0001193125-26-210292 | 10-Q | XBRL Viewer | Amylyx Pharmaceuticals INC

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Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2026
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Rule 10b5-1 Arrangement Modified	false
Non-Rule 10b5-1 Arrangement Modified	false

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2026	Mar. 31, 2025
Pay vs Performance Disclosure
Net Income (Loss)	$ (41,284)	$ (35,907)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Fair Value Measurements

3 Months Ended

Mar. 31, 2026

Fair Value Disclosures [Abstract]

Fair Value Measurements

5. FAIR VALUE MEASUREMENTS

The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicates the level of the fair value hierarchy utilized to determine such fair values (in thousands):


	March 31, 2026
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	205,722	$	—	$	—	$	205,722
Restricted cash equivalents		986		—		—		986
Treasury bills		50,632		—		—		50,632
Total financial assets	$	257,340	$	—	$	—	$	257,340


	December 31, 2025
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	207,599	$	—	$	—	$	207,599
Restricted cash equivalents		985		—		—		985
Treasury bills		90,328		—		—		90,328
Total financial assets	$	298,912	$	—	$	—	$	298,912

The Company classifies its cash equivalents and marketable securities as Level 1 assets under the fair value hierarchy, as these assets have been valued using quoted market prices for identical assets in active markets without any valuation adjustment.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

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+ Details

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2026

Fair Value Disclosures [Abstract]

Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis


	March 31, 2026
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	205,722	$	—	$	—	$	205,722
Restricted cash equivalents		986		—		—		986
Treasury bills		50,632		—		—		50,632
Total financial assets	$	257,340	$	—	$	—	$	257,340


	December 31, 2025
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	207,599	$	—	$	—	$	207,599
Restricted cash equivalents		985		—		—		985
Treasury bills		90,328		—		—		90,328
Total financial assets	$	298,912	$	—	$	—	$	298,912

Marketable Securities - Schedule of Marketable Securities Classified as Available-for-sale (Details) - Marketable Securitites - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	$ 50,635	$ 90,288
Unrealized Gain	1	40
Unrealized Loss	(4)
Fair Value	50,632	90,328
Treasury Bills
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	50,635	90,288
Unrealized Gain	1	40
Unrealized Loss	(4)
Fair Value	$ 50,632	$ 90,328

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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+ Details

Segments - Additional Information (Details)	3 Months Ended
Segments - Additional Information (Details)	Mar. 31, 2026 Segment
Segment Reporting [Abstract]
Number of operating segments	1
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]	CO Chief Executive Officer [Member]
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description	The CODM assess segment performance and decide how to allocate resources based on consolidated net loss. The CODM use net loss to monitor budget and forecast versus actual results in assessing segment performance and to determine how to allocate resources.

Stock Option and Grant Plan - Summary of Restricted Stock Unit Activity (Details) - Restricted Stock Unit	3 Months Ended
	Mar. 31, 2026 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Nonvested \| shares	2,725,084
Number of shares, Granted \| shares	1,952,447
Number of shares, Vested \| shares	(676,314)
Number of shares, Forfeited \| shares	(68,067)
Number of shares, Nonvested \| shares	3,933,150
Weighted Average Grant Date Fair Value, Nonvested \| $ / shares	$ 8.12
Weighted Average Grant Date Fair Value, Granted \| $ / shares	14.01
Weighted Average Grant Date Fair Value, Vested \| $ / shares	10.95
Weighted Average Grant Date Fair Value, Forfeited \| $ / shares	7.76
Weighted Average Grant Date Fair Value, Nonvested \| $ / shares	$ 10.56

Net Loss Per Share - Schedule of Antidilutive Shares Excluded from the Calculation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total excluded common stock equivalents	17,424,661	14,159,728
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total excluded common stock equivalents	11,441,942	9,620,559
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total excluded common stock equivalents	3,933,150	3,174,067
Performance-Based Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total excluded common stock equivalents	2,049,569	1,365,102

Stock Option and Grant Plan - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 6,120	$ 6,833
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	1,755	1,822
Selling, General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 4,365	$ 5,011

- Definition

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+ Details

Stock Option and Grant Plan - Summary of Performance-Based Restricted Stock Unit Activity (Details) - Performance-Based Restricted Stock Unit	3 Months Ended
	Mar. 31, 2026 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares, Nonvested \| shares	2,089,494
Number of shares, Forfeited \| shares	(39,925)
Number of shares, Nonvested \| shares	2,049,569
Weighted Average Grant Date Fair Value, Nonvested \| $ / shares	$ 6.01
Weighted Average Grant Date Fair Value, Forfeited \| $ / shares	6.48
Weighted Average Grant Date Fair Value, Nonvested \| $ / shares	$ 6

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Nature of the Business

3 Months Ended

Mar. 31, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of the Business

1. Nature of the Business

Amylyx Pharmaceuticals, Inc., together with its wholly-owned subsidiaries, known as Amylyx or the Company, is a clinical-stage pharmaceutical company with a mission to develop novel therapies for communities with high unmet medical needs. The Company has preclinical and clinical development programs underway in endocrine conditions and neurodegenerative diseases. The Company is currently developing four investigational therapies for potential impact across several diseases: avexitide in PBH, AMX0035 in Wolfram syndrome, AMX0114 in ALS, and AMX0318 in PBH and other rare diseases.

Risks and Uncertainties

The Company is subject to risks and uncertainties common to companies in the biotechnology industry, including, but not limited to, the outcome of preclinical studies and clinical trials, potential difficulties with or delays in timing with respect to regulatory approval processes, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, ability to secure additional capital to fund operations, and risks associated with the economic challenges caused by economic uncertainty in various global markets caused by geopolitical instability and conflict. The Company and its contractors may experience disruptions in supply of items that are essential for its research and development activities, including, for example, raw materials and bulk drug substances that the Company imports from Europe and Canada used in the manufacturing of AMX0035 and any additional or future product candidates.

