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Filed Pursuant to Rule 424(b)(5)
Registration No. 333-278015

PROSPECTUS SUPPLEMENT
(To Prospectus dated May 9, 2024)

Up to $200,000,000 of Common Stock

We have entered into a Controlled Equity OfferingSM Sales Agreement (the “Sales Agreement”) with Cantor Fitzgerald & Co. (“Cantor”), dated November 12, 2025, relating to shares of our common stock, $0.001 par value per share, offered by this prospectus supplement. In accordance with the terms of the Sales Agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $200,000,000 from time to time to or through Cantor, acting as principal and/or sales agent.

Sales of our common stock, if any, under this prospectus supplement may be made by any method permitted that is deemed an “at the market offering” as defined in Rule 415 under the Securities Act of 1933, as amended (the “Securities Act”). Subject to the terms of the Sales Agreement, Cantor is not required to sell any specific amount but will act as our sales agent and use commercially reasonable efforts to sell on our behalf the shares of common stock requested to be sold by us, consistent with its normal trading and sales practices, on mutually agreed terms between Cantor and us. There is no arrangement for funds to be received in escrow, trust or similar arrangement. Cantor will be entitled to compensation at a commission rate of up to 3.0% of the gross sales price per share of common stock sold under the Sales Agreement. In connection with the sale of shares of our common stock on our behalf, Cantor will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation of Cantor will be deemed to be underwriting commissions or discounts. We have also agreed to reimburse Cantor for certain expenses and provide indemnification and contribution to Cantor with respect to certain liabilities, including liabilities under the Securities Act and the Securities Exchange Act of 1934, as amended (the “Exchange Act”). See “Plan of Distribution” beginning on page S-9 regarding the compensation to be paid to Cantor.

As of November 12, 2025, our common stock was listed on the Nasdaq Capital Market under the symbol “LPTX.” Effective on or about November 13, 2025, our symbol is expected to change to “CYPH.” On November 11, 2025, the last reported sales price of our common stock on the Nasdaq Capital Market was $0.4375 per share.

We are a “smaller reporting company” as that term is defined in Item 10(f)(1) of Regulation S-K and, as such, we have elected to comply with certain reduced public company reporting requirements for this prospectus and future filings with the U.S. Securities and Exchange Commission (the “SEC”). See “Prospectus Supplement Summary — Implications of Being a Smaller Reporting Company”.

Investing in our securities involves a high degree of risk. See the section entitled “Risk Factors” commencing on page S-6 of this prospectus supplement, the accompanying base prospectus, and the risk factors that are incorporated by reference into this prospectus from our filings made with the SEC pursuant to the Exchange Act for a discussion of information that should be considered in connection with an investment in our securities.

Neither the SEC nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is November 12, 2025.

TABLE OF CONTENTS

Prospectus Supplement

	Page
ABOUT THIS PROSPECTUS SUPPLEMENT		S-1
PROSPECTUS SUPPLEMENT SUMMARY		S-2
RISK FACTORS		S-6
FORWARD-LOOKING STATEMENTS		S-8
USE OF PROCEEDS		S-9
PLAN OF DISTRIBUTION		S-9
LEGAL MATTERS		S-11
EXPERTS		S-11
INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE		S-11
WHERE YOU CAN FIND MORE INFORMATION		S-12

Prospectus

	ABOUT THIS PROSPECTUS					1
	LEAP THERAPEUTICS, INC					1
	SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS					2
	RISK FACTORS					3
	USE OF PROCEEDS					3
	DESCRIPTION OF CAPITAL STOCK					4
	DESCRIPTION OF WARRANTS					9
	DESCRIPTION OF DEBT SECURITIES					11
	DESCRIPTION OF RIGHTS					17
	DESCRIPTION OF UNITS					19
	PLAN OF DISTRIBUTION					20
	LEGAL MATTERS					22
	EXPERTS					22
	WHERE YOU CAN FIND MORE INFORMATION					22
	INFORMATION INCORPORATED BY REFERENCE					23
	DISCLOSURE OF COMMISSION’S POSITION ON INDEMNIFICATION FOR SECURITIES ACT LIABILITY					24

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ABOUT THIS PROSPECTUS SUPPLEMENT

This prospectus supplement and the accompanying base prospectus are part of a registration statement that we filed with the SEC utilizing a “shelf” registration process. Each time we conduct an offering to sell securities under the accompanying base prospectus we will provide a prospectus supplement that will contain specific information about the terms of that offering, including the price, the amount of securities being offered and the plan of distribution. This prospectus supplement describes the specific details regarding this offering and may add, update or change information contained in the accompanying base prospectus. The base prospectus, as filed with the SEC on March 18, 2024 and declared effective May 9, 2024, including the documents incorporated by reference therein, provides general information about us and our securities, some of which, such as the section entitled “Plan of Distribution,” may not apply to this offering. This prospectus supplement and the accompanying base prospectus are an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so. We are not, and Cantor is not, making offers to sell or solicitations to buy our common stock in any jurisdiction in which an offer or solicitation is not authorized or in which the person making that offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make an offer or solicitation.

If information in this prospectus supplement is inconsistent with the accompanying base prospectus or the information incorporated by reference with an earlier date, you should rely on this prospectus supplement. This prospectus supplement, together with the base prospectus, the documents incorporated by reference into this prospectus supplement and the accompanying base prospectus and any free writing prospectus we have provided for use in connection with this offering, include all material information relating to this offering. We have not, and Cantor has not, authorized anyone to provide you with different or additional information and you must not rely on any unauthorized information or representations. You should assume that the information appearing in this prospectus supplement, the accompanying base prospectus, the documents incorporated by reference in this prospectus supplement and the accompanying base prospectus and any free writing prospectus we have provided for use in connection with this offering is accurate only as of the respective dates of those documents. Our business, financial condition, results of operations and prospects may have changed since those dates. You should carefully read this prospectus supplement, the accompanying base prospectus and the information and documents incorporated herein by reference herein and therein, as well as any free writing prospectus we have provided for use in connection with this offering, before making an investment decision. See “Incorporation of Certain Documents by Reference” and “Where You Can Find More Information” in this prospectus supplement and in the accompanying base prospectus.

This prospectus supplement and the accompanying base prospectus contain 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 full text of the actual documents, some of which have been filed or will be filed and incorporated by reference herein. See “Where You Can Find More Information” in this prospectus supplement. We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference into this prospectus supplement or the accompanying base prospectus were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreements, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties or covenants were accurate only as of the date when made. Accordingly, such representations, warranties and covenants should not be relied on as accurately representing the current state of our affairs.

This prospectus supplement and the accompanying base prospectus contain and incorporate by reference certain market data and industry statistics and forecasts that are based on company-sponsored studies, independent industry publications and other publicly available information. Although we believe these sources are reliable, estimates as they relate to projections involve numerous assumptions, are subject to risks and uncertainties, and are subject to change based on various factors, including those discussed under “Risk Factors” in this prospectus supplement and the accompanying base prospectus and under similar headings in the documents incorporated by reference herein and therein. Accordingly, investors should not place undue reliance on this information.

Unless the context otherwise indicates, references in this prospectus supplement to “Cypherpunk Technologies Inc.,” “Cypher,” “Leap Therapeutics,” “Leap,” the “Company,” “we,” “our” and “us” refer to Cypherpunk Technologies Inc., a Delaware corporation, and its subsidiaries.

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PROSPECTUS SUPPLEMENT SUMMARY

This prospectus summary highlights information contained elsewhere in this prospectus supplement, the accompanying base prospectus and the documents incorporated by reference herein and therein. This summary does not contain all of the information that you should consider before deciding to invest in our securities. You should read this entire prospectus supplement and the accompanying base prospectus carefully, including the section entitled “Risk Factors” beginning on page S-6 and our consolidated financial statements and the related notes and the other information incorporated by reference into this prospectus supplement and the accompanying base prospectus, before making an investment decision.

Our Company

Cypherpunk Technologies Inc. is a biopharmaceutical company developing biomarker-targeted antibody therapies designed to treat patients with cancer. Our clinical stage program is sirexatamab (DKN-01), a monoclonal antibody that inhibits Dickkopf-related protein 1, or DKK1. We also have a preclinical antibody program, FL-501, that is designed to treat cachexia-related indications.

We have historically devoted substantially all of our resources to development efforts relating to our product candidates, including manufacturing and conducting clinical trials of our product candidates, providing general and administrative support for these operations and protecting our intellectual property. We do not have any products approved for sale and have not generated any revenue from product sales. We have funded our operations primarily through proceeds from our sales of common stock and preferred stock and proceeds from the issuance of notes payable.

