Tourmaline Bio (TRML) 10-Q 7 Nov 24 2024 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 30, 2024	Nov. 01, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-40384
Entity Registrant Name	TOURMALINE BIO, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-2377352
Entity Address, Address Line One	27 West 24th Street
Entity Address, Address Line Two	Suite 702
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10010
City Area Code	646
Local Phone Number	481-9832
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	TRML
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		25,642,610
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001827506
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 35,008	$ 140,726
Short-term investments	246,916	62,225
Prepaid expenses and other current assets	11,861	5,923
Total current assets	293,785	208,874
Property and equipment, net	55	85
Long-term investments	32,467	0
Restricted cash	227	227
Operating lease right-of-use asset	252	362
Other non-current assets	1,661	747
Total assets	328,447	210,295
Current liabilities
Accounts payable	2,054	1,071
Accrued expenses and other current liabilities	5,004	3,710
Operating lease liability, current portion	226	221
Total current liabilities	7,284	5,002
Operating lease liability, net of current portion	64	194
Other liabilities	31	57
Total liabilities	7,379	5,253
Commitments and Contingencies (Note 11)
Stockholders’ equity
Undesignated preferred stock, $0.0001 par value – 10,000,000 shares authorized as of September 30, 2024 and December 31, 2023, no shares issued or outstanding as of September 30, 2024 or December 31, 2023	0	0
Common stock, $0.0001 par value – 140,000,000 voting shares authorized as of September 30, 2024 and December 31, 2023, 25,649,002 voting shares issued and 25,642,610 voting shares outstanding as of September 30, 2024; 20,337,571 voting shares issued and outstanding as of December 31, 2023; 10,000,000 non-voting shares authorized as of September 30, 2024 and December 31, 2023, no non-voting shares issued or outstanding as of September 30, 2024 or December 31, 2023	3	2
Additional paid-in capital	433,270	267,024
Accumulated other comprehensive income	821	67
Accumulated deficit	(113,026)	(62,051)
Total stockholders’ equity	321,068	205,042
Total liabilities and stockholders’ equity	$ 328,447	$ 210,295
Common stock, shares authorized (in shares)	140,000,000	25,649,002

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Undesignated preferred stock, par value (usd per share)	$ 0.0001	$ 0.0001
Undesignated preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Undesignated preferred stock, shares outstanding (in shares)	0	0
Undesignated preferred stock, shares issued (in shares)	0	0
Common stock, par value (usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	140,000,000	25,649,002
Common stock, shares, issued (in shares)	25,642,610	20,337,571
Common stock, shares, outstanding (in shares)	25,642,610	20,337,571
Nonvoting Common Stock
Common stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, shares, issued (in shares)	0	0
Common stock, shares, outstanding (in shares)	0	0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Operating expenses:
Research and development	$ 19,330	$ 3,762	$ 46,440	$ 24,353
General and administrative	5,108	2,881	17,486	6,166
Total operating expenses	24,438	6,643	63,926	30,519
Loss from operations	(24,438)	(6,643)	(63,926)	(30,519)
Other income, net	4,261	1,052	12,951	1,297
Net loss	$ (20,177)	$ (5,591)	$ (50,975)	$ (29,222)
Net loss per share, basic (usd per share)	$ (0.78)	$ (5.16)	$ (2.02)	$ (29.40)
Net loss per share, diluted (usd per share)	$ (0.78)	$ (5.16)	$ (2.02)	$ (29.40)
Weighted-average, common shares outstanding, basic (in shares)	25,767	1,084	25,197	994
Weighted-average, common shares outstanding, diluted (in shares)	25,767	1,084	25,197	994
Other comprehensive income:
Unrealized gain on investments	$ 1,273	$ 0	$ 754	$ 0
Comprehensive loss	$ (18,904)	$ (5,591)	$ (50,221)	$ (29,222)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' (Deficit) Equity (unaudited) - USD ($) $ in Thousands		Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Series A Convertible Preferred Stock
Beginning balance (in shares) at Dec. 31, 2022							27,125,000
Beginning balance at Dec. 31, 2022							$ 27,125
Ending balance at Mar. 31, 2023							$ 27,125
Ending balance (in shares) at Mar. 31, 2023							27,125,000
Beginning balance (in shares) at Dec. 31, 2022	[1]		867,499
Beginning balance at Dec. 31, 2022		$ (19,732)	$ 0	$ 195	$ 0	$ (19,927)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense		393		393
Net loss		(7,502)				(7,502)
Ending balance at Mar. 31, 2023		(26,841)	$ 0	588	0	(27,429)
Ending balance (in shares) at Mar. 31, 2023	[1]		867,499
Beginning balance (in shares) at Dec. 31, 2022							27,125,000
Beginning balance at Dec. 31, 2022							$ 27,125
Ending balance at Sep. 30, 2023							$ 127,772
Ending balance (in shares) at Sep. 30, 2023							128,148,529
Beginning balance (in shares) at Dec. 31, 2022	[1]		867,499
Beginning balance at Dec. 31, 2022		$ (19,732)	$ 0	195	0	(19,927)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from exercise of stock options, including early exercises (in shares)		1,800,000
Unrealized gain on investments		$ 0
Net loss		(29,222)
Ending balance at Sep. 30, 2023		(47,407)	$ 0	1,742	0	(49,149)
Ending balance (in shares) at Sep. 30, 2023			1,562,641
Beginning balance (in shares) at Mar. 31, 2023							27,125,000
Beginning balance at Mar. 31, 2023							$ 27,125
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series A convertible preferred units, net of issuance costs (in shares)							92,200,000
Issuance of Series A convertible preferred stock, net of issuance costs							$ 91,823
Issuance of Series A convertible preferred stock pursuant to anti-dilution provision of license agreement with Pfizer Inc. (in shares)							8,823,529
Issuance of Series A convertible preferred stock pursuant to anti-dilution provision of the Pfizer License Agreement							$ 8,824
Ending balance at Jun. 30, 2023							$ 127,772
Ending balance (in shares) at Jun. 30, 2023							128,148,529
Beginning balance (in shares) at Mar. 31, 2023	[1]		867,499
Beginning balance at Mar. 31, 2023		(26,841)	$ 0	588	0	(27,429)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense		416		416
Issuance of common stock from exercise of stock options, including early exercises (in shares)	[1]		695,142
Issuance of common stock from exercise of stock options, including early exercises		7		7
Vesting of early exercised stock options		18		18
Net loss		(16,129)				(16,129)
Ending balance at Jun. 30, 2023		(42,529)	$ 0	1,029	0	(43,558)
Ending balance (in shares) at Jun. 30, 2023	[1]		1,562,641
Ending balance at Sep. 30, 2023							$ 127,772
Ending balance (in shares) at Sep. 30, 2023							128,148,529
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense		$ 706		706
Issuance of common stock from exercise of stock options, including early exercises (in shares)		0
Vesting of early exercised stock options		$ 7		7
Unrealized gain on investments		0
Net loss		(5,591)				(5,591)
Ending balance at Sep. 30, 2023		$ (47,407)	$ 0	1,742	0	(49,149)
Ending balance (in shares) at Sep. 30, 2023			1,562,641
Beginning balance (in shares) at Dec. 31, 2023							0
Beginning balance at Dec. 31, 2023							$ 0
Ending balance at Mar. 31, 2024							$ 0
Ending balance (in shares) at Mar. 31, 2024							0
Beginning balance (in shares) at Dec. 31, 2023		20,337,571	20,337,571
Beginning balance at Dec. 31, 2023		$ 205,042	$ 2	267,024	67	(62,051)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from public offering, net of issuance costs (in shares)			5,307,691
Issuance of common stock from public offering, net of issuance costs		161,353	$ 1	161,352
Stock-based compensation expense		1,388		1,388
Vesting of early exercised stock options		7		7
Issuance of common stock upon vesting of restricted stock units (in shares)			1,247
Unrealized gain on investments		(320)			(320)
Net loss		(13,311)				(13,311)
Ending balance at Mar. 31, 2024		$ 354,159	$ 3	429,771	(253)	(75,362)
Ending balance (in shares) at Mar. 31, 2024			25,646,509
Beginning balance (in shares) at Dec. 31, 2023							0
Beginning balance at Dec. 31, 2023							$ 0
Ending balance at Sep. 30, 2024							$ 0
Ending balance (in shares) at Sep. 30, 2024							0
Beginning balance (in shares) at Dec. 31, 2023		20,337,571	20,337,571
Beginning balance at Dec. 31, 2023		$ 205,042	$ 2	267,024	67	(62,051)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from exercise of stock options, including early exercises (in shares)		0
Unrealized gain on investments		$ 754
Net loss		(50,975)
Ending balance at Sep. 30, 2024		$ 321,068	$ 3	433,270	821	(113,026)
Ending balance (in shares) at Sep. 30, 2024		25,642,610	25,642,610
Beginning balance (in shares) at Mar. 31, 2024							0
Beginning balance at Mar. 31, 2024							$ 0
Ending balance at Jun. 30, 2024							$ 0
Ending balance (in shares) at Jun. 30, 2024							0
Beginning balance (in shares) at Mar. 31, 2024			25,646,509
Beginning balance at Mar. 31, 2024		$ 354,159	$ 3	429,771	(253)	(75,362)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense		1,789		1,789
Vesting of early exercised stock options		20		20
Issuance of common stock upon vesting of restricted stock units (in shares)			1,246
Unrealized gain on investments		(199)			(199)
Net loss		(17,487)				(17,487)
Ending balance at Jun. 30, 2024		338,282	$ 3	431,580	(452)	(92,849)
Ending balance (in shares) at Jun. 30, 2024			25,647,755
Ending balance at Sep. 30, 2024							$ 0
Ending balance (in shares) at Sep. 30, 2024							0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense		$ 1,681		1,681
Issuance of common stock from exercise of stock options, including early exercises (in shares)		0
Vesting of early exercised stock options		$ 9		9
Repurchase of common stock (in shares)			(6,392)
Issuance of common stock upon vesting of restricted stock units (in shares)			1,247
Unrealized gain on investments		1,273			1,273
Net loss		(20,177)				(20,177)
Ending balance at Sep. 30, 2024		$ 321,068	$ 3	$ 433,270	$ 821	$ (113,026)
Ending balance (in shares) at Sep. 30, 2024		25,642,610	25,642,610
[1] * Amounts have been restated for the impact of the reverse merger outlined further within Notes 1 and 3.

