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Summary of Significant Accounting Policies - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 1,437	$ 1,131
Less: accumulated depreciation and amortization	(381)	(133)
Total property and equipment, net	1,056	998
Internal Use Software
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 296	245
Useful Life	3 years
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 380	375
Useful Life	5 years
Lab Equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 514	279
Useful Life	7 years
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 247	$ 232
Useful Life	7 years

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Schedule of Property and Equipment, Net

The following is the summary of property and equipment and related accumulated depreciation as of December 31, 2023, and December 31, 2022 (years not stated in thousands):


	Useful Life		December 31, 2023			December 31, 2022
Internal use software		3 years	$	296		$	245
Furniture and fixtures		5 years		380			375
Lab equipment		7 years		514			279
Leasehold improvements		7 years		247			232

Total property and equipment				1,437			1,131
Less: accumulated depreciation and amortization				(381	)		(133	)

Total property and equipment, net			$	1,056		$	998

Leases - Components of Equipment Finance Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Reduction in the carrying amount of ROU assets, finance	$ 306	$ 148
Interest on finance lease liabilities	176	77
Total finance lease expense	482	225
Cash paid for amounts included in the measurement of lease liabilities, included in financing cash flows	$ 425	$ 163

Convertible Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2023

Temporary Equity Disclosure [Abstract]

Schedule of Convertible Preferred Stock

As of December 31, 2022 and until the closing of the Company’s IPO on November 7, 2023, convertible preferred stock consisted of the following:


	Convertible Preferred Stock Authorized		Convertible Preferred Stock Issued and Outstanding		Proceeds Received		Liquidation Preference		Common Stock Issuable Upon Conversion
Series A convertible preferred stock		85,495,722		85,495,722	$	85,496	$	85,496		8,070,027
Series B convertible preferred stock		58,157,824		58,157,823		100,060		100,060		5,489,573

		143,653,546		143,653,545	$	185,556	$	185,556		13,559,600

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) - IPO $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Convertible Preferred Stock
Net of issuance costs	$ 519
SAFE
Net of issuance costs	113
Underwriting Discounts, Commissions and Offering Costs
Net of issuance costs	$ 11,285

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net loss	$ (66,394)	$ (59,277)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Reduction in the carrying amount of ROU assets, operating	1,266	877
Reduction in the carrying amount of ROU assets, finance	306	148
Stock based compensation expense	3,043	1,781
Depreciation and amortization expense	271	120
Change in fair value of convertible SAFE Note liability	530
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	990	(1,889)
Security deposits		2
Accounts payable	(180)	(426)
Change in deferred income		(46)
Accrued expenses and other current liabilities	2,440	4,476
Taxes payable	(349)	(22)
Lease liability, operating	(1,414)	(298)
Lease liabilities, finance	(5)	(6)
Net cash used in operating activities	(59,496)	(54,560)
Cash flows from investing activities:
Purchase of internal use software	(50)	(229)
Purchase of property and equipment	(115)	(672)
Net cash used in investing activities	(165)	(901)
Cash flows from financing activities:
Proceeds from issuance of series A convertible preferred stock		20
Proceeds from exercise of stock options	51	332
Payments on finance leases	(425)	(163)
Payments of issuance costs on convertible SAFE Note	(86)
Proceeds from issuance of convertible SAFE Note	4,000
Proceeds from issuance of common stock upon initial public offering, net of underwriters discounts, commissions and other offering costs	100,251
Net cash provided by financing activities	103,791	189
Net change in cash, cash equivalents and restricted cash	44,130	(55,272)
Total cash, cash equivalents and restricted cash at beginning of period	80,588	135,860
Total cash, cash equivalents and restricted cash at end of period	124,718	80,588
Cash and cash equivalents at beginning of period	77,335	135,860
Restricted cash included in long-term assets at beginning of period	3,253
Cash and cash equivalents at end of period	121,466	77,335
Restricted cash included in long-term assets at end of period	3,252	3,253
Supplemental disclosures of cash flow information
Interest paid	176	77
Supplemental disclosure of non-cash activities
Deferred financing costs included in accounts payable and accrued expenses	1,105
Issuance costs related to convertible debt included in accounts payable and accrued expenses	50
Purchase of property and equipment included in accounts payable and accrued expenses	141	43
Operating lease right-of-use assets and operating lease liabilities recognized		11,585
Finance lease right-of use assets and finance lease liabilities recognized		2,364
Conversion of convertible preferred stock into common stock in connection with initial public offering, net of issuance costs	185,032
Conversion of SAFE Note into common stock in connection with initial public offering, net of issuance costs	4,417
Amounts reclassified from deposit liabilities upon the vesting of early-exercised stock options previously subject to repurchase, (net of proceeds received from early exercise of unvested stock options subject to repurchase and recorded as deposit liabilities)	$ 87	$ (188)

Convertible Preferred Stock - Schedule of Convertible Preferred Stock (Details) - USD ($) $ in Thousands	27 Months Ended
	Nov. 07, 2023	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Convertible Preferred Stock Authorized	143,653,546		143,653,546
Convertible Preferred Stock Issued	143,653,545		143,653,545
Convertible Preferred Stock Outstanding	143,653,545		143,653,545
Proceeds Received	$ 185,556
Liquidation Preference	$ 185,556		$ 185,556
Common Stock Issuable Upon Conversion	13,559,600		13,559,600
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Convertible Preferred Stock Authorized	85,495,722	0	85,495,722
Convertible Preferred Stock Issued	85,495,722	0	85,495,722
Convertible Preferred Stock Outstanding	85,495,722	0	85,495,722
Proceeds Received	$ 85,496
Liquidation Preference	$ 85,496		$ 85,496
Common Stock Issuable Upon Conversion	8,070,027		8,070,027
Series B Convertible Preferred Stock
Class of Stock [Line Items]
Convertible Preferred Stock Authorized	58,157,824	0	58,157,824
Convertible Preferred Stock Issued	58,157,823	0	58,157,823
Convertible Preferred Stock Outstanding	58,157,823	0	58,157,823
Proceeds Received	$ 100,060
Liquidation Preference	$ 100,060		$ 100,060
Common Stock Issuable Upon Conversion	5,489,573		5,489,573

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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Reference 18: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Temporary equity, balance, shares at Dec. 31, 2021		143,653,545
Temporary equity, balance, value at Dec. 31, 2021		$ 185,013
Balance, shares at Dec. 31, 2021			1,580,651
Balance, value at Dec. 31, 2021	$ (55,602)			$ 567	$ (56,169)
Proceeds from issuance of series A convertible preferred stock		$ 20
Exercise of stock options, shares			68,083
Exercise of stock options, value	332			332
Proceeds received from early exercise of unvested stock options subject to repurchase and recorded as deposit liabilities, net of amounts reclassified from deposit liabilities upon the vesting of early-exercised stock options previously subject to repurchase, shares			(41,549)
Proceeds received from early exercise of unvested stock options subject to repurchase and recorded as deposit liabilities, net of amounts reclassified from deposit liabilities upon the vesting of early-exercised stock options previously subject to repurchase, value	(188)			(188)
Stock-based compensation expense	1,781			1,781
Net loss	$ (59,277)				(59,277)
Temporary equity, balance, shares at Dec. 31, 2022	143,653,545	143,653,545
Temporary equity, balance, value at Dec. 31, 2022		$ 185,033
Balance, shares at Dec. 31, 2022			1,607,185
Balance, value at Dec. 31, 2022	$ (112,954)			2,492	(115,446)
Exercise of stock options, shares			11,916
Exercise of stock options, value	51			51
Amounts reclassified from deposit liabilities upon the vesting of early-exercised stock options previously subject to repurchase, net of proceeds received from early exercise of unvested stock options subject to repurchase and recorded as deposit liabilities, share			19,442
Amounts reclassified from deposit liabilities upon the vesting of early-exercised stock options previously subject to repurchase, net of proceeds received from early exercise of unvested stock options subject to repurchase and recorded as deposit liabilities, value	87			87
Conversion of SAFE Note into common stock in connection with initial public offering, Share			411,815
Conversion of SAFE Note into common stock in connection with initial public offering, net of issuance costs, value	4,417			4,417
Issuance of common stock upon initial public offering and subsequent partial exercise of underwriters' option to purchase additional shares, Shares			10,139,656
Issuance of common stock upon initial public offering and subsequent partial exercise of underwriters' option to purchase additional shares, Value	100,251		$ 1	100,250
Conversion of convertible preferred stock into common stock in connection with initial public offering, shares		(143,653,545)
Conversion of convertible preferred stock into common stock in connection with initial public offering, value		$ (185,033)
Conversion of convertible preferred stock into common stock in connection with initial public offering, share			14,456,364
Conversion of convertible preferred stock into common stock in connection with initial public offering, value	185,034		$ 2	185,032
Stock-based compensation expense	3,043			3,043
Net loss	(66,394)				(66,394)
Balance, shares at Dec. 31, 2023			26,646,378
Balance, value at Dec. 31, 2023	$ 113,535		$ 3	$ 295,372	$ (181,840)

Leases (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Components of Operating Lease

The components of this operating lease were as follows:


	Year Ended December 31,
	2023		2022
Operating lease expense	$	2,147	$	1,610
Variable lease expense		355		185

Total operating lease expense	$	2,502	$	1,795
Cash paid for amounts included in the measurement of lease liabilities, included in operating cash flows	$	2,294	$	1,032

Reconciliation of Remaining Undiscounted Contractual Rent Obligations

The following table provides a reconciliation of the Company’s remaining undiscounted contractual rent obligations due within each year ended December 31 to the operating lease liabilities recognized as of December 31, 2023:


Year ended December 31	Operating Leases
2024	$	2,112
2025		2,152
2026		2,206
2027		2,261
2028		2,318
Thereafter		1,372

Total lease payments		12,421
Less: present value adjustment		(2,548	)

Total operating lease liabilities	$	9,873

Included in the consolidated balance sheet:
Current portion of lease liabilities—operating		2,087
Non-current portion of lease liabilities—operating		7,786

Total operating lease liabilities	$	9,873

Components of Equipment Finance Leases

The components of the equipment finance leases were as follows:


	Year Ended December 31,
	2023		2022
Reduction in the carrying amount of ROU assets, finance	$	306	$	148
Interest on finance lease liabilities		176		77

Total finance lease expense	$	482	$	225
Cash paid for amounts included in the measurement of lease liabilities, included in financing cash flows	$	425	$	163

Reconciliation of Remaining Equipment Finance Lease Obligations

The following table provides a reconciliation of the Company’s remaining equipment finance lease obligations due within each year ending December 31 to the equipment finance lease liabilities recognized at December 31, 2023:


Year ended December 31	Equipment Finance Leases
2024	$	531
2025		579
2026		579
2027		357
2028		11
Thereafter		—

Total lease payments		2,057
Less: imputed interest		(292	)

Total finance lease liabilities	$	1,765

Included in the consolidated balance sheet:
Current portion of lease liabilities—finance		518
Non-current portion of lease liabilities—finance		1,247

Total finance lease liabilities	$	1,765

Stock-Based Compensation - Additional Information (Details) - USD ($)		2 Months Ended	12 Months Ended		36 Months Ended	37 Months Ended
	Nov. 07, 2023	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Nov. 07, 2023	Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, shares reserved for issuance		4,948,156	4,948,156	16,476,313		4,948,156
Unrecognized stock-based compensation expense		$ 9,800,000	$ 9,800,000			$ 9,800,000
Unrecognized compensation expense, weighted-average period of recognition			2 years 11 months 19 days
Employee Stock Option Member
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Repurchase of Common stock					$ 0
Total grant date fair values of options vested			$ 2,400,000	$ 1,600,000
Expected dividend yields percentage			0.00%	0.00%
Employee Stock Option Member \| Non-employee
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total grant date fair values of options vested				$ 100,000
Granted, shares				342,404
2021 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, shares reserved for issuance	582,699				582,699
Number of shares available for future grants		0	0			0
2021 Plan \| Employee Stock Option Member
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period						4 years
Vesting period, percentage						25.00%
2021 Plan \| Employee Stock Option Member \| Non-employee
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share based compensation payment description					vest over a four-year period with 25% of the options granted vesting after one year and the remainder vesting in equal monthly installments over the following 36 months
2023 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, shares reserved for issuance	1,803,980	2,293,816	2,293,816		1,803,980	2,293,816
Number of shares authorized	4,737,000				4,737,000
Percentage of automatically increase in available shares of common stock on beginning of each calendar year	5.00%
2023 Plan \| Employee Stock Option Member
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period		4 years
Vesting period, percentage		25.00%
Share based compensation payment description		vest over a four-year period with 25% of the options granted vesting after one year and the remainder vesting in equal monthly installments over the following 36 months
2023 ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, shares reserved for issuance	238,600	238,600	238,600		238,600	238,600
Number of shares available for future grants		0	0			0
Number of shares automatically increase in available shares of common stock under plan	477,200
2023 ESPP \| Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Percentage of automatically increase in available shares of common stock on beginning of each calendar year	1.00%