Zcash Treasury Strategy

On October 6, 2025, we entered into a Securities Purchase Agreement (the “Securities Purchase Agreement”) with Winklevoss Treasury Investments, LLC (“Winklevoss Capital”) as Lead Investor and the other investors named therein (together with Winklevoss Capital, the “PIPE Purchasers”), pursuant to which we agreed to sell and issue to the PIPE Purchasers in a private placement offering the (“PIPE Offering”): (i) 15,212,311 shares of common stock at an offering price of $0.52064 per share, (ii) pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to an aggregate of 80,768,504 shares of common stock (the “Pre-Funded Warrant Shares”) at an offering price of $0.51964 per Pre-Funded Warrant, each exercisable for one share of common stock at the exercise price of $0.001 per Pre-Funded Warrant Share and (iii) common warrants (the “Common Warrants”) to purchase up to an aggregate of 71,985,605 shares of common stock (the “Common Warrant Shares”), each exercisable for one share of common stock at an exercise price of $0.5335 per Common Warrant Share. The PIPE Offering closed on October 8, 2025 (the “Closing Date”), with the Company receiving aggregate gross proceeds of approximately $58.88 million, before deducting fees and expenses. The Company also issued 4,000,000 Common Warrants to Parcrest International, in connection with their service as the Company’s placement agent in connection with the PIPE Offering (the “Placement Agent Warrants”).

Immediately following the Closing Date, the Company established a digital asset treasury strategy focused on Zcash (“ZEC”), using a portion of the funds received in the PIPE Offering that were not required to provide working capital for the Company’s ongoing operations. Zcash is a protocol and blockchain network of connected devices all over the world, working together to validate transactions and maintain the Zcash ledger, and ZEC is the monetary unit, or coin, of Zcash. Zcash functions much like Bitcoin, and it was created from the original Bitcoin code base. Like Bitcoin, Zcash is a digital currency that can be transmitted over a peer-to-peer payment system, except that Zcash uses a protocol called “zero-knowledge proofs” that allows users to engage in blockchain transactions while maintaining greater privacy. This cryptographic technology allows parties to decide whether or not to reveal sensitive information and enables private, public, shielding, and deshielding transactions on the Zcash blockchain. For example, the owner of a specific address is able to choose to disclose an address and transaction details to a trusted third party, potentially for compliance or audit reasons. Alternatively, transacting can work in a similar manner to the Bitcoin blockchain, where the sender and receiver addresses and value of the transfer are all publicly visible.

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We believe that privacy-protecting assets and related technologies will be critical in an increasingly digital world. We intend to acquire and hold ZEC as our primary digital asset and to be an active participant in the Zcash community. As of November 11, 2025, we have acquired 203,775.27 ZEC at an aggregate purchase price of approximately $50.0 million, or $245.37 per ZEC.

We renamed our Company “Cypherpunk Technologies Inc.” to reflect the strategic focus on acquiring ZEC, participating in the development of Zcash, and the values of privacy and liberty. Our ongoing research and development operations will be conducted under a wholly-owned subsidiary named “Leap Therapeutics, Inc.”

Implications of Being a Smaller Reporting Company

We are a “smaller reporting company” as defined in Item 10(f)(1) of Regulation S-K. Smaller reporting companies may take advantage of certain reduced disclosure obligations, including, among other things, providing only two years of audited financial statements. We will remain a smaller reporting company until the last day of the fiscal year in which (1) the market value of our common stock held by non-affiliates exceeds $250 million as of the last business day of our second fiscal quarter, or (2) our annual revenues exceed $100 million during such completed fiscal year and the market value of our common stock held by non-affiliates exceeds $700 million as of the last business day of our second fiscal quarter.

We have elected to take advantage of certain of the reduced disclosure obligations available to us and may elect to take advantage of other reduced reporting requirements in future filings with the SEC. As a result, the information that we provide to our stockholders may be different from the information you receive from other public reporting companies.

Our Corporate Information

We were incorporated in the state of Delaware as Dekkun Corporation on January 3, 2011 and changed our name to HealthCare Pharmaceuticals, Inc. effective May 29, 2014, then to Leap Therapeutics, Inc. effective November 16, 2015, and then to Cypherpunk Technologies Inc. effective November 12, 2025.

Our principal executive offices are located at 47 Thorndike St, Suite B1-1, Cambridge, MA 02141, and our phone number is (617) 714-0360. You may also visit our website at www.cypherpunk.com or www.leaptx.com. Information contained in, or accessible through, our website does not constitute part of this prospectus supplement and inclusions of our website address in this prospectus supplement are inactive textual references only.

As of November 12, 2025, our common stock was listed on the Nasdaq Capital Market under the symbol “LPTX.” Effective on or about November 13, 2025, our symbol is expected to change to “CYPH.”

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The Offering

The following is a brief summary of some of the terms of the offering and is qualified in its entirety by reference to the more detailed information appearing elsewhere in this prospectus supplement and the accompanying base prospectus. For a more complete description of the terms of our common stock, see the description of our capital stock in the accompanying base prospectus.

Common stock offered by us

Shares of our common stock, par value $0.001 per share, having an aggregate offering price of up to $200,000,000.

Common stock outstanding

56,651,840 shares of common stock outstanding as of November 11, 2025. The actual number of shares issued by us in this offering will vary depending on the sales price under this offering.

Manner of offering

We have entered into a Controlled Equity OfferingSM Sales Agreement with Cantor Fitzgerald & Co., dated November 12, 2025, relating to the sale of up to $200,000,000 of shares of our common stock. In accordance with the terms of the Sales Agreement, under this prospectus supplement we may offer and sell common stock having an aggregate offering price of up to $200,000,000 from time to time through Cantor, acting as our principal and/or sales agent. Sales of common stock, if any, under this prospectus supplement may be made by any method permitted that is deemed an “at the market offering” as defined in Rule 415 under the Securities Act of 1933, as amended. See the section entitled “Plan of Distribution” on page S-9 of this prospectus supplement.

Use of proceeds

We expect to use the net proceeds from this offering for working capital and general corporate purposes, including to acquire the native cryptocurrency of the Zcash blockchain commonly referred to as “ZEC”, which will serve as the Company’s primary treasury reserve asset. See “Use of Proceeds” on page S-9.

Risk factors

Investing in our common stock involves a high degree of risk. See “Risk Factors” beginning on page S-6 and the other information included or incorporated by reference in this prospectus supplement and the accompanying base prospectus for a discussion of factors you should carefully consider before deciding to invest in our common stock.

The Nasdaq Capital Market symbol

As of November 12, 2025, our common stock was listed on the Nasdaq Capital Market under the symbol “LPTX.” Effective on or about November 13, 2025, our symbol is expected to change to “CYPH.”

The 56,651,840 shares of our common stock outstanding as of November 11, 2025 excludes the following:

•

80,768,504 shares of common stock issuable upon exercise of the Pre-Funded Warrants at an exercise price of $0.001 per share;

•

71,985,605 shares of common stock issuable upon exercise of the Common Warrants at an exercise price of $0.5355 per share;

•

4,000,000 shares of common stock issuable upon exercise of the Placement Agent Warrants at an exercise price of $0.5355 per share;

•

2,594,503 shares of common stock issuable upon exercise of warrants at an exercise price of $21.10 per share;

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•

690,813 shares of common stock issuable upon exercise of warrants at an exercise price of $19.50 per share;

•

5,450 shares of common stock issuable upon exercise of warrants at an exercise price of $0.10 per share;

•

2,777,586 shares of common stock issuable upon vesting and exercise of outstanding stock options issued under our equity incentive plans;

•

5,653,387 shares of common stock issuable upon vesting of restricted stock units issued under our equity incentive plans; and

•

523,812 shares of common stock available to be granted under our equity incentive plans.

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RISK FACTORS

Investing in our common stock involves a high degree of risk. Before purchasing our common stock, you should read and consider carefully the following risk factors and the risk factors included in our most recent Annual Report on Form 10-K filed with the SEC, any subsequent Quarterly Reports on Form 10-Q as well as all other information contained and incorporated by reference in this prospectus supplement and the accompanying base prospectus, including our consolidated financial statements and the related notes. Each of these risk factors, either alone or taken together, could adversely affect our business, operating results and financial condition, as well as adversely affect the value of an investment in our common stock. There may be additional risks that we do not presently know of or that we currently believe are immaterial, which could also impair our business and financial position. If any of the events described below were to occur, our financial condition, our ability to access capital resources, our results of operations and/or our future growth prospects could be materially and adversely affected and the market price of our common stock could decline. As a result, you could lose some or all of any investment you may make in our common stock.

Risks Related to This Offering

Our management will have broad discretion over the use of the net proceeds from this offering; you may not agree with how we use the proceeds and the proceeds may not be invested successfully.