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Operating activities:
Net loss	$ (20,177)	$ (13,311)	$ (5,591)	$ (7,502)	$ (50,975)	$ (29,222)
Adjustments to reconcile net loss to net cash used in operating activities:
In-process research and development expense					0	8,824
Stock-based compensation expense					4,858	1,515
Non-cash lease expense					110	93
Depreciation on property and equipment					30	22
Accretion of discount on investments					(5,622)	0
Realized gain on investments					(87)	0
Other non-cash items					0	10
Changes in operating assets and liabilities:
Prepaid expenses and other current assets					(5,938)	(1,565)
Other non-current assets					(915)	0
Accounts payable					983	551
Accrued expenses and other current liabilities					1,308	1,044
Operating lease liabilities					(126)	0
Net cash used in operating activities					(56,374)	(18,728)
Investing activities:
Purchases of property and equipment					0	(54)
Purchases of investments					(346,445)	0
Maturities of investments					135,750	0
Net cash used in investing activities					(210,695)	(54)
Financing activities:
Proceeds from public offering of common stock, net of issuance costs					161,352	0
Proceeds from issuance of Series A convertible preferred stock					0	91,823
Proceeds from exercise of stock options					0	144	$ 100
Payment of deferred offering costs					0	(3,389)
Repurchase of common stock originally issued upon early exercise of stock options					(1)	0
Net cash provided by financing activities					161,351	88,578
Net (decrease) increase in cash, cash equivalents and restricted cash					(105,718)	69,796
Cash, cash equivalents and restricted cash—Beginning of period		$ 140,953		$ 8,474	140,953	8,474	8,474
Cash, cash equivalents and restricted cash—End of period	35,235		78,270		35,235	78,270	140,953
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	35,008		78,043		35,008	78,043	140,726
Restricted cash	227		227		227	227
Total cash, cash equivalents and restricted cash	$ 35,235		$ 78,270		35,235	78,270	$ 140,953
Non-cash investing and financing activities:
Issuance of Series A convertible preferred stock pursuant to Pfizer License Agreement					0	8,824
Unpaid deferred offering costs included in accounts payable and accrued expenses					$ 0	$ 1,366

Nature of Business

Nature of Business	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	Nature of Business Overview Tourmaline Bio, Inc. (the “Company”) is a late-stage clinical biotechnology company focused on developing transformative medicines that dramatically improve the lives of patients with life-altering immune and inflammatory diseases. The Company is developing pacibekitug (also referred to as TOUR006), a fully human monoclonal antibody that selectively binds to interleukin-6, a key proinflammatory cytokine involved in the pathogenesis of many autoimmune and inflammatory disorders. The Company’s corporate headquarters are in New York, New York. The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive clinical testing and regulatory approval, prior to commercialization. These efforts will require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance-reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize revenue from product sales. Reverse Merger and Pre-Merger Financing Transaction On October 19, 2023, the Company completed its reverse merger with Tourmaline Sub, Inc. (formerly Tourmaline Bio, Inc.) (“Legacy Tourmaline”) in accordance with the terms of the Agreement and Plan of Merger, dated as of June 22, 2023 (the “Merger Agreement”), by and among the Company, Terrain Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of the Company (“Merger Sub”), and Legacy Tourmaline, pursuant to which, among other matters, Merger Sub merged with and into Legacy Tourmaline, with Legacy Tourmaline surviving as a wholly owned subsidiary of the Company (the “Reverse Merger”). In connection with the completion of the Reverse Merger, the Company changed its name from “Talaris Therapeutics, Inc.” to “Tourmaline Bio, Inc.,” and the business conducted by the Company became primarily the business conducted by Legacy Tourmaline. References to “the Company” refer to Legacy Tourmaline for periods prior to the closing of the Reverse Merger, and to Tourmaline Bio, Inc. (formerly Talaris Therapeutics, Inc., or “Talaris”) for all other periods, as the context requires. Immediately prior to the effective time of the Reverse Merger, Talaris effected a 1-for-10 reverse stock split of its common stock. At the effective time of the Reverse Merger, the Company issued an aggregate of 15,877,090 shares of Company common stock to the Legacy Tourmaline stockholders, based on the exchange ratio of approximately 0.07977 shares of Company common stock for each share of Legacy Tourmaline common stock, including those shares of Legacy Tourmaline common stock issued upon the conversion of Legacy Tourmaline Series A convertible preferred stock and those shares of the Legacy Tourmaline common stock issued in the Pre-Merger Financing Transaction (as defined below), resulting in 20,336,741 shares of Company common stock being issued and outstanding following the effective time of the Reverse Merger. At the effective time of the Reverse Merger, Legacy Tourmaline’s 2022 Equity Incentive Plan was assumed by the Company, and each outstanding and unexercised option to purchase shares of Legacy Tourmaline common stock immediately prior to the effective time of the Reverse Merger was assumed by the Company and converted into an option to purchase shares of Company common stock, with necessary adjustments to the number of shares and exercise price to reflect the exchange ratio. The Reverse Merger was accounted for as a reverse recapitalization in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”). Under this method of accounting, Legacy Tourmaline was deemed to be the accounting acquirer for financial reporting purposes. This determination was primarily based on the expectation that, immediately following the Reverse Merger: (i) Legacy Tourmaline’s stockholders own a substantial majority of the voting rights in the combined company; (ii) Legacy Tourmaline’s largest stockholders retain the largest interest in the combined company; (iii) Legacy Tourmaline designated a majority (five of seven) of the initial members of the board of directors of the combined company; and (iv) Legacy Tourmaline’s executive management team became the management team of the combined company. Accordingly, for accounting purposes: (i) the Reverse Merger was treated as the equivalent of Legacy Tourmaline issuing stock to acquire the net assets of Talaris; (ii) the net assets of Talaris are recorded at their acquisition-date fair value in the consolidated financial statements of Legacy Tourmaline and (iii) the reported historical operating results of the combined company prior to the Reverse Merger are those of Legacy Tourmaline. Historical common share figures of Legacy Tourmaline have been retroactively restated based on the exchange ratio of 0.07977. Additional information regarding the accounting for the Reverse Merger is included in Note 3, “Reverse Merger”. Concurrently with the execution and delivery of the Merger Agreement, and in order to provide Legacy Tourmaline with additional capital for its development programs, Legacy Tourmaline entered into a Securities Purchase Agreement (the “Private Placement Agreement”), with certain investors named therein (the “Private Placement Investors”), pursuant to which, subject to the terms and conditions of the Private Placement Agreement, immediately prior to the effective time of the Reverse Merger, Legacy Tourmaline issued and sold, and the Private Placement Investors purchased 4,092,035 shares (as eff ected by the exchange ratio described above) of Legacy Tourmaline common stock for gross proceeds of approximately $75.0 million (the “Pre-Merger Financing Transaction”). Following the completion of the Reverse Merger, on June 30, 2024, Legacy Tourmaline merged with and into the Company, with the Company as the surviving entity (the “Roll-Up Merger”). Liquidity As of September 30, 2024, the Company had cash, cash equivalents, and investments of $314.4 million. The Company expects that its existing cash, cash equivalents and investments will enable it to fund its expected operating expenses and capital expenditure requirements for at least 12 months from November 7, 2024, the filing date of this Quarterly Report on Form 10-Q. The Company expects to finance its future cash needs through a combination of equity or debt financings, collaborations, licensing arrangements and strategic alliances.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements as of September 30, 2024 and December 31, 2023, and for the three and nine months ended September 30, 2024 and 2023, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) and generally accepted accounting principles in the United States of America (“GAAP”) as found in the Accounting Standards Codification (“ASC”) of the Financial Accounting Standards Board (“FASB”) for condensed consolidated financial information. In the opinion of management, these condensed consolidated financial statements reflect all normal recurring adjustments which are necessary for a fair presentation of the Company’s financial position and results of its operations, as of and for the periods presented. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 filed with the SEC on March 19, 2024 (the “2023 Form 10-K”). The information presented in the condensed consolidated financial statements and related notes as of September 30, 2024, and for the three and nine months ended September 30, 2024 and 2023, is unaudited. The condensed consolidated balance sheet as of December 31, 2023 included herein was derived from the audited financial statements included in the 2023 Form 10-K. Interim results for the three and nine months ended September 30, 2024 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2024, or any future period. The condensed consolidated financial statements include the accounts of Tourmaline Bio, Inc. and, except in the case of the interim results for the three months ended September 30, 2024, its former wholly owned subsidiary, Tourmaline Sub, Inc. As outlined within Note 1, “Nature of Business”, Tourmaline Sub, Inc. was merged with and into Tourmaline Bio, Inc., with Tourmaline Bio, Inc. as the surviving entity, upon the consummation of the Roll-Up Merger on June 30, 2024. All historical intercompany transactions and balances have been eliminated in consolidation. Summary of Significant Accounting Policies The significant accounting policies and estimates used in the preparation of the condensed consolidated financial statements are described in the Company’s audited financial statements as of and for the year ended December 31, 2023 and the notes thereto, which are included in the related Annual Report on Form 10-K. There have been no material changes in the Company’s significant accounting policies during the nine months ended September 30, 2024. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates, which include, but are not limited to, accrued expenses and stock-based compensation expense. The Company bases its estimates on historical experience and other market specific or other relevant assumptions it believes to be reasonable under the circumstances. Actual results could differ from those estimates. Recent Accounting Pronouncements - Yet to be Adopted In November 2023, the FASB issued Accounting Standards Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures . This guidance is intended to improve reportable segment disclosure requirements through enhanced disclosures as well as clarify that entities with a single reportable segment are subject to new and existing segment reporting requirements. This guidance is effective for annual periods in fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. Entities must apply this guidance on a retrospective basis. The Company is currently evaluating this guidance to determine the impact it may have on its condensed consolidated financial statements. In March 2024, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures . The amendments in ASU 2023-09 address investor requests for enhanced income tax information primarily through changes to disclosure regarding rate reconciliation and income taxes paid both in the United States and in foreign jurisdictions. This guidance is effective for fiscal years beginning after December 15, 2024 on a prospective basis, with the option to apply the standard retrospectively, and early adoption is permitted. The Company is currently evaluating this guidance to determine the impact it may have on its condensed consolidated financial statements. In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses

Reverse Merger

Reverse Merger	9 Months Ended
	Sep. 30, 2024
Reverse Recapitalization [Abstract]
Reverse Merger	Reverse Merger As described within Note 1, “Nature of Business”, the Reverse Merger was completed on October 19, 2023. The Reverse Merger was accounted for as a reverse recapitalization in accordance with U.S. GAAP with Legacy Tourmaline as the accounting acquirer of Talaris. Under reverse recapitalization accounting, the assets and liabilities of Talaris were recorded at their fair value in the Company’s financial statements at the effective time of the Reverse Merger. No goodwill or intangible assets were recognized. Consequently, the consolidated financial statements of the Company reflect the operations of Legacy Tourmaline for accounting purposes together with a deemed issuance of shares, equivalent to the shares held by the former stockholders of Talaris, the legal acquirer, and a recapitalization of the equity of Legacy Tourmaline, the accounting acquirer. The Company acquired the following assets and liabilities as part of the Reverse Merger (in thousands): Amount Cash and cash equivalents $ 392 Short-term investments 65,515 Prepaid expenses and other current assets 4,254 Accounts payable (726) Accrued expenses (543) Net assets acquired $ 68,892 The Company incurred $2.9 million in stock-based compensation expense as a result of the acceleration of vesting and settlement of Talaris share-based awards at the time of the Reverse Merger. In the consolidated statement of operations and comprehensive loss for the year ended December 31, 2023, $1.4 million and $1.5 million were recorded as research and development expense and general and administrative expense, respectively. Additionally, the Company incurred transaction costs of $6.1 million, which were recorded as a reduction to additional paid-in capital.

Pfizer License Agreement

Pfizer License Agreement	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Pfizer License Agreement	Pfizer License Agreement On May 3, 2022 (the “Effective Date”), the Company entered into a License Agreement (the “Pfizer License Agreement”) with Pfizer Inc. (“Pfizer”), pursuant to which the Company obtained an exclusive, sublicensable, royalty-bearing, worldwide right to use and license under certain know-how for the development, commercialization and manufacture of PF-04236921 (the “Compound”, now known as pacibekitug) and any pharmaceutical or biopharmaceutical product incorporating the Compound (the “Product”), for the treatment, diagnosis, or prevention of any and all diseases, disorders, illnesses and conditions in humans and animals. In consideration for the license and other rights the Company received under the Pfizer License Agreement, the Company paid Pfizer an upfront payment of $5.0 million and issued to Pfizer 7,125,000 Series A preferred units of Tourmaline Bio, LLC (the predecessor of Legacy Tourmaline), which subsequently converted to 7,125,000 shares of Series A convertible preferred stock of Legacy Tourmaline, representing a 15% interest in the Company on a fully-diluted basis at the time of issuance. The units were issued for $1.00 per unit, representing a total value of $7.1 million. In accordance with ASC Topic 805, Business Combinations , the Pfizer License Agreement was accounted for as an asset acquisition as the licensed compound represented substantially all of the fair value of the gross assets acquired. On the Effective Date, the licensed compound had not yet received regulatory approval and did not have an alternative use. Accordingly, the total consideration transferred of $12.1 million was recorded as research and development expense in the consolidated statement of operations and comprehensive loss for the year ended December 31, 2022. As additional consideration for the license, the Company is obligated to pay Pfizer up to $128.0 million upon the achievement of specific development and regulatory milestones. The Company is also obligated to pay Pfizer up to $525.0 million upon the first achievement of specific sales milestones. The Company is also obligated to pay Pfizer a marginal royalty rate in the low double digits (less than 15%), subject to specified royalty reductions. The royalty term, on a Product-by-Product and country-by-country basis, begins on the first commercial sale of such Product and expires upon the later of twelve years following the date of the first commercial sale or the expiration of regulatory exclusivity protecting such Product. In the event the Company completes a Significant Transaction (as defined in the Pfizer License Agreement), the Company will be obligated to pay Pfizer a one-time payment in the low-eight digits (up to $20.0 million); the amount of such payment is based on the timing of the transaction. As of September 30, 2024, the Company does not owe any milestone or royalties under the Pfizer License Agreement and no such milestones or royalties have been paid to date. The Pfizer License Agreement originally contained an anti-dilution provision allowing Pfizer to maintain a 15% interest in the Company on a fully-diluted basis unless and until certain thresholds are met, whereupon the anti-dilution provision would no longer apply. As outlined further within Note 9, “Convertible Preferred Stock”, on May 2, 2023, the Company issued 8,823,529 additional shares of Series A convertible preferred stock to Pfizer pursuant this anti-dilution provision. The Company recognized research and development expense of $8.8 million related to this issuance of Series A convertible preferred stock. Subsequent to the issuance of these additional shares of Series A convertible preferred stock, the anti-dilution provision is no longer in force and effect.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company measures the fair value of money market funds based on quoted prices in active markets for identical securities. Investments also include commercial paper, government securities, and corporate debt securities which are valued either based on recent trades of securities in inactive markets or based on quoted market prices of similar instruments and other significant inputs derived from or corroborated by observable market data. The carrying amounts reflected in the condensed consolidated balance sheets for cash, prepaid expenses and other current assets, accounts payable, and accrued expenses and other current liabilities approximate their fair values, due to their short-term nature. Assets measured at fair value on a recurring basis as of September 30, 2024 were as follows (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 18,838 $ 18,838 $ — $ — Commercial paper 54,394 — 54,394 — Government securities 70,449 54,564 15,885 — Corporate debt securities 122,072 — 122,072 — Total cash equivalents and short-term investments 265,753 73,402 192,351 — Long-term investments: Corporate debt securities 32,467 — 32,467 — Total long-term investments 32,467 — 32,467 — Total cash equivalents and investments $ 298,220 $ 73,402 $ 224,818 $ — Assets measured at fair value on a recurring basis as of December 31, 2023 were as follows (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 4,604 $ 4,604 $ — $ — Commercial paper 32,555 — 32,555 — Government securities 26,724 7,907 18,817 — Corporate debt securities 2,947 — 2,947 — Total cash equivalents and short-term investments 66,830 12,511 54,319 — Total cash equivalents and investments $ 66,830 $ 12,511 $ 54,319 $ —