Net Loss Per Share

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Net Loss Per Share

10. Net Loss per Share

Basic and diluted net loss per common share attributable to common stockholders was calculated as follows:


	Year Ended December 31,
	2023			2022
Numerator:
Net loss attributable to common stockholders	$	(66,394	)	$	(59,277	)
Denominator:
Weighted-average common shares outstanding, basic and diluted		5,354,368			1,630,348

Net loss per share attributable to common stockholders, basic and diluted	$	(12.40	)	$	(36.36	)

Convertible Safe Note - Additional Information (Details) - SAFE - USD ($) $ in Millions		12 Months Ended
	Nov. 02, 2023	Dec. 31, 2023	Aug. 24, 2023
Debt Instrument [Line Items]
Issuance costs			$ 0.1
Increase in fair value of safe instrument	$ 0.5
Total liabilities	4.5
Unamortized discount	$ 4.4
Common Stock \| IPO
Debt Instrument [Line Items]
Number of common shares on conversion of debt instrument	411,815
Sarepta Therapeutics, Inc
Debt Instrument [Line Items]
Convertible safe note, principal amount			$ 4.0
Annual interest rate			10.00%
Debt Instrument, Description		Upon a qualified equity financing event, the convertible SAFE Note would have automatically converted into a number of shares of corresponding preferred stock based on a certain discount to the price of such preferred stock issued to the other investors applied to the then-current Cash-Out Amount. Upon the effective date of an IPO or a direct listing, or immediately prior to the closing of a SPAC transaction, the convertible SAFE Note would have automatically converted, and did automatically convert upon the effectiveness of the Company's IPO registration statement on November 2, 2023, into a number of shares of common stock based on a certain discount to the public offering price of such common stock applied to the then-current Cash-Out Amount (see Note 8). Upon a change of control, the Investor would have been entitled to receive the greater of (i) an amount equal to a certain premium applied to the then-current Cash-Out Amount, or (ii) the amount that would have been payable on the number of shares of the senior-most series of the Company’s preferred stock after applying a certain discount to the original issue price of such senior-most preferred stock together with a certain premium applied to the then-current Cash-Out Amount (the greater of (i) and (ii), the “Conversion Amount”). Upon the one-year maturity of the convertible SAFE Note, or upon dissolution of the Company, the Investor was to be paid an amount equal to the Cash-Out Amount. Upon the event of a change of control or dissolution, the Investor’s right to receive its Cash-Out Amount or its Conversion Amount would have been junior to payment of outstanding indebtedness and creditor claims, on par with payments for the Company’s most senior series of preferred stock or other SAFE note holders, if any, and senior to payments for the Company’s common stock and any other series or class of stock. The convertible SAFE Note did not maintain any voting rights.

Description of Business and Basis of Presentation - Additional Information (Details) - USD ($) $ in Thousands			1 Months Ended	12 Months Ended		24 Months Ended	27 Months Ended
	Nov. 07, 2023	Oct. 13, 2023	Aug. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Nov. 07, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Reverse stock split		10.594230-for-1
Net Loss				$ 66,394	$ 59,277
Cash and cash equivalents, including restricted cash				121,466	77,335	$ 135,860
Accumulated deficit				$ (181,840)	$ (115,446)
Aggregate total net proceeds raised with issuance of convertible preferred stock							$ 185,556
Series A and Series B Convertible Preferred Stock [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Aggregate total net proceeds raised with issuance of convertible preferred stock						$ 185,000
IPO [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net proceeds	$ 100,300
SAFE [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net proceeds			$ 3,900

Summary of Significant Accounting Policies - Additional Information (Details)			12 Months Ended		82 Months Ended
	Nov. 07, 2023 shares	Nov. 02, 2023 shares	Dec. 31, 2023 USD ($) Segment shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2023 USD ($)
Summary of Significant Accounting Policies [Line Items]
Loss recognized from uninsured balances \| $					$ 0
Number of operation segment \| Segment			1
Deferred offering costs \| $			$ 0	$ 0	0
Uncertain tax positions \| $			$ 0	$ 0	$ 0
Common Stock
Summary of Significant Accounting Policies [Line Items]
Number of shares issued during the period upon conversion of convertible securities			14,456,364
SAFE \| Common Stock \| IPO
Summary of Significant Accounting Policies [Line Items]
Number of common shares on conversion of debt instrument		411,815
Exercise of Outstanding Stock Options
Summary of Significant Accounting Policies [Line Items]
Antidilutive securities excluded from Computation of diluted net loss per common share			2,415,740	1,916,194
Series A Convertible Preferred Stock
Summary of Significant Accounting Policies [Line Items]
Antidilutive securities excluded from Computation of diluted net loss per common share			8,070,027	8,070,027
Number of shares issued during the period upon conversion of convertible securities	8,070,027
Series A Convertible Preferred Stock \| Common Stock
Summary of Significant Accounting Policies [Line Items]
Number of shares issued during the period upon conversion of convertible securities	8,070,027
Series B Convertible Preferred Stock
Summary of Significant Accounting Policies [Line Items]
Antidilutive securities excluded from Computation of diluted net loss per common share			5,489,573	5,489,573
Series B Convertible Preferred Stock \| Common Stock
Summary of Significant Accounting Policies [Line Items]
Number of shares issued during the period upon conversion of convertible securities	6,386,337

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards
Uncertain tax positions	$ 0	$ 0
Uncertain tax positions, accrued interest or penalties	0	0
Federal
Operating Loss Carryforwards
Net operating loss carryforwards	70,200,000	48,600,000
Tax credit carryforward	$ 7,100,000	3,900,000
Tax credit carryforward, expiration year	2041
State and Local
Operating Loss Carryforwards
Net operating loss carryforwards	$ 139,300,000	$ 109,300,000
Net operating loss carryforwards, expiration year	2040

Convertible Preferred Stock - Additional Information (Details)		12 Months Ended	27 Months Ended	36 Months Ended
	Nov. 07, 2023 USD ($) $ / shares shares	Dec. 31, 2023 $ / shares shares	Nov. 07, 2023 $ / shares shares	Nov. 07, 2023 USD ($) Director $ / shares shares	Dec. 31, 2022 $ / shares shares
Class of Stock [Line Items]
Convertible preferred stock, shares authorized	143,653,546		143,653,546	143,653,546	143,653,546
Gross proceeds \| $	$ 100,300,000
Qualified IPO minimum number of directors approval required \| Director				2
Convertible preferred stock, shares outstanding	143,653,545		143,653,545	143,653,545	143,653,545
Common stock issuable upon conversion	13,559,600		13,559,600	13,559,600	13,559,600
Series A and B Convertible Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares authorized	143,653,546		143,653,546	143,653,546
Convertible preferred stock, par value \| $ / shares	$ 0.0001		$ 0.0001	$ 0.0001
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares authorized	85,495,722	0	85,495,722	85,495,722	85,495,722
Convertible preferred stock, par value \| $ / shares		$ 0			$ 0.0001
Percentage of dividends per share			8.00%
Liquidation preference \| $ / shares	$ 10.59423		$ 10.59423	$ 10.59423
Convertible preferred stock, shares outstanding	85,495,722	0	85,495,722	85,495,722	85,495,722
Common stock issuable upon conversion	8,070,027		8,070,027	8,070,027	8,070,027
Number of shares issued during the period upon conversion of convertible securities	8,070,027
Series B Convertible Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares authorized	58,157,824	0	58,157,824	58,157,824	58,157,824
Convertible preferred stock, par value \| $ / shares		$ 0			$ 0.0001
Percentage of dividends per share			8.00%
Liquidation preference \| $ / shares	$ 18.227267		$ 18.227267	$ 18.227267
Convertible preferred stock, shares outstanding	58,157,823	0	58,157,823	58,157,823	58,157,823
Common stock issuable upon conversion	5,489,573		5,489,573	5,489,573	5,489,573
Series B Convertible Preferred Stock \| Antidilutive Securities [Member]
Class of Stock [Line Items]
Common stock issuable upon conversion	6,386,337		6,386,337	6,386,337
Number of shares issued during the period upon conversion of convertible securities	896,764
Common Stock
Class of Stock [Line Items]
Number of shares issued during the period upon conversion of convertible securities		14,456,364
Common Stock \| Series A Convertible Preferred Stock
Class of Stock [Line Items]
Number of shares issued during the period upon conversion of convertible securities	8,070,027
Common Stock \| Series B Convertible Preferred Stock
Class of Stock [Line Items]
Number of shares issued during the period upon conversion of convertible securities	6,386,337
Maximum \| Series B Convertible Preferred Stock
Class of Stock [Line Items]
Percentage of outstanding shares for deemed liquidation			64.00%
Maximum \| Series A Liquidation Preference
Class of Stock [Line Items]
Liquidation preference \| $ / shares	$ 31.782691		$ 31.782691	$ 31.782691
Maximum \| Series B Liquidation Preference
Class of Stock [Line Items]
Liquidation preference \| $ / shares	54.681802		54.681802	54.681802
Maximum \| Common Stock
Class of Stock [Line Items]
Sale of shares of common stock \| $ / shares	$ 22.784057		$ 22.784057	$ 22.784057
Gross proceeds \| $				$ 75,000,000

Stock-Based Compensation - Summary of Following Assumptions Presented on Weighted Average Basis (Details) - Employee Stock Option Member	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	3.43%	2.76%
Expected term (in years)	5 years 9 months 10 days	6 years 10 days
Expected volatility	67.59%	73.36%
Expected dividend yield	0.00%	0.00%

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Leases - Reconciliation of Remaining Undiscounted Contractual Rent Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
2024	$ 2,112
2025	2,152
2026	2,206
2027	2,261
2028	2,318
Thereafter	1,372
Total lease payments	12,421
Less: present value adjustment	(2,548)
Total operating lease liabilities	9,873
Included in the consolidated balance sheet:
Current portion of lease liabilities—operating	2,087	$ 2,287
Non-current portion of lease liabilities—operating	$ 7,786	$ 9,000

Capital Stock (Tables)

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

Schedule of Common Stock Reserved for Future Issuances

The Company had reserved the following number of shares of common stock for the exercise of outstanding stock options, future issuance of stock-based awards, and conversion of outstanding shares of convertible preferred stock:


	December 31, 2023		December 31, 2022
Shares of series A convertible preferred stock		—		8,070,027
Shares of series B convertible preferred stock		—		5,489,573
Options to purchase shares of common stock under the 2021 Plan and 2023 Plan		2,415,740		1,916,194
Shares available for issuance under the 2021 Plan and 2023 Plan		2,293,816		1,000,519
Shares available for issuance under the 2023 ESPP		238,600		—

Total shares of common stock reserved for future issuance		4,948,156		16,476,313

Fair Value Measurements - Summary of Estimated Fair Value Assumptions (Details) - IPO - Black-Scholes Model	Nov. 07, 2023 USD ($)
Stock Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	11
Exercise Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1,100
Weighted Average Risk-free Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	553
Expected Term
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.0008
Expected Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.6588
Expected Dividend Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0

Net Loss Per Share - Schedule of Net Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net loss	$ (66,394)	$ (59,277)
Denominator:
Weighted-average common shares outstanding, basic	5,354,368	1,630,348
Weighted-average common shares outstanding, diluted	5,354,368	1,630,348
Net loss per share attributable to common stockholders, basic	$ (12.4)	$ (36.36)
Net loss per share attributable to common stockholders, diluted	$ (12.4)	$ (36.36)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
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-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

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+ Details

- Definition

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

+ References

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+ Details

Accrued Expenses and Other Current Liabilities

12 Months Ended

Dec. 31, 2023

Accrued Liabilities and Other Liabilities [Abstract]

Accrued Expenses and Other Current Liabilities

4. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following:


	December 31, 2023		December 31, 2022
Accrued research and development expenses	$	6,384	$	4,755
Accrued payroll expenses		242		796
Accrued professional fees		1,078		629
Other current liabilities		169		240

Total accrued expenses and other current liabilities	$	7,873	$	6,420

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events Subsequent events have been evaluated through March 11, 2024, which is the date that these consolidated financial statements were issued and were available to be issued. On March 11, 2024, the Company entered into a common stock purchase agreement to issue and sell an aggregate of 6,278,905 shares of its common stock at a price of $15.13 per share, in a private placement. The Company anticipates the gross proceeds from the private placement to be approximately $95.0 million, before deducting any offering related expenses. The private placement financing is expected to close on March 13, 2024, subject to customary closing conditions.

