ArriVent BioPharma, Inc. Common Stock (AVBP) 10-Q14 Nov 242024 Q3 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2024	Nov. 12, 2024
Document and Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Securities Act File Number	001-41929
Entity Registrant Name	ARRIVENT BIOPHARMA, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	86-3336099
Entity Address, Address Line One	18 Campus Boulevard Suite 100
Entity Address, City or Town	Newtown Square
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19073
City Area Code	628
Local Phone Number	277-4836
Title of 12(b) Security	Common Stock, $0.0001 Par Value per Share
Trading Symbol	AVBP
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		33,697,161
Entity Central Index Key	0001868279
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Amendment Flag	false

BALANCE SHEETS

BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 282,855	$ 150,389
Prepaid expenses and other current assets	9,543	9,579
Total current assets	292,398	159,968
Right of use assets - operating leases	187	291
Deferred offering costs		2,732
Other assets	126	107
Total assets	292,711	163,098
Current liabilities:
Accounts payable	4,646	4,532
Accrued expenses	10,359	6,952
Operating lease liabilities	157	140
Total current liabilities	15,162	11,624
Operating lease liabilities, net of current amount	56	177
Total liabilities	15,218	11,801
Commitments and contingencies (Note 7)
Stockholders' equity (deficit):
Preferred stock $0.0001 par value, 10,000,000 shares authorized; no shares issued and outstanding
Common stock $0.0001 par value, 200,000,000 shares authorized; 33,694,355 and 2,745,480 shares issued and outstanding at September 30, 2024 and December 31, 2023, respectively	3
Additional paid-in capital	495,190	4,652
Accumulated deficit	(217,700)	(157,845)
Total stockholders' equity (deficit)	277,493	(153,193)
Total liabilities, convertible preferred stock and stockholders' equity	$ 292,711	163,098
Series A convertible preferred stock
Current liabilities:
Convertible preferred stock		149,865
Series B convertible preferred stock
Current liabilities:
Convertible preferred stock		$ 154,625

BALANCE SHEETS (Parenthetical)

BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	33,694,355	2,745,480
Common stock, shares outstanding (in shares)	33,694,355	2,745,480
Series A convertible preferred stock
Convertible preferred stock, par value (in dollars per share)		$ 0.0001
Convertible preferred stock, shares authorized (in shares)		150,000,000
Convertible preferred stock, shares issued (in shares)		150,000,000
Convertible preferred stock, shares outstanding (in shares)		150,000,000
Series B convertible preferred stock
Convertible preferred stock, par value (in dollars per share)		$ 0.0001
Convertible preferred stock, shares authorized (in shares)		147,619,034
Convertible preferred stock, shares issued (in shares)		147,619,034
Convertible preferred stock, shares outstanding (in shares)		147,619,034

STATEMENTS OF OPERATIONS

STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Operating expenses:
Research and development	$ 20,088	$ 14,280	$ 58,841	$ 44,874
General and administrative	4,144	2,436	11,762	6,598
Total operating expenses	24,232	16,716	70,603	51,472
Operating loss	(24,232)	(16,716)	(70,603)	(51,472)
Interest income	3,668	2,315	10,748	3,332
Net loss	$ (20,564)	$ (14,401)	$ (59,855)	$ (48,140)
Share information:
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.61)	$ (5.52)	$ (1.95)	$ (24.69)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.61)	$ (5.52)	$ (1.95)	$ (24.69)
Weighted-average shares of common stock outstanding, basic (in shares)	33,581,810	2,607,192	30,720,711	1,949,597
Weighted-average shares of common stock outstanding, diluted (in shares)	33,581,810	2,607,192	30,720,711	1,949,597

STATEMENTS OF CONVERTIBLE PREFE

STATEMENTS OF CONVERTIBLE PREFERRED STOCK (DEFICIT) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023
Series A convertible preferred stock
Change in convertible preferred stock
Beginning balance	$ 149,865	$ 149,865	$ 149,865
Beginning balance (in shares)	150,000,000	150,000,000	150,000,000
Conversion of convertible preferred stock into common stock	$ (149,865)
Conversion of convertible preferred stock into common stock (in shares)	(150,000,000)
Ending balance		$ 149,865	$ 149,865
Ending balance (in shares)		150,000,000	150,000,000
Series B convertible preferred stock
Change in convertible preferred stock
Beginning balance	$ 154,625	$ 154,649	$ 109,706
Beginning balance (in shares)	147,619,034	147,619,034	104,761,894
Issuance of Series B convertible preferred stock at $1.05 per share, net of issuance costs of $57			$ 44,943
Issuance of Series B convertible preferred stock at $1.05 per share, net of issuance costs of $57 (in shares)			42,857,140
Issuance costs of Series B convertible preferred stock		$ (24)	$ (57)
Conversion of convertible preferred stock into common stock	$ (154,625)
Conversion of convertible preferred stock into common stock (in shares)	(147,619,034)
Ending balance		$ 154,625	$ 154,649
Ending balance (in shares)		147,619,034	147,619,034

STATEMENTS OF CONVERTIBLE PRE_2

STATEMENTS OF CONVERTIBLE PREFERRED STOCK (Parenthetical) - Series B convertible preferred stock $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) $ / shares
Convertible preferred stock, issued price per share \| $ / shares	$ 1.05
Issuance costs \| $	$ 57