Our management will have broad discretion as to the use of the net proceeds from this offering and could use them for purposes other than those contemplated at the time of this offering. We will retain broad discretion over the use of the net proceeds from the sale of the securities offered hereby. We currently expect to use the net proceeds from this offering for working capital and general corporate purposes, including to progress the development programs of our drug candidates and to purchase Zcash pursuant to our digital asset treasury strategy. See the section entitled “Use of Proceeds” below for a more detailed discussion. Accordingly, you will be relying on the judgment of our management with regard to the use of these net proceeds, and you will not have the opportunity, as part of your investment decision, to assess whether the proceeds will be used appropriately. It is possible that the proceeds will be invested in a way that does not yield a favorable, or any, return for the Company and cause the price of our common stock to decline.

The market price of our shares may be subject to fluctuation and volatility. You could lose all or part of your investment.

The market price of our common stock is subject to wide fluctuations in response to various factors, many of which are beyond our control. In the twelve months ended November 7, 2025, ZEC has traded between approximately $26.14 and $736.51. This volatility may affect the price at which you could sell the shares of our common stock, and the sale of substantial amounts of our common stock could adversely affect the price of our common stock. Our stock price is likely to continue to be volatile and subject to significant price and volume fluctuations in response to market and other factors. As a result, you may not be able to sell your shares of common stock at or above the price at which you purchase them.

In addition, the stock of digital asset and blockchain technology companies in particular, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. Broad market and industry factors may negatively affect the market price of our common stock, regardless of our actual operating performance. These factors and any corresponding price fluctuations may materially and adversely affect the market price of our shares and result in substantial losses being incurred by our investors. In the past, following periods of market volatility, public company stockholders have often instituted securities class action litigation. If we were involved in securities litigation, it could impose a substantial cost upon us and divert the resources and attention of our management from our business.

You may experience immediate and substantial dilution.

Because the prices per share at which shares of our common stock are sold in this offering may be substantially higher than the net tangible book value per share of our common stock, you may suffer immediate and substantial dilution in the net tangible book value of the common stock you purchase in this offering. The shares sold in this offering, if any, will be sold from time to time at various prices. If we sell

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shares in this offering at a price that is higher than the net tangible book value per share of our common stock, investors in this offering will experience dilution. The exercise of outstanding stock options and warrants, and the vesting of outstanding restricted stock units, may result in further dilution of your investment.

Future sales of substantial amounts of our common stock, or the perception that such sales could occur, could adversely affect the market price of our common stock.

We cannot predict the effect, if any, that future issuances or sales of our securities or the availability of our securities for future issuance or sale, will have on the market price of our common stock, including but not limited to the issuance of shares of our common stock upon the exercise of certain warrants pursuant to the Securities Purchase Agreement or pursuant to the Sales Agreement. Issuances or sales of substantial amounts of our securities, including sales of our common stock pursuant to the Sales Agreement, or the perception that such issuances or sales might occur, could negatively impact the market price of our common stock and the terms upon which we may obtain additional equity financing in the future.

It is not possible to predict the actual number of shares of our common stock we will sell under the Sales Agreement, or the gross proceeds resulting from those sales.

Subject to certain limitations in the Sales Agreement and compliance with applicable law, we have the discretion to deliver a placement notice to the sales agent at any time throughout the term of the Sales Agreement. The number of shares of our common stock that are sold through the sales agent after delivering a placement notice will fluctuate based on a number of factors, including the market price of our common stock during the sales period, the limits we set with the sales agent in any applicable placement notice, and the demand for our common stock during the sales period. Because the price per share of each share sold will fluctuate during the sales period, it is not currently possible to predict the number of shares that will be sold or the gross proceeds to be raised in connection with those sales.

The common stock offered hereby will be sold in “at the market offerings,” and investors who buy shares at different times will likely pay different prices.

Investors who purchase common stock in this offering at different times will likely pay different prices, and so may experience different levels of dilution and different outcomes in their investment results. We will have discretion, subject to market demand, to vary the timing, prices, and numbers of shares sold in this offering. In addition, there is no minimum or maximum sales price for shares to be sold in this offering. Investors may experience a decline in the value of the shares they purchase in this offering as a result of sales made at prices lower than the prices they paid.

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FORWARD-LOOKING STATEMENTS

This prospectus supplement, the accompanying base prospectus and the documents we have filed with the SEC that are incorporated by reference herein and therein contain forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act. In addition, from time to time we or our representatives have made or will make forward-looking statements in various other filings that we make with the SEC or in other documents, including press releases or other similar announcements. Forward-looking statements concern our current plans, intentions, beliefs, expectations and statements of future economic performance. Statements containing terms such as “anticipate,” “expect,” “project,” “intend,” “believe,” “may,” “will,” “should,” “plan,” “could,” “continue,” “target,” “contemplate,” “estimate,” “forecast,” “guidance,” “predict,” “possible,” “potential,” “pursue,” “likely,” and words and terms of similar substance used in connection with any discussion of future plans, actions or events, and other phrases of similar meaning are considered to be forward-looking statements.

Forward-looking statements are based on our assumptions and are subject to known and unknown risks and uncertainties that could cause actual results to differ materially from those reflected in or implied by these forward-looking statements. Factors that might cause actual results to differ include, among others, those set forth under “Risk Factors” in this prospectus supplement and those discussed in “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q and in our future periodic reports filed with the SEC, all of which are incorporated by reference herein. Readers are cautioned not to place undue reliance on any forward-looking statements contained in this prospectus supplement, the accompanying base prospectus or the documents we have filed with the SEC that are incorporated by reference herein and therein, which reflect management’s views and opinions only as of their respective dates. We assume no obligation to update forward-looking statements to reflect actual results, changes in assumptions or changes in other factors affecting such forward-looking statements, except to the extent required by applicable securities laws. You are advised, however, to consult any additional disclosures we have made or will make in the filings we make with the SEC, including reports on Forms 10-K, 10-Q and 8-K. All subsequent forward-looking statements attributable to us or persons acting on our behalf are expressly qualified in their entirety by the cautionary statements contained in this prospectus supplement, the accompanying base prospectus or any related issuer free writing prospectus.

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USE OF PROCEEDS

We may issue and sell shares of our common stock having aggregate gross proceeds of up to $200,000,000 from time to time (before deducting sales agent commissions and expenses). Because there is no minimum offering amount required, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. There can be no assurance that we will sell any shares under or fully utilize the Sales Agreement as a source of financing.

We expect to use the net proceeds from the sale of our common stock offered under this prospectus supplement for working capital and general corporate purposes, including to acquire the native cryptocurrency of the Zcash blockchain commonly referred to as “ZEC”, which will serve as the Company’s primary treasury reserve asset. We have not determined the amount of net proceeds to be used specifically for such purposes. As a result, management will retain broad discretion over the allocation of net proceeds. Pending the uses described above, we intend to invest the net proceeds from this offering in short-term, investment-grade interest-bearing securities such as money market accounts, certificates of deposit, commercial paper, and guaranteed obligations of the U.S. government.

PLAN OF DISTRIBUTION

We have entered into a Controlled Equity OfferingSM Sales Agreement, with Cantor Fitzgerald & Co. Pursuant to this prospectus supplement, we may offer and sell shares of our common stock having an aggregate gross sales price of up to $200,000,000 from time to time to or through Cantor acting as principal and/or sales agent. A copy of the Sales Agreement will be filed as an exhibit to a Current Report on Form 8-K and will be incorporated by reference into this prospectus supplement.

Upon delivery of a placement notice to Cantor and subject to the terms and conditions of the Sales Agreement, Cantor may sell shares of our common stock by any method permitted by law deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act. We may instruct Cantor not to sell shares of our common stock if the sales cannot be effected at or above the price designated by us from time to time. We or Cantor may suspend the offering of common stock upon notice and subject to other conditions.

We will pay Cantor commissions, in cash, for its service in acting as agent in the sale of our common stock. Cantor will be entitled to compensation at a commission rate of up to 3.0% of the gross sales price per share sold under the Sales Agreement. Because there is no minimum offering amount required as a condition of this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. We have also agreed to reimburse Cantor for certain specified fees and expenses, including the fees and disbursements of its legal counsel in an amount not to exceed (a) $100,000 in connection with the execution of the Sales Agreement, (b) $25,000 per calendar quarter thereafter payable in connection with each representation date with respect to which the Company is obligated to deliver a certificate pursuant to the terms of the Sales Agreement, and (c) $40,000 for each program “refresh” (filing of a new registration statement, prospectus or prospectus supplement relating to the shares of common stock and/or an amendment of the Sales Agreement) executed pursuant to the Sales Agreement. We estimate that the total expenses for the offering, excluding compensation and reimbursements payable to Cantor under the terms of the Sales Agreement, will be approximately $300,000.

