prta-20250630

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

______________________________________

FORM 10-Q

_____________________________________

(Mark One)


☒			QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended June 30, 2025


☐			TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

Commission file number: 001-35676

______________________________________

PROTHENA CORPORATION PUBLIC LIMITED COMPANY

(Exact name of registrant as specified in its charter)

______________________________________


Ireland						98-1111119
(State or other jurisdiction of incorporation or organization)						(I.R.S. Employer Identification Number)


77 Sir John Rogerson’s Quay, Block C
Grand Canal Docklands
Dublin 2,	D02 VK60,	Ireland
(Address of principal executive offices including Zip Code)

Registrant’s telephone number, including area code: 011-353-1-236-2500

______________________________________

Securities registered pursuant to Section 12(b) of the Act:


Title of Each Class	Trading Symbol	Name of Each Exchange on Which Registered
Ordinary Shares, par value $0.01 per share	PRTA	The Nasdaq Global Select Market

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.


Large accelerated filer	☒	Accelerated filer	☐
Non-accelerated filer	☐	Smaller reporting company	☐
		Emerging growth company	☐
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.			☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

The number of ordinary shares outstanding was 53,829,982 as of July 25, 2025.

PROTHENA CORPORATION PLC

Form 10-Q – QUARTERLY REPORT

For the Quarter Ended June 30, 2025

TABLE OF CONTENTS


			Page

PART I. FINANCIAL INFORMATION			1
Item 1. Financial Statements (unaudited)			1
Condensed Consolidated Balance Sheets as of June 30, 2025 and December 31, 2024			1
Condensed Consolidated Statements of Operations for the three and six months ended June 30, 2025 and 2024			2
Condensed Consolidated Statements of Cash Flows for the six months ended June 30, 2025 and 2024			3
Condensed Consolidated Statements of Shareholders' Equity for the three and six months ended June 30, 2025 and 2024			5
Notes to Condensed Consolidated Financial Statements			6
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations			24
Item 3. Quantitative and Qualitative Disclosures About Market Risk			35
Item 4. Controls and Procedures			35

PART II. OTHER INFORMATION			37
Item 1. Legal Proceedings			37
Item 1A. Risk Factors			37
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds			73
Item 3. Defaults Upon Senior Securities			73
Item 4. Mine Safety Disclosures			73
Item 5. Other Information			73
Item 6. Exhibits			74

SIGNATURES			75

EXHIBIT INDEX			74

Note Regarding Forward-Looking Statements

In addition to historical information, this Quarterly Report on Form 10-Q contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended. Forward-looking statements may include words such as “aim,” “anticipate,” “assume,” “believe,” “contemplate,” “continue,” “could,” “due,” “estimate,” “expect,” “goal,” “intend,” “may,” “objective” “plan,” “predict,” “potential,” “positioned,” “seek,” “should,” “target,” “will,” “would,” and other similar expressions that are predictions of or indicate future events and future trends, or the negative of these terms or other comparable terminology. In addition, any statements that refer to expectations, projections, or other characterizations of future events or circumstances are forward-looking statements.

These forward-looking statements, which reflect our beliefs, assumptions, expectations, estimates, forecasts, and projections about our business and the industry in which we operated as of the date hereof, are estimates based on our best judgment. These statements relate to, among other things, our goal to continue building a biology-directed discovery engine targeting protein dysregulation; the treatment potential, designs, proposed mechanisms of action, and potential administration of our drug candidates; potential indications and attributes of epitopes and antibodies we have identified in our programs; plans for ongoing and future clinical trials of our drug candidates; our potential to advance, initiate, and complete investigational new drug (“IND”) enabling studies for our discovery and preclinical programs; the expected timing of reporting data from clinical trials of our drug candidates, including initial data in August 2025 from our Phase 1 clinical trials for PRX012; our collaborations with F. Hoffman-La Roche Ltd and Hoffmann-La Roche Inc. (together “Roche”), Bristol Myers Squibb Company (“BMS”), and Novo Nordisk, and amounts we may receive under such collaborations; the sufficiency of our cash position to fund advancement of a broad pipeline and completion of our ongoing clinical trials; potential advancement of our PRX012 and PRX123 programs through non-dilutive and capital efficient structures; and our anticipated need for additional capital.

These forward-looking statements are not guarantees of future performance or development and involve known and unknown risks, uncertainties, and other factors that are in some cases beyond our control. As a result, any or all of our forward-looking statements in this Quarterly Report on Form 10-Q may turn out to be inaccurate. Factors that could cause our actual results to differ materially include, but are not limited to, the risks and uncertainties set forth below, those discussed under Part II Item 1A “Risk Factors” of this Quarterly Report on Form 10-Q, and in our other filings with the U.S. Securities and Exchange Commission.