Investments

Investments	9 Months Ended
	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Investments	Investments Cash equivalents, short-term and long-term investments as of September 30, 2024 were comprised as follows (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 18,838 $ — $ — $ 18,838 Commercial paper 54,285 116 (7) 54,394 Government securities 70,345 106 (2) 70,449 Corporate debt securities 121,760 317 (5) 122,072 Total cash equivalents and short-term investments 265,228 539 (14) 265,753 Long-term investments: Corporate debt securities 32,171 298 (2) 32,467 Total long-term investments 32,171 298 (2) 32,467 Total cash equivalents and investments $ 297,399 $ 837 $ (16) $ 298,220 Cash equivalents and short-term investments as of December 31, 2023 were comprised as follows (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 4,604 $ — $ — $ 4,604 Commercial paper 32,515 44 (4) 32,555 Government securities 26,703 25 (4) 26,724 Corporate debt securities 2,941 6 — 2,947 Total cash equivalents and short-term investments 66,763 75 (8) 66,830 Total cash equivalents and investments $ 66,763 $ 75 $ (8) $ 66,830 As of September 30, 2024, the aggregate fair value of securities that were in an unrealized loss position for less than twelve months was $27.0 million. As of December 31, 2023, the aggregate fair value of securities that were in an unrealized loss position for less than twelve months was $49.3 million. As of September 30, 2024 and December 31, 2023, the Company did not hold any securities that were in an unrealized loss position for greater than twelve months. Based upon its assessment of securities in an unrealized loss position, the Company did not record any allowances for credit losses during the nine months ended September 30, 2024 or during the year ended December 31, 2023.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	9 Months Ended
	Sep. 30, 2024
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities as of September 30, 2024 and December 31, 2023 were comprised as follows (in thousands): September 30, December 31, 2024 2023 Accrued bonus $ 2,794 $ 1,994 Accrued clinical and manufacturing costs 1,242 438 Accrued consulting fees 190 341 Accrued external audit and tax fees 302 351 Accrued legal fees 141 237 Other accrued expenses and other current liabilities 335 349 Total accrued expenses and other current liabilities $ 5,004 $ 3,710

Convertible Preferred Stock

Convertible Preferred Stock	9 Months Ended
	Sep. 30, 2024
Temporary Equity Disclosure [Abstract]
Convertible Preferred Stock	Convertible Preferred Stock On April 18, 2022, the Company entered into a Securities Purchase Agreement (the “Initial Series A Securities Purchase Agreement”) with various entities and individuals for the purchase of Series A convertible preferred units. As part of the Initial Series A Securities Purchase Agreement, the Company authorized the issuance and sale of up to 20,000,000 shares of its Series A convertible preferred units at a price of $1.00 per unit for total proceeds of $20.0 million. The Series A convertible preferred units were convertible into the Company’s Common Units at a 1:1 ratio. The obligations of the parties to purchase and sell the Series A convertible preferred units were subject to the Company entering into the Pfizer License Agreement. As outlined further within Note 4, “Pfizer License Agreement,” the Company also issued to Pfizer 7,125,000 Series A convertible preferred units in May 2022 conjunction with the Pfizer License Agreement. On September 2, 2022, Legacy Tourmaline converted from Tourmaline Bio, LLC, a Delaware limited liability company, to Tourmaline Bio, Inc., a Delaware corporation (the “Conversion”). As part of the Conversion, Series A convertible preferred units were converted at a 1:1 ratio to shares of Series A convertible preferred stock. Upon the Conversion, the Company was authorized to issue up to 27,125,000 shares of Series A convertible preferred stock with a par value of $0.0001. The Company subsequently entered into a Series A Preferred Stock Purchase Agreement on May 2, 2023 (the “Closing Date”) with various entities and individuals for the purchase of additional shares of Series A convertible preferred stock (the “Series A Extension”). On the Closing Date, the Company authorized the issuance and sale of 92,200,000 shares of Series A convertible preferred stock at a price of $1.00 per share for total gross proceeds of $92.2 million. In addition, pursuant to the anti-dilution provision of the Pfizer License Agreement, the Company issued 8,823,529 additional shares of Series A convertible preferred stock to Pfizer in connection with the Series A Extension and recognized corresponding research and development expense of $8.8 million during the second quarter of 2023. The additional shares of Series A convertible preferred stock had the same terms, conditions, rights and preferences as the Series A convertible preferred stock issued during the year ended December 31, 2022. Upon consummation of the Series A Extension, the anti-dilution provision of the Pfizer License Agreement was no longer in force and effect. Prior to the completion of the Reverse Merger, the Company classified its Series A convertible preferred stock outside of permanent equity as the shares had redemption features that were not entirely within the control of the Company. Upon the consummation of the Reverse Merger, all outstanding shares of Series A convertible preferred stock were converted into 10,222,414 shares of common stock.

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Common Stock	Common Stock On January 25, 2024, the Company entered into an underwriting agreement with Jefferies LLC, Piper Sandler & Co., Guggenheim Securities, LLC and Truist Securities, Inc. (collectively, the “Underwriters”) in connection with the offering, issuance and sale by the Company of 4,615,384 shares of the Company’s common stock at a public offering price of $32.50 per share, less underwriting discounts and commissions, pursuant to an effective shelf registration statement on Form S-3 (the “January 2024 Offering”). Under the January 2024 Offering, the Company also granted the Underwriters a 30-day option to purchase up to 692,307 shares of common stock at the public offering price, less the underwriting discounts and commissions, which was exercised by the Underwriters in full on January 25, 2024. The January 2024 Offering closed on January 29, 2024. Total gross proceeds from the January 2024 Offering were approximately $172.5 million, including the full exercise by the Underwriters of their option to purchase additional shares. Net proceeds were approximately $161.4 million after deducting underwriting discounts and commissions and offering expenses payable by the Company. As of September 30, 2024, the Company is authorized to issue 140,000,000 shares of voting common stock and 10,000,000 shares of non-voting common stock. Holders of voting common stock are entitled to one vote per share. In addition, holders of voting common stock are entitled to receive dividends, if and when declared by the Company’s Board of Directors. As of September 30, 2024, no dividends had been declared. As of September 30, 2024 and December 31, 2023, the Company had reserved for future issuance the following number of shares of common stock: September 30, December 31, 2024 2023 Exercises of outstanding stock options under 2022 Equity Incentive Plan 1,363,685 1,403,409 Exercises of outstanding stock options under 2023 Equity Incentive Plan 1,531,538 1,042,291 Vesting of restricted stock units under 2023 Equity Incentive Plan 15,373 19,113 Common stock subject to repurchase related to early exercised stock options 241,722 388,943 Future issuances under 2023 Equity Incentive Plan 1,499,075 971,444 Future issuances under 2023 Employee Stock Purchase Plan 406,742 203,367 Total shares reserved for future issuance 5,058,135 4,028,567