The accompanying consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company expects to continue to generate operating losses for the foreseeable future. The Company expects that its cash, cash equivalents and marketable securities will be sufficient to fund its operating expenses and capital expenditure requirements for at least 12 months from the issuance of these consolidated financial statements.

To continue its development efforts, the Company may need to obtain substantial additional funding through public or private equity offerings, debt financings, collaborations, strategic alliances and/or licensing arrangements in order to fund its research and development and ongoing operating expenses. The Company may not be able to obtain financing on acceptable terms, when needed or at all, and the Company may not be able to enter into collaborations, strategic alliances or licensing arrangements. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. Any collaborations, strategic alliances or licensing arrangements may require the Company to relinquish rights to certain of its technologies, future revenue streams, research programs or product candidates or grant licenses on terms that may not be favorable to the Company. If the Company is unable to obtain funding, the Company could be forced to delay, limit, reduce or eliminate some or all of its research and development programs, pipeline expansion or future commercialization efforts or grant rights to develop and market product candidates, which could adversely affect its business prospects. Although management will continue to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations when needed or at all.

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	$ 50,632	$ 90,328
Fair Value Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	257,340	298,912
Fair Value Measurements, Recurring \| Cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	205,722	207,599
Fair Value Measurements, Recurring \| Restricted Cash Equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	986	985
Fair Value Measurements, Recurring \| Treasury Bills
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	50,632	90,328
Fair Value Measurements, Recurring \| Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	257,340	298,912
Fair Value Measurements, Recurring \| Level 1 \| Cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	205,722	207,599
Fair Value Measurements, Recurring \| Level 1 \| Restricted Cash Equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	986	985
Fair Value Measurements, Recurring \| Level 1 \| Treasury Bills
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	$ 50,632	$ 90,328

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025	Oct. 30, 2025
Commitments And Contingencies [Line Items]
Restricted cash	$ 1.0	$ 1.0
Claims settlement amount			$ 6.5
Collateral for Letter of Credit Issued
Commitments And Contingencies [Line Items]
Restricted cash	0.9
Collateral for Corporate Credit Card Program
Commitments And Contingencies [Line Items]
Restricted cash	$ 0.1

Subsequent Events - Additional Information (Details) - USD ($)	Apr. 09, 2026	Mar. 31, 2026	Oct. 30, 2025
Subsequent Event [Line Items]
Settlement liability		$ 0
Claims settlement amount			$ 6,500,000
Subsequent Event
Subsequent Event [Line Items]
Claims settlement amount	$ 6,500,000

Marketable Securities - Additional Information (Details)	3 Months Ended
	Mar. 31, 2026 USD ($) Security	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($)
Debt Securities, Available-for-Sale [Line Items]
Realized gains	$ 0	$ 0
Realized loss	$ 0	$ 0
Debt securities available-for-sale in an unrealized loss position for greater than 12 months \| Security	0
Available-for-Sale Securities \| Maximum
Debt Securities, Available-for-Sale [Line Items]
Accrued interest receivable	$ 100,000		$ 100,000

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Accrued Expenses (Tables)

3 Months Ended

Mar. 31, 2026

Payables and Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses consisted of the following (in thousands):


	March 31, 2026		December 31, 2025
Accrued external research and development	$	5,858	$	5,355
Accrued employee compensation and benefits		3,196		10,055
Accrued consulting and other professional fees		1,833		1,855
Other accrued expenses		395		645
Total accrued expenses	$	11,282	$	17,910

Stockholders' Equity - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Equity [Abstract]
Dividends paid	$ 0	$ 0

Net Loss Per Share

3 Months Ended

Mar. 31, 2026

Earnings Per Share [Abstract]

Net Loss Per Share

8. NET LOSS PER SHARE

Net Loss per Share

Basic earnings per share is computed by dividing net loss by the weighted average number of common shares outstanding during the period. Diluted earnings per share is calculated based on the combined weighted average number of common shares and potentially dilutive shares, which include the assumed exercise of employee stock options, unvested RSUs and unvested PSUs. In computing diluted earnings per share, the Company utilizes the treasury stock method.

Because the Company reports a net loss attributable to common stockholders, basic and diluted net loss per share attributable to common stockholders are the same for both periods presented.

All stock options, RSUs and PSUs units were excluded from the computation of diluted weighted-average shares outstanding because such securities would have an antidilutive impact for the three months ended March 31, 2026. The following stock options, RSUs and PSUs outstanding at each period end have been excluded from the calculation of diluted net loss per share because their inclusion would have been antidilutive:


	Three Months Ended March 31,
	2026		2025
Options to purchase common stock		11,441,942		9,620,559
Restricted stock units		3,933,150		3,174,067
Performance-based restricted stock units		2,049,569		1,365,102
Total excluded common stock equivalents		17,424,661		14,159,728

Segments - Schedule of Segment Revenue and Expenses to Consolidated Net Loss (Details) - USD ($)
$ in Thousands

3 Months Ended

Mar. 31, 2026

Mar. 31, 2025

Direct research and development expenses by program:

Selling, general and administrative

$ 16,169

$ 15,684

Interest income

(2,570)

(2,231)

Net loss

(41,284)

(35,907)

Operating Segments [Member]

Direct research and development expenses by program:

^[1]

8,994

8,358

Selling, general and administrative

16,169

15,684

Interest income

(2,570)

(2,231)

Other segment items

^[2]

335

Net loss

(41,284)

(35,907)

Operating Segments [Member] | Avexitide

Direct research and development expenses by program:

Total direct research and development expenses by program

^[3],[4]

9,990

5,426

Operating Segments [Member] | AMX0035 - PSP

Direct research and development expenses by program:

Total direct research and development expenses by program

^[3],[4]

649

4,563

Operating Segments [Member] | Other programs

Direct research and development expenses by program:

Total direct research and development expenses by program

^[5]

$ 7,977

$ 3,772

[1]	The Company does not allocate personnel and other similar costs to specific programs because these costs are deployed across multiple programs.
[2]	Other segment items primarily consists of net realized and unrealized losses on foreign exchange transactions.
[3]	Depreciation and amortization expense of $0.1 million during the three months ended March 31, 2026, and $0.2 million during the three months ended March 31, 2025, are allocated across the significant expense captions.
[4]	The significant expense categories and amounts align with the segment-level information that is regularly provided to the CODM. As the Company has one reportable segment, there were no intersegment eliminations for the three months ended March 31, 2026 and 2025.
[5]	Other programs includes milestone payments totaling $4.0 million made to Gubra following the selection and handover of AMX0318 as a development candidate for PBH and other rare diseases during the three months ended March 31, 2026.

Stockholders' Equity

3 Months Ended

Mar. 31, 2026

Stockholders' Equity Note [Abstract]

Stockholders' Equity

7. STOCKHOLDERS’ EQUITY

Common Stock

Under the Company’s Fourth Amended and Restated Certificate of Incorporation, or the certificate of incorporation, each share of common stock entitles the holder to one vote on all matters submitted to the stockholders for a vote provided, however, that, except as otherwise required by law, holders of common stock shall not be entitled to vote on any amendment to the Company’s certificate of incorporation that relates solely to the terms of one or more outstanding series of preferred stock if the holders of such affected series are entitled, either separately or together with the holders of one or more other such series, to vote thereon pursuant to the certificate of incorporation or pursuant to the Delaware General Corporation Law. Holders of common stock are entitled to receive dividends, as may be declared by the Company’s Board of Directors, if any, subject to the preferential dividend rights of the preferred stock. No dividends were declared or paid during the three months ended March 31, 2026 and 2025.

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2026	Apr. 27, 2026
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2026
Document Fiscal Year Focus	2026
Document Fiscal Period Focus	Q1
Trading Symbol	AMLX
Entity Registrant Name	Amylyx Pharmaceuticals, Inc.
Entity Central Index Key	0001658551
Current Fiscal Year End Date	--12-31
Entity File Number	001-41199
Entity Tax Identification Number	46-4600503
Entity Address, Address Line One	55 Cambridge Parkway
Entity Address, Address Line Two	Suite 6W
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	617
Local Phone Number	682-0917
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		111,186,317
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Asset Acquisitions and Collaboration Agreements

3 Months Ended

Mar. 31, 2026

Asset Acquisition [Abstract]

Asset Acquisitions and Collaboration Agreements

10. asset aCQUISITIONS and collaboration agreements

Gubra A/S Collaboration and License Agreement

On December 23, 2024, the Company entered into a collaboration and license agreement, or the Gubra Agreement, with Gubra pursuant to which the parties will perform research and discovery activities for the development of a potential novel long-acting GLP-1 receptor antagonist, under the oversight of a joint research committee. The collaboration provides the Company an exclusive license to develop, manufacture, commercialize and otherwise exploit any development candidate and product(s) arising in the performance of activities under the agreement.

The Company made an immaterial upfront payment in January 2025, which became due upon the effective date of the Gubra Agreement. Since the payment was made for the use of Gubra’s intellectual property and research and development services and there is no alternative use, the Company recorded the upfront payment to research and development expense on the consolidated statements of operations in 2024. Gubra is eligible to receive an additional $53.5 million upon the achievement of certain development, regulatory and commercial milestones, as well as tiered royalties on future sales from any products that result from the agreement. Certain milestones were met and paid in the first quarter of 2026, specifically the selection and handover of the development candidate, which provided a milestone payment of $4 million to Gubra.

Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2026

Investments, Debt and Equity Securities [Abstract]

Schedule of Marketable Securities Classified as Available-for-sale

Marketable securities, which are classified as available-for-sale, consisted of the following (in thousands):


Balance at March 31, 2026:	Amortized Cost Basis		Unrealized Gain		Unrealized Loss			Fair Value
Treasury bills	$	50,635	$	1	$	(4	)	$	50,632
Total marketable securities	$	50,635	$	1	$	(4	)	$	50,632


Balance at December 31, 2025:	Amortized Cost Basis		Unrealized Gain		Unrealized Loss		Fair Value
Treasury bills	$	90,288	$	40	$	—	$	90,328
Total marketable securities	$	90,288	$	40	$	—	$	90,328

- Definition

Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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+ Details

Asset Acquisitions and Collaboration Agreements - Additional Information (Details) - Gubra Agreement - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Dec. 31, 2024
Asset Acquisition [Line Items]
Additional amount eligible to receive upon achievement of certain milestones		$ 53.5
Milestone payment for development candidate	$ 4.0

Segments - Schedule of Segment Revenue and Expenses to Consolidated Net Loss (Parenthetical) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2026 USD ($) Segment	Mar. 31, 2025 USD ($) Segment
Segment Reporting Information [Line Items]
Number of operating segments	1
Gubra Agreement [Member]
Segment Reporting Information [Line Items]
Milestone payment for development candidate \| $	$ 4.0
Operating Segments [Member]
Segment Reporting Information [Line Items]
Number of operating segments	1
Depreciation and amortization expense \| $	$ 0.1	$ 0.2
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Number of operating segments	0	0

Segments

3 Months Ended

Mar. 31, 2026

Segment Reporting [Abstract]

Segments

11. Segments

The Company views its operations and manages its business as one operating segment and reporting unit. Our operating segments are determined based on how our Co-Chief Executive Officers, who collectively serve as our chief operating decision makers, or CODM, manage our business, regularly access discrete financial information, and evaluate performance for operating decision-making purposes, including allocation of resources or capital to specific compounds or projects in line with the Company’s overall strategies and goals. The Company’s entire business is managed by a single management team, which reports to the CODM.

