Alumis Inc. Common Stock (ALMS) 10-Q 13 Nov 24 2024 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2024	Nov. 07, 2024
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-42143
Entity Registrant Name	Alumis Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	86-1771129
Entity Address, Address Line One	280 East Grand Avenue
Entity Address, City or Town	South San Francisco
Entity Address State Or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	650
Local Phone Number	231-6625
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
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	ALMS
Security Exchange Name	NASDAQ
Entity Central Index Key	0001847367
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Amendment Flag	false
Voting common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		47,222,419
Non-voting common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		7,184,908

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 213,417	$ 45,996
Restricted cash		113
Marketable securities	148,453	2,956
Research and development prepaid expenses	12,241	2,661
Other prepaid expenses and current assets	3,236	1,631
Total current assets	377,347	53,357
Restricted cash, non-current	1,024	1,024
Property and equipment, net	21,429	22,441
Operating lease right-of-use assets, net	12,752	12,783
Other long-term assets	7	7
Total assets	412,559	89,612
Current liabilities
Accounts payable	6,444	1,118
Research and development accrued expenses	18,140	10,946
Other accrued expenses and current liabilities	7,464	7,087
Operating lease liabilities, current	1,467	1,720
Total current liabilities	33,515	20,871
Operating lease liabilities, non-current	29,631	30,860
Share repurchase liability	1,024	1,771
Total liabilities	64,170	53,502
Commitments and contingencies (Note 7)
Redeemable convertible preferred stock, $0.0001 par value; zero and 89,016,578 shares authorized as of September 30, 2024 and December 31, 2023, respectively; zero and 85,960,088 shares issued and outstanding as of September 30, 2024 and December 31, 2023, respectively; aggregate liquidation preference of zero and $370,540 as of September 30, 2024 and December 31, 2023, respectively		375,370
Stockholders' equity (deficit):
Preferred stock, $0.0001 par value; 50,000,000 shares authorized, zero shares issued and outstanding as of September 30, 2024; zero shares authorized issued and outstanding as of December 31, 2023
Additional paid-in capital	912,037	25,055
Accumulated other comprehensive income	139	2
Accumulated deficit	(563,792)	(364,318)
Total stockholders' equity (deficit)	348,389	(339,260)
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	412,559	89,612
Voting common stock
Stockholders' equity (deficit):
Common Stock	4	$ 1
Non-voting common stock
Stockholders' equity (deficit):
Common Stock	$ 1

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Redeemable convertible preferred stock, Par Value	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, Shares Authorized	0	89,016,578
Redeemable convertible preferred stock, Shares Issued	0	85,960,088
Redeemable convertible preferred stock, Shares Outstanding	0	85,960,088
Redeemable convertible preferred stock, Aggregate Liquidation Preference	$ 0	$ 370,540
Preferred stock, par or stated value per share	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Voting common stock
Common Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized	492,815,092	125,000,000
Common Stock, Shares, Issued	47,221,880	2,675,979
Common Stock, Shares, Outstanding	47,221,880	2,675,979
Non-voting common stock
Common Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized	7,184,908	85,960,088
Common Stock, Shares, Issued	7,184,908	0
Common Stock, Shares, Outstanding	7,184,908	0

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ 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 expenses, including related party expenses of $160, $385, $731 and $1,139 for the three and nine months ended September 30, 2024 and 2023, respectively	$ 87,824	$ 37,788	$ 178,350	$ 103,071
General and administrative expenses	10,575	5,971	23,782	14,971
Total operating expenses	98,399	43,759	202,132	118,042
Loss from operations	(98,399)	(43,759)	(202,132)	(118,042)
Other income (expense):
Interest income	5,322	951	8,153	2,509
Change in fair value of derivative liability		(551)	(5,406)	(119)
Other income (expenses), net	(40)	(18)	(89)	(41)
Total other income (expense), net	5,282	382	2,658	2,349
Net loss	(93,117)	(43,377)	(199,474)	(115,693)
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities, net	140	(3)	137	127
Net loss and other comprehensive loss	$ (92,977)	$ (43,380)	$ (199,337)	$ (115,566)
Net loss per share attributable to common stockholders, basic	$ (1.73)	$ (19.76)	$ (10.15)	$ (54.98)
Net loss per share attributable to common stockholders, diluted	$ (1.73)	$ (19.76)	$ (10.15)	$ (54.98)
Weighted-average shares of common stock outstanding, basic	53,752,223	2,194,988	19,647,690	2,104,282
Weighted-average shares of common stock outstanding, diluted	53,752,223	2,194,988	19,647,690	2,104,282

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Research and development expenses	$ 87,824	$ 37,788	$ 178,350	$ 103,071
Related party
Research and development expenses	$ 160	$ 385	$ 731	$ 1,139

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT ) - USD ($) $ in Thousands	IPO Common Stock	IPO Additional Paid-in Capital	IPO	Private Placement Common Stock Voting common stock	Private Placement Additional Paid-in Capital Voting common stock	Private Placement Voting common stock	Common Stock Voting common stock	Common Stock	Additional Paid-in Capital Voting common stock	Additional Paid-in Capital	Accumulate Other Comprehensive Income (Loss)	Accumulated Deficit	Series C redeemable convertible preferred stock	Series B-2 And B-2A Redeemable Convertible Preferred Stock	Series B-2A redeemable convertible preferred stock	Voting common stock	Total
Redeemable Convertible Preferred Stock, Beginning balance at Dec. 31, 2022																	$ 285,473
Redeemable Convertible Preferred Stock, Beginning balance (in shares) at Dec. 31, 2022																	67,960,088
Redeemable Convertible Preferred Stock, Ending balance at Mar. 31, 2023																	$ 285,473
Redeemable Convertible Preferred Stock, Ending balance (in shares) at Mar. 31, 2023																	67,960,088
Beginning balance at Dec. 31, 2022								$ 1		$ 14,209	$ (127)	$ (209,325)					$ (195,242)
Beginning balance (in shares) at Dec. 31, 2022								2,642,334
Stockholders' deficit
Vesting of early exercised stock options										694							694
Vesting of restricted shares of common stock										5							5
Repurchase of unvested shares of restricted common stock (in shares)								(13,369)
Stock-based compensation expense										1,831							1,831
Other comprehensive income (loss), net											100						100
Net loss												(36,027)					(36,027)
Ending balance at Mar. 31, 2023								$ 1		16,739	(27)	(245,352)					(228,639)
Ending balance (in shares) at Mar. 31, 2023								2,628,965
Redeemable Convertible Preferred Stock, Beginning balance at Dec. 31, 2022																	$ 285,473
Redeemable Convertible Preferred Stock, Beginning balance (in shares) at Dec. 31, 2022																	67,960,088
Redeemable Convertible Preferred Stock, Ending balance at Sep. 30, 2023																	$ 343,152
Redeemable Convertible Preferred Stock, Ending balance (in shares) at Sep. 30, 2023																	79,960,088
Beginning balance at Dec. 31, 2022								$ 1		14,209	(127)	(209,325)					$ (195,242)
Beginning balance (in shares) at Dec. 31, 2022								2,642,334
Stockholders' deficit
Issuance of common stock upon exercise of stock options and early exercised stock options (in shares)																	25,506
Net loss																	$ (115,693)
Ending balance at Sep. 30, 2023								$ 1		21,945		(325,018)					(303,072)
Ending balance (in shares) at Sep. 30, 2023								2,653,043
Redeemable Convertible Preferred Stock, Beginning balance at Mar. 31, 2023																	$ 285,473
Redeemable Convertible Preferred Stock, Beginning balance (in shares) at Mar. 31, 2023																	67,960,088
Redeemable convertible preferred stock
Issuance of redeemable convertible preferred stock for cash, net of derivative liability of issuance cost														$ 51,290	$ 6,389
Issuance of redeemable convertible preferred stock for cash, net of derivative liability of issuance cost (in shares)														10,722,340	1,277,660
Redeemable Convertible Preferred Stock, Ending balance at Jun. 30, 2023																	$ 343,152
Redeemable Convertible Preferred Stock, Ending balance (in shares) at Jun. 30, 2023																	79,960,088
Beginning balance at Mar. 31, 2023								$ 1		16,739	(27)	(245,352)					$ (228,639)
Beginning balance (in shares) at Mar. 31, 2023								2,628,965
Stockholders' deficit
Issuance of common stock upon exercise of stock options and early exercised stock options										71							71
Issuance of common stock upon exercise of stock options and early exercised stock options (in shares)								18,395
Vesting of early exercised stock options										559							559
Vesting of restricted shares of common stock										6							6
Stock-based compensation expense										1,909							1,909
Other comprehensive income (loss), net											30						30
Net loss												(36,289)					(36,289)
Ending balance at Jun. 30, 2023								$ 1		19,284	3	(281,641)					(262,353)
Ending balance (in shares) at Jun. 30, 2023								2,647,360
Redeemable Convertible Preferred Stock, Ending balance at Sep. 30, 2023																	$ 343,152
Redeemable Convertible Preferred Stock, Ending balance (in shares) at Sep. 30, 2023																	79,960,088
Stockholders' deficit
Issuance of common stock upon exercise of stock options and early exercised stock options										23							$ 23
Issuance of common stock upon exercise of stock options and early exercised stock options (in shares)								7,111
Vesting of early exercised stock options										362							362
Vesting of restricted shares of common stock										6							6
Repurchase of unvested shares of restricted common stock (in shares)								(1,428)
Stock-based compensation expense										2,270							2,270
Other comprehensive income (loss), net											(3)						(3)
Net loss												(43,377)					(43,377)
Ending balance at Sep. 30, 2023								$ 1		21,945		(325,018)					(303,072)
Ending balance (in shares) at Sep. 30, 2023								2,653,043
Redeemable Convertible Preferred Stock, Beginning balance at Dec. 31, 2023															$ 8,928		$ 375,370
Redeemable Convertible Preferred Stock, Beginning balance (in shares) at Dec. 31, 2023																	85,960,088
Redeemable convertible preferred stock
Issuance of redeemable convertible preferred stock for cash, net of derivative liability of issuance cost													$ 120,205
Issuance of redeemable convertible preferred stock for cash, net of derivative liability of issuance cost (in shares)													41,264,891
Redeemable Convertible Preferred Stock, Ending balance at Mar. 31, 2024																	$ 495,575
Redeemable Convertible Preferred Stock, Ending balance (in shares) at Mar. 31, 2024																	127,224,979
Beginning balance at Dec. 31, 2023								$ 1		25,055	2	(364,318)					$ (339,260)
Beginning balance (in shares) at Dec. 31, 2023								2,675,979								2,675,979
Stockholders' deficit
Issuance of common stock upon exercise of stock options and early exercised stock options										29							29
Issuance of common stock upon exercise of stock options and early exercised stock options (in shares)								3,186
Vesting of early exercised stock options										494							494
Vesting of restricted shares of common stock										6							6
Stock-based compensation expense										2,657							2,657
Other comprehensive income (loss), net											(3)						(3)
Net loss												(49,849)					(49,849)
Ending balance at Mar. 31, 2024								$ 1		28,241	(1)	(414,167)					(385,926)
Ending balance (in shares) at Mar. 31, 2024								2,679,165
Redeemable Convertible Preferred Stock, Beginning balance at Dec. 31, 2023															$ 8,928		$ 375,370
Redeemable Convertible Preferred Stock, Beginning balance (in shares) at Dec. 31, 2023																	85,960,088
Redeemable Convertible Preferred Stock, Ending balance (in shares) at Sep. 30, 2024																	0
Beginning balance at Dec. 31, 2023								$ 1		25,055	2	(364,318)					$ (339,260)
Beginning balance (in shares) at Dec. 31, 2023								2,675,979								2,675,979
Stockholders' deficit
Issuance of common stock upon exercise of stock options and early exercised stock options (in shares)																	71,662
Net loss																	$ (199,474)
Ending balance at Sep. 30, 2024								$ 5		912,037	139	(563,792)					348,389
Ending balance (in shares) at Sep. 30, 2024								54,406,788								47,221,880
Redeemable Convertible Preferred Stock, Beginning balance at Mar. 31, 2024																	$ 495,575
Redeemable Convertible Preferred Stock, Beginning balance (in shares) at Mar. 31, 2024																	127,224,979
Redeemable convertible preferred stock
Issuance of redeemable convertible preferred stock for cash, net of derivative liability of issuance cost													$ 143,662
Issuance of redeemable convertible preferred stock for cash, net of derivative liability of issuance cost (in shares)													41,264,892
Redeemable Convertible Preferred Stock, Ending balance at Jun. 30, 2024																	$ 639,237
Redeemable Convertible Preferred Stock, Ending balance (in shares) at Jun. 30, 2024																	168,489,871
Beginning balance at Mar. 31, 2024								$ 1		28,241	(1)	(414,167)					$ (385,926)
Beginning balance (in shares) at Mar. 31, 2024								2,679,165
Stockholders' deficit
Issuance of common stock upon exercise of stock options and early exercised stock options										287							287
Issuance of common stock upon exercise of stock options and early exercised stock options (in shares)								62,333
Vesting of early exercised stock options										253							253
Vesting of restricted shares of common stock										6							6
Stock-based compensation expense										3,133							3,133
Net loss												(56,508)					(56,508)
Ending balance at Jun. 30, 2024								$ 1		31,920	(1)	(470,675)					(438,755)
Ending balance (in shares) at Jun. 30, 2024								2,741,498
Redeemable convertible preferred stock
Redeemable Convertible Preferred Stock, Conversion and redesignation of redeemable convertible preferred stock into 28,855,656 shares of voting common stock and 7,184,908 shares of non-voting common stock in connection with initial public offering																	$ (639,237)
Redeemable Convertible Preferred Stock, Conversion and redesignation of redeemable convertible preferred stock into 28,855,656 shares of voting common stock and 7,184,908 shares of non-voting common stock in connection with initial public offering (in shares)																	(168,489,871)
Redeemable Convertible Preferred Stock, Ending balance (in shares) at Sep. 30, 2024																	0
Stockholders' deficit
Issuance of voting common stock	$ 1	$ 193,315	$ 193,316		$ 40,000	$ 40,000
Issuance of voting common stock (in shares)	13,125,000			2,500,000
Conversion and redesignation of redeemable convertible preferred stock into 28,855,656 shares of voting common stock and 7,184,908 shares of non-voting common stock in connection with initial public offering								$ 3		639,234							$ 639,237
Conversion and redesignation of redeemable convertible preferred stock into 28,855,656 shares of voting common stock and 7,184,908 shares of non-voting common stock in connection with initial public offering (in shares)								36,040,564
Issuance of common stock upon exercise of stock options and early exercised stock options									$ 54							$ 54
Issuance of common stock upon exercise of stock options and early exercised stock options (in shares)							6,143
Vesting of early exercised stock options										201							201
Vesting of restricted shares of common stock										4							4
Repurchase of unvested shares of restricted common stock (in shares)								(6,417)
Stock-based compensation expense										7,309							7,309
Other comprehensive income (loss), net											140						140
Net loss												(93,117)					(93,117)
Ending balance at Sep. 30, 2024								$ 5		$ 912,037	$ 139	$ (563,792)					$ 348,389
Ending balance (in shares) at Sep. 30, 2024								54,406,788								47,221,880