Convertible Safe Note	12 Months Ended
Convertible Safe Note	Dec. 31, 2023
Debt Disclosure [Abstract]
Convertible Safe Note	6. Convertible SAFE Note On August 24, 2023, the Company entered into a convertible SAFE Note with Sarepta Therapeutics, Inc. (the “Investor”) in a principal amount of $4.0 million bearing simple interest at an annual rate of 10% to be repaid (the “Cash-Out Amount”) after one year in the absence of the occurrence of certain settlement events, including upon a qualified preferred stock equity financing, a public offering or a Special Purpose Acquisition Company (“SPAC”) transaction, a change of control, or dissolution. The convertible SAFE Note was accounted for as a liability in accordance with the provisions of ASC Topic 480, Distinguishing Liabilities from Equity , which was initially and subsequently measured at fair value with changes in fair value recognized in earnings (see Note 3). Upon a qualified equity financing event, the convertible SAFE Note would have automatically converted into a number of shares of corresponding preferred stock based on a certain discount to the price of such preferred stock issued to the other investors applied to the then-current Cash-Out Amount. Upon the effective date of an IPO or a direct listing, or immediately prior to the closing of a SPAC transaction, the convertible SAFE Note would have automatically converted, and did automatically convert upon the effectiveness of the Company’s IPO registration statement on November 2, 2023, into a number of shares of common stock based on a certain discount to the public offering price of such common stock applied to the then-current Cash-Out Amount (see Note 8). Upon a change of control, the Investor would have been entitled to receive the greater of (i) an amount equal to a certain premium applied to the then-current Cash-Out Amount, or (ii) the amount that would have been payable on the number of shares of the senior-most series of the Company’s preferred stock after applying a certain discount to the original issue price of such senior-most preferred stock together with a certain premium applied to the then-current Cash-Out Amount (the greater of (i) and (ii), the “Conversion Amount”). Upon the one-year maturity of the convertible SAFE Note, or upon dissolution of the Company, the Investor was to be paid an amount equal to the Cash-Out Amount. Upon the event of a change of control or dissolution, the Investor’s right to receive its Cash-Out Amount or its Conversion Amount would have been junior to payment of outstanding indebtedness and creditor claims, on par with payments for the Company’s most senior series of preferred stock or other SAFE note holders, if any, and senior to payments for the Company’s common stock and any other series or class of stock. The convertible SAFE Note did not maintain any voting rights. In connection with the convertible SAFE Note, the Company incurred issuance costs of $0.1 million that were recorded as a discount to the liability balance and amortized to interest expense over the term of the convertible SAFE Note. As of November 2, 2023, the estimated fair value of the convertible SAFE Note, gross of unamortized discount, increased by $0.5 million to $4.5 million (see Note 3), and the corresponding carrying value was $4.4 million, net of unamortized discount, which automatically converted into 411,815 shares of the Company’s common stock upon the declaration of effectiveness of the Company’s IPO registration statement on November 2, 2023 (see Note 8).

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

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-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
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-Topic 235
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+ Details

Income Taxes - Schedule of Reconciliation of Statutory Income Tax Rate to Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Federal statutory rate	21.00%	21.00%
State Taxes, net of federal benefit	10.80%	11.77%
Change in valuation allowance	(36.12%)	(36.43%)
Permanent differences	(0.36%)	0.08%
Tax credits	4.80%	3.66%
Other	(0.12%)	(0.08%)
Effective income tax rate	0.00%	0.00%

Fair Value Measurements - Schedule of Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value Recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 102,484	$ 74,802
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	102,484	74,802
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	102,484	74,802
Level 1 [Member] \| Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 102,484	$ 74,802

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Use of Estimates

—The preparation of the financial statements in accordance with U.S. 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 income and expense during the reporting period. The most significant estimates relate to the accruals of research and development costs, including accruals of research contract costs, and assump

tions use

d to estimate the fair value of the Company’s stock option awards and, prior to its IPO, to determine the fair value of its common stock. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, and makes adjustments when facts and circumstances dictate. These estimates are based on information available as of the date of the financial statements; therefore, actual results could differ from those estimates.

Cash and Cash Equivalents and Restricted Cash

—The Company considers all highly liquid investments with a remaining maturity when purchased of three months or less to be cash equivalents. Cash equivalents are reported at carrying values, which approximated their fair values and are based on quoted prices in active markets for identical securities. At December 31, 2023 and December 31, 2022, the Company’s cash equivalents were held in a money market fund. As of December 31, 2023 and 2022, cash consists of cash on deposit with U.S. banks denominated in U.S. dollars, and restricted cash consists of cash on deposit with U.S. banks denominated in U.S. dollars for which its use is restricted and is classified

as non-current in

the Company’s consolidated balance sheet according to the timing of maturity, and is associated with collateral for letters of credit issued in connection with its operating

lease right-of-use and

finance

lease right-of-use assets

and corresponding lease liabilities. Cash is stated at its historical carrying amount, which approximates fair value due to its short-term nature. Restricted cash is stated at its historical carrying amount, which approximates fair value. The Company regularly maintains cash and cash equivalents and restricted cash balances with financial institutions that exceed Federal Deposit Insurance Corporation insurance limits.

Net Loss per Share—

The Company follows the

two-class

method when computing net income (loss) per common share as the Company has issued shares that meet the definition of participating securities. The

two-class

method determines net income (loss) per common share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The

two-class

method requires income (loss) available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. The Company considers its convertible preferred stock to be participating securities as, in the event a dividend is paid on common stock, the

holders

of these securities would be entitled to receive dividends on a basis consistent with the common stockholders. The Company also considers the shares issued upon the early exercise of stock options that are subject to repurchase to be participating securities because holders of such shares have

non-forfeitable

dividend rights in the event a dividend is paid on common stock. There is no allocation required under the

two-class

method during periods of loss since the participating securities do not have a contractual obligation to share in the losses of the Company.

Basic net income (loss) per common share is computed by dividing the net income (loss) per common share by the weighted-average number of common shares outstanding for the period. Diluted net income (loss) per common share is computed by adjusting net income (loss) to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per common share is computed by dividing the diluted net loss by the weighted-average number of common shares outstanding for the period, including potential dilutive common shares. For the purposes of this calculation, shares of convertible preferred stock are considered potential dilutive common shares.

In periods in which the Company reported a net loss, diluted net loss per common share was the same as basic net loss per common share since dilutive common shares were not assumed to have been issued if their effect was anti-dilutive. During (i) the year ended December 31, 2023, potential common shares related to the conversion of the convertible SAFE Note, which converted into 411,815 common shares in connection with the Company’s IPO on November 2, 2023 (see Note 6), (ii) the years ended December 31, 2023 and December 31, 2022, 8,070,027 potential common shares related to the conversion of series A convertible preferred stock and 5,489,573 potential common shares related to the conversion of series B convertible preferred stock, which converted into 8,070,027 common shares and 6,386,337 common shares, respectively, in connection with the Company’s IPO on November 7, 2023 (see Note 7), and (iii) the years ended December 31, 2023 and December 31, 2022, 2,415,740 and 1,916,194 potential common shares, respectively, related to the exercise of outstanding stock options (see No

te 9), were excluded from the computation of diluted net loss per common share because including them would have had an anti-dilutive ef

fect as the Company reported net losses for those periods.

Deferred Offering Costs

—The Company capitalizes certain legal, accounting and other third-party fees that are directly associated with equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded as a reduction of the proceeds from the offering, either as a reduction of the carrying value of preferred stock or in stockholders’ equity (deficit) as a reduction of additional capital generated as a result of the offering. Should the equity financing be abandoned, the deferred offering costs would be expensed immediately as a charge to operating

expe

nses in the consolidated statement of operations and comprehensive loss. The Company had no deferred offering costs recorded as of December 31, 2023 or December 31, 2022.

Accounts Receivable and Allowance for Doubtful Accounts

—Accounts receivable are recorded net of allowances for doubtful accounts. The Company does not have any accounts receivable but in certain cases had a grant receivable balance. For the Company to be in a receivable position related to grants, the cumulative total spend on grants must exceed the cu

mulative

cash receipts if there remains additional award money to be collected.

Classification of Convertible Preferred Stock

—Until the closing of the Company’s IPO on November 7, 2023, the holders of the series A and series B convertible preferred stock had certain liquidation rights in the event of a

deemed liquidation that, in certain situations, were not solely within the control of the Company and could have called for the redemption of the then outstanding series A convertible preferred stock. Therefore, the series A and series B convertible preferre

d stock

were classified outside of the stockholders’ equity (deficit) on the Company’s consolidated balance sheets. The carrying value of the convertible preferred stock was not subsequently remeasured to the redemption value until the contingent redemption events were considered to be probable of occurring.

Grant Revenue

—Grants received are recognized as grant revenue in the statements of operations as and when they are earned for the specific research and development projects for which these grants are designated. Grant paym

ents r

eceived in excess of grant revenue earned are recognized as deferred grant revenue on the Company’s consolidated balance sheet and grant revenue earned in excess of grant payments received is recognized as grant receivable on the Company’s consolidated balance sheet.

Research and Development

—Research and development costs are expensed as incurred. Research and development expenses consist of costs incurred to discover, research, and develop drug candidates, including personnel expenses, allocated facility-related and depreciation expenses, and third-party license fees. Costs incurred to obtain technology licenses are charged immediately to research and development expense if the technology licensed has not reached technological feasibility and has no alternative future use.

General and Administrative—

General and administrative expenses consist primarily of the cost of employees to engage in corporate functions, such as finance and accounting, information technology, human resources, and legal and executive

manage

ment. General and administrative expenses also include rent occupancy costs, office expenses, depreciation and amortization, other general overhead costs, insurance premiums, professional service fees, and costs related to regulatory and litigation matters.

Stock Based Compensation Expense—

The Company accounts for stock-based payment awards granted to employees

and non-employees as

stock-based compensation expense at fair value. The Company’s stock-based payments include stock options and grants of common stock, including common stock subject to vesting. The measurement date for employee awards is the date of grant, and stock-based compensation costs are recognized as expense over the employees’ requisite service period, which is the vesting period, on a straight-line basis. The measurement date

for non-employee awards

is the date of grant without changes in the fair value of the award. Stock-based compensation costs

for non-employees are

recognized as expense over the vesting period on a straight-line basis. Stock-based compensation expense is classified in the accompanying statement of operations based on the function to which the related services are provided. As the Company is per

mitte

d to repurchase shares legally issued for unvested stock options exercised at their exercise price, (i) cash received for unvested stock options exercised is recorded as a deposit liability as a reclassification from

additional paid-in capital

in the Company’s consolidated balance sheet, which is relieved to

additional paid-in capital

as such awards vest, (ii) stock based compensation expense is recognized over the requisite service period for each such award, and (iii) the amount and number of shares of common stock outstanding in the Company’s consolidated balance sheet and consolidated statement of convertible preferred stock and stockholders’ equity (deficit) are reduced until such awards vest. The Company recognizes stock-based compensation expense for the portion of awards that have vested. Forfeitures are recorded as they occur. The Company recognizes the cumulative effect of changes in the probability outcomes in the period in which the changes occur.