Settlement for sales of shares of our common stock will occur on the first trading day following the date on which any sales are made, or on such other date that is agreed upon by us and Cantor in connection with a particular transaction, in return for payment of the net proceeds to us. Sales of our common stock as contemplated in this prospectus supplement will be settled through the facilities of The Depository Trust Company or by such other means as we and Cantor may agree upon. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.

Cantor will use its commercially reasonable efforts, consistent with its sales and trading practices, to solicit offers to purchase the common stock under the terms and subject to the conditions set forth in the Sales Agreement. In connection with the sale of the common stock on our behalf, Cantor will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation of Cantor will be deemed to be underwriting commissions or discounts. We have agreed to provide indemnification and

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contribution to Cantor and specified other persons against certain civil liabilities, including liabilities under the Securities Act and the Exchange Act.

The offering of shares of our common stock pursuant to the Sales Agreement will terminate upon the termination of the Sales Agreement as permitted therein. We and Cantor may each terminate the Sales Agreement at any time upon ten business days’ prior notice.

Cantor and its affiliates may in the future provide various investment banking, commercial banking and other financial services for us and our affiliates, for which services they may in the future receive customary fees. To the extent required by Regulation M, Cantor will not engage in any market-making activities involving our common stock while the offering is ongoing under this prospectus supplement.

This prospectus supplement and the accompanying prospectus may be made available in electronic format on a website maintained by Cantor, and Cantor may distribute this prospectus supplement and the accompanying prospectus electronically.

This summary of the material provisions of the Sales Agreement does not purport to be a complete statement of its terms and conditions.

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LEGAL MATTERS

The validity of the securities offered by this prospectus supplement will be passed upon for us by Morgan, Lewis & Bockius LLP, New York, New York. Cantor Fitzgerald & Co.is being represented in connection with this offering by Paul Hastings LLP, Palo Alto, California.

EXPERTS

The consolidated balance sheets of Cypherpunk Technologies Inc. (formerly known as Leap Therapeutics, Inc.) and Subsidiaries as of December 31, 2024 and 2023, and the related consolidated statements of operations, comprehensive loss, stockholders’ equity, and cash flows for each of the years then ended have been audited by EisnerAmper LLP, independent registered public accounting firm, as stated in their report, which is incorporated herein by reference. Such financial statements have been incorporated herein by reference in reliance on the report of such firm given upon their authority as experts in accounting and auditing.

INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The SEC permits us to “incorporate by reference” the information and reports we file with it. This means that we can disclose important information to you by referring to another document. The information that we incorporate by reference is considered to be part of this prospectus supplement, and later information that we file with the SEC automatically updates and supersedes this information. We incorporate by reference the documents listed below, except to the extent information in those documents is different from the information contained in this prospectus supplement, and all future documents filed with the SEC under Sections 13(a), 13(c), 14, or 15(d) of the Exchange Act (other than filings or portions thereof, including exhibits, deemed to be furnished to the SEC pursuant to Item 9 or Item 12 of Form S-3) until we terminate the offering of these securities:

•

our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, filed with the SEC on March 26, 2025;

•

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 on Schedule 14A for our 2025 annual meeting of stockholders, filed with the SEC on April 28, 2025;

•

our Quarterly Reports on Form 10-Q for the fiscal quarters ended March 31, 2025, June 30, 2025 and September 30, 2025;

•

our Current Reports on Form 8-K filed with the SEC on January 28, 2025, March 17, 2025, March 26, 2025, June 23, 2025, September 11, 2025, October 6, 2025, October 9, 2025, October 20, 2025 and November 12, 2025 (excluding any portions thereof that have been furnished rather than filed); and

•

the description of our common stock contained in the Description of the Company’s securities registered pursuant to Section 12 of the Securities Exchange Act of 1934 filed as Exhibit 4.6 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2019 and any further amendments thereto or reports filed for the purposes of updating this description.

To the extent that any statement in this prospectus supplement is inconsistent with any statement that is incorporated by reference and that was made on or before the date of this prospectus supplement, the statement in this prospectus supplement shall supersede such incorporated statement. The incorporated statement shall not be deemed, except as modified or superseded, to constitute a part of this prospectus supplement or the registration statement. Statements contained in this prospectus supplement as to the contents of any contract or other document are not necessarily complete and, in each instance, we refer you to the copy of each contract or document filed as an exhibit to our various filings made with the SEC.

We will provide to each person, including any beneficial owner, to whom a prospectus supplement is delivered, without charge upon written or oral request, a copy of any or all of the documents that are incorporated by reference into this prospectus supplement but not delivered with the prospectus supplement,

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including exhibits which are specifically incorporated by reference into such documents. You may request a copy of these filings, at no cost, by writing or telephoning us at the following address or telephone number:

Leap Therapeutics, Inc.
47 Thorndike Street, Suite B1-1
Cambridge, Massachusetts 02141
Telephone number: (617) 714-0360
Attention: Investor Relations

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement under the Securities Act that registers the securities offered hereby. The registration statement, including the exhibits and schedules attached thereto and the information incorporated by reference therein, contains additional relevant information about the securities and our Company, which we are allowed to omit from this prospectus supplement pursuant to the rules and regulations of the SEC. In addition, we file annual, quarterly and current reports and proxy statements and other information with the SEC. Our SEC filings are available on 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.cypherpunk.com or www.leaptx.com. We have not incorporated by reference into this prospectus supplement the information on our website and it is not a part of this document.

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PROSPECTUS

[MISSING IMAGE: lg_leaptherapeutics-4c.jpg]

$200,000,000

LEAP THERAPEUTICS, INC.

Common Stock

Preferred Stock

Warrants

Debt Securities

Rights to Purchase Common Stock, Preferred Stock,

Debt Securities or Units

Units

We may offer and sell from time to time our shares of common stock, shares of preferred stock, warrants, debt securities and rights to purchase common stock, preferred stock, debt securities or units, as well as units that include any of these securities. We may sell any combination of these securities in one or more offerings with an aggregate offering price of up to $200,000,000.

This prospectus provides you with a general description of the securities we may offer. Each time we offer securities pursuant to this prospectus, we will provide a prospectus supplement containing specific terms of the particular offering together with this prospectus. You should read this prospectus and the applicable prospectus supplement carefully before you invest in any securities. The prospectus supplement also may add, update or change information contained in this prospectus. This prospectus may not be used to offer and sell securities unless accompanied by the applicable prospectus supplement.

Our common stock is listed on the Nasdaq Capital Market under the symbol “LPTX.” On March 13, 2024, the closing price of our common stock was $2.29.

Investing in our securities involves significant risks. We strongly recommend that you read carefully the risks we describe in this prospectus and in any accompanying prospectus supplement, as well as the risk factors that are incorporated by reference into this prospectus from our filings made with the Securities and Exchange Commission. See “Risk Factors” on page 3 of this prospectus.

We may sell the securities directly or to or through underwriters or dealers, and also to other purchasers or through agents. The names of any underwriters or agents that are included in a sale of securities to you, and any applicable commissions or discounts, will be stated in an accompanying prospectus supplement. In addition, the underwriters, if any, may over-allot a portion of the securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is May 9, 2024

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	ABOUT THIS PROSPECTUS					1
	LEAP THERAPEUTICS, INC					1
	SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS					2
	RISK FACTORS					3
	USE OF PROCEEDS					3
	DESCRIPTION OF CAPITAL STOCK					4
	DESCRIPTION OF WARRANTS					9
	DESCRIPTION OF DEBT SECURITIES					11
	DESCRIPTION OF RIGHTS					17
	DESCRIPTION OF UNITS					19
	PLAN OF DISTRIBUTION					20
	LEGAL MATTERS					22
	EXPERTS					22
	WHERE YOU CAN FIND MORE INFORMATION					22
	INFORMATION INCORPORATED BY REFERENCE					23
	DISCLOSURE OF COMMISSION’S POSITION ON INDEMNIFICATION FOR SECURITIES ACT LIABILITY					24

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ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission (the “SEC”), using a “shelf” registration process. Under this shelf registration process, we may offer and sell from time to time any combination of the securities described in this prospectus in one or more offerings in amounts, at prices and on terms that we determine at the time of the offering, with an aggregate offering price of up to $200,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we offer securities under this registration statement we will provide a prospectus supplement that describes the terms of the relevant offering. The prospectus supplement also may add, update or change information contained in this prospectus. Before making an investment decision, you should read carefully both this prospectus and any prospectus supplement together with the documents incorporated by reference into this prospectus as described below under the heading “Information Incorporated by Reference.”