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation 2022 Equity Incentive Plan On September 2, 2022, the Board of Directors and the stockholders of the Company adopted the 2022 Equity Incentive Plan (the “2022 Plan”), which provided for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards and other stock awards to employees, consultants, and non-employee directors of the Company. 2023 Equity Incentive Plan On October 17, 2023, the Company adopted the 2023 Equity Incentive Plan (the “2023 Plan”) which became effective upon completion of the Reverse Merger. The 2023 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance awards and other forms of awards to employees, consultants, and non-employee directors of the Company. The terms of stock award agreements, including vesting requirements, are determined by the Company’s Board of Directors and are subject to the provisions of the 2023 Plan. The term of each stock option shall be no more than ten years from the date of grant. Following the effectiveness of the 2023 Plan, no further grants will be made under the 2022 Plan; however, any outstanding equity awards granted under the 2022 Plan will continue to be governed by the terms of the 2022 Plan. The 2023 Plan initially provided for the issuance of up to 2,033,677 shares of common stock (the “Initial 2023 Plan Share Reserve”). Subject to any other adjustments as defined in the 2023 Plan, such aggregate number of shares of common stock will automatically increase on January 1st of each year for a period of ten years commencing on January 1, 2024 and ending on (and including) January 1, 2033, in an amount equal to 5% of the total number of shares of common stock issued and outstanding determined as of the day prior to such increase (such increase, the “2023 Plan Evergreen Refresh”); provided, however, that the board of directors may act prior to January 1st of a given year to provide that the increase for such year will be a lesser number of shares of common stock. The aggregate maximum number of shares of common stock that may be issued pursuant to the exercise of incentive stock options is three multiplied by the Initial 2023 Plan Share Reserve. Under the aforementioned 2023 Plan Evergreen Refresh, 1,016,878 shares were added to the Initial 2023 Plan Share Reserve effective January 1, 2024. As of September 30, 2024, there were 1,499,075 shares available for issuance under the 2023 Plan. 2023 Employee Stock Purchase Plan On October 17, 2023, the Company adopted the 2023 Employee Stock Purchase Plan (the “2023 ESPP”), which became effective upon completion of the Reverse Merger. The maximum number of shares of common stock that may be issued under the 2023 ESPP will not exceed 203,367 shares (the “Initial ESPP Share Reserve”), plus the number of shares of common stock that are automatically added on January 1st of each year for a period of up to ten years commencing on January 1, 2024 and ending on (and including) January 1, 2033, in an amount equal to the lesser of (x) 1% of the total number of shares of common stock issued and outstanding determined as of the day prior to such increase and (y) a number of shares equal to three times the Initial ESPP Share Reserve (such increase, the “ESPP Evergreen Refresh”). Notwithstanding the foregoing, the Board of Directors may act prior to the first day of any calendar year to provide that there will be no January 1st increase in the share reserve for such calendar year or that the increase in the share reserve for such calendar year will be a lesser number of shares of common stock than would otherwise occur pursuant to the preceding sentence. Under the aforementioned ESPP Evergreen Refresh, 203,375 shares were added to the Initial ESPP Share Reserve effective January 1, 2024 such that 406,742 shares of common stock may be issued under the 2023 ESPP as of September 30, 2024. No offering periods under the 2023 ESPP had been initiated as of September 30, 2024. Stock-based Compensation Expense Total stock-based compensation expense recognized in the condensed consolidated statements of operations and comprehensive loss for the three and nine months ended September 30, 2024 and 2023 was as follows (in thousands): Three Months Ended Nine Months Ended September 30, 2024 2023 2024 2023 Research and development $ 656 $ 239 $ 1,910 $ 355 General and administrative 1,025 467 2,948 1,160 Total stock-based compensation expense $ 1,681 $ 706 $ 4,858 $ 1,515 Stock Option Activity The fair value of stock options granted during the three and nine months ended September 30, 2024 and 2023 was calculated on the date of grant using the following assumptions: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Risk-free interest rate 3.5% – 4.2% 4.3% – 4.4% 3.5% – 4.7% 3.4% – 4.4% Dividend yield —% —% —% —% Volatility 81.5% – 82.2% 82.2% – 82.5% 81.5% – 85.7% 82.2% – 84.3% Expected term (in years) 6.1 6.0 - 6.1 5.5 - 6.1 5.5 – 6.1 The weighted-average fair value of the Company’s common stock utilized in the valuation of stock options granted during the three months ended September 30, 2024 and 2023 was $15.47 and $13.92 per share, respectively. The weighted-average fair value of the Company’s common stock utilized in the valuation of stock options granted during the nine months ended September 30, 2024 and 2023 was $17.91 and $6.97 per share, respectively. Using the Black-Scholes option pricing model, the weighted-average grant date fair value of stock options granted during the three months ended September 30, 2024 and 2023 was $11.16 and $10.12 per share, respectively. The weighted-average grant date fair value of stock options granted during the nine months ended September 30, 2024 and 2023 was $13.10 and $5.84 per share, respectively. The following table summarizes changes in stock option activity during the nine months ended September 30, 2024: Options Weighted- Weighted- Aggregate Intrinsic Value Outstanding as of December 31, 2023 2,445,700 $ 9.29 9.6 $ 41,320 Granted 545,550 $ 17.91 Exercised — $ — Cancelled (96,027) $ 10.03 Outstanding as of September 30, 2024 2,895,223 $ 10.89 9.0 $ 43,274 Exercisable as of September 30, 2024 515,246 $ 8.54 8.5 $ 8,849 No stock options were exercised during the three or nine months ended September 30, 2024 or during the three months ended September 30, 2023. The aggregate intrinsic value of stock options exercised during the nine months ended September 30, 2023 was $1.8 million. As of September 30, 2024, the total unrecognized stock-based compensation expense related to unvested stock options was $18.4 million, which the Company expects to recognize over a weighted-average period of approximately 2.9 years. Early Exercise of Stock Options The 2022 Plan and certain stock options issued under the 2022 Plan were amended in February 2023 to permit the stock option holder to early exercise at any time between the grant date and the vesting date. The amendment did not result in any incremental stock-based compensation expense. During the year ended December 31, 2023, certain employees, advisors and non-employee directors early exercised 647,386 stock options. In the event of termination of an employee, advisor or non-employee director, the Company can repurchase early exercised and unvested stock options for a period of six months following the later of (i) the termination date of the employee or non-employee director or (ii) the exercise date. The Company received $0.1 million in cash proceeds related to the early exercise of stock options during the year ended December 31, 2023. As a result of the aforementioned repurchase right, the Company initially records the proceeds received from the early exercise of stock options as a liability in the condensed consolidated balance sheets. Amounts are reclassified to additional paid-in capital when the underlying stock options vest and the Company’s right of repurchase lapses. The aggregate liability associated with the early exercise of stock options was less than $0.1 million as of September 30, 2024. As of September 30, 2024, 241,722 early exercised stock options remain unvested. The shares of common stock subject to repurchase related to early exercised stock options are legally outstanding, as each holder is deemed to be a common stockholder that has dividend and voting rights during the vesting term. During the three months ended September 30, 2024, upon the termination of service of an employee, the Company repurchased 6,392 shares of common stock subject to a repurchase right arising from unvested early exercised stock options. These shares were repurchased at the original exercise price. Restricted Stock Unit Activity The following table summarizes changes in restricted stock unit activity during the nine months ended September 30, 2024: Shares Weighted- Unvested as of December 31, 2023 19,113 $ 11.89 Granted — $ — Vested (3,740) $ 11.89 Cancelled — $ — Unvested as of September 30, 2024 15,373 $ 11.89

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies From time to time, the Company may become subject to legal proceedings, claims and litigation arising in the ordinary course of business. Between July 25 and October 3, 2023, Talaris received eleven demand letters (the “Demands”) regarding the Proxy Statement (as defined below). In addition, three lawsuits were filed (captioned Wieder v. Talaris Therapeutics, Inc., et al., No. 1:23-cv-08355 (S.D.N.Y. filed Sept. 21, 2023), Carlisle v. Talaris Therapeutics, Inc., et al., No. 1:23-cv-08520 (S.D.N.Y. filed Sept. 27, 2023), and Roberts v. Talaris Therapeutics, Inc., et al., No. 1:23-cv-01063 (D. Del. filed Sept. 27, 2023)) (the “Lawsuits,” and together with the Demands, the “Actions”), in each case, by purported stockholders of Talaris challenging the proposed Reverse Merger and the disclosures in the definitive proxy statement filed by Talaris with the SEC on July 20, 2023, and as amended on August 25, 2023 and September 11, 2023 (the “Proxy Statement”). The Actions generally alleged that certain disclosures in the Proxy Statement were false or misleading and asserted claims against Talaris and its Board of Directors for violations of Sections 14(a) and 20(a) of the Exchange Act of 1934. The purported stockholders sought unspecified monetary damages and an award of costs and expenses, including reasonable attorney’s fees. On October 10, 2023, Talaris filed a Current Report on Form 8-K to update and supplement the Proxy Statement, which contained certain additional disclosures relating to the Reverse Merger (the “Supplemental Disclosures”). Thereafter, plaintiffs in the Lawsuits voluntarily dismissed their complaints, and opposing counsel (for the stockholders in the Actions) requested a mootness fee in connection with the Supplemental Disclosures. The Reverse Merger subsequently closed on October 19, 2023. Thereafter, the parties engaged in a negotiation over payment of a potential mootness fee(s) to resolve all the fee demands. On February 13, 2024, the parties entered into an agreement, under which the Company agreed to pay a total of approximately $0.2 million to resolve all the fee demands and the stockholders released all claims in connection with the Reverse Merger. This amount was recognized as general and administrative expense by the Company during the year ended December 31, 2023.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2024
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions In May 2023, an advisor affiliated with Fourth Avenue FF Opportunities LP – Series Z, previously a beneficial owner of the Company’s outstanding capital stock, exercised stock options to purchase 75,782 shares of the Company’s common stock for $0.13 per share. The Company subsequently repurchased the shares from the advisor at $2.76 per share, equivalent to fair value as of the repurchase date, for an aggregate purchase price of $0.2 million. Fourth Avenue FF Opportunities LP – Series Z then purchased the shares from the Company at the same amount $2.76 per share for an aggregate purchase price of $0.2 million. There were no amounts due to or from any related party as of either September 30, 2024 or December 31, 2023.