The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The Company has historically been a private company and lacks company-specific historical and implied volatility information for stock options granted prior to the Company’s IPO. Therefore, the Company estimated its expected stock volatility entirely based on the historical volatility of a publicly traded set of peer companies for stock options granted prior to its IPO, and estimates its expected stock price volatility primarily based on the historical volatility of a publicly traded set of peer companies for stock options granted since its IPO, each for a period equal to the expected life of the stock options granted, and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. The expected term of the

Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. The expected dividend yield is zero as the Company has never paid cash dividends on its common stock and does not expect to pay any cash dividends in the foreseeable future.

Income Taxes

—Prior to November 20, 2020, the Company was an LLC entity and elected to be treated under the Partnership provisions of the Internal Revenue Code. Accordingly, the LLC entity was not viewed as

a tax-paying entity

in any jurisdiction and all income and deductions of the LLC entity flowed through to the individual members and therefore no income tax

es were

recorded by the Company. On November 20, 2020, the Company converted to a C Corporation.

The Company accounts for income taxes under the asset and liability method pursuant to ASC 740,

Income Taxes

. Under this method, the Company recognizes deferred tax assets and liabilities for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is recorded for deferred tax assets if it is more likely than not that some portion or all of the deferred tax assets will not be realized based on all available positive and negative evidence. Under the Tax Cuts and Jobs Act of 2017, the Company is required to capitalize, and subsequently amortize, research and development expenses over five years for research activities conducted in the U.S. and over fifteen years for research activities conducted outside of the U.S commencing in 2022. The capitalization of research and development expenses during the year resulted in a decrease to our operating loss generation during the years ended December 31, 2023 and December 31, 2022 as compared to prior periods (see Note 11). As of December 31, 2023 and December 31, 2022, the Company continues to maintain a full valuation allowance against its deferred tax assets.

The Company recognizes a tax benefit only if it is more likely than not the tax position will be sustained on examination by the local taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such positions are then measured based on the largest benefit greater than 50% likelihood of being realized upon settlement with the related tax authority. The changes in recognition or measurement are reflected in the period in which the change in judgment occurs. As of December 31, 2023 and December 31, 2022, the Company has not identified any uncertain tax positions.

The Company records interest and penalties related to uncertain tax positions in the provision for income taxes.

Fair Value Measurements

—Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The three levels of inputs that may be used to measure fair value are as follows:

Level 1

—Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

Level 2

—Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities 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 related assets or liabilities.

Level 3

—Inputs are unobservable inputs for the asset or liability.

Concentrations of Credit Risk

—Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and restricted cash. The Company’s cash and

restricted cash balances exceed Federal Deposit Insurance Corporation insurance limits, and the Company’s cash equivalents consist of investments in a U.S. government money market fund. The Company’s cash and cash equivalents and restricted cash is held with large financial institutions that management believes to be of high credit quality. To date, the Company has not recognized any losses caused by uninsured balances.

Segment Information

—The Company manages its operations as a

single

segment for the purposes of assessing performance and allocating resources. The Company is focused on preclinical and clinical stage gene therapies, and speci

ficall

y on hereditary and acquired diseases of high unmet need. The Company’s chief operating decision maker (“CODM”) reviews the Company’s financial informati

on on

an aggregated basis for purposes of assessing performance and allocating resources. All assets are held in the United States. The Company has not earned any product revenue through December 31, 2023.

Property and Equipment

—Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization is recognized using the straight-line method over the estimated useful life of each asset. Such costs are periodically reviewed for recoverability when impairment indicators are present. Such indicators include, among other factors, unused capacity, market value declines, and technology obsolescence. Recorded values of asset groups of equipment that are not expected to be recovered through undiscounted future net cash flows are written down to current fair value, which generally is determined from estimated discounted future net cash flows (assets held for use) or net realizable value (assets held for sale).

Costs for capital assets not yet placed into service are capitalized

as construction-in-progress and

depreciated once placed into service. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation and amortization are removed from the accounts and any resulting gain or loss is included in loss from operations. Expenditures for repairs and maintenance that do no improve or extend the life of the respective assets are charged to expense in the period incurred. See Note 5 for information regarding the Company’s capitalized operating and finance

lease right-of-use assets.

The following is the summary of property and equipment and related accumulated depreciation as of December 31, 2023, and December 31, 2022 (years not stated in thousands):


	Useful Life		December 31, 2023			December 31, 2022
Internal use software		3 years	$	296		$	245
Furniture and fixtures		5 years		380			375
Lab equipment		7 years		514			279
Leasehold improvements		7 years		247			232

Total property and equipment				1,437			1,131
Less: accumulated depreciation and amortization				(381	)		(133	)

Total property and equipment, net			$	1,056		$	998

Leases

—In accordance with ASC 842,

Leases

, the Company determines if an arrangement is or contains a lease at inception. A contract is or contains a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. The Company classifies leases at the lease commencement date as operating or finance leases and records

a right-of-use asset

and a lease liability on the consolidated balance sheet for all leases with an initial lease term of greater than 12 months. Leases with an initial term of 12 months or less are not recorded in the balance sheet, but payments are recognized as expense on a straight-line basis over the lease term. The Company has elected not to recognize leases with terms of 12 months or less.

A lease qualifies as a finance lease if any of the following criteria are met at the inception of the lease: (i) there is a transfer of ownership of the leased asset to the Company by the end of the lease term, (ii) the Company holds

an option to purchase the leased asset that it is reasonably certain to exercise, (iii) the lease term is for a major part of the remaining economic life of the leased asset, (iv) the present value of the sum of lease payments equals or exceeds substantially all of the fair value of the leased asset, or (v) the nature of the leased asset is specialized to the point that it is expected to provide the lessor no alternative use at the end of the lease term. All other leases are recorded as operating leases.

The Company enters into contracts that contain both lease

and non-lease components. Non-lease components

may include maintenance, utilities, and other operating costs. The Company combines the lease

and non-lease components

of fixed costs in its lease arrangements as a single lease component. Variable costs, such as utilities or maintenance costs, are not included in the measurement

of right-of-use assets

and lease liabilities, but rather are expensed when the event determining the amount of variable consideration to be paid occurs.

Operating

lease right-of-use assets

and lease liabilities are recognized at the lease commencement date based on the present value of the lease payments over the lease term using the discount rate implicit in the lease. If the implicit rate is not readily determinable, the Company utilizes an estimate of its incremental borrowing rate based upon the available information at the operating lease commencement date. Operating lease

right-of-use

assets are further adjusted for prepaid or accrued lease payments. Operating lease payments are expensed using the straight-line method as an operating expense over the lease term. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Finance

lease right-of-use assets

and lease liabilities are recognized upon receipt of the assets based on their fair values, and are amortized to depreciation expense using the straight-line method over the estimated useful lives of the related assets. Finance lease liability payments are bifurcated into (i) a portion that is recorded as interest expense and (ii) a portion that reduces the finance liability associated with the lease, according to the interest rates implicit in the leases.

Certain of the Company’s leases include options to extend or terminate the lease. The amounts determined for the

Company’s right-of-use assets

and lease liabilities generally do not assume that renewal options or early-termination provisions, if any, are exercised, unless it is reasonably certain that the Company will exercise such options.

Recent Accounting Pronouncements Not Yet Adopted—

In December 2023, the FASB issued ASU No.

2023-09,

Income Taxes

(Topic 740). ASU

No. 2023-09

requires disaggregation of the effective tax rate reconciliation into standard categories, enhances disclosure of income taxes paid, and modifies other income

tax-related

disclosures. ASU

No. 2023-09

will be effective for t

he Co

mpany starting in annual periods in 2025, with early adoption permitted. The Company is currently assessing the impact of adopting this guidance on its consolidated financial statements.

In November 2023, the FASB issued ASU No.

2023-07,

Segment Reporting—Improving Reportable Segment Disclosures

(Topic 280). ASU

No. 2023-07

requires disclosures to include significant segment expenses that are regularly provided to the CODM, a description of other segment items by reportable segment, and any additional measures of a segment’s profit or loss used by the CODM when deciding how to allocate resources. ASU

No. 2023-07

also requires all annual disclosures currently required by Topic 280 to be included in interim periods. ASU

No. 2023-07

is effective for the Company starting in annual periods in 2024 and interim periods in 2025, with early adoption permitted and retrospective application required to all prior periods presented in the financial statements. The Company is currently assessing the impact of adopting this guidance on its consolidated financial statements but does not expect it to have a material impact.

Fair Value Measurements - Schedule of Rollforward of Changes in Fair Value of Financial Liabilities (Details) - Fair Value, Inputs, Level 3 [Member] - Convertible SAFE Note [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	$ 0
Convertible SAFE Note issuance at August 24, 2023	4,000
Change in estimated fair value since issuance	$ 530
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Gain (Loss) on Fair Value Hedges Recognized in Earnings
Conversion of SAFE Note into common stock in connection with initial public offering	$ (4,530)
Ending balance	$ 0

Leases - Components of Operating Lease (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating lease expense	$ 2,147	$ 1,610
Variable lease expense	355	185
Total operating lease expense	2,502	1,795
Cash paid for amounts included in the measurement of lease liabilities, included in operating cash flows	$ 2,294	$ 1,032

Fair Value Measurements - Schedule of Significant Unobservable Inputs Used In the Valuation Model to Estimate Fair Value (Details) - Fair Value, Inputs, Level 3 [Member] - Convertible SAFE Note [Member]	2 Months Ended
	Nov. 02, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Probability of meeting change in control event	5.00%
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Probability of meeting qualified equity financing event	10.00%
Probability of meeting public offering event	75.00%
Time until qualified equity financing event (in years)	2 months 1 day
Time until public offering event (in years)	29 days
Time until change in control event (in years)	6 months
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Probability of meeting qualified equity financing event	20.00%
Probability of meeting public offering event	85.00%
Time until qualified equity financing event (in years)	3 months 7 days
Time until public offering event (in years)	2 months 8 days
Time until change in control event (in years)	7 months 6 days