STATEMENTS OF STOCKHOLDERS' EQU

STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Common stock	Subscription receivable	Additional paid-in capital	Accumulated deficit	Total
Beginning balance at Dec. 31, 2022			$ 3,403	$ (88,512)	$ (85,109)
Beginning balance (in shares) at Dec. 31, 2022	2,597,738
Exercise of stock options			26		26
Exercise of stock options (in shares)	11,417
Stock-based compensation expense			166		166
Net Income (Loss)				(12,172)	(12,172)
Ending balance at Mar. 31, 2023			3,595	(100,684)	(97,089)
Ending balance (in shares) at Mar. 31, 2023	2,609,155
Beginning balance at Dec. 31, 2022			3,403	(88,512)	(85,109)
Beginning balance (in shares) at Dec. 31, 2022	2,597,738
Net Income (Loss)					(48,140)
Ending balance at Sep. 30, 2023		$ (106)	4,154	(136,652)	(132,604)
Ending balance (in shares) at Sep. 30, 2023	2,667,129
Beginning balance at Mar. 31, 2023			3,595	(100,684)	(97,089)
Beginning balance (in shares) at Mar. 31, 2023	2,609,155
Repurchase of common stock (in shares)	(7,387)
Exercise of stock options			4		4
Exercise of stock options (in shares)	1,647
Stock-based compensation expense			193		193
Net Income (Loss)				(21,567)	(21,567)
Ending balance at Jun. 30, 2023			3,792	(122,251)	(118,459)
Ending balance (in shares) at Jun. 30, 2023	2,603,415
Exercise of stock options		(106)	145		39
Exercise of stock options (in shares)	63,714
Stock-based compensation expense			217		217
Net Income (Loss)				(14,401)	(14,401)
Ending balance at Sep. 30, 2023		$ (106)	4,154	(136,652)	(132,604)
Ending balance (in shares) at Sep. 30, 2023	2,667,129
Beginning balance at Dec. 31, 2023			4,652	(157,845)	(153,193)
Beginning balance (in shares) at Dec. 31, 2023	2,745,480
Issuance of common stock in initial public offering, net of issuance costs of $18,032	$ 1		183,216		183,217
Issuance of common stock in initial public offering, net of issuance costs of $18,032 (in shares)	11,180,555
Conversion of convertible preferred stock into common stock	$ 2		304,488		304,490
Conversion of convertible preferred stock into common stock (in shares)	19,567,306
Exercise of stock options			1		1
Exercise of stock options (in shares)	409
Stock-based compensation expense			625		625
Net Income (Loss)				(17,417)	(17,417)
Ending balance at Mar. 31, 2024	$ 3		492,982	(175,262)	317,723
Ending balance (in shares) at Mar. 31, 2024	33,493,750
Beginning balance at Dec. 31, 2023			4,652	(157,845)	$ (153,193)
Beginning balance (in shares) at Dec. 31, 2023	2,745,480
Exercise of stock options (in shares)					201,014
Net Income (Loss)					$ (59,855)
Ending balance at Sep. 30, 2024	$ 3		495,190	(217,700)	277,493
Ending balance (in shares) at Sep. 30, 2024	33,694,355
Beginning balance at Mar. 31, 2024	$ 3		492,982	(175,262)	317,723
Beginning balance (in shares) at Mar. 31, 2024	33,493,750
Exercise of stock options			44		44
Exercise of stock options (in shares)	15,340
Stock-based compensation expense			766		766
Net Income (Loss)				(21,874)	(21,874)
Ending balance at Jun. 30, 2024	$ 3		493,792	(197,136)	296,659
Ending balance (in shares) at Jun. 30, 2024	33,509,090
Exercise of stock options			532		532
Exercise of stock options (in shares)	185,265
Stock-based compensation expense			866		866
Net Income (Loss)				(20,564)	(20,564)
Ending balance at Sep. 30, 2024	$ 3		$ 495,190	$ (217,700)	$ 277,493
Ending balance (in shares) at Sep. 30, 2024	33,694,355

STATEMENTS OF STOCKHOLDERS' E_2

STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT)
Issuance costs	$ 18,032

STATEMENTS OF CASH FLOWS

STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities:
Net loss	$ (59,855)	$ (48,140)
Adjustment to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	2,256	576
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	36	5,630
Other assets	(19)
Accounts payable	114	1,084
Accrued expenses	3,406	(79)
Operating lease liabilities	2
Net cash used in operating activities	(54,060)	(40,929)
Cash flows from investing activities:
Purchase of short-term investments		(25,000)
Net cash used in investing activities		(25,000)
Cash flows from financing activities:
Proceeds from issuance of common stock in an initial public offering, net of issuance costs	185,950
Proceeds from the exercise of stock options	576	69
Proceeds from the sale of Series B convertible preferred stock, net of issuance costs		44,919
Payment of deferred offering costs		(1,072)
Net cash provided by financing activities	186,526	43,916
Net increase (decrease) in cash and cash equivalents	132,466	(22,013)
Cash and cash equivalents at beginning of the year	150,389	163,372
Cash and cash equivalents at end of the year	282,855	141,359
Supplemental disclosures of non-cash financing and investing activities
Deferred offering costs included in accounts payable		$ 820
Deferred offering costs transferred to additional paid in capital	$ 2,733

Background

Background	9 Months Ended
Background	Sep. 30, 2024
Background
Background	(1) Background ArriVent BioPharma, Inc., a Delaware Corporation (the “Company”), founded on April 14, 2021, is a clinical-stage biopharmaceutical company focused on identifying, licensing and globalizing top biopharma innovations from around the world to deliver important medicines to patients. In June 2021, the Company entered into a license agreement with Shanghai Allist Pharmaceuticals Co. Ltd. (“Allist”) which granted the Company an exclusive license under certain intellectual property owned or controlled by Allist to develop, manufacture and commercialize any product containing firmonertinib or any of its derivatives as an active ingredient, for all uses, in all countries and territories other than greater China, which includes mainland China, Hong Kong, Macau and Taiwan (See Note 9). The Company’s lead development candidate, firmonertinib, is a third-generation tyrosine kinase inhibitor currently being evaluated in multiple clinical trials across a range of epidermal growth factor receptor (“EGFR”) mutations in non-small cell lung cancer, many for which there are limited treatment options. On January 30, 2024, the Company completed the closing of its initial public offering of 9,722,222 shares of common stock at a price of $18.00 per share. Additionally, the underwriters exercised their option to purchase an additional 1,458,333 shares of common stock at a price of $18.00 per share. The shares of common stock began trading on The Nasdaq Global Market on January 26, 2024, under the symbol “AVBP”. The Company received net proceeds of $183.2 million, after deducting underwriting discounts and commissions and other offering expenses. In addition, as a result of the closing of the Company’s initial public offering, the Company’s Series A and Series B convertible preferred stock converted into 19,567,306 shares of common stock in January 2024.