Net Loss per Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share The following common stock equivalents have been excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive: Three and Nine Months Ended 2024 2023 Series A convertible preferred stock — 10,222,414 Outstanding stock options under 2022 Equity Inventive Plan 1,363,685 1,403,409 Outstanding stock options under 2023 Equity Inventive Plan 1,531,538 — Unvested restricted stock units under 2023 Equity Incentive Plan 14,958 — Common stock subject to repurchase related to early exercised stock options 241,722 449,692 Total 3,151,903 12,075,515

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements as of September 30, 2024 and December 31, 2023, and for the three and nine months ended September 30, 2024 and 2023, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) and generally accepted accounting principles in the United States of America (“GAAP”) as found in the Accounting Standards Codification (“ASC”) of the Financial Accounting Standards Board (“FASB”) for condensed consolidated financial information. In the opinion of management, these condensed consolidated financial statements reflect all normal recurring adjustments which are necessary for a fair presentation of the Company’s financial position and results of its operations, as of and for the periods presented. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 filed with the SEC on March 19, 2024 (the “2023 Form 10-K”). The information presented in the condensed consolidated financial statements and related notes as of September 30, 2024, and for the three and nine months ended September 30, 2024 and 2023, is unaudited. The condensed consolidated balance sheet as of December 31, 2023 included herein was derived from the audited financial statements included in the 2023 Form 10-K. Interim results for the three and nine months ended September 30, 2024 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2024, or any future period.
Use of Estimates	Use of Estimates
Recent Accounting Pronouncements - Yet to be Adopted	Recent Accounting Pronouncements - Yet to be Adopted In November 2023, the FASB issued Accounting Standards Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures . This guidance is intended to improve reportable segment disclosure requirements through enhanced disclosures as well as clarify that entities with a single reportable segment are subject to new and existing segment reporting requirements. This guidance is effective for annual periods in fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. Entities must apply this guidance on a retrospective basis. The Company is currently evaluating this guidance to determine the impact it may have on its condensed consolidated financial statements. In March 2024, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures . The amendments in ASU 2023-09 address investor requests for enhanced income tax information primarily through changes to disclosure regarding rate reconciliation and income taxes paid both in the United States and in foreign jurisdictions. This guidance is effective for fiscal years beginning after December 15, 2024 on a prospective basis, with the option to apply the standard retrospectively, and early adoption is permitted. The Company is currently evaluating this guidance to determine the impact it may have on its condensed consolidated financial statements. In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses

Reverse Merger (Tables)

Reverse Merger (Tables)	9 Months Ended
	Sep. 30, 2024
Reverse Recapitalization [Abstract]
Schedule Of Reverse Capitalization	The Company acquired the following assets and liabilities as part of the Reverse Merger (in thousands): Amount Cash and cash equivalents $ 392 Short-term investments 65,515 Prepaid expenses and other current assets 4,254 Accounts payable (726) Accrued expenses (543) Net assets acquired $ 68,892

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value, Assets Measured on Recurring Basis	Assets measured at fair value on a recurring basis as of September 30, 2024 were as follows (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 18,838 $ 18,838 $ — $ — Commercial paper 54,394 — 54,394 — Government securities 70,449 54,564 15,885 — Corporate debt securities 122,072 — 122,072 — Total cash equivalents and short-term investments 265,753 73,402 192,351 — Long-term investments: Corporate debt securities 32,467 — 32,467 — Total long-term investments 32,467 — 32,467 — Total cash equivalents and investments $ 298,220 $ 73,402 $ 224,818 $ — Assets measured at fair value on a recurring basis as of December 31, 2023 were as follows (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 4,604 $ 4,604 $ — $ — Commercial paper 32,555 — 32,555 — Government securities 26,724 7,907 18,817 — Corporate debt securities 2,947 — 2,947 — Total cash equivalents and short-term investments 66,830 12,511 54,319 — Total cash equivalents and investments $ 66,830 $ 12,511 $ 54,319 $ —

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Available-for-Sale	Cash equivalents, short-term and long-term investments as of September 30, 2024 were comprised as follows (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 18,838 $ — $ — $ 18,838 Commercial paper 54,285 116 (7) 54,394 Government securities 70,345 106 (2) 70,449 Corporate debt securities 121,760 317 (5) 122,072 Total cash equivalents and short-term investments 265,228 539 (14) 265,753 Long-term investments: Corporate debt securities 32,171 298 (2) 32,467 Total long-term investments 32,171 298 (2) 32,467 Total cash equivalents and investments $ 297,399 $ 837 $ (16) $ 298,220 Cash equivalents and short-term investments as of December 31, 2023 were comprised as follows (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 4,604 $ — $ — $ 4,604 Commercial paper 32,515 44 (4) 32,555 Government securities 26,703 25 (4) 26,724 Corporate debt securities 2,941 6 — 2,947 Total cash equivalents and short-term investments 66,763 75 (8) 66,830 Total cash equivalents and investments $ 66,763 $ 75 $ (8) $ 66,830

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2024
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued expenses and other current liabilities as of September 30, 2024 and December 31, 2023 were comprised as follows (in thousands): September 30, December 31, 2024 2023 Accrued bonus $ 2,794 $ 1,994 Accrued clinical and manufacturing costs 1,242 438 Accrued consulting fees 190 341 Accrued external audit and tax fees 302 351 Accrued legal fees 141 237 Other accrued expenses and other current liabilities 335 349 Total accrued expenses and other current liabilities $ 5,004 $ 3,710

Common Stock (Tables)

Common Stock (Tables)	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Schedule of Stock by Class	As of September 30, 2024 and December 31, 2023, the Company had reserved for future issuance the following number of shares of common stock: September 30, December 31, 2024 2023 Exercises of outstanding stock options under 2022 Equity Incentive Plan 1,363,685 1,403,409 Exercises of outstanding stock options under 2023 Equity Incentive Plan 1,531,538 1,042,291 Vesting of restricted stock units under 2023 Equity Incentive Plan 15,373 19,113 Common stock subject to repurchase related to early exercised stock options 241,722 388,943 Future issuances under 2023 Equity Incentive Plan 1,499,075 971,444 Future issuances under 2023 Employee Stock Purchase Plan 406,742 203,367 Total shares reserved for future issuance 5,058,135 4,028,567

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount	Total stock-based compensation expense recognized in the condensed consolidated statements of operations and comprehensive loss for the three and nine months ended September 30, 2024 and 2023 was as follows (in thousands): Three Months Ended Nine Months Ended September 30, 2024 2023 2024 2023 Research and development $ 656 $ 239 $ 1,910 $ 355 General and administrative 1,025 467 2,948 1,160 Total stock-based compensation expense $ 1,681 $ 706 $ 4,858 $ 1,515
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions	The fair value of stock options granted during the three and nine months ended September 30, 2024 and 2023 was calculated on the date of grant using the following assumptions: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Risk-free interest rate 3.5% – 4.2% 4.3% – 4.4% 3.5% – 4.7% 3.4% – 4.4% Dividend yield —% —% —% —% Volatility 81.5% – 82.2% 82.2% – 82.5% 81.5% – 85.7% 82.2% – 84.3% Expected term (in years) 6.1 6.0 - 6.1 5.5 - 6.1 5.5 – 6.1
Share-Based Payment Arrangement, Option, Activity	The following table summarizes changes in stock option activity during the nine months ended September 30, 2024: Options Weighted- Weighted- Aggregate Intrinsic Value Outstanding as of December 31, 2023 2,445,700 $ 9.29 9.6 $ 41,320 Granted 545,550 $ 17.91 Exercised — $ — Cancelled (96,027) $ 10.03 Outstanding as of September 30, 2024 2,895,223 $ 10.89 9.0 $ 43,274 Exercisable as of September 30, 2024 515,246 $ 8.54 8.5 $ 8,849
Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity	The following table summarizes changes in restricted stock unit activity during the nine months ended September 30, 2024: Shares Weighted- Unvested as of December 31, 2023 19,113 $ 11.89 Granted — $ — Vested (3,740) $ 11.89 Cancelled — $ — Unvested as of September 30, 2024 15,373 $ 11.89

Net Loss per Share (Tables)