Description of Business and Basis of Presentation	12 Months Ended
Description of Business and Basis of Presentation	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	1. Description of Business and Basis of Presentation Description of Business —Lexeo Therapeutics, Inc. (the “Company”), together with its consolidated subsidiary, Stelios Therapeutics Inc. (“Stelios”), until such subsidiary was merged into the Company on December 15, 2022 and ceased to exist, is a clinical stage genetic medicine company with a focus on hereditary and acquired diseases of high unmet need. The Company’s investigational therapies have the potential to offer gene therapy-based treatments to address many diseases that have eluded today’s existing drug delivery platforms. The Company utilizes adeno-associated viruses (“AAV”) that have been engineered to transfer genes to patients. The Company’s therapeutic investigational treatments include gene therapies primarily in the early clinical and late pre-clinical stages of research and development. The Company is located in New York, NY and was first formed on February 17, 2017, as an LLC under the laws of the State of Delaware under the legal name Lexeo Therapeutics, LLC. The Company filed and executed a certificate of conversion to corporation on November 20, 2020, to convert the LLC to Lexeo Therapeutics, Inc, a Delaware corporation. All of the Company’s tangible assets are held in the United States (“U.S.”). Basis of Presentation and Principles of Consolidation —The accompanying consolidated financial statements reflect the operations of the Company and its wholly-owned subsidiary that have been prepared in conformity with generally accepted accounting principles in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). The accounts of the wholly owned subsidiary are included in these consolidated financial statements and accompanying notes, and the Company has no unconsolidated subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. A 10.594230-for-1 reverse share split of the Company’s series A convertible preferred stock, series B convertible preferred stock, common stock, and options to purchase common stock under the Company’s 2021 Equity Incentive Plan, as well as corresponding adjustments in the respective conversion prices of the series A convertible preferred stock and series B convertible preferred stock, was effected on October 13, 2023 as approved by the Company’s board of directors (the “Board of Directors”) and its shareholders (the “Stock Split”). The Stock Split reduced the number of shares of the Company’s authorized, issued and outstanding common stock, as well as the numbers of shares reserved and available for future issuance and underlying outstanding options to purchase common stock under its 2021 Equity Incentive Plan, on a 10.594230-for-1 basis. As such, all references to series A convertible preferred stock and series B convertible preferred stock conversion ratios, conversion share and per share amounts, and post- conversion share and per share amounts, as well as common stock option, option per common share, common share and common per share amounts, in these consolidated financial statements and accompanying notes have been retroactively restated to reflect the Stock Split and the Stock Split’s effect on the respective series A convertible preferred stock and series B convertible preferred stock conversion ratios for each series of convertible preferred stock. The Stock Split did not affect the par values per share. Need for Additional Capital —Since inception, the Company has incurred net losses and negative cash flows from operations, including net losses of $66.4 million and $59.3 million during the years ended December 31, 2023 and December 31, 2022, respectively. As of December 31, 2023, the Company had cash and cash equivalents of $121.5 million and an accumulated deficit of $181.8 million and expects to incur substantial operating losses and negative cash flows from operations for the foreseeable future. During the years ended December 31, 2021 and December 31, 2020, the Company raised aggregate total net proceeds of $185.0 million in connection with the issuance of series A and series B convertible preferred stock. During the year ended December 31, 2023 the Company raised $100.3 million of total net proceeds in connection with the closing of its planned initial public offering (“IPO”) on November 7, 2023 and subsequent partial exercise of the underwriters’ option to purchase additional shares (see Note 8), as well $3.9 million of net proceeds from the issuance of a convertible Simple Agreement for Future Equity (“SAFE”) note (the “SAFE Note”) in August 2023 (see Note 6). Management estimates that the Company’s current cash and cash equivalents balance is sufficient to fund its operations for at least 12 months from the issuance date of these consolidated financial statements. If the Company is unable to obtain additional funding before achieving sufficient profitability and positive cash flows from operations, if ever, the Company will be forced to delay, reduce or eliminate some or all of its research and development programs, which could adversely affect its business prospects, or the Company may be unable to continue operations. Although management continues to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms accep table to the Company to fund continuing operations, if at all. Risks and Uncertainties —The Company is subject to risks and uncertainties common to early-stage companies in the biopharmaceutical industry, including, but not limited to, successful discovery and development of its product candidates, development by competitors of new technological innovations, dependence on key personnel, the ability to attract and retain qualified employees, protection of proprietary technology, compliance with governmental regulations, the ability to secure additional capital to fund operations, and commercial success of its product candidates. Any of the Company’s current product candidates and future product candidates that it may develop will require extensive nonclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel, infrastructure, and extensive compliance- reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Revenue
Total revenue		$ 654
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	Grant [Member]	Grant [Member]
Operating expenses
Research and development expenses	$ 53,130	$ 49,162
General and administrative	15,383	12,001
Total operating expenses	68,513	61,163
Operating loss	(68,513)	(60,509)
Other income and expense
Loss on fair value adjustment to convertible SAFE Note	(530)
Other income (expense), net	(13)	(2)
Interest expense	(205)	(91)
Interest income	2,867	1,325
Total other income and expense	2,119	1,232
Loss from operations before income taxes	(66,394)	(59,277)
Net loss and comprehensive loss	$ (66,394)	$ (59,277)
Net loss per common share, basic	$ (12.4)	$ (36.36)
Net loss per common share, diluted	$ (12.4)	$ (36.36)
Weighted average number of shares outstanding used in computation of net loss per common share, basic	5,354,368	1,630,348
Weighted average number of shares outstanding used in computation of net loss per common share, diluted	5,354,368	1,630,348

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Reconciliation of Statutory Income Tax Rate to Effective Income Tax Rate

A reconciliation of the Company’s statutory income tax rate to the Company’s effective income tax rate is as follows for the years ended December 31, 2023, and 2022:


	Year Ended December 31,
	2023			2022
Federal statutory rate		21.00	%		21.00	%
State Taxes, net of federal benefit		10.80			11.77
Change in valuation allowance		(36.12	)		(36.43	)
Permanent differences		(0.36	)		0.08
Tax credits		4.80			3.66
Other		(0.12	)		(0.08	)

Effective income tax rate		0.00	%		0.00	%

Schedule of Components of Deferred Tax Assets and Liabilities

The principal components of the Company’s deferred tax assets and liabilities at December 31, 2023 and 2022 are as follows:


	Year Ended December 31,
	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	21,904		$	15,379
Tax credits		7,070			3,883
Intangibles		4,241			3,407
Capitalized R&D expenses		25,127			13,823
Lease liabilities		3,244			4,423
Other deferred tax assets		3,753			1,309

Total deferred tax assets		65,339			42,224

Valuation allowance		(61,974	)		(37,992	)

Net deferred tax assets	$	3,365		$	4,232


	Year Ended December 31,
	2023			2022
Deferred tax liabilities:
Right of use asset	$	(3,102	)	$	(4,214	)
Other deferred tax liabilities		(263	)		(18	)

Total deferred tax liabilities		(3,365	)		(4,232	)

Net deferred tax assets (liabilities)	$	—		$	—

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value, Option, Quantitative Disclosures [Line Items]

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

The following table presents information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicates the level of the fair value hierarchy utilized to determine such fair values:


	As of December 31, 2023:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents (money market)	$	102,484	$	—	$	—	$	102,484

	$	102,484	$	—	$	—	$	102,484


	As of December 31, 2022:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents (money market)	$	74,802	$	—	$	—	$	74,802

	$	74,802	$	—	$	—	$	74,802

Schedule of Rollforward of Changes in Fair Value of Financial Liabilities

The following table sets forth a roll forward of changes in the fair value of financial liabilities, gross of unamortized discount, classified as Level 3 in the fair value hierarchy:


	Convertible SAFE Note, gross
Beginning balance at December 31, 2022	$	—
Convertible SAFE Note issuance at August 24, 2023		4,000
Change in estimated fair value since issuance		530
Conversion of SAFE Note into common stock in connection with initial public offering		(4,530	)

Ending balance at December 31, 2023	$	—

Schedule of Significant Unobservable Inputs Used in Valuation Model to Estimate Fair Value

The ranges of the significant unobservable inputs used in the valuation model to estimate the fair value of the Company’s convertible SAFE Note that was categorized within Level 3 of the fair value hierarchy as of August 24, 2023 (issuance) until November 2, 2023 (settlement) were as follows (not stated in thousands):


Probability of meeting qualified equity financing event	10.0% - 20.0	%
Probability of meeting public offering event	75.0% - 85.0	%
Probability of meeting change in control event	5	%
Time until qualified equity financing event (in years)	0.17 - 0.27
Time until public offering event (in years)	0.08 - 0.19
Time until change in control event (in years)	0.50 - 0.60

IPO

Fair Value, Option, Quantitative Disclosures [Line Items]

Summary of Estimated Fair Value Assumptions

The total grant date fair value of this option of approximately $1.2 million, or $0.85 per share, was recorded as an offset to additional

paid-in

capital and was estimated using a Black-Scholes model incorporating the following assumptions (not stated in thousands):


Stock price	$	11.00
Exercise price	$	11.00
Weighted average risk-free interest rate		5.53	%
Expected term (in years)		0.08
Expected volatility		65.88	%
Expected dividend yield		0.00	%

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accrued Liabilities and Other Liabilities [Abstract]
Accrued research and development expenses	$ 6,384	$ 4,755
Accrued payroll expenses	242	796
Accrued professional fees	1,078	629
Other current liabilities	169	240
Total accrued expenses and other current liabilities	$ 7,873	$ 6,420

Leases

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Leases

5. Leases

Operating Lease

Right-of-Use

Asset

In January 2022, the Company entered into a lease agreement for an office facility and laboratory space in New York, New York that commenced in April 2022 and ends in July 2029 with an additional five-year option to extend the lease beyond July 2029 at the then-prevailing effective market rental rate. Upon commencement of this lease, the Company recorded operating lease

right-of-use

assets and operating lease liabilities of $11.6 million based on the present value of payments over the lease term using an estimated incremental borrowing rate of 8.53% in accordance with the provisions of ASC 842. In connection with the Company’s lease of office space and laboratory space, the Company provided a security deposit to the landlord in the form of a letter of credit totaling $1.2 million. The cash collateralizing the letter of credit was included in long-term restricted cash in the Company’s consolidated balance sheets as of December 31, 2023, and December 31, 2022. This lease was classified as an operating lease in accordance with the provisions of ASC 842. The Company did not recognize any

right-of-use

assets and lease liabilities associated with the potential option to renew or extend. The Company’s operating lease agreement does not contain any significant residual value guarantees or restrictive covenants.

The remaining lease terms and payment terms as of December 31, 2023 and December 31, 2022 were 5.6 years and 6.6 years, respectively. The components of this operating lease were as follows:


	Year Ended December 31,
	2023		2022
Operating lease expense	$	2,147	$	1,610
Variable lease expense		355		185

Total operating lease expense	$	2,502	$	1,795
Cash paid for amounts included in the measurement of lease liabilities, included in operating cash flows	$	2,294	$	1,032


Year ended December 31	Operating Leases
2024	$	2,112
2025		2,152
2026		2,206
2027		2,261
2028		2,318
Thereafter		1,372

Total lease payments		12,421
Less: present value adjustment		(2,548	)

Total operating lease liabilities	$	9,873

Included in the consolidated balance sheet:
Current portion of lease liabilities—operating		2,087
Non-current portion of lease liabilities—operating		7,786

Total operating lease liabilities	$	9,873

Equipment Finance Leases

Commencing in April 2022, the Company leases certain laboratory equipment under financing arrangements accounted for as finance leases in accordance with the provisions of ASC 842 that are classified in the Company’s consolidated balance sheet as finance lease liabilities with related

right-of-use

assets recorded and depreciated on a straight-line basis over the estimated useful life of 7 years. In connection with the Company’s leases of laboratory equipment, the Company provided a security deposit to the lessor in the form of a letter of credit totaling $1.9 million and assigned all rights and interests in the equipment to the lessor. The cash collateralizing the letter of credit is included in long-term restricted cash in the Company’s consolidated balance sheet as of December 31, 2023. The total gross, accumulated amortization, and net book values of equipment finance lease

right-of-use

assets capitalized under such finance lease arrangements at December 31, 2023 were $2.2 million, $0.5 million and $1.7 million, respectively. Under the terms of the equipment finance lease agreements executed through the issuance of these consolidated financial statements, the principal balances plus interest for the equipment are to be repaid in full after 60 monthly installments following lease commencement, with lease commencement dates ranging from April 1, 2022 to April 1, 2023, annual imputed interest rates ranging from 7.90% to 9.30%, and monthly installment payment amounts ranging from $4,000 to $18,000. The total aggregate monthly installment payment amount was $49,000 for equipment finance lease agreements executed through the issuance date of these consolidated financial statements.