The registration statement that contains this prospectus, including the exhibits to the registration statement and the information incorporated by reference, provides additional information about us and our securities. That registration statement can be read at the SEC website (www.sec.gov), as discussed below under the heading “Where You Can Find More Information.”

You should rely only on the information provided in the registration statement, this prospectus and in any prospectus supplement, including the information incorporated by reference. We have not authorized anyone to provide you with different information. You should not assume that the information in this prospectus or any supplement to this prospectus is accurate at any date other than the date indicated on the cover page of these documents or the filing date of any document incorporated by reference, regardless of its time of delivery. We are not making an offer to sell the securities in any jurisdiction where the offer or sale is not permitted.

We may sell our securities to or through underwriters, initial purchasers, dealers or agents, directly to purchasers or through a combination of any of these methods of sale, as designated from time to time. We and our agents reserve the sole right to accept or reject in whole or in part any proposed purchase of our securities. An applicable prospectus supplement, which we will provide each time we offer the securities, will set forth the names of any underwriters, initial purchasers, dealers or agents involved in the sale of our securities, and any related fee, commission or discount arrangements. See “Plan of Distribution.”

We own or have rights to trademarks or trade names that we use in conjunction with the operation of our business. KEYTRUDA® is a registered trademark of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc. Each trademark, trade name or service mark of any other company appearing in the registration statement, this prospectus or any document incorporated herein or therein belongs to its holder. Use or display by us of other parties’ trademarks, trade names or service marks is not intended to and does not imply a relationship with, or endorsement or sponsorship by us of, the trademark, trade name or service mark owner.

The terms “Leap,” the “Company,” “our,” “us,” and “we,” as used in this prospectus, refer to Leap Therapeutics, Inc., unless we state otherwise or the context indicates otherwise.

LEAP THERAPEUTICS, INC.

Overview

We are a biopharmaceutical company developing novel biomarker-targeted antibody therapies designed to treat patients with cancer by inhibiting fundamental tumor-promoting pathways, targeting cancer-specific cell surface molecules, and harnessing the immune system to attack cancer cells. Our lead clinical stage program is DKN-01, a monoclonal antibody that inhibits Dickkopf-related protein 1 (“DKK1”). We are currently studying DKN-01 in multiple ongoing clinical trials in patients with esophagogastric cancer, gynecologic cancers, or colorectal cancer. Our second clinical stage program is FL-301, a monoclonal antibody that targets cells that express Claudin18.2 on their cell surface. We also have two preclinical antibody programs, FL-302 and FL-501.

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We were incorporated in the state of Delaware as Dekkun Corporation on January 3, 2011 and changed our name to HealthCare Pharmaceuticals, Inc. effective May 29, 2014, and then to Leap Therapeutics, Inc. effective November 16, 2015. During 2015, HealthCare Pharmaceuticals Pty Ltd. (“HCP Australia”) was formed and is a wholly owned subsidiary of the Company. During January 2017, the Company merged with Macrocure Ltd. (now “Leap Therapeutics Ltd.”) and its wholly-owned subsidiary Macrocure, Inc. On January 17, 2023, we entered into a merger agreement with Flame Biosciences, Inc. (“Flame”), a privately-held biotechnology company, to acquire Flame and Flame’s clinical stage program, FL-301, two preclinical programs, FL-302 and FL-501, and cash balance, whereby Flame became a wholly owned subsidiary under the name Flame Biosciences, LLC (the “Flame Acquisition Transaction”).

Corporate Information

Our principal executive offices are located at 47 Thorndike Street, Suite B1-1, Cambridge, Massachusetts 02141, and our telephone number is (617) 714-0360. Our website address is www.leaptx.com. The information contained on our website is not incorporated by reference into this prospectus, and you should not consider any information contained on, or that can be accessed through, our website as part of this prospectus or in deciding whether to purchase our common stock.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus, including the documents that we incorporate by reference in this prospectus, contains or may contain forward-looking statements as that term is defined in the federal securities laws. The events described in forward-looking statements contained in this prospectus, including the documents that we incorporate by reference in this prospectus, may not occur. Generally, these statements relate to our business plans or strategies, projected or anticipated benefits or other consequences of our plans or strategies, financing plans, projected or anticipated benefits from acquisitions that we may make, or projections involving anticipated revenues, earnings or other aspects of our operating results or financial position, and the outcome of any contingencies. Any such forward-looking statements are based on current expectations, estimates and projections of management. We intend for these forward-looking statements to be covered by the safe-harbor provisions for forward-looking statements. Words such as “anticipate,” “expect,” “project,” “intend,” “believe,” “may,” “will,” “should,” “plan,” “could,” “continue,” “target,” “contemplate,” “estimate,” “forecast,” “guidance,” “predict,” “possible,” “potential,” “pursue,” “likely,” and their opposites and similar expressions are intended to identify forward-looking statements. All statements, other than historical facts, including statements regarding estimations of projected cash runway; our future product development plans; the potential, safety, efficacy, and regulatory and clinical progress of the our product candidates, including the anticipated timing for initiation of clinical trials and release of clinical trial data and the expectations surrounding potential regulatory submissions, approvals and timing thereof; and any assumptions underlying any of the foregoing, are forward-looking statements.

Forward looking statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward looking statements. We believe that these factors include, but are not limited to, the factors that we identify in any of the documents incorporated or deemed incorporated into this prospectus and the registration statement by reference, including in our most recent Annual Report on Form 10-K and in any of our subsequent proxy statements, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K.

You should also consider carefully the information set forth in the section titled “Risk Factors” or elsewhere in this prospectus and the documents incorporated or deemed incorporated herein by reference, including in our most recent Annual Report on Form 10-K and in our updates to those risk factors in our subsequent proxy statements, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K and other factors described elsewhere in this prospectus. Any one or more of these uncertainties, risks, factors and other influences could materially affect our results of operations and whether forward-looking statements made by us ultimately prove to be accurate. Our actual results, performance and achievements could differ materially from those expressed or implied in these forward-looking statements. Except as otherwise required by law, we undertake no obligation to publicly update or revise any forward-looking statements, whether from new information, future events or otherwise.

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RISK FACTORS

An investment in our securities involves a high degree of risk. Before making an investment decision, you should carefully consider the risks described under “Risk Factors” contained in our most recent Annual Report on Form 10-K, and in our updates to those Risk Factors in our proxy statements, Quarterly Reports on Form 10-Q or Current Reports on Form 8-K following the most recent Annual Report on Form 10-K, and in all other information appearing in this prospectus or incorporated by reference into this prospectus and any applicable prospectus supplement. Each of the risk factors could adversely affect our business, operating results and financial condition, as well as adversely affect the value of an investment in our securities, and the occurrence of any of these risks might cause you to lose all or part of your investment.

The prospectus supplement applicable to each type or series of securities we offer may contain a discussion of risks applicable to the particular types of securities that we are offering under that prospectus supplement. Prior to making a decision about investing in our securities, you should carefully consider the specific factors discussed under the caption “Risk Factors” in the applicable prospectus supplement, together with all of the other information contained in, or incorporated by reference in, the prospectus supplement and this prospectus. These risks could materially affect our business, results of operations or financial condition and cause the value of our securities to decline. You could lose all or part of your investment. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations. Please also read carefully the section above titled “Special Note Regarding Forward-Looking Statements.”

USE OF PROCEEDS

We will retain broad discretion over the use of the net proceeds from the sale of the securities offered hereby. Except as described in any prospectus supplement or any related free writing prospectus that we may authorize to be provided to you, we currently intend to use the estimated net proceeds from the sale of the securities offered hereby for general corporate purposes, which may include capital expenditures, working capital and general and administrative expenses. We may also use a portion of the net proceeds to acquire or invest in businesses that are complementary to our own, although we have no current plans, commitments or agreements with respect to any acquisitions as of the date of this prospectus. We have not yet determined the amount of net proceeds to be used specifically for any of the foregoing purposes. We will set forth in the applicable prospectus supplement or free writing prospectus our intended use for the net proceeds received from the sale of any securities sold pursuant to the prospectus supplement or free writing prospectus.

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DESCRIPTION OF CAPITAL STOCK

The description below of our capital stock and provisions of our certificate of incorporation and bylaws, each as amended and currently in effect, are summaries and are qualified by reference to our certificate of incorporation, our bylaws, and the applicable provisions of Delaware law.

General

Our certificate of incorporation authorizes us to issue up to 240,000,000 shares of common stock, $0.001 par value per share, 10,000,000 shares of preferred stock, $0.001 par value per share, of which one share is currently designated Special Voting Stock (the “Special Voting Stock”).

As of March 11, 2024, there were 25,600,137 shares of common stock outstanding, warrants for the purchase of up to 5,008,139 shares of our common stock outstanding, and one share of Special Voting Stock outstanding.