Development-Stage Risks and Liq

Development-Stage Risks and Liquidity	9 Months Ended
Development-Stage Risks and Liquidity	Sep. 30, 2024
Development-Stage Risks and Liquidity
Development-Stage Risks and Liquidity	(2) Development-Stage Risks and Liquidity The Company has incurred losses since inception and has an accumulated deficit of $217.7 million as of September 30, 2024. The Company anticipates incurring additional losses until such time, if ever, that it can generate significant sales from its product candidates currently in development. Management believes that cash and cash equivalents of $282.9 million as of September 30, 2024 are sufficient to sustain planned operations through at least twelve months from the issuance date of these financial statements. The Company is subject to those risks associated with any specialty biotechnology company that has substantial expenditures for research and development. There can be no assurance that the Company’s research and development projects will be successful, that products developed will obtain necessary regulatory approval, or that any approved product will be commercially viable. In addition, the Company operates in an environment of rapid technological change and is largely dependent on the services of its employees and consultants.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2024
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	(3) Summary of Significant Accounting Policies The summary of significant accounting policies included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, filed with the Securities and Exchange Commission on March 28, 2024 (the “Annual Report”) has not materially changed, except as set forth below. (a) Interim Financial Statements The accompanying unaudited interim financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). Any references in these notes to applicable guidance are meant to refer to GAAP as found in Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) promulgated by the Financial Accounting Standards Board (“FASB”). In the opinion of management, the accompanying interim financial statements include all the normal and recurring adjustments (which consist primarily of accruals, estimates, and assumptions that impact financial statements) considered necessary to present fairly the Company’s financial position as of September 30, 2024 and its results of operations for the three and nine months ended September 30, 2024 and 2023. Certain information and disclosures normally included in the annual financial statements prepared in accordance with GAAP, but that is not required for interim reporting purposes, have been condensed or omitted. These interim financial statements should be read in conjunction with the audited financial statements and related notes as of and for the year ended December 31, 2023, which are included in the Annual Report. The December 31, 2023 balance sheet has been derived from the audited financial statements. The results of operations for the interim periods are not necessarily indicative of the results to be expected for a full year, any other interim periods or any future year or period. (b) Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from such estimates. Estimates and assumptions are periodically reviewed, and the effects of revisions are reflected in the financial statements in the period they are determined to be necessary. Significant areas that require management’s estimates include the fair value of the Company’s common stock prior to the completion of the Company’s initial public offering, stock-based compensation expense assumptions and accrued research and development expenses. (c) Fair Value Measurements The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels: • Level 1 Inputs: Unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date. • Level 2 Inputs: Other than quoted prices included in Level 1 inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability. • Level 3 Inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date. Management believes that the carrying amounts of the Company’s financial instruments, principally cash equivalents and accounts payable, approximate fair value due to the short-term nature of those instruments. (d) Net Loss per Share Basic net loss per share of common stock is computed by dividing net loss by the weighted-average number of shares of common stock outstanding during each period. Diluted net loss per share of common stock includes the effect, if any, from the potential exercise or conversion of securities, such as convertible preferred stock and stock options, which would result in the issuance of incremental shares of common stock. For diluted net loss per share, the weighted- average number of shares of common stock is the same for basic net loss per share since when a net loss exists, potentially dilutive securities are not included in the calculation as their impact is anti-dilutive. The Company’s convertible preferred stock entitled the holder to participate in dividends and earnings of the Company, and, if the Company had recognized net income, it would have used the two-class method to calculate earnings per share. The two-class method was not applicable during periods with a net loss, as the holders of the convertible preferred stock had no obligation to fund losses. The following table sets forth the computation of net loss, basic and diluted (in thousands, except share and per share data): Three Months Ended Nine Months Ended September 30, September 30, 2024 2023 2024 2023 Numerator: Net loss $ (20,564) $ (14,401) $ (59,855) $ (48,140) Denominator: Weighted-average shares of common stock outstanding 33,581,810 2,607,192 30,720,711 2,603,861 Less: Weighted-average shares of common stock subject to repurchase — — — (654,264) Weighted-average shares of common stock outstanding, basic and diluted 33,581,810 2,607,192 30,720,711 1,949,597 Net loss per share attributable to common stockholders, basic and diluted $ (0.61) $ (5.52) $ (1.95) $ (24.69) The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares of common stock outstanding, as they would be anti-dilutive: Nine Months Ended September 30, 2024 2023 Series A convertible preferred stock (as converted to common stock) — 9,861,923 Series B convertible preferred stock (as converted to common stock) — 9,705,383 Stock options 2,527,417 1,777,093 2,527,417 21,344,399 (e) Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU 2023-07 Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures Segment Reporting segment expense categories identified and disclosed in the period of adoption. The Company is currently evaluating the impact that this standard may have on its financial statements. In December 2023, the FASB issued ASU 2023-09 Income Taxes (Topic 740): Improvements to Income Tax Disclosures In November 2024, the FASB issued ASU 2024-03 Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures: Disaggregation of Income Statement Expenses (f) Reverse Stock Split On January 23, 2024, the Company filed an amendment to its Articles of Incorporation and effected a 15.21 (g) License and Collaboration Agreements Collaborative Arrangements Revenue from Contracts with Customers If the Company concludes that some or all aspects of the arrangement are within the scope of ASC 808 and do not represent a transaction with a customer, it recognizes costs incurred as a component of the related expense in the period incurred. The arrangements may also require the Company to make payments on achievement of certain milestones, including clinical, regulatory, and development milestones. Clinical, regulatory, and development milestones are recognized as research and development expense only when such milestones are deemed probable of being achieved.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
Fair Value Measurements	Sep. 30, 2024
Fair Value Measurements
Fair Value Measurements	(4) Fair Value Measurements The following table presents information about the Company’s financial assets measured at fair value on a recurring basis and indicates the level of the fair value hierarchy utilized to determine such fair values (in thousands): September 30, 2024 Level 1 Level 2 Level 3 Total Current assets: Cash equivalents - money market funds $ 277,855 $ — $ — $ 277,855 Total assets measured at fair value $ 277,855 $ — $ — $ 277,855 December 31, 2023 Level 1 Level 2 Level 3 Total Current assets: Cash equivalents - money market funds $ 124,322 $ — $ — $ 124,322 Total assets measured at fair value $ 124,322 $ — $ — $ 124,322 Money market accounts are highly liquid investments. The pricing information on the Company’s money market account is based on quoted prices in active markets. This approach results in a classification of these securities as Level 1 of the fair value hierarchy.