The weighted-average remaining lease payment term, weighted-average remaining amortization term, and weighted-average effective interest rate for the Company’s equipment finance lease agreements as of December 30, 2023 were 3.7 years, 5.7 years, and 8.59%, respectively. The weighted-average remaining lease payment term, weighted-average remaining amortization term, and weighted-average effective interest rate for the Company’s equipment finance lease agreements as of December 31, 2022 were 4.6 years, 6.6 years, and 8.66%, respectively. The components of the equipment finance leases were as follows:


	Year Ended December 31,
	2023		2022
Reduction in the carrying amount of ROU assets, finance	$	306	$	148
Interest on finance lease liabilities		176		77

Total finance lease expense	$	482	$	225
Cash paid for amounts included in the measurement of lease liabilities, included in financing cash flows	$	425	$	163


Year ended December 31	Equipment Finance Leases
2024	$	531
2025		579
2026		579
2027		357
2028		11
Thereafter		—

Total lease payments		2,057
Less: imputed interest		(292	)

Total finance lease liabilities	$	1,765

Included in the consolidated balance sheet:
Current portion of lease liabilities—finance		518
Non-current portion of lease liabilities—finance		1,247

Total finance lease liabilities	$	1,765

Stock-Based Compensation - Summary of Stock-based Compensation Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 3,043	$ 1,781
Research and development expense
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	1,751	966
General and administrative expense
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 1,292	$ 815

Convertible Preferred Stock

12 Months Ended

Dec. 31, 2023

Temporary Equity Disclosure [Abstract]

Convertible Preferred Stock

7. Convertible Preferred Stock

As of December 31, 2022 and until the closing of the Company’s IPO on November 7, 2023, the Company’s certificate of incorporation authorized the Company to issue 143,653,546 shares of series A and series B convertible preferred stock each with a par value of $0.0001 per share. Upon the closing of the Company’s IPO on November 7, 2023, all 85,495,722 outstanding shares of the Company’s series A convertible preferred stock and all 58,157,823 outstanding shares of the Company’s series B convertible preferred stock converted into 8,070,027 shares and 6,386,337 shares of common stock, respectively, including 896,764 shares of common stock issued as a result of series B convertible preferred stock antidilution provisions (see Note 8).

As of December 31, 2022 and until the closing of the Company’s IPO on November 7, 2023, convertible preferred stock consisted of the following:


	Convertible Preferred Stock Authorized		Convertible Preferred Stock Issued and Outstanding		Proceeds Received		Liquidation Preference		Common Stock Issuable Upon Conversion
Series A convertible preferred stock		85,495,722		85,495,722	$	85,496	$	85,496		8,070,027
Series B convertible preferred stock		58,157,824		58,157,823		100,060		100,060		5,489,573

		143,653,546		143,653,545	$	185,556	$	185,556		13,559,600

As of December 31, 2022 and until the closing of the Company’s IPO on November 7, 2023, the rights and privileges of the holders of the convertible preferred stock were as follows:

Voting

—Holders of preferred stock were to vote together with the holders of common stock as a single class and on an as converted to common stock basis.

Dividends

—The holders of shares of series B convertible preferred stock were entitled to receive, as declared by the Company’s Board of Directors, dividends per share at the rate of 8% of the issue price per share of series B

convertible preferred stock, prior and in preference to any declaration or payment of any other dividend (other than dividends on shares of common stock payable in shares of common stock). After payment of dividends to the holders of shares of series B convertible preferred stock, the holders of shares of series A convertible preferred stock were entitled to receive, as declared by the Company’s Board of Directors, dividends per share at the rate of 8% of the issue price per share of series A convertible preferred stock, prior and in preference to any declaration or payment of any other dividend (other than dividends on shares of common stock payable in shares of common stock).

Deemed Liquidation Event

—Each of the following events was to be considered a “Deemed Liquidation Event” unless the holders of a majority of the outstanding shares of preferred stock and the holders of at least 64% of the outstanding shares of series B convertible preferred stock elected otherwise by written notice to be sent to the Company at least five business days prior to the effective date of any such event; (a) a merger or consolidation in which the Company is a constituent party or a subsidiary of the Company was a constituent party and the Company issued shares of its capital stock pursuant to such merger or consolidation, except: any such merger or consolidation involving the Company or a subsidiary in which the shares of capital stock of the Company outstanding immediately prior to such merger or consolidation continued to represent, or were converted into or exchanged for shares of capital stock that represented, immediately following such merger or consolidation, at least a majority by voting power of the capital stock of (1) the surviving or resulting company; or (2) if the surviving or resulting company was a wholly owned subsidiary of another company immediately following such merger or consolidation, the parent company of such surviving or resulting corporation; (b) (1) the sale, lease, transfer, exclusive license or other disposition, in a single transaction or series of related transactions, by the Company or any subsidiary of the Company of all or substantially all the assets of the Company and its subsidiaries taken as a whole, or (2) the sale or disposition (whether by merger, consolidation or otherwise, and whether in a single transaction or a series of related transactions) of one or more subsidiaries of the Company if substantially all of the assets of the Company and its subsidiaries taken as a whole were held by such subsidiary or subsidiaries, except where such sale, lease, transfer, exclusive license or other disposition was to a wholly owned subsidiary of the Company; or (c) the Corporation’s completion of (1) a reverse merger into a public shell, or (2) a merger or consolidation with a special purpose acquisition company or its subsidiary in which the common stock (or similar securities) of the surviving or parent entity were publicly traded in a public offering pursuant to an effective registration statement under the 1933 Securities Act, as amended.

Liquidation Preference

—In the event of any voluntary or involuntary liquidation, dissolution, or winding up of the Company, the holders of shares of series B convertible preferred stock were entitled to be paid out of the assets of the Company or, in the case of a Deemed Liquidation Event, out of the consideration payable to stockholders or the available proceeds, before any payment would be made to the holders of common stock or series A convertible preferred stock, an amount per share equal to the series B convertible preferred stock issue price of $18.227267 per share (subject to adjustment in the event of any stock dividend, stock split, combination or other similar recapitalization), plus any dividends declared but unpaid. If upon any such liquidation, dissolution or winding up of the Company or Deemed Liquidation Event, the assets of the Company available for distribution to its stockholders was insufficient to pay the holders of shares of series B convertible preferred stock the full amount to which they were entitled, the holders of shares of series B convertible preferred stock would have shared ratably in any distribution of the assets available for distribution in proportion to the respective amounts which would otherwise be payable in respect of the shares held by them upon such distribution if all amounts payable on or with respect to such shares were paid in full (the “Series B Liquidation Preference”).

In the event of any voluntary or involuntary liquidation, dissolution, or winding up of the Company, after payment of the Series B Liquidation Preference, the holders of shares of series A convertible preferred stock were entitled to be paid out of the assets of the Company or, in the case of a Deemed Liquidation Event, out of the consideration payable to stockholders or the available proceeds, before any payment shall be made to the holders of common stock or series A convertible preferred stock, an amount per share equal to the series A convertible preferred stock issue price of $10.594230 per share (subject to adjustment in the event of any stock

dividend, stock split, combination or other similar recapitalization), plus any dividends declared but unpaid. If upon any such liquidation, dissolution or winding up of the Company or Deemed Liquidation Event, the assets of the Company available for distribution to its stockholders was insufficient to pay the holders of shares of series A convertible preferred stock the full amount to which they were entitled, the holders of shares of series A convertible preferred stock would have shared ratably in any distribution of the assets available for distribution in proportion to the respective amounts which would otherwise be payable in respect of the shares held by them upon such distribution if all amounts payable on or with respect to such shares were paid in full (the “Series A Liquidation Preference”).

In the event that there were additional assets to be distributed after payment of the Series A Liquidation Preference and the Series B Liquidation Preference, the holders of the series A convertible p

refe

rred stock and series B convertible preferred stock would have shared in the distribution along with common stockholders as if the shares of the series A convertible preferred stock and series B convertible preferred stock had converted to common stock immediately prior to the distribution, up to an amount, (a) taken together with the Series A Liquidation Preference, not to exceed $31.782691 per share with respect to the series A convertible preferred stockholders; and (b) taken together with the Series B Liquidation Preference, not to exceed $54.681802 per share with respect to the series B convertible preferred stockholders.

Redemption

—The preferred stock did not contain a mandatory redemption provision. Upon a deemed liquidation event, the holders would have been paid their preference amounts according to their priority. Remeasurement to redemption value would only have been required if a deemed liquidation event was probable.

Conversion

—Upon either (a) the closing of the sale of shares of common stock to the public at a price of at least $22.784057 per share (subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other similar recapitalization with respect to the common stock), in a firm-commitment underwritten public offering pursuant to an effective registration statement under the Securities Act of 1933, as amended, resulting in at least $75,000,000 of gross proceeds to the Company and in connection with the offering of the common stock listed for trading on the Nasdaq Stock Market’s National Market, the New York Stock Exchange or another exchange or marketplace approved by the Company’s Board of Directors, including the approval of at least two (2) preferred directors (a “Qualified IPO”), which occurred on November 7, 2023, or (b) the date and time, or the occurrence of an event specified by vote or written consent of the Noteholders, then (i) all outstanding shares of convertible preferred stock were to automatically be converted into shares of common stock, at the then effective conversion rate.

Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Nov. 07, 2023	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Weighted average grant date fair value, granted	$ 0.85
Employee Stock Option Member \| 2021 Plan and 2023 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares outstanding, beginning		1,916,194
Granted, shares		1,227,954
Exercised, shares		(11,916)
Forfeited, shares		(500,542)
Expired, shares		(215,950)
Number of shares outstanding, ending		2,415,740	1,916,194
Number of shares, vested and exercisable		933,200	661,239
Number of shares, unvested and exercisable		1,482,540	1,254,955
Weighted average exercise price, beginning balance		$ 4.64
Weighted average exercise price, granted		13.63
Weighted average exercise price, exercised		4.27
Weighted average exercise price, forfeited		9.36
Weighted average exercise price, Expired		3.73
Weighted average exercise price, ending balance		8.32	$ 4.64
Weighted average exercise price, vested and exercisable		5.68	3.75
Weighted average exercise price, unvested and exercisable		9.98	5.12
Weighted average grant date fair value, beginning		3
Weighted average grant date fair value, granted		9.89
Weighted average grant date fair value, exercised		2.75
Weighted average grant date fair value, forfeited		6.67
Weighted average grant date fair value, expired		2.38
Weighted average grant date fair value, ending		5.8	3
Weighted average grant date fair value, vested and exercisable		3.53	2.39
Weighted average grant date fair value, Unvested and exercisable		$ 7.22	$ 3.32
Weighted average remaining contractual term		7 years 9 months 29 days	8 years 7 months 24 days
Weighted average remaining contractual term, vested and exercisable		6 years 9 months 10 days	8 years 6 months 18 days
Weighted average remaining contractual term, unvested and exercisable		8 years 5 months 26 days	8 years 8 months 12 days
Aggregate intrinsic value, Outstanding		$ 13,689	$ 20,130
Aggregate intrinsic value, vested and exercisable		7,552	7,540
Aggregate intrinsic value, unvested and exercisable		$ 6,137	$ 12,590