The CODM assess segment performance and decide how to allocate resources based on consolidated net loss. The CODM use net loss to monitor budget and forecast versus actual results in assessing segment performance and to determine how to allocate resources. The measure of segment assets used in determining how to manage and allocate resources is reported on the consolidated balance sheets as total assets. All of the Company's long-lived assets were held within the U.S.

The following table reconciles segment revenue and expenses to consolidated net loss for the three months ended March 31, 2026 and 2025 (in thousands):


	Three Months Ended March 31,
	2026			2025
Direct research and development expenses by program1,2:
Avexitide	$	9,990		$	5,426
AMX0035 - PSP		649			4,563
Other programs3		7,977			3,772
Personnel-related research and development4		8,994			8,358
Selling, general and administrative		16,169			15,684
Interest income		(2,570	)		(2,231	)
Other segment items5		75			335
Net loss	$	(41,284	)	$	(35,907	)

1. The significant expense categories and amounts align with the segment-level information that is regularly provided to the CODM. As the Company has one reportable segment, there were no intersegment eliminations for the three months ended March 31, 2026 and 2025.

2. Depreciation and amortization expense of $0.1 million during the three months ended March 31, 2026, and $0.2 million during the three months ended March 31, 2025, are allocated across the significant expense captions.

3. Other programs includes milestone payments totaling $4.0 million made to Gubra following the selection and handover of AMX0318 as a development candidate for PBH and other rare diseases during the three months ended March 31, 2026.

4. The Company does not allocate personnel and other similar costs to specific programs because these costs are deployed across multiple programs.

5. Other segment items primarily consists of net realized and unrealized losses on foreign exchange transactions.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 47
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-47

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-22

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Section 50
-Paragraph 34
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-34

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-26C

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Publisher FASB
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Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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Reference 24: http://www.xbrl.org/2003/role/disclosureRef
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Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-41

+ Details

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Payables and Accruals [Abstract]
Accrued external research and development	$ 5,858	$ 5,355
Accrued employee compensation and benefits	3,196	10,055
Accrued consulting and other professional fees	1,833	1,855
Other accrued expenses	395	645
Total accrued expenses	$ 11,282	$ 17,910

Marketable Securities

3 Months Ended

Mar. 31, 2026

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

3. MARKETABLE SECURITIES

The Company has classified all of its marketable securities at March 31, 2026 as “available-for-sale”. The Company records available-for-sale securities at fair value, with the unrealized gains and losses included as a separate component of other accumulated comprehensive loss. There were no realized gains or losses recognized during the three months ended March 31, 2026 and 2025.

The Company adjusts the cost of available-for-sale debt securities for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. The cost of securities sold is based on the specific identification method. The Company includes interest and dividends on securities classified as available-for-sale in interest income. Accrued interest receivable relating to the Company’s available-for-sale securities is presented within prepaid expenses and other current assets in the accompanying condensed consolidated balance sheets, and amounted to less than $0.1 million and $0.1 million at March 31, 2026 and December 31, 2025, respectively.

As of March 31, 2026, there were no securities in an unrealized loss position for greater than 12 months. The Company does not intend to sell the investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases. The Company did not record an allowance for credit losses as of March 31, 2026.

Marketable securities, which are classified as available-for-sale, consisted of the following (in thousands):


Balance at March 31, 2026:	Amortized Cost Basis		Unrealized Gain		Unrealized Loss			Fair Value
Treasury bills	$	50,635	$	1	$	(4	)	$	50,632
Total marketable securities	$	50,635	$	1	$	(4	)	$	50,632


Balance at December 31, 2025:	Amortized Cost Basis		Unrealized Gain		Unrealized Loss		Fair Value
Treasury bills	$	90,288	$	40	$	—	$	90,328
Total marketable securities	$	90,288	$	40	$	—	$	90,328

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Current assets:
Cash and cash equivalents	$ 229,136	$ 226,651
Marketable securities	50,632	90,328
Prepaid expenses and other current assets	5,256	6,692
Total current assets	285,024	323,671
Property and equipment, net	212	310
Restricted cash equivalents	986	985
Operating lease right-of-use assets	4,881	5,181
Other assets	2,500	2,498
Total assets	293,603	332,645
Current liabilities:
Accounts payable	3,529	3,519
Accrued expenses	11,282	17,910
Operating lease liabilities, current portion	1,155	1,259
Total current liabilities	15,966	22,688
Operating lease liabilities, net of current portion	4,476	4,698
Total liabilities	20,442	27,386
Commitments and contingencies (Note 9)
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized; 0 and 0 shares issued and outstanding as of March 31, 2026 and December 31, 2025, respectively
Common stock, $0.0001 par value; 300,000,000 shares authorized; 111,026,477 and 109,884,502 shares issued and outstanding as of March 31, 2026 and December 31, 2025, respectively	11	11
Additional paid-in capital	1,065,621	1,056,271
Accumulated deficit	(792,711)	(751,427)
Accumulated other comprehensive income	240	404
Total stockholders' equity	273,161	305,259
Total liabilities and stockholders' equity	$ 293,603	$ 332,645

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Operating expenses:
Research and development	$ 27,610	$ 22,119
Selling, general and administrative	16,169	15,684
Total operating expenses	43,779	37,803
Loss from operations	(43,779)	(37,803)
Other income, net:
Interest income	2,570	2,231
Other expense, net	(75)	(335)
Total other income, net	2,495	1,896
Net loss	$ (41,284)	$ (35,907)
Net loss per share - basic	$ (0.37)	$ (0.42)
Net loss per share - diluted	$ (0.37)	$ (0.42)
Weighted-average shares used in computing net loss per share - basic	110,563,360	85,697,108
Weighted-average shares used in computing net loss per share - diluted	110,563,360	85,697,108