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT ) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023
Series C redeemable convertible preferred stock
Derivative liability		$ 14,319	$ 8,913
Issuance costs		$ 157	$ 382
Series B-2 And B-2A Redeemable Convertible Preferred Stock
Derivative liability				$ 2,112
Issuance costs				$ 208
IPO | Voting common stock
Underwriting discounts and commissions and other offering costs	$ 16,684
Number of common shares issued upon conversion of temporary equity	28,855,656
IPO | Non-voting common stock
Number of common shares issued upon conversion of temporary equity	7,184,908

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities
Net loss	$ (199,474)	$ (115,693)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	13,099	6,010
Non-cash lease expense	31	1,975
Depreciation and amortization	2,332	558
Net accretion of discounts on marketable securities	(1,987)	(524)
Loss on disposal of fixed assets	5	266
Change in fair value of derivative liability	5,406	119
Loss on abandonment of right-of-use assets		645
Changes in operating assets and liabilities:
Research and development prepaid expenses	(9,581)	3,605
Other prepaid expenses and other assets	(1,605)	(150)
Accounts payable	5,322	2,645
Research and development accrued expenses	7,193	3,342
Other accrued expenses and current liabilities	426	864
Operating lease liabilities	(1,481)	90
Net cash used in operating activities	(180,314)	(96,248)
Cash flows from investing activities
Maturities of marketable securities	42,000	76,250
Purchases of marketable securities	(185,374)	(8,345)
Purchases of property and equipment	(1,366)	(3,289)
Net cash (used in) provided by investing activities	(144,740)	64,616
Cash flows from financing activities
Proceeds from issuance of redeemable convertible preferred stock and derivative liability, net of issuance costs	258,461	59,791
Proceeds from initial public offering, net of underwriter discounts and commissions and other offering costs	193,316	(10)
Proceeds from a private placement transaction	40,000
Proceeds from issuance of common stock upon exercise of stock options	591	241
Repurchase of unvested common stock shares issued upon early exercised stock options	(6)	(64)
Net cash provided by financing activities	492,362	59,958
Net increase in cash, cash equivalents and restricted cash	167,308	28,326
Cash, cash equivalents and restricted cash at beginning of period	47,133	26,954
Cash, cash equivalents and restricted cash at end of period	214,441	55,280
Supplemental disclosures:
Conversion of 168,489,871 redeemable convertible preferred stock upon the closing of initial public offering	639,237
Right-of-use assets obtained in exchange for operating lease liabilities		14,255
Property and equipment acquired through tenant improvement allowance		16,641
Vesting of early exercised stock options and unvested restricted shares of common stock	964	1,632
Purchases of property and equipment in other accrued expenses and current liabilities	6	960
Recognition of derivative liability upon issuance of redeemable convertible preferred stock	8,913	2,112
Settlement of derivative liability upon issuance of redeemable convertible preferred stock	(14,319)
Deferred offering costs in accounts payable and other accrued expenses and current liabilities		544
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	213,417	53,937
Restricted cash		319
Restricted cash, non-current	1,024	1,024
Total cash, cash equivalents and restricted cash	$ 214,441	$ 55,280

CONDENSED CONSOLIDATED STATEM_6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)	9 Months Ended
	Sep. 30, 2024 shares
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
Conversion of redeemable convertible preferred stock (in shares)	168,489,871

Organization and Nature of the

Organization and Nature of the Business	9 Months Ended
	Sep. 30, 2024
Organization and Nature of the Business
Organization and Nature of the Business	1. Organization and Nature of the Business Organization and Business Alumis Inc. (the “Company”) is a clinical stage biopharmaceutical company focused on identifying, acquiring, and accelerating the development and commercialization of transformative medicines for autoimmune disorders. The Company leverages its proprietary precision data analytics platform, biological insights, and a team of experts with deep experience in precision medicine drug discovery, development, and immunology, to create medicines that significantly improve the lives of patients by replacing broad immunosuppression with targeted therapies. The Company was founded on January 29, 2021, as a Delaware corporation under the name FL2021-001, Inc. FL2021-001, Inc.’s name was changed to Esker Therapeutics, Inc. on March 8, 2021, and to Alumis Inc. on January 6, 2022. The Company is headquartered in South San Francisco, California. Reverse Stock Split On June 19, 2024, the board of directors approved, and on June 20, 2024, the Company effected, a reverse stock split of the shares of the Company’s outstanding common stock at a ratio of 1 Initial Public Offering and Concurrent Private Placement On June 28, 2024, the Company’s Registration Statement on Form S-1 for its IPO was declared effective, and on July 1, 2024, the Company completed its IPO, pursuant to which it issued and sold 13,125,000 shares of its common stock at $16.00 price per share to the public. Net proceeds from the IPO were $193.3 million, after deducting underwriting discounts and commissions and other offering costs totaling $16.7 million. In connection with the IPO, an existing investor and a holder of more than 5% of the Company’s capital stock, purchased an additional 2,500,000 shares of the Company’s common stock at the IPO price per share for total gross and net proceeds of $40.0 million in a private placement transaction (the “Concurrent Private Placement”). The closing of the Concurrent Private Placement was contingent on the closing of the IPO. The sale of such shares is not registered under the Securities Act of 1933, as amended (the “Securities Act”), and as such, the shares may not be offered or sold absent registration or an applicable exemption from registration. The shares sold in connection with the Concurrent Private Placement are subject to existing resale registration rights and are subject to a 180-day lock-up agreement with the underwriters in the IPO. The Concurrent Private Placement closed on July 17, 2024. Immediately prior to the closing of the IPO on July 1, 2024, all of the shares of the Company’s redeemable convertible preferred stock then outstanding converted into 28,855,656 shares of Class A common stock and 7,184,908 shares of Class B common stock at a 1 Unless the context otherwise requires a different meaning, all references to “common stock” in these notes refers to the Company’s voting common stock and non-voting common stock combined. Liquidity The Company has incurred negative operating cash flows and significant losses from operations since its inception. For the three and nine months ended September 30, 2024 and 2023, the Company incurred net losses of $93.1 million, $199.5 million, $43.4 million and $115.7 million, respectively. Cash used in operating activities was $180.3 million and $96.2 million for the nine months ended September 30, 2024 and 2023, respectively. As of September 30, 2024, the Company had an accumulated deficit of $563.8 million. The Company has historically financed its operations primarily through issuance of common stock and redeemable convertible preferred stock and convertible promissory notes in private placements, and most recently, through its IPO and Concurrent Private Placement. The Company expects to continue to incur substantial losses for the foreseeable future, and its ability to achieve and sustain profitability will depend on the successful development, approval, and commercialization of any product candidates it may develop, and on the achievement of sufficient revenue to support its cost structure. The Company may never achieve profitability and, unless and until it does, it will need to continue to raise additional capital. Management believes that its existing cash, cash equivalents and marketable securities of $361.9 million as of September 30, 2024, will be sufficient to meet its operating and capital requirements for at least 12 months from the date of issuance of these unaudited condensed consolidated financial statements. ​ The Company will need to raise significant additional capital to fund ongoing research and development activities and maintain future operations. The Company’s management plans to monitor expenses and may raise additional capital through a combination of public and private equity, debt financings, strategic alliances, and licensing arrangements. The Company’s ability to access capital when needed is not assured and, if capital is not available to the Company when, and in the amounts, needed, on the terms which are favorable, the Company could be required to delay, scale back, or abandon some or all of its planned development programs and other operations, which could materially harm the Company’s business, financial condition and results of operations.

Summary of Significant Accounti

Summary of Significant Accounting Policies and Basis of Presentation	9 Months Ended
	Sep. 30, 2024
Summary of Significant Accounting Policies and Basis of Presentation
Summary of Significant Accounting Policies and Basis of Presentation	2. Summary of Significant Accounting Policies and Basis of Presentation The significant accounting policies and estimates used in the preparation of the accompanying unaudited condensed consolidated financial statements are described in the Company’s audited consolidated financial statements for the year ended December 31, 2023 included in the Company’s final prospectus for its IPO filed pursuant to Rule 424(b)(4) under the Securities Act with the Securities and Exchange Commission (the “SEC”), on June 28, 2024 (the “Prospectus”). There have been no material changes in the Company’s significant accounting policies during the three months ended September 30, 2024. Basis of Presentation The unaudited condensed consolidated financial statements and accompanying notes are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and applicable rules and regulations of the SEC regarding interim financial reporting and do not contain all information that is included in the annual financial statements and notes thereto of the Company. Prior to their dissolution, the Company’s condensed consolidated financial statements included the accounts of FronThera U.S. Holdings, Inc. and FronThera U.S. Pharmaceuticals LLC, two wholly owned subsidiaries, and all intercompany transactions were eliminated. FronThera U.S. Holdings, Inc. was dissolved on April 8, 2024 and FronThera U.S. Pharmaceuticals LLC was dissolved on March 14, 2024. The unaudited condensed consolidated interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the Company’s financial position as of September 30, 2024 and the results of its operations and its cash flows for the three and nine months ended September 30, 2024 and 2023. The condensed balance sheet as of December 31, 2023, included in this filing, was derived from audited annual consolidated financial statements but does not include all disclosures required by U.S. GAAP. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results of operations to be expected for the full year or for any other subsequent interim period. Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected within these condensed consolidated financial statements include, but are not limited to, the fair value of the Company’s common stock and redeemable convertible preferred stock, the fair value of the derivative liability, stock-based compensation expense, accruals for research and development expenses and the valuation of deferred tax assets. The Company bases its estimates on known trends and other market-specific or relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, as there are changes in circumstances, facts and experience. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ materially from those estimates. Segment and Geographical Information The Company operates and manages its business as one reportable and operating segment, which is the business of developing medicines for autoimmune disorders. The chief executive officer, who is the chief operating decision maker, reviews financial information on an aggregate basis for purposes of allocating resources and evaluating financial performance. All of the Company’s long-lived assets are located in the United States. Concentration of Credit Risk Financial instruments which potentially subject the Company to concentration of credit risk consist primarily of cash and cash equivalents, investments in marketable securities and restricted cash. The Company maintains bank deposits in federally insured financial institutions and these deposits exceed federally insured limits. To date, the Company has not experienced any losses on its deposits of cash and periodically evaluates the creditworthiness of financial institutions at which bank deposits are maintained. The Company also invests in money market funds and U.S. treasuries, which are subject to certain credit risks. The Company mitigates the risks by investing in high-grade instruments, limiting its exposure to any one issuer and monitoring the ongoing creditworthiness of the financial institutions and issuers. The Company has not experienced any loss of principal on its financial instruments. Risks and Uncertainties The Company is subject to certain risks and uncertainties, including, but not limited to, changes in any of the following areas that the Company believes could have a material adverse effect on the future financial position or results of operations: the Company’s ability to advance the development of its proprietary precision data analytics platform, timing and ability to advance its product candidates through preclinical and clinical development; costs and timelines associated with the manufacturing of clinical supplies; regulatory approval, market acceptance of, and reimbursement for, any product candidates the Company may develop; performance of third-party vendors; competition from pharmaceutical or other biotechnology companies with greater financial resources or expertise; protection of intellectual property; litigation or claims against the Company based on intellectual property or other factors; and its ability to attract and retain employees necessary to support its growth. The Company’s business and operations may be affected by worldwide economic conditions, which may continue to be impacted by global macroeconomic challenges, such as the effects of the ongoing military conflicts in Ukraine, Israel, and the Middle East, tensions in U.S.-China relations, uncertainty in the markets, including disruptions in the banking industry, the COVID-19 pandemic and inflationary trends. Fiscal year 2023 was marked by significant market uncertainty and increasing inflationary pressures. These market dynamics continue into 2024, and these and similar adverse market conditions may negatively impact the Company’s business, financial position and results of operations. Deferred Finance Issuance Costs Deferred finance issuance costs, consisting of legal, accounting and other third-party fees directly relating to in-process equity financings or offerings are capitalized. The deferred finance issuance costs are offset against offering proceeds upon the completion of the financing or the offering. In the event the financing or the offering is terminated or delayed, deferred finance issuance costs are expensed immediately as a charge to general and administrative expenses in the condensed consolidated statements of operations and comprehensive loss. The Company had $4.3 million in deferred finance issuance costs capitalized and included in other long-term assets in its unaudited condensed consolidated balance sheet as of June 30, 2024, which were reclassified to equity upon the closing of the IPO in the third quarter of 2024. There were no deferred finance issuance costs capitalized and included in other long-term assets in the condensed consolidated balance sheets as of September 30, 2024 and December 31, 2023. Net Loss Per Share Attributable to Common Stockholders ​ Basic and diluted net loss per share attributable to common stockholders is presented in conformity with the two-class method required for participating securities. As such, net income is attributed to common stockholders and participating securities based on their participation rights. Prior to the IPO, under the two-class method, the net loss attributable to common stockholders was not allocated to the redeemable convertible preferred stock as the holders of the redeemable convertible preferred stock did not have a contractual obligation to share in the Company’s losses. Upon the IPO, the Company’s redeemable convertible preferred stock converted into either Class A or Class B common stock, and were immediately thereafter redesignated into voting and non-voting common stock, respectively, and therefore are included in the allocation of net loss attributable to common stockholders as they share in the Company’s losses. Voting and non-voting common stock participate in the Company’s losses equally. Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. As the Company has reported losses for all periods presented, all potentially dilutive securities are antidilutive and accordingly, basic net loss per share equals diluted net loss per share. ​ Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. The Company qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), and has elected not to “opt out” of the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and private companies, the Company will adopt the new or revised standard at the time private companies adopt the new or revised standard and will do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. The Company may choose to early adopt any new or revised accounting standards whenever such early adoption is permitted for nonpublic companies. Recently Issued and Not Yet Adopted Accounting Pronouncements In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosure In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures In March 2024, the FASB issued ASU No. 2024-02, Codification Improvements - Amendments to Remove References to the Concepts Statements ​ In November 2024, the FASB issued ASU No. 2024-03, Disaggregation of Income Statement Expenses (Topic 220)