License, Acquisition, Research Collaboration and Sponsored Research Agreements - Additional Information (Details)								1 Months Ended	3 Months Ended			12 Months Ended		25 Months Ended	35 Months Ended
	Dec. 03, 2021 USD ($) IntegerItem	Oct. 04, 2021 USD ($)	Jul. 16, 2021 USD ($)	Jan. 25, 2021 USD ($)	Aug. 06, 2020 USD ($)	May 27, 2020 USD ($) IntegerItem	Apr. 23, 2020 USD ($)	Nov. 30, 2020 USD ($) shares	Mar. 31, 2023 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development expenses												$ 53,130,000	$ 49,162,000
Stelios Therapeutics Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Asset acquisition date of acquisition			Jul. 16, 2021
Asset acquisition percentage of outstanding stock acquisition			100.00%
Payment to selling shareholders										$ 2,000,000
Maximum \| Stelios Therapeutics Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment to selling shareholders			$ 20,500,000
Adverum License Agreement \| Adverum Biotechnologies Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
One-time up-front non-refundable fee paid				$ 7,500,000					$ 7,500,000
Development milestone paid									$ 3,500,000
Royalty payments description												The Company is obligated to pay Adverum tiered royalties ranging from high single-digits to sub teens based on annual aggregate worldwide net sales of Products (as defined in the Adverum Agreement).
Research and development expenses												$ 0
License agreement termination notice period				120 days
Adverum License Agreement \| Adverum Biotechnologies Inc \| Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development and regulatory milestones due				$ 17,500,000
Commercialization milestones due				$ 49,000,000
Cornell License Agreements \| Cornell University
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development expenses												$ 0	100,000
License agreement termination notice period						90 days
Number of license agreements \| IntegerItem						2
Upfront payment in cash						$ 300,000
Notes issued						1,300,000
Notes with outstanding principal exchanged								$ 1,300,000
Cornell License Agreements \| Cornell University \| Series A Convertible Preferred Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Shares issued on debt exchanged \| shares								1,337,610
Cornell First License Agreements \| Cornell University \| Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Specific clinical and regulatory milestones due						8,400,000
Cornell Second License Agreements \| Cornell University
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Clinical and regulatory milestone paid											$ 100,000
Cornell Second License Agreements \| Cornell University \| Maximum \| Two Portfolios
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Specific clinical and regulatory milestones due						4,300,000
Cornell Second License Agreements \| Cornell University \| Maximum \| Third Portfolio
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Specific clinical and regulatory milestones due						$ 600,000
First UCSD License Agreement \| Stelios Therapeutics Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
One-time up-front non-refundable fee paid					$ 20,000		$ 20,000
License agreement termination notice period							60 days
First UCSD License Agreement \| Stelios Therapeutics Inc \| Research and Development Expense
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
One-time up-front non-refundable fees							$ 20,000
First UCSD License Agreement \| Maximum \| Stelios Therapeutics Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development and commercialization milestones due							$ 4,800,000
Second UCSD License Agreement \| Stelios Therapeutics Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License agreement termination notice period					60 days
Second UCSD License Agreement \| Stelios Therapeutics Inc \| Research and Development Expense
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
One-time up-front non-refundable fees					$ 20,000
Second UCSD License Agreement \| Maximum \| Stelios Therapeutics Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development and commercialization milestones due					$ 2,400,000
Third UCSD License Agreement \| Stelios Therapeutics Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
One-time up-front non-refundable fee paid		$ 20,000
License agreement termination notice period		60 days
Development and commercialization milestones description												the Company to pay aggregate development and commercialization milestones of up to $4.0 million, and low-to mid-single digit royalties based on aggregate net sales.
Third UCSD License Agreement \| Stelios Therapeutics Inc \| Research and Development Expense
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
One-time up-front non-refundable fees		$ 20,000
Third UCSD License Agreement \| Maximum \| Stelios Therapeutics Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development and commercialization milestones due		$ 4,000,000
UCSD Sponsored Research Agreements \| Stelios Therapeutics Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development expenses												$ 1,600,000	2,300,000
Number of research agreements \| IntegerItem	2
Research agreements term	2 years
Research agreement termination notice period	30 days
Costs incurred for research	$ 5,600,000
Payment to research and development												400,000	2,800,000	$ 3,200,000
Research Collaboration Agreement \| Weill Cornell Medical College
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development expenses												1,000,000	6,100,000
Payment to research and development												$ 2,100,000	$ 5,500,000		$ 9,900,000

Cover Page	12 Months Ended
Cover Page	Dec. 31, 2023
Document Information [Line Items]
Document Type	S-1
Amendment Flag	false
Entity Registrant Name	LEXEO THERAPEUTICS, INC.
Entity Central Index Key	0001907108
Entity Tax Identification Number	85-4012572
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Address, Address Line One	345 Park Avenue South
Entity Address, Address Line Two	Floor 6
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10010
City Area Code	212
Local Phone Number	547-9879
Entity Primary SIC Number	2836
Entity Incorporation, State or Country Code	DE
Business Contact [Member]
Document Information [Line Items]
Entity Address, Address Line One	345 Park Avenue South
Entity Address, Address Line Two	Floor 6
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10010
City Area Code	212
Local Phone Number	547-9879
Contact Personnel Name	R. Nolan Townsend

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Stock Option Activity

The following table summarizes the stock option activity under the 2021 Plan and the 2023 Plan for the years ended December 31, 2023 and December 31, 2022 (weighted-average remaining contractual term (in years) is not stated in thousands):


	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Grant Date Fair Value		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding as of December 31, 2022		1,916,194		$	4.64	$	3.00		8.65	$	20,130
Granted		1,227,954			13.63		9.89
Exercised		(11,916	)		4.27		2.75				—
Forfeited		(500,542	)		9.36		6.67
Expired		(215,950	)		3.73		2.38

Outstanding as of December 31, 2023		2,415,740		$	8.32	$	5.80		7.83	$	13,689

Vested options outstanding and exercisable as of December 31, 2022		661,239		$	3.75	$	2.39		8.55	$	7,540
Unvested options outstanding and exercisable as of December 31, 2022		1,254,955		$	5.12	$	3.32		8.70	$	12,590
Vested options outstanding and exercisable as of December 31, 2023		933,200		$	5.68	$	3.53		6.78	$	7,552
Unvested options outstanding and exercisable as of December 31, 2023		1,482,540		$	9.98	$	7.22		8.49	$	6,137

Summary of Following Assumptions Presented on Weighted Average Basis

The Company estimated the fair value of options granted using a Black-Scholes option pricing model with the following assumptions presented on a weighted average basis (not stated in thousands):


	Year Ended December 31,
	2023			2022
Risk-free interest rate		3.43	%		2.76	%
Expected term (in years)		5.78			6.03
Expected volatility		67.59	%		73.36	%
Expected dividend yield		0.00	%		0.00	%

Summary of Stock-Based Compensation Expenses

Stock-based compensation expense was classified as follows in the Company’s consolidated statements of operations and comprehensive loss:


	Year Ended December 31,
	2023		2022
Research and development expense	$	1,751	$	966
General and administrative expense		1,292		815

Total stock-based compensation expense	$	3,043	$	1,781

Capital Stock

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

Capital Stock

8. Capital Stock

As of December 31, 2023, the Company’s amended and restated certificate of incorporation provided that the authorized capital stock of the Company was 510,000,000 shares consisting of 500,000,000 shares of common stock and 10,000,000 shares of undesignated preferred stock, both with a par value of $0.0001 per share. As of December 31, 2023, 26,668,485 shares of the Company’s common stock authorized were issued, including 22,107 shares that were legally issued upon the early exercise of unvested stock options and that are excluded from the number of shares outstanding until the right to repurchase subsequently lapses upon vesting. Until the closing of the Company’s IPO on November 7, 2023, the voting, dividend and liquidation rights of the holders of the Company’s common shares were subject to and qualified by the rights, powers and preferences of the holders of the convertible preferred stock set forth in Note 7. Each common share entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive dividends, if any, as may be declared by the Company’s Board of Directors, and were subject to the preferential dividend rights of the convertible preferred stock until the closing of the Company’s IPO. No cash dividends have been declared or paid by the Company.

Upon the declaration of effectiveness of the Company’s IPO registration statement on November 2, 2023, the Company’s convertible SAFE Note automatically converted into 411,815 shares of common stock (see Note 6). Upon the closing of the Company’s IPO on November 7, 2023, the Company issued and sold 9,090,910 shares of

its common stock, and subsequently, the underwriters partially exercised their associated

30-day

option to purchase additional shares of common stock with 1,048,746 additional shares issued (see Note 3). The net proceeds to the Company from the IPO and subsequent partial exercise of the underwriters’

30-day

option to purchase additional shares were approximately $100.3 million based on the initial offering price of $11.00 per share, after deducting underwriting discounts, commissions and offering expenses totaling $11.3 million. Also upon the closing of the Company’s IPO on November 7, 2023, all 85,495,722 outstanding shares of the Company’s series A convertible preferred stock and all 58,157,823 outstanding shares of the Company’s series B convertible preferred stock converted into 8,070,027 shares and 6,386,337 shares of common stock, respectively, including 896,764 shares of common stock issued as a result of series B convertible preferred stock antidilution provisions (see Note 7).


	December 31, 2023		December 31, 2022
Shares of series A convertible preferred stock		—		8,070,027
Shares of series B convertible preferred stock		—		5,489,573
Options to purchase shares of common stock under the 2021 Plan and 2023 Plan		2,415,740		1,916,194
Shares available for issuance under the 2021 Plan and 2023 Plan		2,293,816		1,000,519
Shares available for issuance under the 2023 ESPP		238,600		—

Total shares of common stock reserved for future issuance		4,948,156		16,476,313

On March 11, 2024, the Company entered into a common stock purchase agreement to issue and sell an aggregate of 6,278,905 shares of its common stock at a price of $15.13 per share, in a private placement. The Company anticipates the gross proceeds from the private placement to be approximately $95.0 million, before deducting any offering related expenses. The private placement financing is expected to close on March 13, 2024, subject to customary closing conditions (see Note 14).

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481004/946-505-50-6

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480237/815-40-50-6

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480008/505-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//505/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-16

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

+ Details

Leases - Additional Information (Details)			1 Months Ended			12 Months Ended		60 Months Ended
Leases - Additional Information (Details)	Apr. 01, 2023	Apr. 01, 2022 USD ($)	Jul. 31, 2029	Apr. 30, 2022	Jan. 31, 2022	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jul. 31, 2034	Aug. 01, 2029 USD ($)	Dec. 11, 2023 USD ($) Installment
Lessee, Lease, Description [Line Items]
Operating lease commencement date				2022-04
Operating lease right-of-use assets						$ 9,442,000	$ 10,708,000
Operating lease liabilities						9,873,000
Net book values						$ 1,763,000	$ 2,069,000
Remaining lease terms						5 years 7 months 6 days	6 years 7 months 6 days
Remaining lease payment terms						5 years 7 months 6 days	6 years 7 months 6 days
Weighted average remaining lease payment term						3 years 8 months 12 days	4 years 7 months 6 days
Weighted average remaining amortization term						5 years 8 months 12 days	6 years 7 months 6 days
Weighted average effective interest rate						8.59%	8.66%
Office Facility and Laboratory Space
Lessee, Lease, Description [Line Items]
Operating lease agreement entered date					2022-01
Operating lease end date			2029-07
Option to extend						additional five-year option to extend the lease beyond July 2029 at the then-prevailing effective market rental rate
Existence of option to extend								true
Operating lease right-of-use assets		$ 11,600,000
Operating lease liabilities		$ 11,600,000
Incremental borrowing rate		8.53%
Office Facility and Laboratory Space \| Scenario Forecast
Lessee, Lease, Description [Line Items]
Renewal term									5 years
Operating lease right-of-use assets									$ 0
Operating lease liabilities									$ 0
Office Facility and Laboratory Space \| Letter of Credit
Lessee, Lease, Description [Line Items]
Security deposit		$ 1,200,000
Laboratory Equipment
Lessee, Lease, Description [Line Items]
Estimated useful life						7 years
Total gross						$ 2,200,000
Accumulated amortization						500,000
Net book values						1,700,000
Number of monthly installments \| Installment										60
Finance lease, commencement date range, start		Apr. 01, 2022
Finance lease, commencement date range, end	Apr. 01, 2023
Total aggregate monthly installment payment amount						$ 49,000
Laboratory Equipment \| Letter of Credit
Lessee, Lease, Description [Line Items]
Security deposit		$ 1,900,000
Laboratory Equipment \| Minimum
Lessee, Lease, Description [Line Items]
Imputed interest rate										7.90%
Monthly installment payment amounts										$ 4,000
Laboratory Equipment \| Maximum
Lessee, Lease, Description [Line Items]
Imputed interest rate										9.30%
Monthly installment payment amounts										$ 18,000

Income Taxes - Schedule of Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss carryforwards	$ 21,904	$ 15,379
Tax credits	7,070	3,883
Intangibles	4,241	3,407
Capitalized R&D expenses	25,127	13,823
Lease liabilities	3,244	4,423
Other deferred tax assets	3,753	1,309
Total deferred tax assets	65,339	42,224
Valuation allowance	(61,974)	(37,992)
Net deferred tax assets	3,365	4,232
Deferred tax liabilities:
Right of use asset	(3,102)	(4,214)
Other deferred tax liabilities	(263)	(18)
Total deferred tax liabilities	(3,365)	(4,232)
Net deferred tax assets (liabilities)	$ 0	$ 0

Fair Value Measurements

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value Measurements

3. Fair Value Measurements

The Company’s cash equivalents consist of investments in a U.S. government money market fund stated at carrying value, which approximates fair value and is based on quoted prices in active markets for identical securities. Cash is stated at carrying value, which approximates fair value due to its short-term nature. The

carrying values of the Company’s prepaid expenses, other current assets, accounts payable and accrued expenses approximate their fair values due to the short-term nature of these assets and liabilities. The carrying value of the Company’s convertible SAFE Note, gross of unamortized discount, was estimated using a probability-weighted present value model, which involved the use of significant unobservable inputs (see Note 6). There have been no transfers between fair value levels during the years ended December 31, 2023 and December 31, 2022.