Stock Option and Grant Plan

3 Months Ended

Mar. 31, 2026

Share-Based Payment Arrangement [Abstract]

Stock Option and Grant Plan

6. Stock Option and Grant Plan

Stock Incentive Plan

General Option Information

A summary of option activity for the three months ended March 31, 2026 is as follows:


	Number of Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2025		9,407,851		$	11.93		7.2	$	42,967
Granted		2,574,095		$	13.99
Exercised		(465,661	)	$	6.94			$	3,161
Cancelled or forfeited		(74,343	)	$	11.44
Outstanding at March 31, 2026		11,441,942		$	12.60		7.9	$	49,741
Options exercisable as of March 31, 2026		5,560,686		$	14.84		6.6	$	22,717
Options unvested as of March 31, 2026		5,881,256		$	10.48		9.1	$	27,023
Weighted average grant-date fair value of options granted during the period	$	11.69

The aggregate intrinsic value of options exercised during the three months ended March 31, 2026 and 2025 was $3.2 million and $0.1 million, respectively.

The total fair value of stock options vested during the three months ended March 31, 2026 and 2025 was $4.6 million and $6.7 million, respectively.

Restricted Stock Unit Activity

A summary of restricted stock unit, or RSU, activity for the three months ended March 31, 2026 is as follows:


	Number of Shares			Weighted Average Grant Date Fair Value
Nonvested as of December 31, 2025		2,725,084		$	8.12
Granted		1,952,447		$	14.01
Vested		(676,314	)	$	10.95
Forfeited		(68,067	)	$	7.76
Nonvested as of March 31, 2026		3,933,150		$	10.56

Performance-Based Restricted Stock Unit Activity

In 2025, the Company granted performance-based restricted stock units, or PSUs, whereby vesting depends upon the occurrence of certain milestone events, or the 2025 PSUs. When the achievement of milestone events, which include certain clinical milestones related to avexitide for the treatment of PBH, becomes probable, compensation cost will be recognized from the grant date over the requisite service period and a cumulative catch-up adjustment will be recorded to reflect the portion of the employees' requisite service that has been provided to date. As of March 31, 2026, none of the milestone events related to the 2025 PSUs had been deemed probable of being achieved.

A summary of PSU activity for the three months ended March 31, 2026, is as follows:


	Number of Shares			Weighted Average Grant Date Fair Value
Nonvested as of December 31, 2025		2,089,494		$	6.01
Granted		—		$	—
Vested		—		$	—
Forfeited		(39,925	)	$	6.48
Nonvested as of March 31, 2026		2,049,569		$	6.00

Summary of Stock-Based Compensation Expense

Stock-based compensation expense for the three months ended March 31, 2026 and 2025, is as follows (in thousands):


	Three Months Ended March 31,
	2026		2025
Research and development	$	1,755	$	1,822
Selling, general and administrative		4,365		5,011
Total stock-based compensation expense	$	6,120	$	6,833

The following table summarizes unrecognized stock-based compensation expense as of March 31, 2026, by type of awards (in thousands), and the weighted-average period over which that expense is expected to be recognized (in years). The total unrecognized stock-based compensation expense will be adjusted for actual forfeitures as they occur.


	March 31, 2026
	Unrecognized Expense		Weighted-average Recognition Period
Stock options	$	45,239		3.10
Restricted stock units	$	39,633		3.35
Performance-based restricted stock units	$	12,298		—

Accrued Expenses

3 Months Ended

Mar. 31, 2026

Payables and Accruals [Abstract]

Accrued Expenses

4. Accrued Expenses

Accrued expenses consisted of the following (in thousands):


	March 31, 2026		December 31, 2025
Accrued external research and development	$	5,858	$	5,355
Accrued employee compensation and benefits		3,196		10,055
Accrued consulting and other professional fees		1,833		1,855
Other accrued expenses		395		645
Total accrued expenses	$	11,282	$	17,910

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2026
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements and the related interim disclosures are unaudited and have been prepared in conformity with accounting principles generally accepted in the U.S., or GAAP, and pursuant to the rules and regulations of the SEC for the interim financial information. These unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted as permitted by the SEC’s rules and regulations for interim reporting. Interim period results are not necessarily indicative of results of operations or cash flows for a full year or any subsequent interim period. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025. In the opinion of the Company’s management, all normal and recurring adjustments necessary for a fair presentation have been reflected. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB.
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amount of expenses during the reporting period. Actual results could differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies in developing the estimates and assumptions that are used in the preparation of the financial statements. Management must apply significant judgment in this process. Management’s estimation process often may yield a range of potentially reasonable estimates and management must select an amount that falls within that range of reasonable estimates
New Accounting Pronouncements Not Yet Adopted	New Accounting Pronouncements Not Yet Adopted In November 2024, the FASB issued ASU No. 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which requires new financial statement disclosures in tabular format, in the notes to financial statements, of specified information about certain costs and expenses. The amendments in this update do not change or remove current expense disclosure requirements. The amendments in this update are effective for the Company's annual financial statement disclosure beginning December 31, 2027, and interim periods within the years beginning January 1, 2028. Early adoption is permitted. The Company is currently evaluating the impact of this ASU on its consolidated financial statements and related disclosures.