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2024
Fair Value Measurements
Fair Value Measurements	3. Fair Value Measurements The Company discloses and recognizes the fair value of its assets and liabilities using a hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The guidance establishes three levels of the fair value hierarchy as follows: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. The Company recognizes transfers into and out of levels within the fair value hierarchy in the period in which the actual event or change in circumstances that caused the transfer occurs. The Company’s financial instruments consist of Level 1, Level 2 and Level 3 financial instruments. Changes in the ability to observe valuation inputs may result in a reclassification of levels of certain securities within the fair value hierarchy. Level 1 financial instruments are comprised of money market funds and U.S. treasuries. Level 2 financial instruments are comprised of U.S. treasuries. Usually, short term marketable securities are considered Level 2 when their fair values are determined using inputs that are observable in the market or can be derived principally from or corroborated by observable market data such as pricing for similar securities, recently executed transactions, cash flow models with yield curves, and benchmark securities. In addition, Level 2 financial instruments are valued using comparisons to like-kind financial instruments and models that use readily observable market data as their basis. Level 3 financial instruments include derivative liabilities issued in May 2023 and settled in October 2023 in connection with the closing of the second tranche of the Series B-2 and B-2A redeemable convertible preferred stock financing, and issued in March 2024 and settled in May 2024 in connection with the closing of the second tranche of the Series C redeemable convertible preferred stock financing. The following tables represent the Company’s fair value hierarchy for financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2024 and December 31, 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of September 30, 2024 ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 198,412 ​ $ — ​ $ — ​ $ 198,412 U.S. treasuries ​ — ​ ​ 14,993 ​ ​ — ​ 14,993 Marketable securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. treasuries ​ 67,966 ​ 80,487 ​ — ​ 148,453 Total assets ​ $ 266,378 ​ $ 95,480 ​ $ — ​ $ 361,858 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of December 31, 2023 ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 21,310 ​ $ — ​ $ — ​ $ 21,310 U.S. treasuries ​ ​ 2,000 ​ ​ — ​ ​ — ​ ​ 2,000 Marketable securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. treasuries ​ 1,958 ​ 998 ​ — ​ 2,956 Total assets ​ $ 25,268 ​ $ 998 ​ $ — ​ $ 26,266 ​ The derivative liability issued in May 2023 in connection with the closing of the second tranche of the Series B-2 and B-2A redeemable convertible preferred stock financing was a freestanding financial instrument and represented the Company’s obligation to issue additional shares of Series B-2 and B-2A redeemable convertible preferred stock at a fixed price upon the approval by the Company’s board of directors. In connection with the Series C redeemable convertible preferred stock financing in March 2024, the Company issued to investors two freestanding financial instruments: the Series C second tranche option liability and the put right option liability. The Company estimated their fair value using a Black-Scholes option pricing model weighted by the probability of occurring. The Company used the intrinsic value calculation to estimate the fair value of the Series C second tranche option liability and the put right option liability upon settlement. Significant estimates and assumptions impacting the derivative liability fair value included the probability of each option exercise, redeemable convertible preferred stock fair value, estimated stock volatility and the expected term. The following tables provide a range of assumptions used in the valuation of the derivative liabilities for the nine months ended September 30, 2024 and 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ ​ 2024 2023 Expected term (in years) ​ 0.2 – 0.4 ​ ​ 0.0 – 0.4 ​ Volatility 55.1% – 59.9 % ​ 43.2% – 83.2 % Risk-free interest rate 5.4% – 5.5 % ​ 5.2% – 5.6 % Dividend yield 0.0 % ​ 0.0 % Probability of option exercise 0.0% – 100.0 % ​ 30.0% – 100.0 % ​ The following table provides a roll-forward of the fair value of the Company’s Level 3 financial instrument, the derivative liabilities, for the nine months ended September 30, 2024 and 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ ​ 2024 2023 Fair value at beginning of period ​ $ — ​ $ — Fair value upon issuance ​ 8,913 ​ ​ 2,112 Changes in fair value ​ 5,406 ​ ​ 119 Fair value upon settlement ​ (14,319) ​ ​ — Fair value at end of period $ — ​ ​ 2,231 ​ There were no transfers between Level 1, Level 2 or Level 3 categories for the three and nine months ended September 30, 2024 and 2023.

Marketable Securities

Marketable Securities	9 Months Ended
	Sep. 30, 2024
Marketable Securities
Marketable Securities	4. Marketable Securities Marketable securities, which are classified as available-for-sale marketable securities, consisted of the following as of September 30, 2024 and December 31, 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Gross Fair Value as of ​ ​ Amortized Cost ​ Unrealized ​ Unrealized ​ September 30, ​ ​ Basis ​ Gains ​ Losses ​ 2024 Short-term marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. treasuries ​ $ 148,315 ​ $ 138 ​ $ — ​ $ 148,453 Total short-term marketable securities ​ $ 148,315 ​ $ 138 ​ $ — ​ $ 148,453 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Gross Fair Value as of ​ ​ Amortized Cost ​ Unrealized ​ Unrealized ​ December 31, ​ ​ Basis ​ Gains ​ Losses ​ 2023 Short-term marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. treasuries ​ $ 2,954 ​ $ 2 ​ $ — $ 2,956 Total short-term marketable securities ​ $ 2,954 ​ $ 2 ​ $ — $ 2,956 ​ All marketable securities held as of September 30, 2024 and December 31, 2023, had contractual maturities of less than one year. As of September 30, 2024 and December 31, 2023, no significant facts or circumstances were present to indicate a deterioration in the creditworthiness of the issuers of the marketable securities, and the Company has no requirement or intention to sell these securities before maturity or recovery of their amortized cost basis. The Company considered the current and expected future economic and market conditions and determined that its marketable securities were not significantly impacted. For all marketable securities with a fair value less than its amortized cost basis, the Company determined the decline in fair value below amortized cost basis to be immaterial and non-credit related, and therefore no allowance for expected credit losses was recorded. During the three and nine months ended September 30, 2024 and 2023, the Company did not recognize any impairment losses on its marketable securities.

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2024
Balance Sheet Components
Balance Sheet Components	5. Balance Sheet Components Other Prepaid Expenses and Current Assets Other prepaid expenses and current assets consisted of the following as of September 30, 2024 and December 31, 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2024 ​ 2023 Prepaid insurance ​ $ 952 ​ $ 111 Prepaid subscriptions ​ ​ 896 ​ ​ 703 Interest receivable ​ ​ 767 ​ ​ 108 Tax receivable ​ ​ 364 ​ ​ 614 Other ​ 257 ​ 95 Total other prepaid expenses and current assets ​ $ 3,236 ​ $ 1,631 ​ Property and Equipment, net Property and equipment, net consisted of the following as of September 30, 2024 and December 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated Useful Life September 30, December 31, ​ ​ (in years) ​ 2024 ​ 2023 Leasehold improvements Shorter of useful life or lease term ​ $ 17,618 ​ $ 17,592 Laboratory equipment 5 ​ ​ 4,867 ​ ​ 3,577 Furniture and fixtures 5 ​ 1,709 ​ 1,709 Computer equipment 5 ​ 896 ​ 896 Capitalized software 3 ​ 75 ​ 75 Total property and equipment, gross ​ ​ ​ 25,165 ​ 23,849 Less: Accumulated depreciation and amortization ​ ​ ​ (3,736) ​ (1,408) Total property and equipment, net ​ ​ ​ $ 21,429 ​ $ 22,441 ​ Depreciation and amortization expense was $0.8 million and $0.3 million for the three months ended September 30, 2024 and 2023, respectively, and $2.3 million and $0.6 million for the nine months ended September 30, 2024 and 2023, respectively. Other Accrued Expenses and Current Liabilities Other accrued expenses and current liabilities consist of the following as of September 30, 2024 and December 31, 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2024 ​ 2023 Accrued personnel and related expenses ​ $ 5,396 ​ $ 5,585 Accrued professional services ​ 1,991 ​ 1,093 Accrued other expenses ​ 77 ​ 409 Total other accrued expenses and current liabilities ​ $ 7,464 ​ $ 7,087 ​

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2024
Related Party Transactions
Related Party Transactions	6. Related Party Transactions Foresite Labs Services Agreement Foresite Labs, LLC (“Foresite Labs”) is an affiliate of Foresite Capital Management, a stockholder of the Company. In January 2021, the Company entered into a services agreement with Foresite Labs, which was amended and restated in August 2021 and in December 2023, and expires in December 2026, unless terminated earlier by the parties. Thereafter, on each anniversary of the effective date, the agreement will automatically renew for an additional one-year term, unless terminated earlier by the parties. Foresite Labs provides services to assist the Company in exploring specified immunology genetic targets. For the three months ended September 30, 2024 and 2023, the Company recognized $0.2 million and $0.4 million as research and development expenses under the service agreement, respectively. For the nine months ended September 30, 2024 and 2023, the Company recognized $0.7 million and $1.1 million as research and development expenses under the service agreement, respectively. Accrued expenses under the service agreement were zero as of September 30, 2024 and were less than $0.1 million as of December 31, 2023.

Commitments and Contingent Liab

Commitments and Contingent Liabilities	9 Months Ended
	Sep. 30, 2024
Commitments and Contingent Liabilities
Commitments and Contingent Liabilities	7. Operating Leases In 2021, the Company entered into a lease agreement for 14,000 square feet of office space in South San Francisco, California, which commenced in August 2021 and had a contractual termination date of September 2024. In September 2023, the Company abandoned this right-of-use asset as it had moved to its new office space described below; the Company recognized a loss on this abandonment in the amount of $0.6 million. In January 2022, the Company entered into a lease agreement for 12,000 square feet of office and laboratory space in South San Francisco, California, which commenced in July 2022 and had a contractual termination date of July 2029. This lease contained an early termination option, allowing the Company to terminate this lease before the expiry of the lease term. The Company concluded the lease term for accounting purposes ended in August 2023. In April 2023, this lease was modified to reduce the contractual lease term to terminate in October 2023. The accounting impact of the modification was not material. In August 2022, the Company entered into a lease agreement for 55,000 square feet of additional office and laboratory space in South San Francisco, California, which commenced in January 2023 and has a contractual termination date in August 2033. The Company constructed leasehold improvements in the space, which were concluded to be lessee assets. The lessor provided the Company a tenant improvement allowance of $17.2 million, of which $0.5 million was received in the year ended December 31, 2022, and $16.7 million was received in the year ended December 31, 2023, and was accounted for as a reduction to lease payments. At the commencement date, future lease payments totaled $37.9 million, including $54.6 million in gross fixed payments less $16.7 million in lease incentives expected to be received during the first year of the lease. The lease liability at lease commencement was calculated to be $14.1 million, which is equal to the present value of the future lease payments, discounted at the incremental borrowing rate of 11.4%. Following the commencement date, the Company measured its lease liability and right-of-use asset in accordance with ASC 842-20-35-3. In accordance with this guidance, future lease payments increased as the $16.7 million incentive was received and future gross fixed payments were no longer offset by these incentives. Leasehold improvements are reflected in property and equipment, net in the condensed consolidated balance sheets as of September 30, 2024 and December 31, 2023. The lease agreement also includes a renewal option allowing the Company to extend this lease for an additional three years at the prevailing rental rate, which the Company was not reasonably certain to exercise. The Company maintains a letter of credit of $1.0 million as of September 30, 2024, on its office and laboratory lease, which is reflected on the Company’s unaudited condensed consolidated balance sheets in restricted cash, noncurrent. The Company maintained two letters of credit totaling $1.1 million on its leases in effect as of December 31, 2023, which were reflected on the Company’s condensed consolidated balance sheets in restricted cash, current and restricted cash, noncurrent. The components of lease costs were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2023 2024 2023 ​ Operating lease costs ​ $ 882 ​ $ 1,279 ​ $ 2,593 ​ $ 3,830 ​ Variable lease costs ​ 297 ​ 214 ​ 953 ​ 330 ​ Total lease costs ​ $ 1,179 ​ $ 1,493 ​ $ 3,546 ​ $ 4,160 ​ ​ Supplemental cash flow information related to the operating leases were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ ​ September 30, ​ ​ 2024 2023 ​ Cash payments included in the measurement of operating lease liabilities ​ $ 4,076 ​ $ 1,740 ​ ​ Weighted-average remaining lease term and incremental borrowing rate for the operating leases were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ 2024 2023 ​ Weighted-average remaining lease term (years) 8.9 ​ 9.5 ​ Weighted-average incremental borrowing rate 11.4 % 11.4 % ​ Future minimum lease payments under non-cancelable leases as of September 30, 2024, were as detailed below (in thousands): ​ ​ ​ ​ 2024 (remainder of the year) ​ $ 1,223 2025 ​ ​ 4,959 2026 ​ 5,125 2027 ​ 5,296 2028 ​ 5,474 Thereafter ​ 27,515 Total undiscounted lease payments ​ 49,592 Less: Imputed interest ​ (18,494) Total operating lease liabilities ​ $ 31,098 ​ FronThera Contingent Consideration In March 2021, the Company entered into a stock purchase agreement to acquire FronThera U.S. Holdings, Inc. and its wholly owned subsidiary, FronThera U.S. Pharmaceuticals LLC., and the transaction was accounted for as an asset acquisition. Under the stock purchase agreement, the Company is obligated to pay contingent consideration of up to an aggregate of $120.0 million based on the achievement of specified clinical and approval milestones, of up to an aggregate of $70.0 million payable for clinical milestones, and of up to an aggregate of $50.0 million payable for approval milestones, all related to technology acquired under the agreement. The Company incurred and paid a $37.0 million milestone in 2022 for the first administration of ESK-001 to a patient enrolled in a Phase 2 clinical trial of ESK-001, which was recorded as research and development expense in the consolidated statement of operations and comprehensive loss for the year ended December 31, 2022. In July 2024, the Company met its milestone in connection with the first administration of ESK-001 to a patient enrolled in a Phase 3 clinical trial of ESK-001 and made a $23.0 million milestone payment in August 2024, which was recorded as research and development expense in the unaudited condensed consolidated statements of operations and comprehensive loss for the three and nine months ended September 30, 2024. No other milestones were achieved or probable as of September 30, 2024. Research and Development Agreements The Company enters into various agreements in the ordinary course of business, such as those with suppliers, clinical research organizations, contract manufacturing organizations and clinical trial sites. These agreements provide for termination at the request of either party, generally with less than one-year notice and are, therefore, cancellable contracts and, if cancelled, are not anticipated to have a material effect on the Company’s condensed consolidated financial condition, results of operations, or cash flows. Legal Contingencies From time to time, the Company may become involved in legal proceedings arising from the ordinary course of business. The Company records a liability for such matters when it is probable that future losses will be incurred and that such losses can be reasonably estimated. Significant judgment by the Company is required to determine both probability and the estimated amount. Management is currently not aware of any legal matters that could have a material adverse effect on the Company’s financial position, results of operations or cash flows. Guarantees and Indemnifications In the normal course of business, the Company enters into agreements that contain a variety of representations and provide for general indemnification. Its exposure under these agreements is unknown because it involves claims that may be made against the Company in the future. To the extent permitted under Delaware law, the Company has agreed to indemnify its directors and officers for certain events or occurrences while the director or officer is, or was serving, at a request in such capacity. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. As of September 30, 2024 and December 31, 2023, the Company did not have any material indemnification claims that were probable or reasonably possible and consequently has not recorded related liabilities.