Common Stock

Holders of shares of our common stock are entitled to one vote on all matters on which stockholders of the Company generally are entitled to vote. However, holders of our common stock are not entitled to vote on any amendment to the Company’s Certificate of Incorporation that relates solely to the terms of one or more outstanding classes or series of preferred stock if the holders of such affected classes or series are entitled, either separately or together with the holders of one or more other such class or series, to vote thereon pursuant to the Company’s Certificate of Incorporation, or the Delaware General Corporation Law.

Generally, the Company’s bylaws provide that, subject to applicable law or the Company’s certificate of incorporation, and/or bylaws, all corporate actions to be taken by vote of the stockholders are authorized by a majority of the votes cast by the stockholders entitled to vote thereon who are present in person or represented by proxy, and where a separate vote by class or series is required, a majority of the votes cast by the stockholders of such class or series who are present in person or represented by proxy will be the act of such class or series. Directors are elected by a majority of the votes cast at a meeting of the Company’s stockholders for the election of directors at which a quorum is present, except that directors are elected by a plurality of votes cast at a meeting at which a quorum is present if as of the expiration of the period of time during which stockholders are entitled to nominate persons for election as a director, the number of nominees for director exceeds the number of directors to be elected.

Subject to the rights of holders of any then outstanding class or series of preferred stock, holders of Leap common stock are entitled to receive dividends and other distributions in cash, stock or property of Leap as the board of directors may declare thereon from time to time and share equally on a per share basis in all such dividends and other distributions. In the event of the Company’s dissolution, whether voluntary or involuntary, after the payment in full of the amounts required to be paid to the holders of any outstanding class or series of preferred stock, the remaining assets and funds of the Company available for distribution will be distributed pro rata to the holders of Leap common stock in proportion to the number of shares held by them and to the holders of any class or series of preferred stock entitled to a distribution. Holders of Leap common stock do not have preemptive rights to purchase shares of Leap common stock. The shares of Leap common stock are not subject to any conversion or redemption provisions or entitled to the benefit of a sinking fund. All outstanding shares of Leap common stock will be fully paid and nonassessable. The rights, preferences and privileges of holders of Leap common stock are subject to those of the holders of any outstanding class or series of Leap preferred stock that Leap may issue in the future.

Special Voting Stock

The rights, preferences and privileges of the Special Voting Stock are set forth in the Special Voting Stock Certificate of Designation. At any time when the holder of the Special Voting Stock, together with all of its affiliates and associates, holds at least 9.9% of the then outstanding shares of common stock, the holder of the Special Voting Stock shall be entitled to designate one (1) individual as a director on the board of directors. Upon any liquidation, dissolution or winding up of the Company, the holder of the Special

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Voting Stock shall be entitled to receive, prior and in preference to any distribution to the holders of common stock, an amount equal to $1.00. As of the date of this prospectus, there is one share of Special Voting Stock outstanding.

The foregoing description of the Special Voting Stock does not purport to be complete and is qualified in its entirety by reference to the full text of the Special Voting Stock Certificate of Designation (“Certificate of Designation”), which is filed as Exhibit 3.3 to the Company’s Current Report on Form 8-K as filed with the SEC on January 7, 2020 and amended by the Certificate of Amendment to Certificate of Designation filed as Exhibit 3.1 to the Company Current Report on Form 8-K as filed with the SEC on March 16, 2023, and incorporated herein by reference.

Blank Check Preferred Stock

Leap’s board of directors may, from time to time, authorize the issuance of one or more classes or series of preferred stock without stockholder approval. Our certificate of incorporation permits Leap to issue up to 10,000,000 shares of preferred stock. Subject to the provisions of our certificate of incorporation, and limitations prescribed by law, Leap’s board of directors is expressly authorized, by resolution or resolutions, to provide, out of the unissued shares of preferred stock, for classes and series of preferred stock. The board of directors may fix the number of shares constituting such class or series and the designation of such class or series and the powers (including voting, if any), preferences and relative, participating, optional or other special rights, if any, and any qualifications, limitations or restrictions thereof, of the shares of such class or series. Each class or series will be appropriately designated by a distinguishing designation prior to the issuance of any shares thereof. The powers (including voting, if any), preferences and relative, participating, optional and other special rights of each series of preferred stock, and the qualifications, limitations or restrictions thereof, if any, may differ from those of any and all other classes and series of preferred stock at any time outstanding.

The issuance of preferred stock may adversely affect the rights of the Company’s common stockholders by, among other things:

•

restricting dividends on the common stock;

•

diluting the voting power of the common stock;

•

impairing the liquidation rights of the common stock; or

•

delaying or preventing a change in control without further action by the stockholders.

As a result of these or other factors, the issuance of preferred stock could have an adverse impact on the market price of the common stock of Leap.

Registration Rights

Certain holders of shares of our common stock are entitled to certain rights with respect to the registration of shares under the Securities Act.

In connection with the transactions contemplated by our merger agreement with Macrocure, we entered into a registration rights agreement with each of our holders of common stock outstanding immediately prior to the effective time of the merger. In addition to the former holders of our common stock, certain larger holders of our common stock following the merger (who were among the largest holders of Macrocure ordinary shares prior to the merger) became parties to the registration rights agreement. Under the agreement, certain holders of registrable shares can demand that Leap file a registration statement or request that their shares be included on a registration statement that Leap is otherwise filing, in either case, registering the resale of their shares of Leap common stock. These registration rights are subject to conditions and limitations, including the right, in certain circumstances, of the underwriters of an offering to limit the number of shares included in such registration and our right, in certain circumstances, not to effect a requested registration on Form S-3 if such registration is in connection with any underwritten offering or proposed underwritten public offering.

Concurrently with the execution of a securities purchase agreement on January 3, 2020, with institutional investors named therein (collectively, the “Purchasers,” and each, a “Purchaser”), providing for a private

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placement transaction exempt from the registration requirements of the Securities Act, we entered into two registration rights agreements with the Purchasers, pursuant to which we agreed, following demand by any Purchaser, to file with the SEC a registration statement on Form S-3 covering the resale of the shares of common stock issuable upon conversion of the Series A Preferred Stock, Series B Preferred Stock or exercise of the Pre-Funded Warrants, Series A Coverage Warrants and Series B Coverage Warrants (as applicable) by the Purchasers as promptly as reasonably practicable following such demand, and in any event within 60 days after such demand.

At the closing of the Flame Acquisition Transaction, we entered into a registration rights agreement with those stockholders of Flame that became parties thereto. Pursuant to the registration rights agreement, we agreed to file a registration statement on Form S-3 to register under the Securities Act of 1933, as amended, the resale of the shares of our common stock issued or issuable by us to such stockholders in connection with our acquisition of Flame, and to keep such registration statement effective until January 17, 2026 or, if earlier, the date on which all of the shares of our common stock registered for resale pursuant to such registration statement have been disposed of in accordance with such registration statement, disposed of pursuant to Rule 144 under the Securities Act, or can be resold pursuant to Rule 144 without restriction or limitation (including without any limitation under Rule 144 as to volume of sales and method of sale requirements).

Anti-takeover Effects of Certain Provisions of Our Certificate of Incorporation and Bylaws

General

Our certificate of incorporation and bylaws contain provisions that are intended to enhance the likelihood of continuity and stability in the composition of the Company’s board of directors and that could make it more difficult to acquire control of the Company by means of a tender offer, open market purchases, a proxy contest or otherwise. A description of these provisions is set forth below.

Delaware Anti-Takeover Law

The Company is subject to Section 203 of the Delaware General Corporation Law. Section 203 generally prohibits a public Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a period of three years after the date of the transaction in which the person became an interested stockholder, unless:

•

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

•

upon consummation of the transaction that 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 specified shares; or

•

at or subsequent to the date of the transaction, 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 662∕3% of the outstanding voting stock which is not owned by the interested stockholder.

Section 203 defines a “business combination” to include:

•

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

•

any sale, lease, exchange, mortgage, pledge, transfer or other disposition of 10% or more of the assets of the corporation to or with the interested stockholder;

•

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;

•

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

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•

the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided by or through the corporation.

In general, Section 203 defines an “interested stockholder” as any person that is:

•

the owner of 15% or more of the outstanding voting stock of the corporation;

•

an affiliate or associate of the corporation who was the owner of 15% or more of the outstanding voting stock of the corporation at any time within three years immediately prior to the relevant date; or

•

the affiliates and associates of the above.

Under specific circumstances, Section 203 makes it more difficult for an “interested stockholder” to effect various business combinations with a corporation for a three-year period, although the stockholders may, by adopting an amendment to our certificate of incorporation or bylaws, elect not to be governed by this section, effective 12 months after adoption.