- Definition

Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478671/942-235-S50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477314/942-235-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 275
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482861/275-10-50-12

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 275
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482861/275-10-50-9

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 275
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482836/275-10-55-6

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 275
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-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482861/275-10-50-6

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 275
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-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482861/275-10-50-4

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-SubTopic 10
-Topic 275
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482861/275-10-50-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-SubTopic 10
-Topic 275
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482861/275-10-50-1

+ Details

Stock Option and Grant Plan - Summary of Unrecognized Stock-Based Compensation Expense and Weighted-Average Recognition Period (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2026 USD ($)
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized Expense	$ 45,239
Weighted-average Recognition Period	3 years 1 month 6 days
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized Expense	$ 39,633
Weighted-average Recognition Period	3 years 4 months 6 days
Performance-Based Restricted Stock Unit
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized Expense	$ 12,298

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Stock Option and Grant Plan - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Share-Based Payment Arrangement [Abstract]
Aggregate intrinsic value, exercised	$ 3,161	$ 100
Total fair value of stock options vested	$ 4,600	$ 6,700

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2026

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Significant Accounting Policies

The Company’s significant accounting policies are disclosed in the audited consolidated financial statements for the year ended December 31, 2025 and the notes thereto, which are included in the Company’s most recent Annual Report on Form 10-K. There have been no material changes to its significant accounting policies since the date of those consolidated financial statements.

Basis of Presentation and Consolidation

The accompanying condensed consolidated financial statements and the related interim disclosures are unaudited and have been prepared in conformity with accounting principles generally accepted in the U.S., or GAAP, and pursuant to the rules and regulations of the SEC for the interim financial information. These unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted as permitted by the SEC’s rules and regulations for interim reporting. Interim period results

are not necessarily indicative of results of operations or cash flows for a full year or any subsequent interim period. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025.

In the opinion of the Company’s management, all normal and recurring adjustments necessary for a fair presentation have been reflected. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB.

Use of Estimates

The preparation of the condensed consolidated financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amount of expenses during the reporting period. Actual results could differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies in developing the estimates and assumptions that are used in the preparation of the financial statements. Management must apply significant judgment in this process. Management’s estimation process often may yield a range of potentially reasonable estimates and management must select an amount that falls within that range of reasonable estimates.

New Accounting Pronouncements Not Yet Adopted

In November 2024, the FASB issued ASU No. 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which requires new financial statement disclosures in tabular format, in the notes to financial statements, of specified information about certain costs and expenses. The amendments in this update do not change or remove current expense disclosure requirements. The amendments in this update are effective for the Company's annual financial statement disclosure beginning December 31, 2027, and interim periods within the years beginning January 1, 2028. Early adoption is permitted. The Company is currently evaluating the impact of this ASU on its consolidated financial statements and related disclosures.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Cash flows used in operating activities:
Net loss	$ (41,284)	$ (35,907)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	6,120	6,833
Depreciation expense	98	156
Accretion of investment discounts, net	(609)	(1,703)
Charge for In-Process Research and Development ("IPR&D") milestones	4,000
Other non-cash items	53
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	1,433	879
Operating lease right-of-use assets	300	515
Other assets	(2)	13
Accounts payable	10	1,871
Accrued expenses	(6,674)	(11,882)
Operating lease liabilities	(327)	(599)
Net cash used in operating activities	(36,882)	(39,824)
Cash flows provided by (used in) investing activities:
Purchases of property and equipment		(11)
Milestone payments related to IPR&D	(4,000)
Purchases of investments	(19,738)	(103,648)
Proceeds from maturities of marketable securities	60,000	60,000
Net cash provided by (used in) investing activities	36,262	(43,659)
Cash flows provided by financing activities:
Proceeds from financings, net of issuance costs		65,577
Proceeds from exercise of stock options and RSUs vesting	7,159	970
Withholding taxes paid on stock-based awards	(3,942)	(885)
Net cash provided by financing activities	3,217	65,662
Effect of exchange rate changes on cash, cash equivalents and restricted cash equivalents	(111)	197
Net increase (decrease) in cash, cash equivalents and restricted cash equivalents	2,486	(17,624)
Cash, cash equivalents and restricted cash equivalents, beginning of period	227,636	78,837
Cash, cash equivalents and restricted cash equivalents, end of period	230,122	61,213
Reconciliation of cash, cash equivalents and restricted cash equivalents:
Cash and cash equivalents	229,136	59,764
Restricted cash equivalents	986	1,449
Total cash, cash equivalents and restricted cash equivalents:	$ 230,122	$ 61,213

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Beginning Balance, Shares at Dec. 31, 2024		68,629,738
Beginning Balance at Dec. 31, 2024	$ 164,765	$ 7	$ 771,542	$ (92)	$ (606,692)
Issuance of common stock upon financing, net of issuance costs, Shares		19,714,285
Issuance of common stock upon financing, net of issuance costs	65,577	$ 2	65,575
Issuance of common stock upon exercise of stock options, Shares		36,310
Issuance of common stock upon exercise of stock options	57		57
Issuance of common stock upon vesting of RSUs		700,488
Stock-based compensation expense	6,833		6,833
Other comprehensive income (loss)	92			92
Net loss	(35,907)				(35,907)
Ending Balance, Shares at Mar. 31, 2025		89,080,821
Ending Balance at Mar. 31, 2025	$ 201,417	$ 9	844,007		(642,599)
Beginning Balance, Shares at Dec. 31, 2025	109,884,502	109,884,502
Beginning Balance at Dec. 31, 2025	$ 305,259	$ 11	1,056,271	404	(751,427)
Issuance of common stock upon exercise of stock options, Shares	465,661	465,661
Issuance of common stock upon exercise of stock options	$ 3,230		3,230
Issuance of common stock upon vesting of RSUs		676,314
Stock-based compensation expense	6,120		6,120
Other comprehensive income (loss)	(164)			(164)
Net loss	$ (41,284)				(41,284)
Ending Balance, Shares at Mar. 31, 2026	111,026,477	111,026,477
Ending Balance at Mar. 31, 2026	$ 273,161	$ 11	$ 1,065,621	$ 240	$ (792,711)

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2026	Dec. 31, 2025
Statement of Financial Position [Abstract]
Preferred stock par value	$ 0.0001	$ 0.0001
Preferred stock shares authorized	10,000,000	10,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0
Common stock, stated par value per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares, issued	111,026,477	109,884,502
Common stock, shares, outstanding	111,026,477	109,884,502

Segments (Tables)

3 Months Ended

Mar. 31, 2026

Segment Reporting [Abstract]

Schedule of segment revenue and expenses to consolidated net loss

The following table reconciles segment revenue and expenses to consolidated net loss for the three months ended March 31, 2026 and 2025 (in thousands):


	Three Months Ended March 31,
	2026			2025
Direct research and development expenses by program1,2:
Avexitide	$	9,990		$	5,426
AMX0035 - PSP		649			4,563
Other programs3		7,977			3,772
Personnel-related research and development4		8,994			8,358
Selling, general and administrative		16,169			15,684
Interest income		(2,570	)		(2,231	)
Other segment items5		75			335
Net loss	$	(41,284	)	$	(35,907	)

4. The Company does not allocate personnel and other similar costs to specific programs because these costs are deployed across multiple programs.