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	9 Months Ended
Prepaid Expenses and Other Current Assets	Sep. 30, 2024
Prepaid Expenses and Other Current Assets
Prepaid Expenses and Other Current Assets	(5) Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in thousands): September 30, December 31, 2024 2023 Research and development $ 7,902 $ 8,450 Professional fees 684 240 Insurance 457 128 Tax credit receivable 500 761 $ 9,543 $ 9,579

Accrued Expenses

Accrued Expenses	9 Months Ended
Accrued Expenses	Sep. 30, 2024
Accrued Expenses
Accrued Expenses	(6) Accrued Expenses Accrued expenses consisted of the following (in thousands): September 30, December 31, 2024 2023 Research and development $ 6,835 $ 3,126 Professional fees 229 411 Compensation and related expenses 3,157 3,353 Other accrued expenses 138 62 $ 10,359 $ 6,952

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2024
Commitments and contingencies
Commitments and contingencies	(7) Commitments and Contingencies Leases Operating lease expense was less than $0.1 million for the three months ended September 30, 2024 and 2023, respectively. Operating lease expense was $0.1 million and less than $0.1 million for the nine months ended September 30, 2024 and 2023, respectively. The Company’s remaining lease term and discount rate for its operating lease as of September 30, 2024 were 1.25 years and 10.0%, respectively. Future maturities of operating lease liabilities were as follows as of September 30, 2024 (in thousands): Fiscal year ending: Remainder of 2024 $ 42 2025 173 2026 14 Total future minimum payments 229 Less imputed interest (16) Present value of lease liabilities $ 213 Cash paid for rent expense recorded during the three months ended September 30, 2024 and 2023 was less than $0.1 million. Cash paid for rent expense recorded during the nine months ended September 30, 2024 and 2023 was $0.1 million and less than $0.1 million, respectively.

Stock-based Compensation

Stock-based Compensation	9 Months Ended
Stock-based Compensation	Sep. 30, 2024
Share-Based Payment Arrangement
Stock-based Compensation	(8) Stock-based Compensation In June 2021, the Company adopted the 2021 Employee, Director and Consultant Equity Incentive Plan, as amended (the “2021 Plan”), that authorized the Company to grant up to 803,564 shares of common stock. In 2022, the Company amended the 2021 Plan and increased the total number of shares authorized under the Plan to 2,748,818. In January 2024, the Company adopted the 2024 Employee, Director and Consultant Equity Incentive Plan (the “2024 Plan”) that authorized the Company to grant up to 3,900,000 shares of common stock plus any remaining ungranted or forfeited shares from the 2021 Plan. As of September 30, 2024, there were Three Months Ended Nine Months Ended September 30, September 30, 2024 2023 2024 2023 Research and development $ 315 $ 108 $ 968 $ 291 General and administrative 550 108 1,289 285 $ 866 $ 216 $ 2,256 $ 576 The following is a summary of stock options activity: Weighted Weighted average average remaining Aggregate exercise contractual Intrinsic Value Options price term (years) (in thousands) Outstanding as of December 31, 2023 1,683,156 $ 3.38 Granted 1,121,170 10.83 Exercised (201,014) 2.97 Forfeited/Expired (75,895) 7.29 Outstanding as of September 30, 2024 2,527,417 6.60 $ 8.52 $ 42,866 Exercisable as of September 30, 2024 630,058 2.97 7.63 12,933 Vested and expected to vest at September 30, 2024 2,527,417 $ 6.60 $ 8.52 $ 42,866 The weighted-average grant-date fair value of options granted in the first nine months of 2024 and 2023 were $8.53 and $3.50 per share, respectively. The fair value was estimated using the Black-Scholes option-pricing model based on the following assumptions: Nine Months Ended September 30, 2024 2023 Risk-free interest rate 3.69% - 4.66% 3.45% - 4.46% Expected term 5.5 - 6.1 years 6.0 years Expected volatility 93.1% - 98.6% 87.0% - 89.5% Expected dividend yield — — Estimated fair value of the Company's common stock per share $ 5.85 - 20.79 $ 3.65 - 6.24 Unrecognized compensation cost for awards not vested as of September 30, 2024 was $10.0 million and will be expensed over a weighted-average period of 2.69 years.

