named by us and identified in the applicable prospectus supplement with respect to that series. To the extent the debt securities of a series are issued in global form and as book-entry, a description of terms relating to any book-entry securities will be set forth in the applicable prospectus supplement.

At the option of the holder, subject to the terms of the indenture and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subject to the terms of the indenture and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will impose no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

If we elect to redeem the debt securities of any series, we will not be required to:

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issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or

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register the transfer of or exchange any debt securities so selected for redemption, in whole or in part, except the unredeemed portion of any debt securities we are redeeming in part.

Information Concerning the Trustee

The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the trustee is under no obligation to exercise any of the powers given it by the indenture at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

Payment and Paying Agents

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

Governing Law

The indenture and the debt securities will be governed by and construed in accordance with the internal laws of the State of New York, except to the extent that the Trust Indenture Act is applicable.

DESCRIPTION OF WARRANTS

The following description, together with the additional information we may include in any applicable prospectus supplement and free writing prospectus, summarizes the material terms and provisions of the warrants that we may offer under this prospectus, which may consist of warrants to purchase common stock, preferred stock or debt securities and may be issued in one or more series. Warrants may be offered independently or in combination with common stock, preferred stock or debt securities offered by any prospectus supplement. While the terms we have summarized below will apply generally to any warrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. The following description of warrants will apply to the warrants offered by this prospectus unless we provide otherwise in the applicable prospectus supplement. The applicable prospectus supplement for a particular series of warrants may specify different or additional terms.

We have filed forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants that may be offered as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, and any supplemental agreements, before the issuance of such warrants. The following summaries of material terms and provisions of the warrants are subject to, and qualified in their entirety by reference to, all the provisions of the form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements applicable to a particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplement related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectus, and the complete form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements, that contain the terms of the warrants.

General

We will describe in the applicable prospectus supplement the terms of the series of warrants being offered, including:

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the offering price and aggregate number of warrants offered;

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the currency for which the warrants may be purchased;

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if applicable, the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;

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in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at, and currency in which, this principal amount of debt securities may be purchased upon such exercise;

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in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or preferred stock, as the case may be, purchasable upon the exercise of one warrant and the price at which these shares may be purchased upon such exercise;

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the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreements and the warrants;

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the terms of any rights to redeem or call the warrants;

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any provisions for changes to or adjustments in the exercise price or number of securities issuable upon exercise of the warrants;

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the dates on which the right to exercise the warrants will commence and expire;

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the manner in which the warrant agreements and warrants may be modified;

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a discussion of material or special U.S. federal income tax considerations, if any, of holding or exercising the warrants;

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the terms of the securities issuable upon exercise of the warrants; and

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any other specific terms, preferences, rights or limitations of or restrictions on the warrants.

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:

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in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium, if any, or interest on, the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture; or

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in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any.

Exercise of Warrants

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. The warrants may be exercised as set forth in the prospectus supplement relating to the warrants offered. Unless we otherwise specify in the applicable prospectus supplement, warrants may be exercised at any time up to the close of business on the expiration date set forth in the prospectus supplement relating to the warrants offered thereby. After the close of business on the expiration date, unexercised warrants will become void.

Upon receipt of payment and the warrant or warrant certificate, as applicable, properly completed and duly executed at the corporate trust office of the warrant agent, if any, or any other office, including ours, indicated in the prospectus supplement, we will, as soon as practicable, issue and deliver the securities purchasable upon such exercise. If less than all of the warrants (or the warrants represented by such warrant certificate) are exercised, a new warrant or a new warrant certificate, as applicable, will be issued for the remaining warrants.

Governing Law

Unless we provide otherwise in the applicable prospectus supplement, the warrants and any warrant agreements will be governed by and construed in accordance with the internal laws of the State of New York.

Enforceability of Rights by Holders of Warrants

Each warrant agent, if any, will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

LEGAL OWNERSHIP OF SECURITIES

We may issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee, depositary or warrant agent maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

Book-Entry Holders

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Securities issued in global form will be registered in the name of the depositary or its participants. Consequently, for securities issued in global form, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a book-entry security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not holders, of the securities.

Street Name Holders

We may terminate a global security or issue securities in non-global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

Legal Holders

Our obligations, as well as the obligations of any applicable trustee and of any third parties employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice even if that holder is required, under agreements with depositary participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of the indenture or for other purposes. In such an event, we would seek approval only from the holders, and not the indirect holders, of the securities. Whether and how the holders contact the indirect holders is up to the holders.