5. Other segment items primarily consists of net realized and unrealized losses on foreign exchange transactions.

Stock Option and Grant Plan (Tables)

3 Months Ended

Mar. 31, 2026

Share-Based Payment Arrangement [Abstract]

Summary of Stock Option Activity

A summary of option activity for the three months ended March 31, 2026 is as follows:


	Number of Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2025		9,407,851		$	11.93		7.2	$	42,967
Granted		2,574,095		$	13.99
Exercised		(465,661	)	$	6.94			$	3,161
Cancelled or forfeited		(74,343	)	$	11.44
Outstanding at March 31, 2026		11,441,942		$	12.60		7.9	$	49,741
Options exercisable as of March 31, 2026		5,560,686		$	14.84		6.6	$	22,717
Options unvested as of March 31, 2026		5,881,256		$	10.48		9.1	$	27,023
Weighted average grant-date fair value of options granted during the period	$	11.69

Summary of Restricted Stock Unit Activity

A summary of restricted stock unit, or RSU, activity for the three months ended March 31, 2026 is as follows:


	Number of Shares			Weighted Average Grant Date Fair Value
Nonvested as of December 31, 2025		2,725,084		$	8.12
Granted		1,952,447		$	14.01
Vested		(676,314	)	$	10.95
Forfeited		(68,067	)	$	7.76
Nonvested as of March 31, 2026		3,933,150		$	10.56

Summary of Performance-Based Restricted Stock Unit Activity

A summary of PSU activity for the three months ended March 31, 2026, is as follows:


	Number of Shares			Weighted Average Grant Date Fair Value
Nonvested as of December 31, 2025		2,089,494		$	6.01
Granted		—		$	—
Vested		—		$	—
Forfeited		(39,925	)	$	6.48
Nonvested as of March 31, 2026		2,049,569		$	6.00

Summary of Stock-Based Compensation Expense

Stock-based compensation expense for the three months ended March 31, 2026 and 2025, is as follows (in thousands):


	Three Months Ended March 31,
	2026		2025
Research and development	$	1,755	$	1,822
Selling, general and administrative		4,365		5,011
Total stock-based compensation expense	$	6,120	$	6,833

Summary of Unrecognized Stock-Based Compensation Expense and Weighted-Average Recognition Period


	March 31, 2026
	Unrecognized Expense		Weighted-average Recognition Period
Stock options	$	45,239		3.10
Restricted stock units	$	39,633		3.35
Performance-based restricted stock units	$	12,298		—

Commitments and Contingencies

3 Months Ended

Mar. 31, 2026

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

9. Commitments and Contingencies

Letter of Credit

Restricted cash equivalents consist of $0.9 million of cash serving as collateral for a letter of credit issued for the Company’s office spaces, and $0.1 million as collateral for a corporate credit card program. As of March 31, 2026 and December 31, 2025, the Company’s restricted cash equivalents balance was $1.0 million on its condensed consolidated balance sheets.

Legal Proceedings

On February 9, 2024, a putative class action lawsuit was filed in the U.S. District Court for the Southern District of New York against us and certain of our current and former officers (Shih v. Amylyx Pharmaceuticals, Inc., et al., Case Number 1:24-CV-00988, or the Shih Complaint). Plaintiff filed an amended complaint on June 24, 2024. The Shih Complaint asserts a claim against all defendants for alleged violations of Section 10(b) of the Exchange Act and Rule 10b-5 promulgated thereunder and a claim under Section 20(a) against certain current and former officers as alleged controlling persons. The Shih Complaint alleges that defendants made materially false and misleading statements related to the commercial results and prospects for RELYVRIO. The Shih Complaint seeks unspecified damages, interest, costs and attorneys’ fees, and other unspecified relief that the court deems appropriate. On August 12, 2024, the case was transferred from the U.S. District Court for the Southern District of New York to the U.S. District Court for the District of Massachusetts, or the Court, and assigned docket number 1:24-CV-12068. Following the transfer, on September 6, 2024, defendants moved to dismiss the Shih Complaint. On September 30, 2025, the Court issued an order finding that the majority of the alleged misstatements are inactionable, but ultimately denied the motion to dismiss. The Company filed an answer on October 30, 2025. The parties have reached an agreement in principle to settle the class claims, subject to court approval, for $6.5 million, a significant portion of which will be funded by insurance proceeds.

In addition to the Shih Complaint, on October 2, 2024, a derivative complaint was filed in the U.S. District Court for the District of Massachusetts against certain current and former director and officer defendants, or the Individual Defendants, naming us as a nominal defendant (Jones v. Cohen, et al., 1:24-CV-12527, or the Jones Derivative Complaint). The substantive allegations mirror those of the Shih Complaint but also include claims for alleged violations of Section 14(a) of the Exchange Act, breach of fiduciary duty, insider trading, and unjust enrichment against the Individual Defendants. The Jones Derivative Complaint seeks unspecified damages to be awarded to the Company along with interest, restitution, unspecified corporate governance and internal procedural

reforms and improvements, and plaintiff's attorneys' fees and costs. On October 31, 2024, the Court entered an order staying the action until the earlier of the dismissal of the Shih Complaint with prejudice, including the exhaustion of all appeals, or defendants file an answer to the Shih Complaint.