License and Collaborative Agree

License and Collaborative Agreements	9 Months Ended
License and Collaborative Agreements	Sep. 30, 2024
License and Collaborative Agreements
License and Collaborative Agreements	(9) License and Collaborative Agreements Allist In June 2021, the Company entered into a Global Technology Transfer and License Agreement with Allist (“Allist Agreement”). Pursuant to the Allist Agreement, the Company was granted an exclusive license under certain intellectual property to develop, manufacture and commercialize certain licensed products in the field in the licensed territory. Upon execution of the Allist Agreement, the Company paid Allist a non-refundable cash payment of $40.0 million and issued 1,276,250 shares of its common stock. Upon the achievement of certain clinical, regulatory and commercial milestones using the licensed technology, the Company is obligated to make future milestone payments to Allist. The Company is obligated to make future milestone payments of up to $105.0 million in clinical and regulatory milestones and up to $655.0 million in sales milestones. Furthermore royalties, ranging from high single digit percentages to low mid-teen percentage will be payable on net sales of licensed products in licensed territories. In connection with the Allist Agreement, in December 2021, the parties also entered into a Joint Clinical Collaboration Agreement (“Clinical Collaboration”) to define the framework under which the parties will cooperate and share costs related to global clinical studies to be conducted jointly by the Company and Allist. During the nine months ended September 30, 2024 and 2023, the Company incurred $0.5 million and $1.4 million, respectively, in cost reimbursements to Allist which have been recorded as research and development expense under the Clinical Collaboration. The Company also was entitled to cost reimbursement from Allist of $0.3 million for each of the nine months ended September 30, 2024 and 2023, which has been recorded as a reduction of research and development expenses. During the nine months ended September 30, 2024 and 2023, no milestones were met or achieved, or were probable of achievement. Alphamab In June 2024, the Company entered into a collaboration agreement with Jiangsu Alphamab Biopharmaceuticals Co., Ltd. (“Alphamab”) to discover, develop and commercialize novel antibody drug conjugates (“ADCs”) for the treatment of cancers. Under the agreement, both companies seek to leverage Alphamab’s proprietary linker-payload platform and glycan-conjugation technology to identify novel ADCs for oncology indications. The agreement gives the Company exclusive rights to develop and commercialize ADCs globally, except greater China, which includes mainland China, Hong Kong, Macau and Taiwan where Alphamab retains the right to develop and commercialize the ADCs. The terms of the agreement include combined upfront and potential milestone payments to Alphamab of up to $615.5 million in aggregate for the potential programs, based on the achievement of certain regulatory, development, and sales milestones. In addition, Alphamab is entitled to receive tiered sales royalties from the Company for each ADC product The upfront payment was recorded to research and development expense during the three-month period ending June 30, 2024. No milestones have been met or achieved, or are probable of achievement, since the inception of the agreement. Aarvik In December 2021, the Company entered into a Research Collaboration Agreement, as amended, effective June 30, 2023 (the “Aarvik Collaboration Agreement”), with Aarvik Pharmaceuticals, Inc. (“Aarvik”), under which the Company is required to pay Aarvik up to $3.1 million on statements of work (“SOWs”) and an initiation fee of $0.3 million predefined in the Aarvik Collaboration Agreement. After the completion of the SOWs, the Company has an exclusive option to license the Aarvik intellectual property, and the option to acquire certain of Aarvik’s intellectual property, after which it is the Company’s sole responsibility to research, develop, manufacture and commercialize any applicable compound and product in the field and territory. If the Company exercises that option, it would be obligated to pay up to $18.0 million per product upon the achievement of certain clinical and regulatory milestone events and up to $80.0 million per product in commercial milestones. Additionally, the Company would be obligated to pay Aarvik royalties in the mid-single digits based on net sales of licensed products. On August 9, 2024, the Company entered into an amendment and restatement of the Aarvik Collaboration Agreement (the “Amended and Restated Aarvik Collaboration Agreement”). Under the Amended and Restated Aarvik Collaboration Agreement, Aarvik granted the Company an exclusive option to obtain exclusive rights to certain of Aarvik’s intellectual property for the research, development, manufacture, use, commercialization, or other exploitation of the ADCs related to (i) the two agreed targets to which the compounds being developed under the collaboration bind, which is referred to as the Target Pair, and (ii) the acquisition of exclusive rights to certain intellectual property generated during the collaboration. The Company has not yet selected the indication or indications that it would pursue in the collaboration and anticipates doing so in connection with the identification of a lead candidate for IND-enabling studies. Under the Amended and Restated Aarvik Collaboration Agreement, the Company is required to pay Aarvik a collaboration initiation fee and research fees as provided in the SOWs in an aggregate of up to $4.7 million (based on estimated research fees). The Company incurred $1.7 million and $0.4 million in research and development expenses related to the Aarvik SOWs during the three months ended September 30, 2024 and 2023, respectively. The Company incurred $2.7 million and $1.1 million in research and development expenses related to the Aarvik SOWs during the nine months ended September 30, 2024 and 2023, respectively. With the exception of a $1.0 million payment to exercise an option which was recorded to research and development expense during the three month period ending September 30, 2024, no milestones have been met or achieved since the inception of the Aarvik Collaboration Agreement.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	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)	$ (20,564)	$ (21,874)	$ (17,417)	$ (14,401)	$ (21,567)	$ (12,172)	$ (59,855)	$ (48,140)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	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 (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2024
Summary of Significant Accounting Policies