Special Considerations for Indirect Holders

If you hold securities through a bank, broker or other financial institution, either in book-entry form or in street name, you should check with your own institution to find out:

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the performance of third-party service providers;

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how it handles securities payments and notices;

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whether it imposes fees or charges;

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how it would handle a request for the holders’ consent, if ever required;

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whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if that is permitted in the future;

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how it would exercise rights under the securities if there were a default or other event triggering the need for holders to act to protect their interests; and

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if the securities are in book-entry form, how the depositary’s rules and procedures will affect these matters.

Global Securities

A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, DTC will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations under the section titled “—Special Situations When a Global Security Will Be Terminated” in this prospectus. As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued in global form only, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

Special Considerations for Global Securities

The rights of an indirect holder relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only in the form of a global security, an investor should be aware of the following:

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an investor cannot cause the securities to be registered in his or her name, and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;

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an investor will be an indirect holder and must look to his or her own bank or broker for payments on the securities and protection of his or her legal rights relating to the securities, as we describe above;

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an investor may not be able to sell interests in the securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;

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an investor may not be able to pledge his or her interest in a global security in circumstances where certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

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the depositary’s policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to an investor’s interest in a global security;

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we and any applicable trustee have no responsibility for any aspect of the depositary’s actions or for its records of ownership interests in a global security, nor do we or any applicable trustee supervise the depositary in any way;

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the depositary may, and we understand that DTC will, require that those who purchase and sell interests in a global security within its book-entry system use immediately available funds, and your broker or bank may require you to do so as well; and

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financial institutions that participate in the depositary’s book-entry system, and through which an investor holds its interest in a global security, may also have their own policies affecting payments, notices and other matters relating to the securities.

There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

Special Situations When a Global Security Will Be Terminated

In a few special situations described below, the global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own name, so that they will be direct holders. We have described the rights of holders and street name investors above.

Unless we provide otherwise in the applicable prospectus supplement, the global security will terminate when the following special situations occur:

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if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for that global security and we do not appoint another institution to act as depositary within 90 days;

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if we notify any applicable trustee that we wish to terminate that global security; or

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if an event of default has occurred with regard to securities represented by that global security and has not been cured or waived.

The applicable prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the applicable prospectus supplement. When a global security terminates, the depositary, and not we or any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

PLAN OF DISTRIBUTION

We may sell the securities covered hereby from time to time pursuant to underwritten public offerings, “at-the-market” offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through one or more underwriters or dealers (acting as principal or agent), through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:

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at a fixed price or prices, which may be changed;

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at market prices prevailing at the time of sale;

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at prices related to such prevailing market prices; or

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at negotiated prices.

A prospectus supplement or supplements (and any related free writing prospectus that we may authorize to be provided to you) will describe the terms of the offering of the securities, including, to the extent applicable:

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the name or names of the underwriters, dealers or agents, if any;

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the purchase price of the securities or other consideration therefor, and the proceeds, if any, we will receive from the sale;

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any over-allotment or other options under which underwriters may purchase additional securities from us;

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any agency fees or underwriting discounts and other items constituting agents’ or underwriters’ compensation;

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any public offering price;

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any discounts or concessions allowed or reallowed or paid to dealers; and

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any securities exchange or market on which the securities may be listed.

Only underwriters named in the prospectus supplement will be underwriters of the securities offered by the prospectus supplement. Dealers and agents participating in the distribution of the securities may be deemed to be underwriters, and compensation received by them on resale of the securities may be deemed to be underwriting discounts. If such dealers or agents were deemed to be underwriters, they may be subject to statutory liabilities under the Securities Act.

If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement, other than securities covered by any over-allotment option. If a dealer is used in the sale of securities, we, a selling stockholder, or an underwriter will sell the securities to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale. To the extent required, we will set forth in the prospectus supplement the name of the dealer and the terms of the transaction. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time.

We may use underwriters, dealers or agents with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, dealer or agent, the nature of any such relationship.

We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will describe any commissions payable to the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, the agent will act on a best-efforts basis for the period of its appointment.

We may provide agents, underwriters and dealers with indemnification against civil liabilities, including liabilities under the Securities Act, or contribution with respect to payments that the agents, underwriters or dealers may make with respect to these liabilities. Agents, underwriters and dealers, or their affiliates, may engage in transactions with, or perform services for, us in the ordinary course of business.