Except as required by law or by the rules and regulations of the U.S. Securities and Exchange Commission, we undertake no obligation to revise or update any forward-looking statements to reflect any event or circumstance that arises after the date of this Quarterly Report on Form 10-Q, including without limitation:

•our ability to obtain additional financing in future offerings and/or obtain funding from future collaborations;

•our operating losses;

•our ability to successfully complete research and development of our drug candidates;

•our ability to develop, manufacture and commercialize products;

•our collaborations and other agreements with third parties, including Roche, BMS, and Novo Nordisk;

•our ability to protect our patents and other intellectual property;

•our ability to hire and retain key employees;

•our ability to maintain financial flexibility and sufficient cash, cash equivalents and investments and other assets capable of being monetized to meet our liquidity requirements;

•the timing, receipt, and amount of any capital investments, cost-sharing contributions or reimbursements, milestone payments, or royalties that we might receive under current or potential future collaborations, including any milestone payments pursuant to our agreement with Novo Nordisk;

•potential disruptions in the U.S. and global capital and credit markets, including by geopolitical conflicts and pandemics;

•government regulation of our industry;

•the volatility of the market price of our ordinary shares; and

• business disruptions.

Summary of Risks Affecting Our Business

Our business is subject to numerous risks and uncertainties. The following summary highlights some of the risks you should consider with respect to our business and prospects. These risks are described more fully in Part II Item 1A “Risk

Factors” of this Quarterly Report on Form 10-Q which includes a more complete discussion of the risks summarized below as well as a discussion of other risks related to our business, our prospects, and your investment.

•We anticipate that we will incur losses for the foreseeable future and we may never sustain profitability.

•We will require additional capital to fund our operations, and if we are unable to obtain such capital, we will be unable to successfully develop and commercialize drug candidates.

•Our success is largely dependent on the success of our research and development programs; our drug candidates are in various stages of development and we may not be able to successfully discover, develop, obtain regulatory approval for, or commercialize any drug candidates.

•We have entered into agreements to develop and bring to market drug candidates with Roche, BMS, and Novo Nordisk and may enter into additional agreements in the future, and we might not realize the anticipated benefits of such agreements including receiving anticipated milestone payments pursuant to these agreements.

•If clinical trials of our drug candidates are prolonged, delayed, suspended, or terminated, we may be unable to commercialize our drug candidates on a timely basis, which would require us to incur additional costs and delay our receipt of any revenue from potential product sales.

•Even if any of our drug candidates receives regulatory approval, if such approved product does not achieve broad market acceptance, the revenues that we generate from sales of the product will be limited.

•If we are unable to adequately protect or enforce the intellectual property relating to our drug candidates our ability to successfully commercialize our drug candidates will be harmed.

•Our future success depends on our ability to retain key personnel and to attract, retain, and motivate qualified personnel.

PART I. FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS

Prothena Corporation plc and Subsidiaries

Condensed Consolidated Balance Sheets (unaudited)

(in thousands, except share and per share data)


	June 30,		December 31,
	2025		2024
Assets
Current assets:
Cash and cash equivalents	$	371,435	$	471,388
Prepaid expenses and other current assets	14,040		14,024
Total current assets	385,475		485,412
Non-current assets:
Property and equipment, net	2,690		3,081
Operating lease right-of-use assets	9,563		10,708
Deferred tax assets	—		43,239
Restricted cash, non-current	860		860
Other non-current assets	478		3,808
Total non-current assets	13,591		61,696
Total assets	$	399,066	$	547,108
Liabilities and Shareholders’ Equity
Current liabilities:
Accounts payable	$	12,198	$	7,770
Accrued research and development	10,929		13,428
Deferred revenue, current	5,100		8,850
Restructuring liability	30,330		—
Lease liability, current	2,853		2,610
Other current liabilities	6,397		15,843
Total current liabilities	67,807		48,501
Non-current liabilities:
Deferred revenue, non-current	—		3,448
Lease liability, non-current	6,928		8,233
Total non-current liabilities	6,928		11,681
Total liabilities	74,735		60,182
Commitments and contingencies (Note 6)
Shareholders’ equity:
Euro deferred shares, €22 nominal value:	—		—
Authorized shares — 10,000 at June 30, 2025 and December 31, 2024
Issued and outstanding shares — none at June 30, 2025 and December 31, 2024
Ordinary shares, $0.01 par value:	538		538
Authorized shares — 100,000,000 at June 30, 2025 and December 31, 2024
Issued and outstanding shares — 53,826,982 and 53,826,982 at June 30, 2025 and December 31, 2024, respectively
Additional paid-in capital	1,612,096		1,588,729