Interim Financial Statements	(a) Interim Financial Statements The accompanying unaudited interim financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). Any references in these notes to applicable guidance are meant to refer to GAAP as found in Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) promulgated by the Financial Accounting Standards Board (“FASB”). In the opinion of management, the accompanying interim financial statements include all the normal and recurring adjustments (which consist primarily of accruals, estimates, and assumptions that impact financial statements) considered necessary to present fairly the Company’s financial position as of September 30, 2024 and its results of operations for the three and nine months ended September 30, 2024 and 2023. Certain information and disclosures normally included in the annual financial statements prepared in accordance with GAAP, but that is not required for interim reporting purposes, have been condensed or omitted. These interim financial statements should be read in conjunction with the audited financial statements and related notes as of and for the year ended December 31, 2023, which are included in the Annual Report. The December 31, 2023 balance sheet has been derived from the audited financial statements. The results of operations for the interim periods are not necessarily indicative of the results to be expected for a full year, any other interim periods or any future year or period.
Use of Estimates	(b) Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from such estimates. Estimates and assumptions are periodically reviewed, and the effects of revisions are reflected in the financial statements in the period they are determined to be necessary. Significant areas that require management’s estimates include the fair value of the Company’s common stock prior to the completion of the Company’s initial public offering, stock-based compensation expense assumptions and accrued research and development expenses.
Fair Value Measurements	(c) Fair Value Measurements The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels: • Level 1 Inputs: Unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date. • Level 2 Inputs: Other than quoted prices included in Level 1 inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability. • Level 3 Inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date. Management believes that the carrying amounts of the Company’s financial instruments, principally cash equivalents and accounts payable, approximate fair value due to the short-term nature of those instruments.
Net Loss per Share	(d) Net Loss per Share Basic net loss per share of common stock is computed by dividing net loss by the weighted-average number of shares of common stock outstanding during each period. Diluted net loss per share of common stock includes the effect, if any, from the potential exercise or conversion of securities, such as convertible preferred stock and stock options, which would result in the issuance of incremental shares of common stock. For diluted net loss per share, the weighted- average number of shares of common stock is the same for basic net loss per share since when a net loss exists, potentially dilutive securities are not included in the calculation as their impact is anti-dilutive. The Company’s convertible preferred stock entitled the holder to participate in dividends and earnings of the Company, and, if the Company had recognized net income, it would have used the two-class method to calculate earnings per share. The two-class method was not applicable during periods with a net loss, as the holders of the convertible preferred stock had no obligation to fund losses. The following table sets forth the computation of net loss, basic and diluted (in thousands, except share and per share data): Three Months Ended Nine Months Ended September 30, September 30, 2024 2023 2024 2023 Numerator: Net loss $ (20,564) $ (14,401) $ (59,855) $ (48,140) Denominator: Weighted-average shares of common stock outstanding 33,581,810 2,607,192 30,720,711 2,603,861 Less: Weighted-average shares of common stock subject to repurchase — — — (654,264) Weighted-average shares of common stock outstanding, basic and diluted 33,581,810 2,607,192 30,720,711 1,949,597 Net loss per share attributable to common stockholders, basic and diluted $ (0.61) $ (5.52) $ (1.95) $ (24.69) The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares of common stock outstanding, as they would be anti-dilutive: Nine Months Ended September 30, 2024 2023 Series A convertible preferred stock (as converted to common stock) — 9,861,923 Series B convertible preferred stock (as converted to common stock) — 9,705,383 Stock options 2,527,417 1,777,093 2,527,417 21,344,399
Accounting Pronouncements Not Yet Adopted	(e) Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU 2023-07 Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures Segment Reporting segment expense categories identified and disclosed in the period of adoption. The Company is currently evaluating the impact that this standard may have on its financial statements. In December 2023, the FASB issued ASU 2023-09 Income Taxes (Topic 740): Improvements to Income Tax Disclosures In November 2024, the FASB issued ASU 2024-03 Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures: Disaggregation of Income Statement Expenses
Reverse Stock Split	(f) Reverse Stock Split On January 23, 2024, the Company filed an amendment to its Articles of Incorporation and effected a 15.21
License and Collaboration Agreements	(g) License and Collaboration Agreements Collaborative Arrangements Revenue from Contracts with Customers If the Company concludes that some or all aspects of the arrangement are within the scope of ASC 808 and do not represent a transaction with a customer, it recognizes costs incurred as a component of the related expense in the period incurred. The arrangements may also require the Company to make payments on achievement of certain milestones, including clinical, regulatory, and development milestones. Clinical, regulatory, and development milestones are recognized as research and development expense only when such milestones are deemed probable of being achieved.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
Summary of Significant Accounting Policies (Tables)	Sep. 30, 2024
Summary of Significant Accounting Policies
Schedule of computation of net loss, basic and diluted	The following table sets forth the computation of net loss, basic and diluted (in thousands, except share and per share data): Three Months Ended Nine Months Ended September 30, September 30, 2024 2023 2024 2023 Numerator: Net loss $ (20,564) $ (14,401) $ (59,855) $ (48,140) Denominator: Weighted-average shares of common stock outstanding 33,581,810 2,607,192 30,720,711 2,603,861 Less: Weighted-average shares of common stock subject to repurchase — — — (654,264) Weighted-average shares of common stock outstanding, basic and diluted 33,581,810 2,607,192 30,720,711 1,949,597 Net loss per share attributable to common stockholders, basic and diluted $ (0.61) $ (5.52) $ (1.95) $ (24.69)
Schedule of potentially dilutive securities have been excluded from the computation of diluted weighted-average shares	Nine Months Ended September 30, 2024 2023 Series A convertible preferred stock (as converted to common stock) — 9,861,923 Series B convertible preferred stock (as converted to common stock) — 9,705,383 Stock options 2,527,417 1,777,093 2,527,417 21,344,399