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following common stock equivalents have been excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive: Three and Nine Months Ended 2024 2023 Series A convertible preferred stock — 10,222,414 Outstanding stock options under 2022 Equity Inventive Plan 1,363,685 1,403,409 Outstanding stock options under 2023 Equity Inventive Plan 1,531,538 — Unvested restricted stock units under 2023 Equity Incentive Plan 14,958 — Common stock subject to repurchase related to early exercised stock options 241,722 449,692 Total 3,151,903 12,075,515

Nature of Business (Details)

Nature of Business (Details) $ in Millions	Oct. 19, 2023 USD ($) shares	Sep. 30, 2024 USD ($) shares	Dec. 31, 2023 shares
Class of Stock [Line Items]
Stock split ratio, common stock	0.1
Exchange ratio	0.07977
Common stock, shares, issued (in shares)	20,336,741	25,642,610	20,337,571
Investments and cash | $		$ 314.4
Private Placement
Class of Stock [Line Items]
Sale of stock, number of shares issued in transaction (in shares)	4,092,035
Consideration received on transaction | $	$ 75
Common Stock
Class of Stock [Line Items]
Stock issued during period, shares, new issues (in shares)	15,877,090

Reverse Merger - Narrative (Det

Reverse Merger - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Oct. 19, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Schedule Of Reverse Recapitalization [Line Items]
Goodwill	$ 0
Intangible assets	0
Stock-based compensation expenses	2,900	$ 1,681	$ 706	$ 4,858	$ 1,515
Payment of reverse merger costs	6,100
Research and development
Schedule Of Reverse Recapitalization [Line Items]
Stock-based compensation expenses	1,400	656	239	1,910	355
General and administrative
Schedule Of Reverse Recapitalization [Line Items]
Stock-based compensation expenses	$ 1,500	$ 1,025	$ 467	$ 2,948	$ 1,160

Reverse Merger - Schedule Of Ne

Reverse Merger - Schedule Of Net Assets Acquired (Details) $ in Thousands	Oct. 19, 2023 USD ($)
Reverse Recapitalization [Abstract]
Cash and cash equivalents	$ 392
Short-term investments	65,515
Prepaid expenses and other current assets	4,254
Accounts payable	(726)
Accrued expenses	(543)
Net assets acquired	$ 68,892

Pfizer License Agreement (Detai

Pfizer License Agreement (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended			9 Months Ended		12 Months Ended
	May 02, 2023	May 03, 2022	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development expense			$ 19,330	$ 3,762		$ 46,440	$ 24,353
Pfizer License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment		$ 5,000
Consideration transferred								$ 12,100
Royalty rate payment		15%
Expected timing satisfaction, period		12 years
Maximum payment on the timing of transaction		$ 20,000
Pfizer License Agreement | Development and Regulatory Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contingent consideration, liability		128,000
Pfizer License Agreement | Sales Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contingent consideration, liability		$ 525,000
Series A Convertible Preferred Stock | Pfizer License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Shares issued under license agreement (in shares)		7,125,000
Shares issued, price per share (usd per share)		$ 1
Equity interest issued and issuable		$ 7,100
Series A Convertible Preferred Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development expense					$ 8,800
Series A Convertible Preferred Stock | Pfizer License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Shares issued under license agreement (in shares)		7,125,000
Issuance of Series A convertible preferred stock pursuant to anti-dilution provision of license agreement with Pfizer Inc. (in shares)	8,823,529
Research and development expense	$ 8,800
Series A Convertible Preferred Stock | Pfizer Inc. | Pfizer License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Interest percent		15%

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value, Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	$ 246,916	$ 62,225
Total cash equivalents and short-term investments	265,753	66,830
Corporate debt securities	32,467	0
Total long-term investments	32,467
Total cash equivalents and investments	298,220	66,830
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	54,394	32,555
Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	70,449	26,724
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	122,072	2,947
Corporate debt securities	32,467
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and short-term investments	73,402	12,511
Total long-term investments	0
Total cash equivalents and investments	73,402	12,511
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	54,564	7,907
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Corporate debt securities	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and short-term investments	192,351	54,319
Total long-term investments	32,467
Total cash equivalents and investments	224,818	54,319
Significant Other Observable Inputs (Level 2) | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	54,394	32,555
Significant Other Observable Inputs (Level 2) | Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	15,885	18,817
Significant Other Observable Inputs (Level 2) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	122,072	2,947
Corporate debt securities	32,467
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and short-term investments	0	0
Total long-term investments	0
Total cash equivalents and investments	0	0
Significant Unobservable Inputs (Level 3) | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Significant Unobservable Inputs (Level 3) | Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Significant Unobservable Inputs (Level 3) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Corporate debt securities	0
Money market funds, included in cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash equivalents	18,838	4,604
Money market funds, included in cash equivalents | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash equivalents	18,838	4,604
Money market funds, included in cash equivalents | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash equivalents	0	0
Money market funds, included in cash equivalents | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash equivalents	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Liabilities, fair value disclosure	$ 0	$ 0

Investments - Debt Securities,

Investments - Debt Securities, Available-for-Sale (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	$ 297,399	$ 66,763
Unrealized Gains	837	75
Unrealized Losses	(16)	(8)
Fair Value	298,220	66,830
Short-Term Investments
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	265,228
Unrealized Gains	539
Unrealized Losses	(14)
Fair Value	265,753
Long Term Investments
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	32,171
Unrealized Gains	298
Unrealized Losses	(2)
Fair Value	32,467
Money market funds, included in cash equivalents | Cash and Cash Equivalents
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	18,838	4,604
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	18,838	4,604
Commercial paper | Short-Term Investments
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	54,285	32,515
Unrealized Gains	116	44
Unrealized Losses	(7)	(4)
Fair Value	54,394	32,555
Government securities | Short-Term Investments
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	70,345	26,703
Unrealized Gains	106	25
Unrealized Losses	(2)	(4)
Fair Value	70,449	26,724
Corporate debt securities | Short-Term Investments
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	121,760	2,941
Unrealized Gains	317	6
Unrealized Losses	(5)	0
Fair Value	122,072	$ 2,947
Corporate debt securities | Long Term Investments
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	32,171
Unrealized Gains	298
Unrealized Losses	(2)
Fair Value	$ 32,467

Investments - Narrative (Detail

Investments - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Unrealized loss position, less than 12 months	$ 27	$ 49.3

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued bonus	$ 2,794	$ 1,994
Accrued clinical and manufacturing costs	1,242	438
Accrued consulting fees	190	341
Accrued external audit and tax fees	302	351
Accrued legal fees	141	237
Other accrued expenses and other current liabilities	335	349
Total accrued expenses and other current liabilities	$ 5,004	$ 3,710

Convertible Preferred Stock (De

Convertible Preferred Stock (Details) $ / shares in Units, $ in Thousands			3 Months Ended			9 Months Ended
	May 02, 2023 USD ($) $ / shares shares	Apr. 18, 2022 USD ($) $ / shares shares	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Dec. 31, 2023 shares	Sep. 02, 2022 $ / shares shares	May 03, 2022 shares
Class of Stock [Line Items]
Research and development expense | $			$ 19,330	$ 3,762		$ 46,440	$ 24,353
Conversion of convertible securities (in shares)						10,222,414
Undesignated preferred stock, shares authorized (in shares)			10,000,000			10,000,000		10,000,000
Shares outstanding (in shares)			0			0		0
Stock issued (in shares)			0			0		0
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Conversion ratio		1
Series A Convertible Preferred Stock | Pfizer License Agreement
Class of Stock [Line Items]
Shares issued under license agreement (in shares)										7,125,000
Series A Convertible Preferred Stock | Initial Series A Securities Purchase Agreement
Class of Stock [Line Items]
Sale of stock, number of shares issued in transaction (in shares)		20,000,000
Price per share (usd per share) | $ / shares		$ 1
Consideration received on transaction | $		$ 20,000
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Conversion ratio									1
Convertible preferred stock, shares authorized (in shares)									27,125,000
Convertible preferred stock, par value ( usd per share) | $ / shares									$ 0.0001
Research and development expense | $					$ 8,800
Series A Convertible Preferred Stock | Pfizer License Agreement
Class of Stock [Line Items]
Shares issued under license agreement (in shares)										7,125,000
Issuance of Series A convertible preferred stock pursuant to anti-dilution provision of license agreement with Pfizer Inc. (in shares)	8,823,529
Research and development expense | $	$ 8,800
Series A Convertible Preferred Stock | Series A Extension
Class of Stock [Line Items]
Sale of stock, number of shares issued in transaction (in shares)	92,200,000
Price per share (usd per share) | $ / shares	$ 1
Consideration received on transaction | $	$ 92,200