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock	9 Months Ended
	Sep. 30, 2024
Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock	8. Redeemable Convertible Preferred Stock In May 2023, the Company issued and sold an aggregate of 10,722,340 shares of Series B-2 redeemable convertible preferred stock for gross proceeds of $53.6 million and 1,277,660 shares of Series B-2A redeemable convertible preferred stock for gross proceeds of $6.4 million and incurred $0.2 million of issuance costs. The purchase price for Series B-2 and B-2A redeemable convertible preferred stock was $5.00 per certain events, including the board of directors’ consent. The Company recognized this call option as a derivative liability and estimated its fair value of $2.1 million. In July 2023, the holders of the shares of Series B-2A redeemable convertible preferred stock elected to convert their 1,277,660 shares into the same number of Series B-2 redeemable convertible preferred stock. In October 2023, the Company closed the Second Tranche Series B-2 Closing and issued an additional 4,221,170 shares of Series B-2 redeemable convertible preferred stock and 1,778,830 shares In March 2024, the Company issued and sold an aggregate of 41,264,891 shares of Series C redeemable convertible preferred stock for gross proceeds of $129.5 million and incurred $0.4 million of issuance costs. The purchase price for Series C redeemable convertible preferred stock was $3.13826 per share. Under the Series C stock purchase agreement, any time prior to the earliest of (i) December 31, 2024, (ii) the execution of a letter of intent for the sale of the Company, or (iii) the closing date of the Company’s IPO, at the discretion of the Company’s board of directors, the Company was obligated to sell and each Series C purchaser was obligated to purchase additional shares of Series C redeemable convertible preferred stock with the amount equal to the purchaser’s aggregate purchase price in the first tranche Series C closing less any previous payments by the purchaser as part of the Put Right (as defined below) exercise. If the purchaser did not purchase its full share in the second tranche closing (the “Second Tranche Series C Closing”), all of its existing shares of Series C redeemable convertible stock and Series C-1 redeemable convertible preferred stock were convertible into voting common stock at a 10-to-1 basis. Additionally, a purchaser had a right to purchase shares of Series C-1 redeemable convertible preferred stock at a purchase price of $4.00 per share beginning from the earlier of (a) September 4, 2024 or (b) the date of a significant partnering or collaboration agreement and expiring upon the earlier of (a) December 31, 2024, (b) the public filing of a registration statement on Form S-1 for the IPO, (c) the Second Tranche Series C Closing and (d) the execution of a letter of intent for the sale of the Company (the “Put Right”). The Put Right could only be exercised once. The Company determined that the Second Tranche Series C Closing and the Put Right were two freestanding financial instruments and recognized the derivative liabilities at their estimated fair value of $8.9 million at the issuance date. In May 2024, the Company closed the Second Tranche Series C Closing and issued an additional 41,264,892 shares of Series C redeemable convertible preferred stock at a price of $3.13826 per share. The Company received gross proceeds of $129.5 million and incurred $0.2 million of issuance costs. Accordingly, the derivative liabilities were settled, and the Company reclassified the derivative liabilities, remeasured at fair value of $14.3 million, into redeemable convertible preferred stock. Immediately prior to the closing of the Company’s IPO on July 1, 2024, all outstanding shares of the Company’s redeemable convertible preferred stock were converted and then redesignated into common stock and non-voting common stock (see Note 1) and are no longer outstanding. The Company’s redeemable convertible preferred stock as of December 31, 2023, consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ ​ ​ Shares Issued ​ Aggregate ​ ​ ​ ​ ​ Shares ​ and ​ Liquidation ​ Net Carrying ​ Authorized Outstanding Preference Value ​ ​ (in thousands, except share amounts) Series Seed redeemable convertible preferred stock 10,500,000 10,500,000 ​ $ 10,500 ​ $ 10,480 Series A redeemable convertible preferred stock 7,500,000 7,500,000 ​ 30,000 ​ 29,972 Series B redeemable convertible preferred stock 40,200,000 40,200,000 ​ 201,000 ​ 200,711 Series B-1 redeemable convertible preferred stock 9,760,088 9,760,088 ​ 39,040 ​ 44,310 Series B-2 redeemable convertible preferred stock ​ 18,000,000 ​ 16,221,170 ​ ​ 81,106 ​ ​ 80,969 Series B-2A redeemable convertible preferred stock ​ 3,056,490 ​ 1,778,830 ​ ​ 8,894 ​ ​ 8,928 Total redeemable convertible preferred stock 89,016,578 85,960,088 ​ $ 370,540 ​ $ 375,370 ​

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2024
Stockholders' Equity
Stockholders' Equity	9. Stockholders’ Equity Prior to the IPO, the voting, dividend and liquidation rights of the holders of the Company’s common stock were subject to and qualified by the rights, powers and preferences of the holders of the redeemable convertible preferred stock as described in the Prospectus. In June 2024, the Company’s board of directors approved the amended and restated certificate of incorporation, which was filed upon the closing of the IPO and which authorized the Company to issue up to 50,000,000 shares of preferred stock, with a par value of $0.0001 per share. There are no shares of preferred stock issued or outstanding as of September 30, 2024. As of September 30, 2024, the Company was authorized to issue 492,815,092 shares of voting common stock and 7,184,908 shares of non-voting common stock, both with par values The holders of voting and non-voting common stock have the same rights except that non-voting common stock does not have voting rights, except as may be required by law. Each holder of non-voting common stock has a right to convert each share of non-voting common stock to one share of voting common stock subject to the following limitations. At any time following the Company’s registration of any class of equity securities under the Exchange Act, the holders of shares of non-voting common stock may not convert a number of shares of non-voting common stock into shares of voting common stock in excess of that number of shares of non-voting common stock which would cause the holder thereof to beneficially own (for purposes of Section 13(d) of the Exchange Act), in excess of 4.99% of the total number of issued and outstanding shares of voting common stock. Such maximum percentage may be increased or decreased to such other percentage as any holder of outstanding shares of non-voting common stock may designate in writing (in the case of an increase upon 61 days’ prior written notice). Common stock reserved for issuance, on an as-converted basis, consisted of the following as of September 30, 2024 and December 31, 2023: ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2024 ​ 2023 Outstanding and issued common stock options 8,683,467 5,096,086 Shares available for grant under 2024 Equity Incentive Plan ​ 7,671,516 ​ — Shares available for grant under 2024 Employee Stock Purchase Plan ​ 650,000 ​ — Shares available for grant under 2024 Performance Option Plan ​ 90,661 ​ — Shares available for grant under 2021 Stock Plan — 296,189 Redeemable convertible preferred stock issued and outstanding — 18,387,168 Total 17,095,644 23,779,443 ​ Common Stock Issued to Executives In February 2021, the Company issued 100,532 shares of common stock to two executives at a purchase price of $0.94 per share. The shares vest over a four-year period with a one-year cliff. The holders have voting and dividends rights. The Company has the right to repurchase unvested shares at the price paid by the holder in the event of termination of the holder’s continuous status as a service provider. The Company estimated the fair value of the restricted stock awards based on the fair value of common stock at the grant dates. The expense is recognized ratably over the vesting terms. The Company recognized less than $0.1 million of stock-based compensation expense for the three and nine months ended September 30, 2024 and 2023. In the three months ended September 30, 2024, a holder’s continuous service terminated and the Company repurchased the unvested shares. The following table summarizes the activity for the Company’s restricted common stock for the nine months ended September 30, 2024: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ Shares ​ Fair Value Unvested as of December 31, 2023 29,322 ​ $ 2.90 Vested (16,445) ​ $ 2.90 Repurchased ​ (6,417) ​ $ 2.90 Unvested as of September 30, 2024 6,460 ​ $ 2.90 ​ As of September 30, 2024, the remaining unamortized stock-based compensation expense of less than $0.1 million will be recognized over the remaining vesting period of 0.4 year.