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
Fair Value Measurements (Tables)	Sep. 30, 2024
Fair Value Measurements
Schedule of company's financial assets measured at fair value on a recurring basis	The following table presents information about the Company’s financial assets measured at fair value on a recurring basis and indicates the level of the fair value hierarchy utilized to determine such fair values (in thousands): September 30, 2024 Level 1 Level 2 Level 3 Total Current assets: Cash equivalents - money market funds $ 277,855 $ — $ — $ 277,855 Total assets measured at fair value $ 277,855 $ — $ — $ 277,855 December 31, 2023 Level 1 Level 2 Level 3 Total Current assets: Cash equivalents - money market funds $ 124,322 $ — $ — $ 124,322 Total assets measured at fair value $ 124,322 $ — $ — $ 124,322

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	9 Months Ended
Prepaid Expenses and Other Current Assets (Tables)	Sep. 30, 2024
Prepaid Expenses and Other Current Assets
Schedule of prepaid expenses and other current assets	Prepaid expenses and other current assets consisted of the following (in thousands): September 30, December 31, 2024 2023 Research and development $ 7,902 $ 8,450 Professional fees 684 240 Insurance 457 128 Tax credit receivable 500 761 $ 9,543 $ 9,579

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
Accrued Expenses (Tables)	Sep. 30, 2024
Accrued Expenses
Schedule of Accrued expenses, current	Accrued expenses consisted of the following (in thousands): September 30, December 31, 2024 2023 Research and development $ 6,835 $ 3,126 Professional fees 229 411 Compensation and related expenses 3,157 3,353 Other accrued expenses 138 62 $ 10,359 $ 6,952

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
Commitments and Contingencies (Tables)	Sep. 30, 2024
Commitments and contingencies
Schedule of future maturities of operating lease payments	Future maturities of operating lease liabilities were as follows as of September 30, 2024 (in thousands): Fiscal year ending: Remainder of 2024 $ 42 2025 173 2026 14 Total future minimum payments 229 Less imputed interest (16) Present value of lease liabilities $ 213

Stock-based Compensation (Table

Stock-based Compensation (Tables)	9 Months Ended
Stock-based Compensation (Tables)	Sep. 30, 2024
Share-Based Payment Arrangement
Schedule of stock-based compensation expense	The Company recorded stock-based compensation expense in the following expense categories in its accompanying statements of operations (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2024 2023 2024 2023 Research and development $ 315 $ 108 $ 968 $ 291 General and administrative 550 108 1,289 285 $ 866 $ 216 $ 2,256 $ 576
Schedule of of stock options activity under the Plan	Weighted Weighted average average remaining Aggregate exercise contractual Intrinsic Value Options price term (years) (in thousands) Outstanding as of December 31, 2023 1,683,156 $ 3.38 Granted 1,121,170 10.83 Exercised (201,014) 2.97 Forfeited/Expired (75,895) 7.29 Outstanding as of September 30, 2024 2,527,417 6.60 $ 8.52 $ 42,866 Exercisable as of September 30, 2024 630,058 2.97 7.63 12,933 Vested and expected to vest at September 30, 2024 2,527,417 $ 6.60 $ 8.52 $ 42,866
Schedule of assumptions used in estimating the fair value of options	Nine Months Ended September 30, 2024 2023 Risk-free interest rate 3.69% - 4.66% 3.45% - 4.46% Expected term 5.5 - 6.1 years 6.0 years Expected volatility 93.1% - 98.6% 87.0% - 89.5% Expected dividend yield — — Estimated fair value of the Company's common stock per share $ 5.85 - 20.79 $ 3.65 - 6.24

Background (Details)

Background (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended	9 Months Ended
	Jan. 30, 2024	Jan. 31, 2024	Mar. 31, 2024	Sep. 30, 2024
Background
Proceeds from issuance of common stock in an initial public offering, net of issuance costs	$ 183,200			$ 185,950
Common stock
Background
Issuance of common stock in initial public offering, net of issuance costs of $18,032 (in shares)			11,180,555
Conversion of convertible preferred stock into common stock (in shares)		19,567,306	19,567,306
IPO \| Common stock
Background
Issuance of common stock in initial public offering, net of issuance costs of $18,032 (in shares)	9,722,222
Share price	$ 18
Underwriters allotment \| Common stock
Background
Issuance of common stock in initial public offering, net of issuance costs of $18,032 (in shares)	1,458,333
Share price	$ 18

Development-Stage Risks and L_2

Development-Stage Risks and Liquidity (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Development-Stage Risks and Liquidity
Accumulated deficit	$ 217,700	$ 157,845
Cash and cash equivalents	$ 282,855	$ 150,389
Substantial doubt about ability to continue as going concern within one year	false

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net loss (basic)	$ (20,564)	$ (14,401)	$ (59,855)	$ (48,140)
Net loss (diluted)	$ (20,564)	$ (14,401)	$ (59,855)	$ (48,140)
Denominator:
Weighted-average shares of common stock outstanding	33,581,810	2,607,192	30,720,711	2,603,861
Less: Weighted-average shares of common stock subject to repurchase				(654,264)
Weighted-average shares of common stock outstanding, basic (in shares)	33,581,810	2,607,192	30,720,711	1,949,597
Weighted-average shares of common stock outstanding, diluted (in shares)	33,581,810	2,607,192	30,720,711	1,949,597
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.61)	$ (5.52)	$ (1.95)	$ (24.69)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.61)	$ (5.52)	$ (1.95)	$ (24.69)

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Potentially dilutive securities (Details) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Antidilutive securities
Potentially dilutive securities have been excluded from the computation of diluted weighted-average shares	2,527,417	21,344,399
Convertible preferred stock \| Series A convertible preferred stock
Antidilutive securities
Potentially dilutive securities have been excluded from the computation of diluted weighted-average shares		9,861,923
Convertible preferred stock \| Series B convertible preferred stock
Antidilutive securities
Potentially dilutive securities have been excluded from the computation of diluted weighted-average shares		9,705,383
Employee Stock Option
Antidilutive securities
Potentially dilutive securities have been excluded from the computation of diluted weighted-average shares	2,527,417	1,777,093

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Other (Details)	Jan. 23, 2024
Summary of Significant Accounting Policies
Stock split conversion ratio	0.06575

Fair Value Measurements (Detail

Fair Value Measurements (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value Measurements
Cash equivalents - money market funds	$ 277,855	$ 124,322
Total assets measured at fair value	277,855	124,322
Level 1
Fair Value Measurements
Cash equivalents - money market funds	277,855	124,322
Total assets measured at fair value	$ 277,855	$ 124,322

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Prepaid Expenses and Other Current Assets
Research and development	$ 7,902	$ 8,450
Professional fees	684	240
Insurance	457	128
Tax credit receivable	500	761
Total	$ 9,543	$ 9,579

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Accrued Expenses
Research and development	$ 6,835	$ 3,126
Professional fees	229	411
Compensation and related expenses	3,157	3,353
Other accrued expenses	138	62
Total	$ 10,359	$ 6,952

Commitments and Contingencies -

Commitments and Contingencies - Lease (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Leases
Operating lease expense			$ 0.1
Remaining lease term	1 year 3 months		1 year 3 months
Discount rate (as a percent)	10%		10%
Maximum
Leases
Operating lease expense	$ 0.1	$ 0.1		$ 0.1