Our certificate of incorporation and bylaws do not exclude us from the restrictions of Section 203. We anticipate that the provisions of Section 203 might encourage companies interested in acquiring us to negotiate in advance with our board of directors since the stockholder approval requirement would be avoided if a majority of the directors then in office approve either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder.

No Cumulative Voting

Under Delaware law, the right to vote cumulatively does not exist unless the certificate of incorporation of a Delaware corporation specifically authorizes cumulative voting. Our certificate of incorporation does not grant stockholders the right to vote cumulatively.

Blank Check Preferred Stock

Leap believes that the availability of the preferred stock under our certificate of incorporation provides the Company with flexibility in addressing corporate issues that may arise. Having these authorized shares available for issuance will allow the Company to issue shares of preferred stock without the expense and delay of a special stockholders’ meeting. The authorized shares of preferred stock, as well as shares of common stock, will be available for issuance without further action by the Company’s stockholders, with the exception of any actions required by applicable law or the rules of any stock exchange on which Leap’s securities may be listed. The board of directors will have the power, subject to applicable law, to issue classes or series of preferred stock that could, depending on the terms of the class or series, impede the completion of a merger, tender offer or other takeover attempt.

Advance Notice Procedure

Our bylaws provide an advance notice procedure for stockholders to nominate director candidates for election or to bring business before an annual meeting of stockholders, including proposed nominations of persons for election to the board of directors.

Our bylaws provide that as to the notice of stockholder proposals of business to be brought at the annual meeting of stockholders, notice must be delivered to our secretary (i) not less than 90 days nor more than 120 days prior to the first anniversary of the preceding year’s annual meeting or (ii) if the date of the annual meeting is advanced by more than 30 days or delayed by more than 60 days from the first anniversary of the preceding year’s annual meeting, not more than 120 days nor less than 90 days prior to the date of such annual meeting or, if less than 90 days’ notice is given of such annual meeting, the 10th day following the day on which public announcement of the date of such meeting is first made by Leap. In addition, any proposed business other than the nomination of persons for election to the Company’s board of directors must constitute a proper matter for stockholder action.

In the case of nominations for election at an annual meeting, notice must be delivered to our secretary (i) not less than 90 days nor more than 120 days prior to the first anniversary of the preceding year’s annual

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meeting or (ii) if the date of the annual meeting is advanced by more than 30 days or delayed by more than 60 days from the first anniversary of the preceding year’s annual meeting, not more than 120 days nor less than 90 days prior to the date of such annual meeting or, if less than 90 days’ notice is given of such annual meeting, the 10th day following the day on which public announcement of the date of such meeting is first made by Leap. In the case of nominations for election at a special meeting of stockholders called for the election of directors, a stockholder may nominate candidates by delivering notice to Leap’s secretary not less than 90 days nor more than 120 days prior to such special meeting or, if less than 90 days’ notice is given of such special meeting, the 10th day following the day on which public announcement of the date of such meeting is first made by Leap. In addition, each such stockholder’s notice must include certain information regarding the stockholder and the director nominee as set forth in our bylaws.

Staggered Board

Our certificate of incorporation provides that our board of directors is divided into three classes of directors, with the classes as nearly equal in number as possible. At each annual meeting of the stockholders, a class of directors is elected for a three-year term to succeed the directors of the same class whose terms are then expiring. As a result, approximately one-third of our directors is elected each year.

Our certificate of incorporation, and bylaws provide that the number of our directors shall be fixed from time to time by a resolution of the majority of our board of directors. Any additional directorships resulting from an increase in the number of directors will be distributed among the three classes so that, as nearly as possible, each class shall consist of one third of the board of directors.

The division of our board of directors into three classes with staggered three-year terms may delay or prevent stockholder efforts to effect a change of our management or a change in control.

Action by Written Consent; Special Meetings of Stockholders.

Our certificate of incorporation provides that stockholder action can be taken only at an annual or special meeting of stockholders and cannot be taken by written consent in lieu of a meeting. Our certificate of incorporation and bylaws also provide that, except as otherwise required by law, special meetings of the stockholders can be called only by or at the direction of the board of directors pursuant to a resolution adopted by a majority of the total number of directors, by the chairperson of the board of directors, chief executive officer or president (in the absence of a chief executive officer). Except as provided above, stockholders are not permitted to call a special meeting or to require the board of directors to call a special meeting.

Removal of Directors.

Our certificate of incorporation provides that our directors may be removed only for cause by the affirmative vote of at least two-thirds of the voting power of our outstanding shares of capital stock, voting together as a single class and entitled to vote in the election of directors. This requirement of a supermajority vote to remove directors could enable a minority of our stockholders to prevent a change in the composition of our board.

Transfer Agent And Registrar

The transfer agent and registrar for our common stock is Continental Stock Transfer & Trust Company whose address is One State Street, 30th Floor, New York, NY 10004-1561.

Nasdaq Capital Market Listing

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

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DESCRIPTION OF WARRANTS

The following description, together with the additional information we may include in any applicable prospectus supplements and free writing prospectuses, 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 issued independently or together with common stock, preferred stock or debt securities offered by any prospectus supplement, and may be attached to or separate from those securities. 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 that we may offer in more detail in the applicable prospectus supplement and any applicable free writing prospectus. The terms of any warrants offered under a prospectus supplement may differ from the terms described below. However, no prospectus supplement will fundamentally change the terms that are set forth in this prospectus or offer a security that is not registered and described in this prospectus at the time of its effectiveness.

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 agreement, if any, including a form of warrant certificate, that describes the terms of the particular series of warrants we are offering. The following summaries of material provisions of the warrants and the warrant agreements are subject to, and qualified in their entirety by reference to, all the provisions of the warrant agreement and warrant certificate applicable to the particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplements related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectuses, and the complete warrant agreements and warrant certificates that contain the terms of the warrants.

General

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

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the title of such securities;

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the offering price or prices and aggregate number of warrants offered;

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the currency or currencies 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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if applicable, the date on and after which the warrants and the related securities will be separately transferable;

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if applicable, the minimum or maximum amount of such warrants which may be exercised at any one time;

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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 which, 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, and the currency in 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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the terms of any rights to force the exercise of 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 any material or special United States federal income tax consequences 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. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants by delivering the warrant certificate representing the warrants to be exercised together with specified information, and paying the required amount to the warrant agent in immediately available funds, as provided in the applicable prospectus supplement. We will set forth on the reverse side of the warrant certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver to the warrant agent in connection with the exercise of the warrant.

Upon receipt of the required payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, we will issue and deliver the securities purchasable upon such exercise. If fewer than all of the warrants represented by the warrant certificate are exercised, then we will issue a new warrant certificate for the remaining amount of warrants. If we so indicate in the applicable prospectus supplement, holders of the warrants may surrender securities as all or part of the exercise price for warrants.

Enforceability Of Rights By Holders Of Warrants

Each warrant agent 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.

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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 an indenture to be entered into between us and a trustee to be identified in the applicable prospectus supplement. The indenture will be qualified under the Trust Indenture Act of 1939, as amended, or the Trust Indenture Act. We will file 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 will 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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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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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.

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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, of such series of debt securities 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.

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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;

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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

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, 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 above under “Description of Debt Securities —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 above under “Description of Debt Securities — General” to establish the

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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

The indenture will provide 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 will provide 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.

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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.

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DESCRIPTION OF RIGHTS

The following is a general description of the terms of the rights we may issue from time to time unless we provide otherwise in the applicable prospectus supplement. Particular terms of any rights we offer will be described in the prospectus supplement relating to such rights.

General

We may issue rights to purchase common stock, preferred stock, debt securities or units. Rights may be issued independently or together with other securities and may or may not be transferable by the person purchasing or receiving the rights. In connection with any rights offering to our stockholders, we may enter into a standby underwriting, backstop or other arrangement with one or more underwriters or other persons pursuant to which such underwriters or other persons would purchase any offered securities remaining unsubscribed for after such rights offering. In connection with a rights offering to our stockholders, we would distribute certificates evidencing the rights and a prospectus supplement to our stockholders on or about the record date that we set for receiving rights in such rights offering.