Common Stock - Narrative (Detai

Common Stock - Narrative (Details)		1 Months Ended	9 Months Ended
	Jan. 25, 2024 $ / shares shares	Jan. 31, 2024 USD ($)	Sep. 30, 2024 USD ($) vote shares	Dec. 31, 2023 shares
Class of Stock [Line Items]
Common stock, shares authorized (in shares)			140,000,000	25,649,002
Number of votes for each share of common stock | vote			1
Dividends, common stock | $			$ 0
Underwriting Agreement
Class of Stock [Line Items]
Sale of stock, number of shares issued in transaction (in shares)	4,615,384
Price per share (usd per share) | $ / shares	$ 32.50
Over-Allotment Option
Class of Stock [Line Items]
Sale of stock, number of shares issued in transaction (in shares)	692,307
Period granted to underwriters	30 days
January 2024 Offering
Class of Stock [Line Items]
Gross proceeds from issuance initial public offering | $		$ 172,500,000
Consideration received on transaction | $		$ 161,400,000
Nonvoting Common Stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)			10,000,000	10,000,000

Common Stock - Schedule of Shar

Common Stock - Schedule of Shares Reserved For Future Issuance (Details) - shares	Sep. 30, 2024	Dec. 31, 2023	Oct. 17, 2023
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	5,058,135	4,028,567
2023 Equity Incentive Plan
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	1,499,075	971,444	2,033,677
2023 ESPP
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	406,742	203,367
Employee Stock Option | 2022 Equity Incentive Plan
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	1,363,685	1,403,409
Employee Stock Option | 2023 Equity Incentive Plan
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	1,531,538	1,042,291
Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	15,373	19,113
Early Exercisable Stock Options
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	241,722	388,943

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 01, 2024 shares	Oct. 17, 2023 shares	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) $ / shares shares	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares reserved for future issuance (in shares)			5,058,135		5,058,135		4,028,567
Share-based compensation arrangement by share-based payment award, options, grants in period, weighted average grant date fair value (usd per share) | $ / shares			$ 11.16	$ 10.12	$ 13.10	$ 5.84
Share-based compensation arrangement by share-based payment award, options, exercises in period (in shares)			0	0	0	1,800,000
Share-based payment arrangement, nonvested award, option, cost not yet recognized, amount | $			$ 18,400		$ 18,400
Proceeds from exercise of stock options | $					0	$ 144	$ 100
Deferred compensation share-based arrangements, liability, current | $			$ 100		$ 100
Employee Stock Option
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, fair value assumptions, weighted average fair value of common stock (usd per share) | $ / shares			$ 15.47	$ 13.92	$ 17.91	$ 6.97
Share-based payment arrangement, nonvested award, cost not yet recognized, period for recognition					2 years 10 months 24 days
Early Exercisable Stock Options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares reserved for future issuance (in shares)			241,722		241,722		388,943
Share-based compensation arrangement by share-based payment award, options, exercises in period (in shares)					647,386
Share-based compensation arrangement by share-based payment award, repurchase of options, period					6 months
Share-based compensation arrangement by share-based payment award, options, nonvested, number of shares (in shares)			241,722		241,722
Share-based compensation arrangement by share-based payment award, options, repurchases (in shares)			6,392		6,392
Restricted Stock Units (RSUs)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares reserved for future issuance (in shares)			15,373		15,373		19,113
Share-based payment arrangement, nonvested award, cost not yet recognized, period for recognition					3 years
Share-based compensation arrangement by share-based payment award, equity instruments other than options, vested in period, fair value | $			$ 100	$ 0	$ 100	$ 0
Share-based payment arrangement, nonvested award, excluding option, cost not yet recognized, amount | $			$ 200		$ 200
2023 Equity Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares reserved for future issuance (in shares)		2,033,677	1,499,075		1,499,075		971,444
Share-based compensation arrangement by share-based payment award, number of annual increase of shares authorized, period		10 years
Share-based compensation arrangement by share-based payment award, percentage of outstanding stock maximum		5%
Share-based compensation arrangement by share-based payment award, maximum number of shares authorized, multiple of share reserve		3
Common stock, capital shares added for future issuance (in shares)	1,016,878
2023 Equity Incentive Plan | Employee Stock Option
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, expiration period		10 years
Shares reserved for future issuance (in shares)			1,531,538		1,531,538		1,042,291
2023 ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares reserved for future issuance (in shares)			406,742		406,742		203,367
Share-based compensation arrangement by share-based payment award, number of shares authorized (in shares)			406,742		406,742
Share-based compensation arrangement by share-based payment award, number of additional shares authorized (in shares)	203,375
2023 ESPP | Employee Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of annual increase of shares authorized, period		10 years
Share-based compensation arrangement by share-based payment award, percentage of outstanding stock maximum		1%
Share-based compensation arrangement by share-based payment award, maximum number of shares authorized, multiple of share reserve		3
Share-based compensation arrangement by share-based payment award, number of shares authorized (in shares)		203,367

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Oct. 19, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total stock-based compensation expense	$ 2,900	$ 1,681	$ 706	$ 4,858	$ 1,515
Research and development
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total stock-based compensation expense	1,400	656	239	1,910	355
General and administrative
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total stock-based compensation expense	$ 1,500	$ 1,025	$ 467	$ 2,948	$ 1,160

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Valuation Assumptions (Details) - Employee Stock Option	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate (minimum)	3.50%	4.30%	3.50%	3.40%
Risk-free interest rate (maximum)	4.20%	4.40%	4.70%	4.40%
Dividend yield	0%	0%	0%	0%
Volatility (minimum)	81.50%	82.20%	81.50%	82.20%
Volatility (maximum)	82.20%	82.50%	85.70%	84.30%
Expected term (in years)			6 years 1 month 6 days
Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days		6 years 1 month 6 days
Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)		6 years	5 years 6 months	5 years 6 months

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Options
Beginning balance, outstanding (in shares)			2,445,700
Granted (in shares)			545,550
Exercised (in shares)	0	0	0	(1,800,000)
Cancelled (in shares)			(96,027)
Ending balance, outstanding (in shares)	2,895,223		2,895,223		2,445,700
Exercisable (in shares)	515,246		515,246
Weighted- Average Exercise Price
Beginning balance, outstanding (usd per share)			$ 9.29
Granted (usd per share)			17.91
Exercised (usd per share)			0
Cancelled (usd per share)			10.03
Ending balance, outstanding (usd per share)	$ 10.89		10.89		$ 9.29
Exercisable (usd per share)	$ 8.54		$ 8.54
Stock Options Additional Disclosures
Weighted average remaining contractual term, outstanding			9 years		9 years 7 months 6 days
Weighted average remaining contractual term, exercisable			8 years 6 months
Aggregate intrinsic value, outstanding	$ 43,274		$ 43,274		$ 41,320
Aggregate intrinsic value, exercisable	$ 8,849		$ 8,849

Stock-Based Compensation - Sc_3

Stock-Based Compensation - Schedule of Restricted Stock Unit Activity (Details) - Restricted Stock Units (RSUs)	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Shares
Beginning balance, unvested, outstanding (in shares) | shares	19,113
Granted (in shares) | shares	0
Vested (in shares) | shares	(3,740)
Forfeited (in shares) | shares	0
Ending balance, unvested, outstanding (in shares) | shares	15,373
Weighted- Average Grant Date Fair Value per Share
Beginning balance, unvested (usd per share) | $ / shares	$ 11.89
Granted (usd per share) | $ / shares	0
Vested (usd per share) | $ / shares	11.89
Cancelled (usd per share) | $ / shares	0
Ending balance, unvested (usd per share) | $ / shares	$ 11.89

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) $ in Millions		2 Months Ended
	Feb. 13, 2024 USD ($)	Oct. 03, 2023 lawsuit letter
Commitments and Contingencies Disclosure [Abstract]
Demand letters | letter		11
Number of lawsuits | lawsuit		3
Litigation settlement | $	$ 0.2

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ / shares in Units, $ in Millions			1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 01, 2023	May 31, 2023	May 31, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Related Party Transaction [Line Items]
Share-based compensation arrangement by share-based payment award, options, exercises in period (in shares)				0	0	0	1,800,000
Exercised (usd per share)						$ 0
Shares acquired, average cost per share (usd per share)		$ 2.76
Treasury stock, value, acquired, cost method	$ 0.2
Affiliated Entity
Related Party Transaction [Line Items]
Share-based compensation arrangement by share-based payment award, options, exercises in period (in shares)			75,782
Exercised (usd per share)		$ 0.13

Net Loss per Share (Details)

Net Loss per Share (Details) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	3,151,903	12,075,515
Series A convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	0	10,222,414
Employee Stock Option | 2022 Equity Incentive Plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	1,363,685	1,403,409
Employee Stock Option | 2023 Equity Incentive Plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	1,531,538	0
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	14,958	0
Early Exercisable Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	241,722	449,692