Stock Compensation

Stock Compensation	9 Months Ended
	Sep. 30, 2024
Stock Compensation
Stock Compensation	10. Stock Compensation 2024 Equity Incentive Plan On June 27, 2024, the Company’s board of directors adopted, and its stockholders approved, the 2024 Equity Incentive Plan (the “2024 EIP”), which became effective on June 28, 2024, upon execution of the underwriting agreement related to the Company’s IPO. The Company reserved 7,800,000 new shares of common stock for issuance under the 2024 EIP. In addition, up to 6,829,339 shares subject to awards under the 2021 Stock Plan (the “2021 Plan”) that terminate, expire, or lapse for any reason without the delivery of shares, or are reacquired or withheld (or not issued) to satisfy a tax withholding obligation or the purchase or exercise price, were authorized to be added to the 2024 EIP. The 2024 EIP is a successor to the 2021 Plan and no further grants will be made under the 2021 Plan. The 2024 EIP also provides that the number of shares initially reserved and available for issuance will automatically increase each January 1, beginning on January 1, 2025 through January 1, 2034, by an amount equal to 5% of the outstanding number of shares of the Company’s common stock as of the last day of the immediately preceding fiscal year, or such lesser number of shares as determined by the board of directors prior to the applicable January 1. No more than 43,888,017 shares of common stock may be issued upon the exercise of incentive stock options under the 2024 EIP. The 2024 EIP allows the Company to make equity-based awards to its officers, employees, directors and consultants. The 2024 EIP provides for the grant of incentive stock options (“ISOs”), non-statutory stock options (“NSOs”), restricted stock awards, restricted stock units (“RSUs”), stock appreciation rights, performance awards and other stock-based awards. Options under the 2024 EIP may be granted for periods of up to 10 years at exercise prices no less than the fair market value of common stock on the date of grant; provided, however, that the exercise price of an incentive stock option granted to a 10% stockholder may not be less than 110% of the fair market value of the shares on the date of grant and such option may not be exercisable after the expiration of five years from the date of grant. Stock option grants under the 2024 EIP generally vest over four years. The grant date fair market value of all awards made under the 2024 EIP and all cash compensation paid by the Company to any non-employee director for services as a director in any fiscal year may not exceed $750,000, increased to $1,000,000 in the fiscal year of their initial service as a non-employee director. The terms of the 2024 EIP do not permit option holders to exercise options before their options are vested. 2024 Employee Stock Purchase Plan In June 2024, the Company’s board of directors adopted, and its stockholders approved, the 2024 Employee Stock Purchase Plan (the “2024 ESPP”), which became effective on June 28, 2024, upon execution of the underwriting agreement related to the Company’s IPO. The Company reserved 650,000 shares of common stock for issuance under the 2024 ESPP. The number of shares of common stock reserved for issuance under the 2024 ESPP will be automatically increased each year for ten calendar years beginning on January 1, 2025 through January 1, 2034, by the lesser of (i) 1% of the total number of shares of our common stock outstanding on the last day of the calendar month before the date of the automatic increase, and (ii) 1,950,000 shares; provided that before the date of any such increase, the board of directors may determine that such increase will be less than the amount in (i) and (ii) above. The 2024 ESPP allows an eligible employee to purchase shares of common stock at an amount equal to 85% of the lower of the fair market value of the Company’s common stock at the beginning of the offering period or at each applicable purchase date during an offering period as established by the board of directors. As of September 30, 2024, the board of directors has not provided for the grant of purchase rights under an offering period. 2024 Performance Option Plan In May 2024, the Company’s board of directors adopted, and its shareholders approved, the 2024 Performance Option Plan (the “2024 POP”). The Company reserved 1,880,680 shares of common stock issuable under the 2024 POP. The 2024 POP permits grants of ISOs, NSOs and restricted stock awards to the Company’s employees, directors and consultants. In May 2024, the Company granted NSOs to employees to purchase 1,880,680 shares of common stock at an exercise price of $10.19 under the 2024 POP. Options generally vest on the date when the Company meets certain common stock public market price specified targets after the end of the lock-up period, subject to continuous service through each respective vest date. The price targets are calculated based on the volume weighted average price per share over 30 consecutive trading dates, in accordance with the grant terms. The unvested awards will expire if it is determined that the vesting conditions have not been met during the applicable six-year performance period. The service condition includes monthly vesting over 36 months from the vesting commencement date and the employee’s continuous service with the Company through each such monthly vesting date. 2021 Stock Plan Prior to the IPO, the Company granted stock awards under the 2021 Plan, adopted in February 2021. Subsequent to the adoption of the 2024 EIP in June 2024, no additional shares were available for issuance under the 2021 Plan and any stock options granted under the 2021 Plan that were subsequently forfeited would be made available for issuance under the 2024 EIP. The terms of the 2021 Plan permit option holders to exercise options before their options are vested. The shares of common stock granted upon early exercise that have not yet vested are subject to repurchase by the Company in the event of termination of the holder’s continuous status as a service provider, at the price paid by the holder. Stock Option Repricing In March 2024, the Company’s board of directors approved the repricing of all outstanding options as of March 29, 2024, which have an exercise price exceeding $8.84 per share. The exercise price of outstanding options with a weighted average exercise price of $10.23 for 4,603,443 common stock shares was reduced to the estimated common stock fair value of $8.84 per share at the date of the repricing. The vesting terms and expiration dates remain unchanged from the original grant dates. The stock option repricing was treated as an option modification for accounting purposes and resulted in total incremental expense of $0.7 million, of which $0.1 million incremental expense associated with the vested options was recognized on the modification date. The remaining $0.6 million incremental expense associated with the unvested options as of the modification date is being recognized over the remainder of the original requisite service period. Stock Option Activity The following table summarizes the Company’s option activity under the 2021 Plan and the 2024 EIP for the nine months ended September 30, 2024. The table includes early exercised shares as part of options exercised. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ Exercise Contractual Intrinsic ​ ​ ​ ​ Price Per ​ Term ​ Value ​ ​ Options ​ Share ​ (in years) ​ (in thousands) Outstanding as of December 31, 2023 5,096,086 ​ $ 9.68 8.50 ​ $ 15,033 Options granted 2,104,328 ​ $ 12.22 ​ ​ ​ ​ ​ Options exercised (71,662) ​ $ 8.26 ​ ​ ​ $ 332 Options forfeited or expired (235,304) ​ $ 10.22 ​ ​ ​ ​ ​ Outstanding and expected to vest as of September 30, 2024 6,893,448 ​ $ 9.52 ​ 8.30 ​ $ 12,110 Exercisable as of September 30, 2024 6,585,917 ​ $ 9.31 ​ 8.23 ​ $ 12,110 ​ The total fair value of shares vested for the nine months ended September 30, 2024 and 2023 was $5.4 million and $6.5 million, respectively. The weighted-average grant date fair value of options granted was $10.42 and $9.50 for the nine months ended September 30, 2024 and 2023, respectively. During the nine months ended September 30, 2024 and 2023, 71,662 options and 25,506 options were exercised with intrinsic values of $0.3 million and $0.1 million, respectively, and the Company received $0.6 million and $0.2 million, respectively, in proceeds from issuance of common stock upon exercise of stock options. The following table summarizes the Company’s option activity under the 2024 POP for the nine months ended September 30, 2024. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ Weighted- ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ ​ ​ Exercise ​ Contractual ​ Intrinsic ​ ​ ​ ​ Price Per ​ Term ​ Value ​ ​ Options ​ Share ​ (in years) ​ (in thousands) Outstanding as of December 31, 2023 — ​ $ — ​ — ​ $ — Options granted 1,880,680 ​ $ 10.19 ​ ​ ​ Options forfeited or expired (90,661) ​ $ 10.19 ​ ​ ​ ​ Outstanding and expected to vest as of September 30, 2024 1,790,019 ​ $ 10.19 ​ 9.60 ​ $ 874 Exercisable as of September 30, 2024 — ​ $ — ​ — ​ $ — ​ Valuation of Stock Options Granted under the 2024 EIP and the 2021 Plan The fair value of stock options granted under the 2024 EIP and the 2021 Plan for the nine months ended September 30, 2024 and 2023 was estimated using the Black-Scholes option pricing model with the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2024 2023 ​ 2024 2023 Expected term (in years) ​ 5.75 - 6.06 5.77 - 6.08 ​ 5.75 – 6.08 5.77 – 6.63 Volatility ​ 108.25% - 109.54% 98.45% - 99.44% ​ 103.65% – 109.54% 98.08% – 102.54% Risk-free interest rate ​ 3.47% - 3.83% 3.95% - 4.14% ​ 3.47% – 4.48% 3.66% – 4.14% Dividend yield ​ 0.00% 0.00% ​ 0.00% 0.00% ​ Expected Term The expected term represents the weighted-average period the stock options are expected to remain Expected Volatility The expected stock price volatility assumption was determined by examining the historical volatilities for industry peers, as the Company did not have sufficient trading history of its common stock. The Company will continue to use industry peers in determining historical stock price volatility until sufficient historical data of its common stock becomes available. Risk-Free Interest Rate The risk-free interest rate assumption is based on the U.S. Treasury instruments whose term was consistent with the expected term of the Company’s stock options. Dividends The Company has not paid any cash dividends on common stock since inception and does not anticipate paying any dividends in the foreseeable future. Consequently, an expected dividend yield of zero was used. Valuation of Stock Options Granted under the 2024 POP Stock options granted under the 2024 POP vest based on service, market and performance conditions (the occurrence of the IPO or a change of control) and are classified as equity financial instruments. At the grant date, the fair value of stock options granted under the 2024 POP was estimated using a Monte Carlo simulation model, which uses a distribution of potential outcomes on a monthly basis over the vesting period prioritizing the most reliable information available. The assumptions utilized in the calculation are based on the achievement of certain stock price thresholds, including the Company’s expected common stock price, expected volatility, risk-free rate and expected term. The Company used the following assumptions to estimate the fair value at the grant date in May 2024: common stock fair value of $12.06, vesting term of 6.00 years, volatility of 122.00%, and risk-free rate of 4.38%. The estimates of fair value are uncertain and changes in any of the estimated inputs could have resulted in significant adjustments to the fair value. The Company’s estimated fair value of stock options issued under the 2024 POP of $18.0 million is recognized using graded vesting from July 1, 2024, the closing of the IPO, when the performance condition was met, over the service period of 3.0 years (the longer of (i) the explicit service period of the service condition of 3.0 years or (ii) the derived service period between 1.4 years to 2.1 years). The Company recognized $3.5 million in stock-based compensation expense related to the 2024 POP for the three and nine months ended September 30, 2024. Early Exercise of Employee Stock Options Proceeds from the early exercise of stock options are recorded as share repurchase liability, and as shares vest are recognized to additional paid-in capital in the condensed consolidated balance sheets. As of September 30, 2024 and December 31, 2023, there was $1.0 million and $1.8 million share repurchase liability related to the unvested shares, respectively. The following table summarizes the activity for the Company’s early exercised shares for the nine months ended September 30, 2024: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ Average ​ ​ Number of ​ Exercise Price ​ Shares Per Share Unvested as of December 31, 2023 327,100 ​ $ 5.33 Early exercised 25,034 ​ $ 8.84 Vested (163,568) ​ $ 5.79 Unvested as of September 30, 2024 188,566 ​ $ 5.40 ​ Stock-Based Compensation Expense The following table summarizes the stock-based compensation expense granted to employees and non-employees for the three and nine months ended September 30, 2024 and 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2024 2023 2024 2023 ​ Research and development ​ $ 3,720 ​ $ 1,225 ​ $ 6,805 ​ $ 3,292 ​ General and administrative ​ 3,589 ​ ​ 1,045 ​ ​ 6,294 ​ ​ 2,718 ​ Total stock-based compensation expense ​ $ 7,309 ​ $ 2,270 ​ $ 13,099 ​ $ 6,010 ​ ​ The following table summarizes the stock-based compensation expense related to the following equity-based awards for the three and nine months ended September 30, 2024 and 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2024 2023 2024 2023 ​ Stock options ​ $ 7,291 ​ $ 2,252 ​ $ 13,045 ​ $ 5,956 ​ Restricted stock awards ​ 18 ​ ​ 18 ​ ​ 54 ​ ​ 54 ​ Total stock-based compensation expense ​ $ 7,309 ​ $ 2,270 ​ $ 13,099 ​ $ 6,010 ​ ​ Stock-based compensation expense related to non-employee awards was immaterial for all periods presented. As of September 30, 2024, there was unrecognized stock-based compensation expense of $54.2 million related to issued stock-based awards which the Company expects to recognize over a weighted-average period of 2.5 years.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	9 Months Ended
	Sep. 30, 2024
Net Loss Per Share Attributable to Common Stockholders
Net Loss Per Share Attributable to Common Stockholders	11. Net Loss Per Share Attributable to Common Stockholders The following table sets forth the computation of the basic and diluted net loss per share attributable to common stockholders for the three and nine months ended September 30, 2024 and 2023 (in thousands, except share and per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2024 2023 2024 2023 ​ Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss ​ $ (93,117) ​ $ (43,377) ​ $ (199,474) ​ $ (115,693) ​ Denominator: ​ ​ ​ ​ ​ ​ Weighted-average shares of common stock outstanding ​ 53,970,560 ​ 2,650,252 ​ 19,908,040 ​ 2,640,771 ​ Less: Weighted-average shares of common stock subject to repurchase ​ (218,337) ​ (455,264) ​ (260,350) ​ (536,489) ​ Weighted-average shares of common stock outstanding, basic and diluted ​ ​ 53,752,223 ​ ​ 2,194,988 ​ ​ 19,647,690 ​ ​ 2,104,282 ​ Net loss per share attributable to common stockholders, basic and diluted ​ $ (1.73) ​ $ (19.76) ​ $ (10.15) ​ $ (54.98) ​ ​ The following outstanding potentially dilutive shares were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented, because including them would have been antidilutive (on an as-converted basis): ​ ​ ​ ​ ​ ​ ​ September 30, 2024 September 30, 2023 Common stock options issued and outstanding 8,683,467 4,678,158 Unvested restricted common stock and early exercised stock options 195,026 417,042 Redeemable convertible preferred stock issued and outstanding ​ — ​ 17,103,749 Total 8,878,493 22,198,949 ​

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2024
Employee Benefit Plans
Employee Benefit Plans	12. Employee Benefit Plans The Company sponsors a qualified 401(k) defined contribution plan covering eligible employees. Participants may contribute a portion of their annual compensation limited to a maximum annual amount set by the Internal Revenue Service. There were no employer contributions under this plan during the three and nine months ended September 30, 2024 and 2023.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (93,117)	$ (56,508)	$ (49,849)	$ (43,377)	$ (36,289)	$ (36,027)	$ (199,474)	$ (115,693)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accoun_2

Summary of Significant Accounting Policies and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2024
Summary of Significant Accounting Policies and Basis of Presentation
Basis of Presentation	Basis of Presentation The unaudited condensed consolidated financial statements and accompanying notes are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and applicable rules and regulations of the SEC regarding interim financial reporting and do not contain all information that is included in the annual financial statements and notes thereto of the Company. Prior to their dissolution, the Company’s condensed consolidated financial statements included the accounts of FronThera U.S. Holdings, Inc. and FronThera U.S. Pharmaceuticals LLC, two wholly owned subsidiaries, and all intercompany transactions were eliminated. FronThera U.S. Holdings, Inc. was dissolved on April 8, 2024 and FronThera U.S. Pharmaceuticals LLC was dissolved on March 14, 2024. The unaudited condensed consolidated interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the Company’s financial position as of September 30, 2024 and the results of its operations and its cash flows for the three and nine months ended September 30, 2024 and 2023. The condensed balance sheet as of December 31, 2023, included in this filing, was derived from audited annual consolidated financial statements but does not include all disclosures required by U.S. GAAP. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results of operations to be expected for the full year or for any other subsequent interim period. Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”).
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected within these condensed consolidated financial statements include, but are not limited to, the fair value of the Company’s common stock and redeemable convertible preferred stock, the fair value of the derivative liability, stock-based compensation expense, accruals for research and development expenses and the valuation of deferred tax assets. The Company bases its estimates on known trends and other market-specific or relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, as there are changes in circumstances, facts and experience. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ materially from those estimates.
Segment and Geographical Information	Segment and Geographical Information The Company operates and manages its business as one reportable and operating segment, which is the business of developing medicines for autoimmune disorders. The chief executive officer, who is the chief operating decision maker, reviews financial information on an aggregate basis for purposes of allocating resources and evaluating financial performance. All of the Company’s long-lived assets are located in the United States.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments which potentially subject the Company to concentration of credit risk consist primarily of cash and cash equivalents, investments in marketable securities and restricted cash. The Company maintains bank deposits in federally insured financial institutions and these deposits exceed federally insured limits. To date, the Company has not experienced any losses on its deposits of cash and periodically evaluates the creditworthiness of financial institutions at which bank deposits are maintained. The Company also invests in money market funds and U.S. treasuries, which are subject to certain credit risks. The Company mitigates the risks by investing in high-grade instruments, limiting its exposure to any one issuer and monitoring the ongoing creditworthiness of the financial institutions and issuers. The Company has not experienced any loss of principal on its financial instruments.
Risks and Uncertainties	Risks and Uncertainties The Company is subject to certain risks and uncertainties, including, but not limited to, changes in any of the following areas that the Company believes could have a material adverse effect on the future financial position or results of operations: the Company’s ability to advance the development of its proprietary precision data analytics platform, timing and ability to advance its product candidates through preclinical and clinical development; costs and timelines associated with the manufacturing of clinical supplies; regulatory approval, market acceptance of, and reimbursement for, any product candidates the Company may develop; performance of third-party vendors; competition from pharmaceutical or other biotechnology companies with greater financial resources or expertise; protection of intellectual property; litigation or claims against the Company based on intellectual property or other factors; and its ability to attract and retain employees necessary to support its growth. The Company’s business and operations may be affected by worldwide economic conditions, which may continue to be impacted by global macroeconomic challenges, such as the effects of the ongoing military conflicts in Ukraine, Israel, and the Middle East, tensions in U.S.-China relations, uncertainty in the markets, including disruptions in the banking industry, the COVID-19 pandemic and inflationary trends. Fiscal year 2023 was marked by significant market uncertainty and increasing inflationary pressures. These market dynamics continue into 2024, and these and similar adverse market conditions may negatively impact the Company’s business, financial position and results of operations.
Deferred Finance Issuance Costs	Deferred Finance Issuance Costs Deferred finance issuance costs, consisting of legal, accounting and other third-party fees directly relating to in-process equity financings or offerings are capitalized. The deferred finance issuance costs are offset against offering proceeds upon the completion of the financing or the offering. In the event the financing or the offering is terminated or delayed, deferred finance issuance costs are expensed immediately as a charge to general and administrative expenses in the condensed consolidated statements of operations and comprehensive loss. The Company had $4.3 million in deferred finance issuance costs capitalized and included in other long-term assets in its unaudited condensed consolidated balance sheet as of June 30, 2024, which were reclassified to equity upon the closing of the IPO in the third quarter of 2024. There were no deferred finance issuance costs capitalized and included in other long-term assets in the condensed consolidated balance sheets as of September 30, 2024 and December 31, 2023.
Net Loss Per Share Attributable to Common Stockholders	Net Loss Per Share Attributable to Common Stockholders ​ Basic and diluted net loss per share attributable to common stockholders is presented in conformity with the two-class method required for participating securities. As such, net income is attributed to common stockholders and participating securities based on their participation rights. Prior to the IPO, under the two-class method, the net loss attributable to common stockholders was not allocated to the redeemable convertible preferred stock as the holders of the redeemable convertible preferred stock did not have a contractual obligation to share in the Company’s losses. Upon the IPO, the Company’s redeemable convertible preferred stock converted into either Class A or Class B common stock, and were immediately thereafter redesignated into voting and non-voting common stock, respectively, and therefore are included in the allocation of net loss attributable to common stockholders as they share in the Company’s losses. Voting and non-voting common stock participate in the Company’s losses equally. Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. As the Company has reported losses for all periods presented, all potentially dilutive securities are antidilutive and accordingly, basic net loss per share equals diluted net loss per share.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. The Company qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), and has elected not to “opt out” of the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and private companies, the Company will adopt the new or revised standard at the time private companies adopt the new or revised standard and will do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. The Company may choose to early adopt any new or revised accounting standards whenever such early adoption is permitted for nonpublic companies. Recently Issued and Not Yet Adopted Accounting Pronouncements In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosure In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures In March 2024, the FASB issued ASU No. 2024-02, Codification Improvements - Amendments to Remove References to the Concepts Statements ​ In November 2024, the FASB issued ASU No. 2024-03, Disaggregation of Income Statement Expenses (Topic 220)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value Measurements
Schedule of fair value of assets and liabilities	The following tables represent the Company’s fair value hierarchy for financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2024 and December 31, 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of September 30, 2024 ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 198,412 ​ $ — ​ $ — ​ $ 198,412 U.S. treasuries ​ — ​ ​ 14,993 ​ ​ — ​ 14,993 Marketable securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. treasuries ​ 67,966 ​ 80,487 ​ — ​ 148,453 Total assets ​ $ 266,378 ​ $ 95,480 ​ $ — ​ $ 361,858 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements as of December 31, 2023 ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 21,310 ​ $ — ​ $ — ​ $ 21,310 U.S. treasuries ​ ​ 2,000 ​ ​ — ​ ​ — ​ ​ 2,000 Marketable securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. treasuries ​ 1,958 ​ 998 ​ — ​ 2,956 Total assets ​ $ 25,268 ​ $ 998 ​ $ — ​ $ 26,266
Schedule of assumptions used in the valuation of the derivative liability	​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ ​ 2024 2023 Expected term (in years) ​ 0.2 – 0.4 ​ ​ 0.0 – 0.4 ​ Volatility 55.1% – 59.9 % ​ 43.2% – 83.2 % Risk-free interest rate 5.4% – 5.5 % ​ 5.2% – 5.6 % Dividend yield 0.0 % ​ 0.0 % Probability of option exercise 0.0% – 100.0 % ​ 30.0% – 100.0 %
Schedule of roll-forward of the fair value of the Company's Level 3 financial instrument of the derivative liability	The following table provides a roll-forward of the fair value of the Company’s Level 3 financial instrument, the derivative liabilities, for the nine months ended September 30, 2024 and 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ ​ 2024 2023 Fair value at beginning of period ​ $ — ​ $ — Fair value upon issuance ​ 8,913 ​ ​ 2,112 Changes in fair value ​ 5,406 ​ ​ 119 Fair value upon settlement ​ (14,319) ​ ​ — Fair value at end of period $ — ​ ​ 2,231