On July 2, 2025, a second derivative complaint was filed in the Court against certain current and former directors and officer defendants, naming the Company as nominal defendant (Hassine v. Cohen, et al., 1:25-CV-11879, or the Hassine Derivative Complaint and, together with the Jones Derivative Complaint, the Massachusetts Derivative Complaints). The substantive allegations mirror those of the Shih Complaint but also include claims for alleged violations of Sections 14(a), 10(b), and 21D of the Exchange Act, breach of fiduciary duty, and certain other common law claims. The Hassine Derivative Complaint seeks unspecified damages to be awarded to the Company along with interest, costs, and attorneys’ fees, restitution, and certain corporate governance and internal procedural reforms and improvements. On July 16, 2025, the parties to both Massachusetts Derivative Complaints moved the Court to consolidate the Hassine Derivative Complaint with the Jones Derivative Complaint and stay the action according to the terms of the previously-entered stay of the Jones Derivative Complaint. The Court approved the motion on July 22, 2025. The parties have stipulated to a briefing schedule for Defendants’ anticipated motion to dismiss.

On April 7, 2026, a third derivative complaint was filed in Delaware Chancery Court against certain current and former directors and officer defendants, naming the Company as nominal defendant (Schweitzer v. Klee, et al., 2026-0459-BWD, the Schweitzer Complaint and, together with the Massachusetts Derivative Complaints, the Derivative Complaints). Like the Massachusetts Complaints, the substantive allegations mirror those of the Shih Complaint and allege breach of fiduciary duty and other common law claims. The Schweitzer Complaint seeks unspecified damages to be awarded to the Company along with interest, costs, and attorneys’ fees, restitution, and certain corporate governance and internal procedural reforms and improvements.

We intend to defend against the Derivative Complaints vigorously. At this time, an estimate of the impact, if any, of the claims made in the Derivative Complaints cannot be made.

Royalty Payments

The Company has entered into a limited number of grant and royalty agreements that include payment obligations contingent upon future events, such as commercialization or the receipt of proceeds from revenue-generating transactions related to the underlying technologies. As the conditions that would trigger royalty payments have not been met, no amounts have been recorded in the consolidated financial statements.

Purchase Commitments

The Company enters into agreements in the normal course of business with CMOs for raw material purchases and manufacturing services. As of March 31, 2026, there are no amounts committed under these agreements.

Net Loss Per Share (Tables)

3 Months Ended

Mar. 31, 2026

Earnings Per Share [Abstract]

Schedule of Antidilutive Shares Excluded from the Calculation of Diluted Net Loss Per Share

The following stock options, RSUs and PSUs outstanding at each period end have been excluded from the calculation of diluted net loss per share because their inclusion would have been antidilutive:


	Three Months Ended March 31,
	2026		2025
Options to purchase common stock		11,441,942		9,620,559
Restricted stock units		3,933,150		3,174,067
Performance-based restricted stock units		2,049,569		1,365,102
Total excluded common stock equivalents		17,424,661		14,159,728

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Statement of Comprehensive Income [Abstract]
Net loss	$ (41,284)	$ (35,907)
Other comprehensive income
Foreign currency translation (loss) gain	(121)	249
Net unrealized loss on available-for-sale securities	(43)	(157)
Other comprehensive (loss) income	(164)	92
Comprehensive loss	$ (41,448)	$ (35,815)

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Stock Option and Grant Plan - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Share-Based Payment Arrangement [Abstract]
Number of Options, Outstanding	9,407,851
Number of Options, Granted	2,574,095
Number of Options, Exercised	(465,661)
Number of Options, Cancelled or forfeited	(74,343)
Number of Options, Outstanding	11,441,942		9,407,851
Number of Options, Options exercisable	5,560,686
Number of Options, Options unvested	5,881,256
Weighted average grant-date fair value of options granted during the period	$ 11.69
Weighted-Average Exercise Price, Outstanding	11.93
Weighted-Average Exercise Price, Granted	13.99
Weighted-Average Exercise Price, Exercised	6.94
Weighted-Average Exercise Price, Cancelled or forfeited	11.44
Weighted-Average Exercise Price, Outstanding	12.6		$ 11.93
Weighted-Average Exercise Price, Options exercisable	14.84
Weighted-Average Exercise Price, Options unvested	$ 10.48
Weighted- Average Remaining Contractual Term (in years), Outstanding	7 years 10 months 24 days		7 years 2 months 12 days
Weighted- Average Remaining Contractual Term (in years), Options exercisable	6 years 7 months 6 days
Weighted- Average Remaining Contractual Term (in years), Options unvested	9 years 1 month 6 days
Aggregate Intrinsic Value, Outstanding	$ 42,967
Aggregate Intrinsic Value, Exercised	3,161	$ 100
Aggregate Intrinsic Value, Outstanding	49,741		$ 42,967
Aggregate Intrinsic Value, Options exercisable	22,717
Aggregate Intrinsic Value, Options unvested	$ 27,023

Subsequent Events

3 Months Ended

Mar. 31, 2026

Subsequent Events [Abstract]

Subsequent Events

12. SUBSEQUENT EVENTS

On April 9, 2026, the Company reached an agreement in principle to settle the claims arising from the Shih Complaint. Under the agreement, which is subject to court approval, the Company will pay a settlement amount of $6.5 million, a significant portion of which will be funded through insurance proceeds. The Company did not record a liability related to this matter as of March 31, 2026 as the underlying conditions did not exist at that time.

The Company expects to record the settlement charge during the second quarter of 2026, and does not expect the settlement to have a material impact on the Company's future results of operations, financial position, or liquidity beyond the amounts disclosed.