All securities we may offer, other than common stock, will be new issues of securities with no established trading market. Any agents or underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.

Any underwriter may engage in over-allotment, stabilizing transactions, short-covering transactions and penalty bids in accordance with Regulation M under the Exchange Act. Over-allotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum price. Syndicate-covering or other short-covering transactions involve purchases of the securities, either through exercise of the over-allotment option or in the open market after the distribution is completed, to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a stabilizing or covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time.

Any agents or underwriters that are qualified market makers on The Nasdaq Capital Market may engage in passive market making transactions in the common stock on The Nasdaq Capital Market in accordance with Regulation M under the Exchange Act, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the common stock. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

In compliance with guidelines of the Financial Industry Regulatory Authority, or FINRA, the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate amount of the securities offered pursuant to this prospectus and the applicable prospectus supplement.

LEGAL MATTERS

Unless otherwise indicated in the applicable prospectus supplement, the validity of the securities offered by this prospectus, and any supplement thereto, will be passed upon for us by Cooley LLP, San Francisco, California.

EXPERTS

Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2023, and the effectiveness of our internal control over financial reporting as of December 31, 2023, as set forth in their reports (which contain an explanatory paragraph describing conditions that raise substantial doubt about the Company’s ability to continue as a going concern as described in Note 1 to the consolidated financial statements), which are incorporated by reference in this prospectus and elsewhere in the registration statement. Our financial statements are incorporated by reference in reliance on Ernst & Young LLP’s reports, given on their authority as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

This prospectus is part of the registration statement on Form S-3 we filed with the SEC under the Securities Act and does not contain all the information set forth or incorporated by reference in the registration statement. Whenever a reference is made in this prospectus to any of our contracts, agreements or other documents, the reference may not be complete and you should refer to the exhibits that are a part of the registration statement or the exhibits to the reports or other documents incorporated by reference into this prospectus for a copy of such contract, agreement or other document. Because we are subject to the information and reporting requirements of the Exchange Act, we file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the Internet at the SEC’s website at http://www.sec.gov.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” information from other documents that we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus. Information in this prospectus supersedes information incorporated by reference that we filed with the SEC prior to the date of this prospectus, while information that we file later with the SEC will automatically update and supersede the information in this prospectus. We incorporate by reference the documents listed below and any future filings (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items unless such Form 8-K expressly provides to the contrary) we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (i) after the date of the filing of the registration statement of which this prospectus is a part and prior to effectiveness of the registration statement and (ii) after the effectiveness of the registration statement of which this prospectus is a part but prior to the termination of all offerings of securities covered by this prospectus (Commission File No. 000-30171). Any statements in any such future filings will automatically be deemed to modify and supersede any information in any document we previously filed with the SEC that is incorporated or deemed to be incorporated herein by reference to the extent that statements in the later filed document modify or replace such earlier statements:

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our annual report on Form 10-K for the year ended December 31, 2023, which was filed with the SEC on March 13, 2024;

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the information specifically incorporated by reference into our annual report on Form 10-K for the year ended December 31, 2023 from our definitive proxy statement on Schedule 14A, which was filed with the SEC on April 19, 2024;

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our quarterly reports on Form 10-Q for the quarters ended March 31, 2024, June 30, 2024 and September 30, 2024, which were filed with the SEC on May 9, 2024, August 6, 2024 and November 12, 2024, respectively;

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our current reports on Form 8-K (other than information furnished rather than filed), which were filed with the SEC on January 19, 2024, February 6, 2024, March 25, 2024, April 30, 2024, June 5, 2024 and July 24, 2024; and

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the description of our common stock in our registration statement on Form 8-A, which was filed with the SEC on March 31, 2000, including all amendments and reports filed for the purpose of updating such description, including Exhibit 4.1 of our annual report on Form 10-K for the year ended December 31, 2023.

Sangamo Therapeutics, Inc.

501 Canal Blvd.

Richmond, California 94804

(510) 970-6000

Attention: Investor Relations

LOGO

35,190,292 Shares of Common Stock

Pre-Funded Warrants to Purchase 17,787,033 Shares of Common Stock

Warrants to Purchase 52,977,325 Shares of Common Stock

PROSPECTUS SUPPLEMENT

Cantor

Wells Fargo Securities

February 3, 2026

SEC Form 424B5 filed by Sangamo Therapeutics Inc.