Marketable Securities (Tables)

Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2024
Marketable Securities
Schedule Of marketable securities	Marketable securities, which are classified as available-for-sale marketable securities, consisted of the following as of September 30, 2024 and December 31, 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Gross Fair Value as of ​ ​ Amortized Cost ​ Unrealized ​ Unrealized ​ September 30, ​ ​ Basis ​ Gains ​ Losses ​ 2024 Short-term marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. treasuries ​ $ 148,315 ​ $ 138 ​ $ — ​ $ 148,453 Total short-term marketable securities ​ $ 148,315 ​ $ 138 ​ $ — ​ $ 148,453 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Gross Fair Value as of ​ ​ Amortized Cost ​ Unrealized ​ Unrealized ​ December 31, ​ ​ Basis ​ Gains ​ Losses ​ 2023 Short-term marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. treasuries ​ $ 2,954 ​ $ 2 ​ $ — $ 2,956 Total short-term marketable securities ​ $ 2,954 ​ $ 2 ​ $ — $ 2,956

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2024
Balance Sheet Components
Schedule of other prepaid expenses and current assets	Other prepaid expenses and current assets consisted of the following as of September 30, 2024 and December 31, 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2024 ​ 2023 Prepaid insurance ​ $ 952 ​ $ 111 Prepaid subscriptions ​ ​ 896 ​ ​ 703 Interest receivable ​ ​ 767 ​ ​ 108 Tax receivable ​ ​ 364 ​ ​ 614 Other ​ 257 ​ 95 Total other prepaid expenses and current assets ​ $ 3,236 ​ $ 1,631
Schedule of property and equipment, net	Property and equipment, net consisted of the following as of September 30, 2024 and December 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated Useful Life September 30, December 31, ​ ​ (in years) ​ 2024 ​ 2023 Leasehold improvements Shorter of useful life or lease term ​ $ 17,618 ​ $ 17,592 Laboratory equipment 5 ​ ​ 4,867 ​ ​ 3,577 Furniture and fixtures 5 ​ 1,709 ​ 1,709 Computer equipment 5 ​ 896 ​ 896 Capitalized software 3 ​ 75 ​ 75 Total property and equipment, gross ​ ​ ​ 25,165 ​ 23,849 Less: Accumulated depreciation and amortization ​ ​ ​ (3,736) ​ (1,408) Total property and equipment, net ​ ​ ​ $ 21,429 ​ $ 22,441
Schedule of other accrued expenses and current liabilities	Other accrued expenses and current liabilities consist of the following as of September 30, 2024 and December 31, 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2024 ​ 2023 Accrued personnel and related expenses ​ $ 5,396 ​ $ 5,585 Accrued professional services ​ 1,991 ​ 1,093 Accrued other expenses ​ 77 ​ 409 Total other accrued expenses and current liabilities ​ $ 7,464 ​ $ 7,087 ​

Commitments and Contingent Li_2

Commitments and Contingent Liabilities (Tables)	9 Months Ended
	Sep. 30, 2024
Commitments and Contingent Liabilities
Summary of components of lease costs	The components of lease costs were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2023 2024 2023 ​ Operating lease costs ​ $ 882 ​ $ 1,279 ​ $ 2,593 ​ $ 3,830 ​ Variable lease costs ​ 297 ​ 214 ​ 953 ​ 330 ​ Total lease costs ​ $ 1,179 ​ $ 1,493 ​ $ 3,546 ​ $ 4,160 ​
Schedule of information related to operating lease	Supplemental cash flow information related to the operating leases were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ ​ September 30, ​ ​ 2024 2023 ​ Cash payments included in the measurement of operating lease liabilities ​ $ 4,076 ​ $ 1,740 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ 2024 2023 ​ Weighted-average remaining lease term (years) 8.9 ​ 9.5 ​ Weighted-average incremental borrowing rate 11.4 % 11.4 %
Schedule of future minimum lease payments under non-cancelable leases	Future minimum lease payments under non-cancelable leases as of September 30, 2024, were as detailed below (in thousands): ​ ​ ​ ​ 2024 (remainder of the year) ​ $ 1,223 2025 ​ ​ 4,959 2026 ​ 5,125 2027 ​ 5,296 2028 ​ 5,474 Thereafter ​ 27,515 Total undiscounted lease payments ​ 49,592 Less: Imputed interest ​ (18,494) Total operating lease liabilities ​ $ 31,098

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock (Tables)	9 Months Ended
	Sep. 30, 2024
Redeemable Convertible Preferred Stock
Schedule of redeemable convertible preferred stock	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ ​ ​ Shares Issued ​ Aggregate ​ ​ ​ ​ ​ Shares ​ and ​ Liquidation ​ Net Carrying ​ Authorized Outstanding Preference Value ​ ​ (in thousands, except share amounts) Series Seed redeemable convertible preferred stock 10,500,000 10,500,000 ​ $ 10,500 ​ $ 10,480 Series A redeemable convertible preferred stock 7,500,000 7,500,000 ​ 30,000 ​ 29,972 Series B redeemable convertible preferred stock 40,200,000 40,200,000 ​ 201,000 ​ 200,711 Series B-1 redeemable convertible preferred stock 9,760,088 9,760,088 ​ 39,040 ​ 44,310 Series B-2 redeemable convertible preferred stock ​ 18,000,000 ​ 16,221,170 ​ ​ 81,106 ​ ​ 80,969 Series B-2A redeemable convertible preferred stock ​ 3,056,490 ​ 1,778,830 ​ ​ 8,894 ​ ​ 8,928 Total redeemable convertible preferred stock 89,016,578 85,960,088 ​ $ 370,540 ​ $ 375,370 ​

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2024
Stockholders' Equity
Schedule of common stock reserved for issuance, on an as-converted basis	​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2024 ​ 2023 Outstanding and issued common stock options 8,683,467 5,096,086 Shares available for grant under 2024 Equity Incentive Plan ​ 7,671,516 ​ — Shares available for grant under 2024 Employee Stock Purchase Plan ​ 650,000 ​ — Shares available for grant under 2024 Performance Option Plan ​ 90,661 ​ — Shares available for grant under 2021 Stock Plan — 296,189 Redeemable convertible preferred stock issued and outstanding — 18,387,168 Total 17,095,644 23,779,443
Schedule of summarizes the activity for the company's restricted common stock	​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ Shares ​ Fair Value Unvested as of December 31, 2023 29,322 ​ $ 2.90 Vested (16,445) ​ $ 2.90 Repurchased ​ (6,417) ​ $ 2.90 Unvested as of September 30, 2024 6,460 ​ $ 2.90

Stock Compensation (Tables)

Stock Compensation (Tables)	9 Months Ended
	Sep. 30, 2024
Stock Compensation
Schedule of the Company's option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ Exercise Contractual Intrinsic ​ ​ ​ ​ Price Per ​ Term ​ Value ​ ​ Options ​ Share ​ (in years) ​ (in thousands) Outstanding as of December 31, 2023 5,096,086 ​ $ 9.68 8.50 ​ $ 15,033 Options granted 2,104,328 ​ $ 12.22 ​ ​ ​ ​ ​ Options exercised (71,662) ​ $ 8.26 ​ ​ ​ $ 332 Options forfeited or expired (235,304) ​ $ 10.22 ​ ​ ​ ​ ​ Outstanding and expected to vest as of September 30, 2024 6,893,448 ​ $ 9.52 ​ 8.30 ​ $ 12,110 Exercisable as of September 30, 2024 6,585,917 ​ $ 9.31 ​ 8.23 ​ $ 12,110 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ Weighted- ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ ​ ​ Exercise ​ Contractual ​ Intrinsic ​ ​ ​ ​ Price Per ​ Term ​ Value ​ ​ Options ​ Share ​ (in years) ​ (in thousands) Outstanding as of December 31, 2023 — ​ $ — ​ — ​ $ — Options granted 1,880,680 ​ $ 10.19 ​ ​ ​ Options forfeited or expired (90,661) ​ $ 10.19 ​ ​ ​ ​ Outstanding and expected to vest as of September 30, 2024 1,790,019 ​ $ 10.19 ​ 9.60 ​ $ 874 Exercisable as of September 30, 2024 — ​ $ — ​ — ​ $ —
Schedule of various significant assumptions used to estimate the fair value of stock options	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2024 2023 ​ 2024 2023 Expected term (in years) ​ 5.75 - 6.06 5.77 - 6.08 ​ 5.75 – 6.08 5.77 – 6.63 Volatility ​ 108.25% - 109.54% 98.45% - 99.44% ​ 103.65% – 109.54% 98.08% – 102.54% Risk-free interest rate ​ 3.47% - 3.83% 3.95% - 4.14% ​ 3.47% – 4.48% 3.66% – 4.14% Dividend yield ​ 0.00% 0.00% ​ 0.00% 0.00%
Schedule of activity for the Company's early exercisable shares	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ Average ​ ​ Number of ​ Exercise Price ​ Shares Per Share Unvested as of December 31, 2023 327,100 ​ $ 5.33 Early exercised 25,034 ​ $ 8.84 Vested (163,568) ​ $ 5.79 Unvested as of September 30, 2024 188,566 ​ $ 5.40
Schedule of the stock-based compensation expense granted to employees and non- employees	The following table summarizes the stock-based compensation expense granted to employees and non-employees for the three and nine months ended September 30, 2024 and 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2024 2023 2024 2023 ​ Research and development ​ $ 3,720 ​ $ 1,225 ​ $ 6,805 ​ $ 3,292 ​ General and administrative ​ 3,589 ​ ​ 1,045 ​ ​ 6,294 ​ ​ 2,718 ​ Total stock-based compensation expense ​ $ 7,309 ​ $ 2,270 ​ $ 13,099 ​ $ 6,010 ​ ​ The following table summarizes the stock-based compensation expense related to the following equity-based awards for the three and nine months ended September 30, 2024 and 2023 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2024 2023 2024 2023 ​ Stock options ​ $ 7,291 ​ $ 2,252 ​ $ 13,045 ​ $ 5,956 ​ Restricted stock awards ​ 18 ​ ​ 18 ​ ​ 54 ​ ​ 54 ​ Total stock-based compensation expense ​ $ 7,309 ​ $ 2,270 ​ $ 13,099 ​ $ 6,010 ​

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Sep. 30, 2024
Net Loss Per Share Attributable to Common Stockholders
Schedule of computation of the basic and diluted net loss per share	The following table sets forth the computation of the basic and diluted net loss per share attributable to common stockholders for the three and nine months ended September 30, 2024 and 2023 (in thousands, except share and per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2024 2023 2024 2023 ​ Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss ​ $ (93,117) ​ $ (43,377) ​ $ (199,474) ​ $ (115,693) ​ Denominator: ​ ​ ​ ​ ​ ​ Weighted-average shares of common stock outstanding ​ 53,970,560 ​ 2,650,252 ​ 19,908,040 ​ 2,640,771 ​ Less: Weighted-average shares of common stock subject to repurchase ​ (218,337) ​ (455,264) ​ (260,350) ​ (536,489) ​ Weighted-average shares of common stock outstanding, basic and diluted ​ ​ 53,752,223 ​ ​ 2,194,988 ​ ​ 19,647,690 ​ ​ 2,104,282 ​ Net loss per share attributable to common stockholders, basic and diluted ​ $ (1.73) ​ $ (19.76) ​ $ (10.15) ​ $ (54.98) ​
Schedule of outstanding potentially dilutive shares excluded from computation of diluted net loss per share	​ ​ ​ ​ ​ ​ ​ September 30, 2024 September 30, 2023 Common stock options issued and outstanding 8,683,467 4,678,158 Unvested restricted common stock and early exercised stock options 195,026 417,042 Redeemable convertible preferred stock issued and outstanding ​ — ​ 17,103,749 Total 8,878,493 22,198,949 ​