Commitments and Contingencies_2

Commitments and Contingencies - Operating Lease maturities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Future maturities of operating lease liabilities
Remainder of 2024	$ 42		$ 42
2025	173		173
2026	14		14
Total future minimum payments	229		229
Less imputed interest	(16)		(16)
Present value of lease liabilities	213		213
Cash paid for rent expense			$ 100
Maximum
Future maturities of operating lease liabilities
Cash paid for rent expense	$ 100	$ 100		$ 100

Stock-based Compensation - Plan

Stock-based Compensation - Plans (Details) - shares	1 Months Ended	9 Months Ended
Stock-based Compensation - Plans (Details) - shares	Jan. 31, 2024	Sep. 30, 2024	Dec. 31, 2022	Jun. 30, 2021
Stock-based Compensation
Shares available for grant		3,758,647
2021 Plan
Stock-based Compensation
Shares authorized			2,748,818	803,564
2024 Plan
Stock-based Compensation
Additional shares authorized	3,900,000
Employee Stock Option
Stock-based Compensation
Vesting Period		4 years

Stock-based Compensation - Stoc

Stock-based 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
Stock-based compensation expense	$ 866,000	$ 216,000	$ 2,256	$ 576
Research and development
Stock-based Compensation
Stock-based compensation expense	315,000	108,000	968	291
General and administrative
Stock-based Compensation
Stock-based compensation expense	$ 550,000	$ 108,000	$ 1,289	$ 285

Stock-based Compensation - Summ

Stock-based Compensation - Summary of stock options activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 $ / shares
Options
Outstanding as of beginning of period (in shares) \| shares	1,683,156
Granted (in shares) \| shares	1,121,170
Exercised (in shares) \| shares	(201,014)
Forfeited/Expired (in shares) \| shares	(75,895)
Outstanding as of end of period (in shares) \| shares	2,527,417
Exercisable (in shares) \| shares	630,058
Vested and expected to vest (in shares) \| shares	2,527,417
Weighted average exercise price
Outstanding as of beginning of period (in dollars per shares)	$ 3.38
Granted (in dollars per shares)	10.83
Exercised (in dollars per shares)	2.97
Forfeited/expired (in dollars per shares)	7.29
Outstanding as of end of period (in dollars per shares)	6.60
Exercisable (in dollars per shares)	2.97
Vested and expected to vest (in dollars per shares)	$ 6.60
Weighted average remaining contractual term (years) and Aggregate Intrinsic Value
Weighted average remaining contractual term - Outstanding (years)	8 years 6 months 7 days
Weighted average remaining contractual term - Exercisable (years)	7 years 7 months 17 days
Weighted average remaining contractual term - Vested and expected to vest (years)	8 years 6 months 7 days
Aggregate Intrinsic Value - Outstanding (in dollars) \| $	$ 42,866
Aggregate Intrinsic Value - Exercisable (in dollars) \| $	12,933
Aggregate Intrinsic Value - Vested and expected to vest (in dollars) \| $	$ 42,866
Weighted-average grant-date fair value of options	$ 8.53	$ 3.50

Stock-based Compensation - Fair

Stock-based Compensation - Fair value (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Stock-based Compensation
Weighted-average grant-date fair value of options	$ 8.53	$ 3.50
Unrecognized compensation cost
Unrecognized compensation cost for awards (in dollars)	$ 10
Expected period to be recognized	2 years 8 months 8 days
Employee Stock Option
Fair value assumptions
Risk-free interest rate, minimum (as a percent)	3.69%	3.45%
Risk-free interest rate, maximum (as a percent)	4.66%	4.46%
Expected term		6 years
Expected volatility, minimum (as a percent)	93.10%	87%
Expected volatility, maximum (as a percent)	98.60%	89.50%
Employee Stock Option \| Minimum
Fair value assumptions
Expected term	5 years 6 months
Estimated fair value of the Company's common stock per share (in dollars per share)	$ 5.85	$ 3.65
Employee Stock Option \| Maximum
Fair value assumptions
Expected term	6 years 1 month 6 days
Estimated fair value of the Company's common stock per share (in dollars per share)	$ 20.79	$ 6.24

Licenses and Collaborative Agre

Licenses and Collaborative Agreements - Allist (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Agreement
Research and development		$ 20,088	$ 14,280	$ 58,841	$ 44,874
Global Technology Transfer And License Agreement \| Allist
Agreement
Non-refundable cash payment	$ 40,000
Maximum amount payable upon achievement of certain clinical and regulatory milestone events		105,000		105,000
Maximum amount payable upon achievement of commercial milestones		$ 655,000		655,000
Global Technology Transfer And License Agreement \| Allist \| Common stock
Agreement
Shares issued in execution of agreement (in shares)	1,276,250
Clinical Collaboration Agreement \| Allist
Agreement
Research and development				500	1,400
Cost reimbursement				$ 300	$ 300

Licenses and Collaborative Ag_2

Licenses and Collaborative Agreements - Alphamab (Details) $ in Millions	Jun. 30, 2024 USD ($)
Collaborative Agreement \| Alphamab
Agreement
Maximum amount payable upon achievement of milestones	$ 615.5

Licenses and Collaborative Ag_3

Licenses and Collaborative Agreements - Aarvik (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		34 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Aug. 09, 2024	Jun. 30, 2023
Agreement
Research and development	$ 20,088	$ 14,280	$ 58,841	$ 44,874
Collaborative Agreement \| Aarvik
Agreement
Maximum payment on statements of work							$ 3,100
Initiation fee							300
Maximum amount payable per product upon achievement of certain clinical and regulatory milestone events							18,000
Maximum amount payable per product upon achievement of commercial milestones							$ 80,000
Maximum amount of initiation and research fees to be paid						$ 4,700
Research and development	$ 1,700	$ 400	$ 2,700	$ 1,100
Amount of payment to exercise option to license and/or acquire certain intellectual property					$ 1,000