The applicable prospectus supplement will describe the following terms of any rights we may issue, including some or all of the following:

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the title and aggregate number of the rights;

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the subscription price or a formula for the determination of the subscription price for the rights and the currency or currencies in which the subscription price may be payable;

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

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the number or a formula for the determination of the number of the rights issued to each stockholder;

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the extent to which the rights are transferable;

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in the case of rights to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one right;

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in the case of rights to purchase common stock or preferred stock, the type of stock and number of shares of stock purchasable upon exercise of one right;

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the date on which the right to exercise the rights will commence, and the date on which the rights will expire (subject to any extension);

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if applicable, the minimum or maximum amount of the rights that may be exercised at any one time;

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the extent to which such rights include an over-subscription privilege with respect to unsubscribed securities;

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if applicable, the procedures for adjusting the subscription price and number of shares of common stock or preferred stock purchasable upon the exercise of each right upon the occurrence of certain events, including stock splits, reverse stock splits, combinations, subdivisions or reclassifications of common stock or preferred stock;

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the effect on the rights of any merger, consolidation, sale or other disposition of our business;

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

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information with respect to book-entry procedures, if any;

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the terms of the securities issuable upon exercise of the rights;

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if applicable, the material terms of any standby underwriting, backstop or other purchase arrangement that we may enter into in connection with the rights offering;

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if applicable, a discussion of certain U.S. federal income tax considerations; and

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any other terms of the rights, including terms, procedures and limitations relating to the exchange and exercise of the rights.

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Exercise of Rights

Each right will entitle the holder to purchase for cash or other consideration such shares of stock or principal amount of securities at the subscription price as shall in each case be set forth in, or be determinable as set forth in, the prospectus supplement relating to the rights offered thereby. Rights may be exercised as set forth in the applicable prospectus supplement beginning on the date specified therein and continuing until the close of business on the expiration date set forth in the prospectus supplement relating to the rights offered thereby. After the close of business on the expiration date, unexercised rights will become void.

Upon receipt of payment and a subscription certificate properly completed and duly executed at the corporate trust office of the subscription agent or any other office indicated in the prospectus supplement, we will, as soon as practicable, forward the securities purchasable upon such exercise. If less than all of the rights represented by such subscription certificate are exercised, a new subscription certificate will be issued for the remaining rights. If we so indicate in the applicable prospectus supplement, holders of the rights may surrender securities as all or part of the exercise price for rights.

We may determine to offer any unsubscribed offered securities directly to stockholders, persons other than stockholders, to or through agents, underwriters or dealers or through a combination of such methods, including pursuant to standby underwriting, backstop or other arrangements, as set forth in the applicable prospectus supplement.

Prior to exercising their rights, holders of rights will not have any of the rights of holders of the securities purchasable upon subscription, including, in the case of rights 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 any voting rights or, in the case of rights to purchase debt securities, the right to receive principal, premium, if any, or interest payments, on the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture.

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DESCRIPTION OF UNITS

We may issue units comprising one or more securities described in this prospectus in any combination. The following description sets forth certain general terms and provisions of the units that we may offer pursuant to this prospectus. The particular terms of the units and the extent, if any, to which the general terms and provisions may apply to the units so offered will be described in the applicable prospectus supplement.

Each unit will be issued so that the holder of the unit also is the holder of each security included in the unit. Thus, the unit will have the rights and obligations of a holder of each included security. Units will be issued pursuant to the terms of a unit agreement, which may provide that the securities included in the unit may not be held or transferred separately at any time or at any time before a specified date. A copy of the forms of the unit agreement and the unit certificate relating to any particular issue of units will be filed with the SEC each time we issue units, and you should read those documents for provisions that may be important to you. For more information on how you can obtain copies of the forms of the unit agreement and the related unit certificate, see “Where You Can Find More Information.”

The prospectus supplement relating to any particular issuance of units will describe the terms of those units, including, to the extent applicable, the following:

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the designation and terms of the units and the securities comprising the units, including whether and under what circumstances those securities may be held or transferred separately;

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any provision for the issuance, payment, settlement, transfer or exchange of the units or of the securities comprising the units; and

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whether the units will be issued in fully registered or global form.

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PLAN OF DISTRIBUTION

We may sell the securities covered hereby from time to time pursuant to underwritten public offerings, direct sales to the public, negotiated transactions, block trades or a combination of these methods. A distribution of the securities offered by this prospectus may also be effected through the issuance of derivative securities, including without limitation, warrants and subscriptions. We may sell the securities to or through underwriters or dealers, 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;

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at varying prices determined at the time of sale; or

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at negotiated prices.

We may also sell equity securities covered by this registration statement in an “at the market offering” as defined in Rule 415 under the Securities Act. Such offering may be made into an existing trading market for such securities in transactions at other than a fixed price, either:

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on or through the facilities of The Nasdaq Capital Market or any other securities exchange or quotation or trading service on which such securities may be listed, quoted or traded at the time of sale; and/or

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to or through a market maker otherwise than on The Nasdaq Capital Market or such other securities exchanges or quotation or trading services.

Such at-the-market offerings, if any, may be conducted by financial institutions acting as principal or agent.

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 any underwriters, dealers or agents participating in the offering, if any;

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the purchase price of the securities sold by us to any underwriter or dealer and the net proceeds we expect to receive from the offering;

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any option, under which underwriters may purchase additional securities from us;

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any agency fees or underwriting discounts or commissions 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 are underwriters of the securities offered by the prospectus supplement.

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 option to purchase additional securities. Any public offering price and any discounts, commissions or concessions allowed or reallowed or

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paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, 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 and other compensation we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for the period of its appointment.

We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

We may provide agents and underwriters with indemnification against civil liabilities related to this offering, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may make with respect to these liabilities. Agents and underwriters 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. Accordingly, we cannot guarantee the liquidity of the trading markets for any securities.

Any underwriter may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids in accordance with Regulation M under the Exchange Act. Overallotment 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. Short covering transactions involve purchases of the securities 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. These transactions may be effected on any exchange or over-the-counter market or otherwise.

Any agents and underwriters who are qualified market makers on The Nasdaq Capital Market may engage in passive market making transactions in the securities on The Nasdaq Capital Market in accordance with Rule 103 of Regulation M, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. 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.

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LEGAL MATTERS

Unless otherwise indicated in the applicable prospectus supplement, certain legal matters in connection with the offering and the validity of the securities offered by this prospectus, and any supplement thereto, will be passed upon for us by Morgan, Lewis & Bockius LLP. Additional legal matters may be passed upon for us or any underwriters, dealers or agents, by counsel that we will name in the applicable prospectus supplement.

EXPERTS

The consolidated balance sheets of Leap Therapeutics, Inc. and Subsidiaries as of December 31, 2023 and 2022, and the related consolidated statements of operations, comprehensive loss, stockholders’ equity, and cash flows for each of the years then ended have been audited by EisnerAmper LLP, independent registered public accounting firm, as stated in their report which is incorporated herein by reference. Such financial statements have been incorporated herein by reference in reliance on the report of such firm given upon their authority as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

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.

We maintain a website at www.leaptx.com. Information contained in or accessible through our website does not constitute a part of this prospectus.

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INFORMATION INCORPORATED BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus the information contained in documents that we file with them, 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 before the date of this prospectus, while information that we file later with the SEC will automatically update and supersede prior information. Any information so updated and superseded shall not be deemed, except as so updated and superseded, to constitute a part of this prospectus. We incorporate by reference the documents listed below and any future filings we will make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, prior to the termination of the offering. Notwithstanding the foregoing, unless specifically stated to the contrary, none of the information that is not deemed “filed” with the SEC, including information furnished under Items 2.02 or 7.01 of any Current Report on Form 8-K, will be incorporated by reference into, or otherwise included in, this prospectus:

our annual report on Form 10-K for the fiscal year ended December 31, 2023 filed with the SEC on March 18, 2024 (the “Form 10-K”);

the information contained in our definitive proxy statement on Schedule 14A for our 2023 annual meeting of stockholders filed with the SEC on April 28, 2023, to the extent incorporated by reference in Part III of the Form 10-K;

our current reports on Form 8-K filed with the SEC on January 16, 2024 and January 23, 2024; and

our description of our common stock contained in the registration statement on Form 8-A, filed on January 20, 2017, as updated by Exhibit 4.6 to the Form 10-K, and including any amendments or reports filed for the purpose of updating such description.

We will provide, upon written or oral request, without charge to you, including any beneficial owner to whom this prospectus is delivered, a copy of any or all of the documents incorporated herein by reference other than the exhibits to those documents, unless the exhibits are specifically incorporated by reference into the information that this prospectus incorporates. You should direct a request for copies to us at Attention: Secretary, 47 Thorndike Street, Suite B1-1, Cambridge, Massachusetts 02141 or you may call us at (617) 714-0360.

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DISCLOSURE OF COMMISSION’S POSITION ON INDEMNIFICATION
FOR SECURITIES ACT LIABILITY

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers or persons controlling the Company pursuant to the foregoing provisions, we have been informed that in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, we will, unless in the opinion of our counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by us is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

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Up to $200,000,000 of Common Stock

PROSPECTUS SUPPLEMENT

November 12, 2025

SEC Form 424B5 filed by Leap Therapeutics Inc.