Organization and Nature of th_2

Organization and Nature of the Business (Details) $ / shares in Units, $ in Thousands				3 Months Ended						9 Months Ended
	Jul. 17, 2024 USD ($) shares	Jul. 01, 2024 USD ($) $ / shares shares	Jun. 20, 2024	Sep. 30, 2024 USD ($) shares	Jun. 30, 2024 USD ($) shares	Mar. 31, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) shares
Organization and Nature of the Business
Reverse stock split ratio		0.2139	0.2139
Common stock, shares authorized		500,000,000
Preferred stock, shares authorized		50,000,000		50,000,000	50,000,000					50,000,000		50,000,000
Net loss | $				$ (93,117)	$ (56,508)	$ (49,849)	$ (43,377)	$ (36,289)	$ (36,027)	$ (199,474)	$ (115,693)
Cash used in operating activities | $										(180,314)	$ (96,248)
Accumulated deficit | $				(563,792)						(563,792)		$ (364,318)
Cash, cash equivalents and marketable securities | $				$ 361,900						$ 361,900
Class A common stock
Organization and Nature of the Business
Number of shares issued upon conversion		28,855,656
Class B common stock
Organization and Nature of the Business
Number of shares issued upon conversion		7,184,908
Voting common stock
Organization and Nature of the Business
Number of shares issued upon conversion						0.10
Common stock, shares authorized		492,815,092		492,815,092						492,815,092		125,000,000
Non-voting common stock
Organization and Nature of the Business
Common stock, shares authorized		7,184,908		7,184,908						7,184,908		85,960,088
IPO
Organization and Nature of the Business
Number of shares issued and sold		13,125,000
Issue price per share | $ / shares		$ 16
Net proceeds after deducting underwriting discounts and commissions | $		$ 193,300
Percentage of ownership held by investor	5%
Additional number of shares purchased	2,500,000
Payments of underwriting discounts and commission | $		$ 16,700
Concurrent Private Placement
Organization and Nature of the Business
Aggregate gross and net proceeds | $	$ 40,000

Summary of Significant Accoun_3

Summary of Significant Accounting Policies and Basis of Presentation (Details)	9 Months Ended
	Sep. 30, 2024 USD ($) segment	Mar. 13, 2024 item	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)
Number of wholly owned subsidiaries | item		2
Number of reportable segment	1
Number of operating segment	1
Other Noncurrent Assets
Deferred finance costs non-current net | $	$ 0		$ 0	$ 4,300,000

Fair Value Measurements - Finan

Fair Value Measurements - Financial assets and liabilities (Details) $ in Thousands	1 Months Ended	9 Months Ended
	Mar. 31, 2024 instrument	Sep. 30, 2024 USD ($) item	Dec. 31, 2023 USD ($)
Assets:
Number of Freestanding Financial Instruments | instrument	2
Series C redeemable convertible preferred stock
Assets:
Number of Freestanding Financial Instruments | item		2
Recurring
Assets:
Total assets		$ 361,858	$ 26,266
Recurring | Money market funds
Assets:
Cash equivalents		198,412	21,310
Recurring | U.S. treasuries
Assets:
Cash equivalents		14,993	2,000
Marketable securities		148,453	2,956
Level 1 | Recurring
Assets:
Total assets		266,378	25,268
Level 1 | Recurring | Money market funds
Assets:
Cash equivalents		198,412	21,310
Level 1 | Recurring | U.S. treasuries
Assets:
Cash equivalents			2,000
Marketable securities		67,966	1,958
Level 2 | Recurring
Assets:
Total assets		95,480	998
Level 2 | Recurring | U.S. treasuries
Assets:
Cash equivalents		14,993
Marketable securities		$ 80,487	$ 998

Fair value measurements - Valua

Fair value measurements - Valuation of Derivative Liability (Details)	Sep. 30, 2024 Y	Sep. 30, 2023 Y
Expected term | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability measurement input	0.2	0
Expected term | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability measurement input	0.4	0.4
Volatility | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability measurement input	0.551	0.432
Volatility | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability measurement input	0.599	0.832
Risk-free interest rate | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability measurement input	0.054	0.052
Risk-free interest rate | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability measurement input	0.055	0.056
Dividend yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability measurement input	0	0
Probability of option exercise | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability measurement input	0	0.300
Probability of option exercise | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability measurement input	1	1

Fair Value Measurements - Deriv

Fair Value Measurements - Derivative Liability (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value upon issuance	$ 8,913	$ 2,112
Changes in fair value	5,406	119
Fair value upon settlement	$ (14,319)
Fair value at end of period		$ 2,231

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Fair Value Measurements
Financial Assets Transfer from Level 1 to Level 2	$ 0	$ 0	$ 0	$ 0
Financial Assets Transfer from Level 2 to Level 1	0	0	0	0
Financial Liabilities Transfer from Level 1 to Level 2	0	0	0	0
Financial Liabilities Transfer from Level 2 to Level 1	0	0	0	0
Transfer of Assets Level 3	0	0	0	0
Transfer of liabilities Level 3	$ 0	$ 0	$ 0	$ 0

Marketable Securities (Details)

Marketable Securities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Marketable Securities
Amortized Cost Basis	$ 148,315		$ 148,315		$ 2,954
Gross Unrealized Gains	138		138		2
Fair Value	148,453		148,453		2,956
Allowance for losses	0		0		0
Impairment losses	0	$ 0	0	$ 0
U.S. treasuries
Marketable Securities
Amortized Cost Basis	148,315		148,315		2,954
Gross Unrealized Gains	138		138		2
Fair Value	$ 148,453		$ 148,453		$ 2,956

Balance Sheet Components - Othe

Balance Sheet Components - Other Prepaid Expenses and Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Balance Sheet Components
Prepaid insurance	$ 952	$ 111
Prepaid subscriptions	896	703
Interest receivable	767	108
Tax receivable	364	614
Other	257	95
Total other prepaid expenses and current assets	$ 3,236	$ 1,631

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Property and Equipment, net
Total property and equipment, gross	$ 25,165		$ 25,165		$ 23,849
Less: Accumulated depreciation and amortization	(3,736)		(3,736)		(1,408)
Total property and equipment, net	21,429		21,429		$ 22,441
Depreciation and amortization	$ 800	$ 300	$ 2,300	$ 600
Leasehold improvements
Property and Equipment, net
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember		us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember		us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember
Total property and equipment, gross	$ 17,618		$ 17,618		$ 17,592
Laboratory equipment
Property and Equipment, net
Estimated Useful Life (in years)	5 years		5 years
Total property and equipment, gross	$ 4,867		$ 4,867		3,577
Furniture and fixtures
Property and Equipment, net
Estimated Useful Life (in years)	5 years		5 years
Total property and equipment, gross	$ 1,709		$ 1,709		1,709
Computer equipment
Property and Equipment, net
Estimated Useful Life (in years)	5 years		5 years
Total property and equipment, gross	$ 896		$ 896		896
Capitalized software
Property and Equipment, net
Estimated Useful Life (in years)	3 years		3 years
Total property and equipment, gross	$ 75		$ 75		$ 75

Balance Sheet Components - Ot_2

Balance Sheet Components - Other Accrued Expenses and Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Balance Sheet Components
Accrued personnel and related expenses	$ 5,396	$ 5,585
Accrued professional services	1,991	1,093
Accrued other expenses	77	409
Total other accrued expenses and current liabilities	$ 7,464	$ 7,087

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Related Party Transactions
Research and development expenses	$ 87,824,000	$ 37,788,000	$ 178,350,000	$ 103,071,000
Related party
Related Party Transactions
Research and development expenses	160,000	385,000	$ 731,000	1,139,000
Related party | Foresite labs
Related Party Transactions
Automatic renewal term			1 year
Research and development expenses	200,000	$ 400,000	$ 700,000	$ 1,100,000
Research and development accrued expenses	$ 0		$ 0
Related party | Foresite labs | Maximum
Related Party Transactions
Research and development accrued expenses					$ 100,000

Commitments and Contingent Li_3

Commitments and Contingent Liabilities - Operating Leases (Details) $ in Thousands	1 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) item	Dec. 31, 2022 USD ($)	Sep. 30, 2024 USD ($)	Jan. 31, 2023 USD ($)	Aug. 31, 2022 USD ($) ft²	Jan. 31, 2022 ft²	Dec. 31, 2021 ft²
Commitments and Contingent Liabilities
Lease space | ft²							55,000	12,000	14,000
Loss on abandonment of right-of-use assets	$ 600	$ 645
Tenant improvement allowance provided by lessor			$ 17,200
Tenant improvement allowance received			$ 16,700	$ 500
Lease liability					$ 31,098	$ 14,100
Future lease payments					$ 49,592	37,900
Gross fixed payments						54,600
Lease incentives receivable						$ 16,700	$ 16,700
Weighted-average incremental borrowing rate			11.40%		11.40%	11.40%
Renewal term							3 years
Letters of credit on leases			$ 1,100		$ 1,000
Number of Letter of Credits on Lease Held | item			2

Commitments and Contingent Li_4

Commitments and Contingent Liabilities - components of lease costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Jan. 31, 2023
Components of lease cost
Operating lease costs	$ 882	$ 1,279	$ 2,593	$ 3,830
Variable lease costs	297	214	953	330
Total lease costs	$ 1,179	$ 1,493	3,546	4,160
Cash payments included in the measurement of operating lease liabilities			$ 4,076	$ 1,740
Weighted-average remaining lease term (years)	8 years 10 months 24 days		8 years 10 months 24 days		9 years 6 months
Weighted-average incremental borrowing rate	11.40%		11.40%		11.40%	11.40%

Commitments and Contingent Li_5

Commitments and Contingent Liabilities - Schedule of future minimum lease payments under non-cancelable operating leases (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jan. 31, 2023
Schedule of future minimum lease payments under non-cancelable operating leases
2024 (remainder of the year)	$ 1,223
2025	4,959
2026	5,125
2027	5,296
2028	5,474
Thereafter	27,515
Total undiscounted lease payments	49,592	$ 37,900
Less: Imputed interest	(18,494)
Total operating lease liabilities	$ 31,098	$ 14,100

Commitments and Contingent Li_6

Commitments and Contingent Liabilities - FronThera Contingent Consideration (Details) - FronThera - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Aug. 31, 2024	Mar. 31, 2021	Dec. 31, 2022	Sep. 30, 2024
FronThera Contingent Consideration
Milestone payment obligation				$ 0
Clinical milestones
FronThera Contingent Consideration
Contingent consideration liability		$ 120
Milestone payment made	$ 23	70	$ 37
Approval milestones | Maximum
FronThera Contingent Consideration
Milestone payment made		$ 50

Redeemable Convertible Prefer_3

Redeemable Convertible Preferred Stock (Details) $ / shares in Units, $ in Millions	1 Months Ended				3 Months Ended			9 Months Ended
	May 31, 2024 USD ($) $ / shares shares	Mar. 31, 2024 USD ($) instrument $ / shares shares	Oct. 31, 2023 USD ($) $ / shares shares	May 31, 2023 USD ($) $ / shares shares	Jun. 30, 2024 shares	Mar. 31, 2024 USD ($) $ / shares shares	Jun. 30, 2023 shares	Sep. 30, 2024 item	Jul. 31, 2023 shares
Redeemable Convertible Preferred Stock
Derivative liability, fair value				$ 2.1
Derivative liability reclassified to temporary equity			$ 2.2
Number of freestanding instruments | instrument		2
Fair value of freestanding instrument		$ 8.9				$ 8.9
Series B-2 redeemable convertible preferred stock
Redeemable Convertible Preferred Stock
Shares issued | shares			4,221,170	10,722,340
Proceeds from issuance of shares			$ 21.1	$ 53.6
Issue price per share | $ / shares			$ 5	$ 5
Number of convertible preferred shares issued | shares									1,277,660
Series B-2 redeemable convertible preferred stock | Maximum
Redeemable Convertible Preferred Stock
Issuance cost			$ 0.1
Series B-2A redeemable convertible preferred stock
Redeemable Convertible Preferred Stock
Shares issued | shares			1,778,830	1,277,660			1,277,660
Proceeds from issuance of shares			$ 8.9	$ 6.4
Issue price per share | $ / shares			$ 5	$ 5
Series C redeemable convertible preferred stock
Redeemable Convertible Preferred Stock
Shares issued | shares	41,264,892	41,264,891			41,264,892	41,264,891
Proceeds from issuance of shares	$ 129.5	$ 129.5
Issuance cost	$ 0.2	$ 0.4
Issue price per share | $ / shares	$ 3.13826	$ 3.13826				$ 3.13826
Derivative liability reclassified to temporary equity	$ 14.3
Number of freestanding instruments | item								2
Series C-1 redeemable convertible preferred stock
Redeemable Convertible Preferred Stock
Issue price per share | $ / shares		$ 4				$ 4
Series B-2, B-2A redeemable convertible preferred stock
Redeemable Convertible Preferred Stock
Issuance cost				$ 0.2
Voting common stock
Redeemable Convertible Preferred Stock
Number of shares issued upon conversion | shares		0.10				0.10

Redeemable Convertible Prefer_4

Redeemable Convertible Preferred Stock - Schedule of redeemable convertible preferred stock (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock, Shares Authorized	0			89,016,578
Redeemable convertible preferred stock, Shares Outstanding	0			85,960,088
Redeemable convertible preferred stock, Aggregate Liquidation Preference	$ 0			$ 370,540
Redeemable convertible preferred stock, Net Carrying Value		$ 639,237	$ 495,575	$ 375,370	$ 343,152	$ 343,152	$ 285,473	$ 285,473
Series Seed redeemable convertible preferred stock
Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock, Shares Authorized				10,500,000
Redeemable convertible preferred stock, Shares Outstanding				10,500,000
Redeemable convertible preferred stock, Aggregate Liquidation Preference				$ 10,500
Redeemable convertible preferred stock, Net Carrying Value				$ 10,480
Series A redeemable convertible preferred stock
Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock, Shares Authorized				7,500,000
Redeemable convertible preferred stock, Shares Outstanding				7,500,000
Redeemable convertible preferred stock, Aggregate Liquidation Preference				$ 30,000
Redeemable convertible preferred stock, Net Carrying Value				$ 29,972
Series B redeemable convertible preferred stock
Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock, Shares Authorized				40,200,000
Redeemable convertible preferred stock, Shares Outstanding				40,200,000
Redeemable convertible preferred stock, Aggregate Liquidation Preference				$ 201,000
Redeemable convertible preferred stock, Net Carrying Value				$ 200,711
Series B-1 redeemable convertible preferred stock
Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock, Shares Authorized				9,760,088
Redeemable convertible preferred stock, Shares Outstanding				9,760,088
Redeemable convertible preferred stock, Aggregate Liquidation Preference				$ 39,040
Redeemable convertible preferred stock, Net Carrying Value				$ 44,310
Series B-2 redeemable convertible preferred stock
Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock, Shares Authorized				18,000,000
Redeemable convertible preferred stock, Shares Outstanding				16,221,170
Redeemable convertible preferred stock, Aggregate Liquidation Preference				$ 81,106
Redeemable convertible preferred stock, Net Carrying Value				$ 80,969
Series B-2A redeemable convertible preferred stock
Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock, Shares Authorized				3,056,490
Redeemable convertible preferred stock, Shares Outstanding				1,778,830
Redeemable convertible preferred stock, Aggregate Liquidation Preference				$ 8,894
Redeemable convertible preferred stock, Net Carrying Value				$ 8,928

Stockholders' Equity - Narrativ

Stockholders' Equity - Narratives (Details)	9 Months Ended
	Sep. 30, 2024 $ / shares shares	Jul. 01, 2024 shares	Jun. 30, 2024 $ / shares shares	Dec. 31, 2023 $ / shares shares
Stockholders' Equity
Preferred stock, shares authorized	50,000,000	50,000,000	50,000,000	50,000,000
Preferred stock, par or stated value per share | $ / shares	$ 0.0001		$ 0.0001	$ 0.0001
Preferred stock, shares issued	0			0
Preferred stock, shares outstanding	0			0
Common Stock, Shares Authorized		500,000,000
Number Of Days Prior Notice	61 days
Voting common stock
Stockholders' Equity
Common Stock, Shares Authorized	492,815,092	492,815,092		125,000,000
Common Stock, Par or Stated Value Per Share | $ / shares	$ 0.0001			$ 0.0001
Common Stock, Shares, Outstanding	47,221,880			2,675,979
Conversion ratio	1
Maximum beneficial ownership percent after conversion	4.99
Non-voting common stock
Stockholders' Equity
Common Stock, Shares Authorized	7,184,908	7,184,908		85,960,088
Common Stock, Par or Stated Value Per Share | $ / shares	$ 0.0001			$ 0.0001
Common Stock, Shares, Outstanding	7,184,908			0

Stockholders' Equity - Stock re

Stockholders' Equity - Stock reserved on an as-converted basis (Details) - shares	Sep. 30, 2024	Dec. 31, 2023
Stock reserved on an as-converted basis
Common stock reserved for future issuance	17,095,644	23,779,443
Stock options
Stock reserved on an as-converted basis
Common stock reserved for future issuance	8,683,467	5,096,086
Shares available for grant | 2024 Equity Incentive Plan
Stock reserved on an as-converted basis
Common stock reserved for future issuance	7,671,516
Shares available for grant | 2024 Employee Stock Purchase Plan
Stock reserved on an as-converted basis
Common stock reserved for future issuance	650,000
Shares available for grant | 2021 Stock Plan
Stock reserved on an as-converted basis
Common stock reserved for future issuance		296,189
Shares available for grant | 2024 Performance Option Plan
Stock reserved on an as-converted basis
Common stock reserved for future issuance	90,661
Redeemable convertible preferred stock issued and outstanding
Stock reserved on an as-converted basis
Common stock reserved for future issuance		18,387,168

Stockholders' Equity- Common St

Stockholders' Equity- Common Stock Issued to Executives - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 28, 2021 item $ / shares shares	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)
Common Stock Issued to Executives
Stock-based compensation expense recognized		$ 7,309	$ 2,270	$ 13,099	$ 6,010
Period over which unamortized stock-based compensation expense to be recognized				2 years 6 months
Restricted common stock
Common Stock Issued to Executives
Stock-based compensation expense recognized		18	18	$ 54	54
Unamortized stock-based compensation expense		100		$ 100
Period over which unamortized stock-based compensation expense to be recognized				4 months 24 days
Restricted common stock | Executives
Common Stock Issued to Executives
Number of shares issued under restricted stock award | shares	100,532
Number of executives to whom restricted stock are issued | item	2
Purchase price per share ($ per share) | $ / shares	$ 0.94
Vesting period	4 years
Cliff period (years)	1 year
Restricted common stock | Executives | Maximum
Common Stock Issued to Executives
Stock-based compensation expense recognized		$ 100	$ 100	$ 100	$ 100

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock Issued to Executives - RSU Activity (Details) - Restricted common stock	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Number of Shares
Unvested as on beginning of the period (Shares) | shares	29,322
Vested (Shares) | shares	(16,445)
Repurchased (Shares) | shares	(6,417)
Unvested as on End of the period (Shares) | shares	6,460
Weighted-Average Grant Date Fair Value
Unvested as on beginning of the period ($ per share) | $ / shares	$ 2.90
Vested ($ per shares) | $ / shares	2.90
Repurchased ($ per shares) | $ / shares	2.90
Unvested as on End of the period ($ per share) | $ / shares	$ 2.90

Stock Compensation - 2024 Stock

Stock Compensation - 2024 Stock Plan (Details)			1 Months Ended		9 Months Ended
	Jun. 27, 2024 USD ($) shares	Jun. 26, 2024 USD ($)	Jun. 30, 2024 shares	May 31, 2024 D $ / shares shares	Sep. 30, 2024 shares	Dec. 31, 2023 shares
Stock Compensation
Common stock reserved for future issuance					17,095,644	23,779,443
2024 EIP
Stock Compensation
Common stock reserved for future issuance	7,800,000
Shares authorized to be added from another plan	6,829,339
Increase in annual percentage	5%
Number of shares authorized to grant under the plan	43,888,017
Share based compensation arrangement share based payment award, maximum term	10 years
Percentage of estimated fair market value of common stock (%)	110%
Award expiration period	5 years
Vesting period	4 years
2024 EIP | Maximum | Director | Executives
Stock Compensation
Maximum grant date fair market value of all awards and all cash compensation paid | $	$ 1,000,000	$ 750,000
2024 ESPP
Stock Compensation
Common stock reserved for future issuance			650,000
Increase in annual percentage			1%
Annual increase in number of shares reserved and available for issuance			1,950,000
Percentage of shares purchase rate from fair value on offering date that participants pay for shares.			85%
2024 POP
Stock Compensation
Common stock reserved for future issuance				1,880,680
Number of Stock options granted to purchase shares					1,880,680
2024 POP | Non- Statutory Option
Stock Compensation
Number of Stock options granted to purchase shares				1,880,680
Vesting period				36 months
Grants in period, exercise price | $ / shares				$ 10.19
Consecutive Trading Dates | D				30
Maximum performance condition satisfaction period				6 years
2021 EIP
Stock Compensation
Number of previously granted award reserved for future issuance			0

Stock Compensation - Stock Opti

Stock Compensation - Stock Option Repricing (Details) - USD ($) $ / shares in Units, $ in Millions	Mar. 29, 2024	Mar. 31, 2024
Stock Compensation
Stock option, exercise price ($ per share)	$ 10.23	$ 8.84
Stock option, number of outstanding shares	4,603,443
Stock option repricing, total incremental expense	$ 0.7
Stock option repricing, total incremental expense associated with vested options	0.1
Stock option repricing, total incremental expense associated with unvested options	$ 0.6

Stock Compensation - Stock Op_2

Stock Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	May 31, 2024	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Options Outstanding
Options exercised (shares)					71,662	25,506
Weighted- Average Exercise Price Per Share
Weighted-average exercise price, Outstanding at beginning of the period ($ per shares)
Weighted-average exercise price, Outstanding at end of the period ($ per shares)			$ 8.84
Aggregate Intrinsic Value
Aggregate Intrinsic Value, exercised					$ 300	$ 100
Weighted-average grant date fair value of options granted ($ per share)					$ 10.42	$ 9.50
Vested, fair value					$ 5,400	$ 6,500
Proceeds from Stock Options Exercised					591	241
Stock-based compensation expense recognized		$ 7,309		$ 2,270	$ 13,099	$ 6,010
2021 plan and 2024 employee incentive plan
Options Outstanding
Options outstanding at beginning of the period (shares)			5,096,086		5,096,086
Options granted (shares)					2,104,328
Options exercised (shares)					71,662
Options forfeited or expired (shares)					(235,304)
Options outstanding at end of the period (shares)		6,893,448			6,893,448		5,096,086
Exercisable at end of the period (shares)		6,585,917			6,585,917
Weighted- Average Exercise Price Per Share
Weighted-average exercise price, Outstanding at beginning of the period ($ per shares)			$ 9.68		$ 9.68
Weighted-average exercise price, Granted ($ per shares)					12.22
Weighted-average exercise price, Exercised ($ per shares)					8.26
Weighted-average exercise price, Forfeited or expired ($ per shares)					10.22
Weighted-average exercise price, Outstanding at end of the period ($ per shares)		$ 9.52			9.52		$ 9.68
Exercisable at end of the period ($ per shares)		$ 9.31			$ 9.31
Weighted- Average Remaining Contractual Term
Weighted-average remaining contractual term, Outstanding (in years)					8 years 3 months 18 days		8 years 6 months
Weighted-average remaining contractual term, Exercisable at end of the period (in years)					8 years 2 months 23 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding at beginning of the period			$ 15,033		$ 15,033
Aggregate Intrinsic Value, exercised					332
Aggregate Intrinsic Values, Outstanding at the end of period		$ 12,110			12,110		$ 15,033
Aggregate Intrinsic Values, Exercisable at the end of period		$ 12,110			$ 12,110
2024 POP
Options Outstanding
Options granted (shares)					1,880,680
Options forfeited or expired (shares)					(90,661)
Options outstanding at end of the period (shares)		1,790,019			1,790,019
Weighted- Average Exercise Price Per Share
Weighted-average exercise price, Granted ($ per shares)					$ 10.19
Weighted-average exercise price, Forfeited or expired ($ per shares)					10.19
Weighted-average exercise price, Outstanding at end of the period ($ per shares)		$ 10.19			$ 10.19
Weighted- Average Remaining Contractual Term
Weighted-average remaining contractual term, Outstanding (in years)					9 years 7 months 6 days
Aggregate Intrinsic Value
Aggregate Intrinsic Values, Outstanding at the end of period		$ 874			$ 874
Common stock fair value	$ 12.06
Expected term (in years)	6 years
Volatility rate	122%
Risk Free Interest Rate	4.38%
Share-Based payment award, options, issued in period, fair value		$ 18,000
Performance period		3 years
Stock-based compensation expense recognized		$ 3,500			$ 3,500
2024 POP | Maximum
Aggregate Intrinsic Value
Share-Based payment award, award derived service period		2 years 1 month 6 days
2024 POP | Minimum
Aggregate Intrinsic Value
Share-Based payment award, award derived service period		1 year 4 months 24 days

Stock Compensation - Stock Op_3

Stock Compensation - Stock Option Valuation - 2024 EIP and the 2021 Plan (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Stock Compensation
Dividend yield (%)			0%
2024 EIP and the 2021 Plan | Stock options
Stock Compensation
Minimum Volatility (%)	108.25%	98.45%	103.65%	98.08%
Maximum Volatility (%)	109.54%	99.44%	109.54%	102.54%
Minimum Risk-free interest rate (%)	3.47%	3.95%	3.47%	3.66%
Maximum Risk-free interest rate (%)	3.83%	4.14%	4.48%	4.14%
Dividend yield (%)	0%	0%	0%	0%
2024 EIP and the 2021 Plan | Stock options | Minimum
Stock Compensation
Expected term (in years)	5 years 9 months	5 years 9 months 7 days	5 years 9 months	5 years 9 months 7 days
2024 EIP and the 2021 Plan | Stock options | Maximum
Stock Compensation
Expected term (in years)	6 years 21 days	6 years 29 days	6 years 29 days	6 years 7 months 17 days

Stock Compensation - Early Exer

Stock Compensation - Early Exercise of Employee Stock Options (Details) - Early exercise employee option - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Early Exercisable Shares, Number of shares:
Unvested shares outstanding at beginning of the period (shares)	327,100
Early exercised	25,034
Vested (shares)	(163,568)
Unvested shares outstanding at end of the period (shares)	188,566
Early Exercisable Shares, Weighted-Average Exercise Price Per Share:
Exercise price at the beginning of the period ($ per share)	$ 5.33
Early exercised ($ per share)	8.84
Vested ($ per share)	5.79
Exercise price at the end of the period ($ per share)	$ 5.40
Share repurchase liability related to the unvested shares	$ 1	$ 1.8

Stock Compensation - Stock-Base

Stock Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Stock-Based Compensation Expense
Stock-based compensation expense recognized	$ 7,309	$ 2,270	$ 13,099	$ 6,010
Unrecognized stock-based compensation expense related to unvested stock option	54,200		$ 54,200
Period over which unamortized stock-based compensation expense to be recognized			2 years 6 months
Research and development
Stock-Based Compensation Expense
Stock-based compensation expense recognized	3,720	1,225	$ 6,805	3,292
General and administrative
Stock-Based Compensation Expense
Stock-based compensation expense recognized	3,589	1,045	6,294	2,718
Stock options
Stock-Based Compensation Expense
Stock-based compensation expense recognized	7,291	2,252	13,045	5,956
Restricted stock awards
Stock-Based Compensation Expense
Stock-based compensation expense recognized	$ 18	$ 18	$ 54	$ 54
Period over which unamortized stock-based compensation expense to be recognized			4 months 24 days

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net loss	$ (93,117)	$ (56,508)	$ (49,849)	$ (43,377)	$ (36,289)	$ (36,027)	$ (199,474)	$ (115,693)
Denominator:
Weighted-average shares of common stock outstanding	53,970,560			2,650,252			19,908,040	2,640,771
Less: Weighted-average shares of common stock subject to repurchase	(218,337)			(455,264)			(260,350)	(536,489)
Weighted-average shares of common stock outstanding, basic	53,752,223			2,194,988			19,647,690	2,104,282
Weighted-average shares of common stock outstanding, diluted	53,752,223			2,194,988			19,647,690	2,104,282
Net loss per share attributable to common stockholders, basic	$ (1.73)			$ (19.76)			$ (10.15)	$ (54.98)
Net loss per share attributable to common stockholders, diluted	$ (1.73)			$ (19.76)			$ (10.15)	$ (54.98)

Net Loss Per Share Attributab_4

Net Loss Per Share Attributable to Common Stockholders - Potentially dilutive securities excluded from computation (Details) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Net Loss Per Share Attributable to Common Stockholders
Potential dilutive shares excluded from computation of diluted net loss per share	8,878,493	22,198,949
Employee Stock Option
Net Loss Per Share Attributable to Common Stockholders
Potential dilutive shares excluded from computation of diluted net loss per share	8,683,467	4,678,158
Unvested restricted common stock and early exercised stock options
Net Loss Per Share Attributable to Common Stockholders
Potential dilutive shares excluded from computation of diluted net loss per share	195,026	417,042
Redeemable convertible preferred stock issued and outstanding
Net Loss Per Share Attributable to Common Stockholders
Potential dilutive shares excluded from computation of diluted net loss per share		17,103,749

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Employee Benefit Plans
Employer contribution under the plan	$ 0	$ 0	$ 0	$ 0