	As of December 31, 2023:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents (money market)	$	102,484	$	—	$	—	$	102,484

	$	102,484	$	—	$	—	$	102,484


	As of December 31, 2022:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents (money market)	$	74,802	$	—	$	—	$	74,802

	$	74,802	$	—	$	—	$	74,802

The following table sets forth a roll forward of changes in the fair value of financial liabilities, gross of unamortized discount, classified as Level 3 in the fair value hierarchy:


	Convertible SAFE Note, gross
Beginning balance at December 31, 2022	$	—
Convertible SAFE Note issuance at August 24, 2023		4,000
Change in estimated fair value since issuance		530
Conversion of SAFE Note into common stock in connection with initial public offering		(4,530	)

Ending balance at December 31, 2023	$	—

The valuation models used to estimate the fair value of the Company’s convertible SAFE Note considered the estimated probabilities of each of qualified equity financing, public offering, and change of control events, together with corresponding estimated periods of time from each valuation date until the achievements of each such event. Future values were converted to present value using a discount rate appropriate for probability-adjusted cash flows. The ranges of the significant unobservable inputs used in the valuation model to estimate the fair value of the Company’s convertible SAFE Note that was categorized within Level 3 of the fair value hierarchy as of August 24, 2023 (issuance) until November 2, 2023 (settlement) were as follows (not stated in thousands):


Probability of meeting qualified equity financing event	10.0% - 20.0	%
Probability of meeting public offering event	75.0% - 85.0	%
Probability of meeting change in control event	5	%
Time until qualified equity financing event (in years)	0.17 - 0.27
Time until public offering event (in years)	0.08 - 0.19
Time until change in control event (in years)	0.50 - 0.60

In connection with the closing of the Company’s IPO on November 7, 2023, the underwriters of the IPO were granted an option for a period of 30 days to purchase up to 1,363,636 additional shares from the Company at the public offering price of $11.00 per share less the underwriting discount, of which 1,048,746 shares were exercised (see Note 8). The total grant date fair value of this option of approximately $1.2 million, or $0.85 per share, was recorded as an offset to additional

paid-in

capital and was estimated using a Black-Scholes model incorporating the following assumptions (not stated in thousands):


Stock price	$	11.00
Exercise price	$	11.00
Weighted average risk-free interest rate		5.53	%
Expected term (in years)		0.08
Expected volatility		65.88	%
Expected dividend yield		0.00	%

- Definition

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

+ References + Details

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies Leases —As of December 31, 2023, the Company had entered into commitments under lease agreements to rent office space and finance equipment (see Note 5). Commitments —As of December 31, 2023, the Company had entered into commitments under license, acquisition, research collaboration and sponsored research agreements with third parties (see Note 13). In addition, the Company has entered into services agreements with third parties for pharmaceutical manufacturing and research activities in the normal course of business, which can generally be terminated by the Company with 30- to 60-days’ written notice, unless otherwise indicated. Further, certain of the Company’s manufacturing agreements could require early termination and wind-down payments due from the Company upon either the termination of its clinical trials or if the Company terminates such agreements for convenience. Contingencies —From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of business. The Company recognizes any associated legal fees as incurred and accrues a liability for such contingent liability matters when it is probable that future expenditures will be made, and such expenditures can be reasonably estimated. For all periods presented, the Company was not a party to any pending material litigation or other material legal proceedings, except that on October 12, 2023, Rocket Pharmaceuticals, Inc. (“Rocket”) filed a lawsuit in the U.S. District Court for the Southern District of New York against the Company and two individuals claiming, among other things, misappropriation of confidential information and trade secrets. The individual defendants are a current employee and a former employee of the Company’s analytical development team, both of whom were employed at Rocket before joining the Company in 2021. The complaint alleges the individual defendants downloaded confidential Rocket company documents and other proprietary materials prior to leaving Rocket in 2021 and that the Company used this information to advance its programs. The complaint seeks unspecified damages and asks the court to enjoin the Company from competing and working in the market for gene therapy treatments targeting cardiac diseases. The Company retained legal counsel to assist with its ongoing review of the allegations in Rocket’s complaint and is confident in its defenses to the allegations. On December 7, 2023, the Company filed a motion to dismiss the complaint, which is now fully briefed and pending before the court. While it is not possible to predict the outcome with certainty and an estimate of the possible loss cannot be made, the Company currently does not expect the final outcome will have a material adverse effect on its timelines for development of its product candidates. Indemnification Agreements —In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its Board of Directors and executive officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. For all periods presented, the Company has not incurred any material costs as a result of such indemnifications.

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Income Taxes

11. Income Taxes

A reconciliation of the Company’s statutory income tax rate to the Company’s effective income tax rate is as follows for the years ended December 31, 2023, and 2022:


	Year Ended December 31,
	2023			2022
Federal statutory rate		21.00	%		21.00	%
State Taxes, net of federal benefit		10.80			11.77
Change in valuation allowance		(36.12	)		(36.43	)
Permanent differences		(0.36	)		0.08
Tax credits		4.80			3.66
Other		(0.12	)		(0.08	)

Effective income tax rate		0.00	%		0.00	%

The principal components of the Company’s deferred tax assets and liabilities at December 31, 2023 and 2022 are as follows:


	Year Ended December 31,
	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	21,904		$	15,379
Tax credits		7,070			3,883
Intangibles		4,241			3,407
Capitalized R&D expenses		25,127			13,823
Lease liabilities		3,244			4,423
Other deferred tax assets		3,753			1,309

Total deferred tax assets		65,339			42,224

Valuation allowance		(61,974	)		(37,992	)

Net deferred tax assets	$	3,365		$	4,232


	Year Ended December 31,
	2023			2022
Deferred tax liabilities:
Right of use asset	$	(3,102	)	$	(4,214	)
Other deferred tax liabilities		(263	)		(18	)

Total deferred tax liabilities		(3,365	)		(4,232	)

Net deferred tax assets (liabilities)	$	—		$	—

As of December 31, 2023 and 2022, the Company had federal net operating loss carryforwards of approximately $70.2 million and $48.6 million, respectively, which can be carried forward indefinitely. As of December 31, 2023 and 2022, the Company had state and local net operating loss carryforwards of approximately $139.3 million and $109.3 million, respectively, which begin to expire in 2040.

As of December 31, 2023 and 2022, the Company had federal tax credits of $7.1 and $3.9 million, respectively, which begin to expire in 2041.

Future realization of the tax benefits of existing temporary differences and net operating loss carryforwards ultimately depends on the existence of sufficient taxable income within the carryforward period. As of December 31, 2023 and 2022, the Company performed an evaluation to determine whether a valuation allowance was needed. The Company considered all available evidence, both positive and negative, which included the results of operations for the current and preceding years. The Company determined that it was not possible to reasonably quantify future taxable income and determined that it is more likely than not that all of the deferred tax assets will not be realized. Accordingly, the Company maintained a full valuation allowance as of December 31, 2023 and 2022.

Under Internal Revenue Code Section 382, if a corporation undergoes an “ownership change,” the corporation’s ability to use its

pre-change

net operating loss (“NOL”) carryforwards and other

pre-change

tax attributes to offset its post-change income may be limited. The Company has not completed a study to assess whether an “ownership change” has occurred or whether there have been multiple ownership changes since it became a “loss corporation” as defined in Section 382. Future changes in the Company’s stock ownership, which may be outside of its control, may trigger an “ownership change.” In addition, future equity offerings or acquisitions that have equity as a component of the purchase price could result in an “ownership change.” If an “ownership change” has

occurred or does occur in the future, utilization of the NOL carryforwards or other tax attributes may be limited, which could potentially result in increased future tax liability to the Company.

The calculation of the Company’s tax liabilities involves dealing with uncertainties in the application of complex tax laws and regulations for both federal taxes and the many states in which it operates or does business in. ASC 740 states that a tax benefit from an uncertain tax position may be recognized when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, on the basis of the technical merits.

The Company records uncertain tax positions as liabilities in accordance with ASC 740 and adjusts these liabilities when its judgment changes as a result of the evaluation of new information not previously available. Because of the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from our current estimate of the unrecognized tax benefit liabilities. These differences will be reflected as increases or decreases to income tax expense in the period in which new information is available. As of December 31, 2023 and 2022, the Company has not recorded any uncertain tax positions in its consolidated financial statements.

The Company recognizes interest and penalties related to uncertain tax positions on the income tax expense line in the accompanying consolidated statements of operations. As of December 31, 2023 and 2022, no accrued interest or penalties are included on the related tax liability line in the consolidated balance sheet.

The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal and state jurisdictions, where applicable. The resolution of tax matters is not expected to have a material effect on the Company’s consolidated financial statements.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Name Accounting Standards Codification
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-Paragraph 21
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-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Name Accounting Standards Codification
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
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-Paragraph 2
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Convertible preferred stock, shares authorized		143,653,546
Convertible preferred stock, shares issued		143,653,545
Convertible preferred stock, shares outstanding		143,653,545
Convertible preferred stock, Liquidation Preference		$ 185,556
Common stock, par value per share	$ 0.0001	$ 0.0001
Common stock, Authorized	500,000,000	18,125,051
Common Stock, Shares issued	26,668,485	1,648,734
Common stock, Outstanding	26,646,378	1,607,185
Series A Convertible Preferred Stock
Convertible preferred stock, par value	$ 0	$ 0.0001
Convertible preferred stock, shares authorized	0	85,495,722
Convertible preferred stock, shares issued	0	85,495,722
Convertible preferred stock, shares outstanding	0	85,495,722
Convertible preferred stock, Liquidation Preference		$ 85,496
Series B Convertible Preferred Stock
Convertible preferred stock, par value	$ 0	$ 0.0001
Convertible preferred stock, shares authorized	0	58,157,824
Convertible preferred stock, shares issued	0	58,157,823
Convertible preferred stock, shares outstanding	0	58,157,823
Convertible preferred stock, Liquidation Preference		$ 100,060

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Schedule of Net Loss Per Share Attributable to Common Stockholders

Basic and diluted net loss per common share attributable to common stockholders was calculated as follows:


	Year Ended December 31,
	2023			2022
Numerator:
Net loss attributable to common stockholders	$	(66,394	)	$	(59,277	)
Denominator:
Weighted-average common shares outstanding, basic and diluted		5,354,368			1,630,348

Net loss per share attributable to common stockholders, basic and diluted	$	(12.40	)	$	(36.36	)

Fair Value Measurements - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Nov. 07, 2023	Dec. 31, 2023
Fair Value, Option, Quantitative Disclosures [Line Items]
Grant date fair value of option	$ 1.2
Weighted average grant date fair value, granted	$ 0.85
Common Stock
Fair Value, Option, Quantitative Disclosures [Line Items]
Shares purchased at public offering		10,139,656
Common Stock \| IPO
Fair Value, Option, Quantitative Disclosures [Line Items]
Shares purchased at public offering	9,090,910
Offering price per share	$ 11
Common Stock \| IPO \| Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Shares purchased at public offering	1,363,636
Common Stock \| Over-Allotment Option
Fair Value, Option, Quantitative Disclosures [Line Items]
Shares purchased at public offering	1,048,746

License, Acquisition, Research Collaboration and Sponsored Research Agreements	12 Months Ended
	Dec. 31, 2023
Business Combinations [Abstract]
License, Acquisition, Research Collaboration and Sponsored Research Agreements	13. License, Acquisition, Research and Collaboration and Sponsored Research Agreements Adverum Biotechnologies —On January 25, 2021, the Company entered into an exclusive license agreement with Adverum Biotechnologies Inc. (“Adverum”) to in-license materials and technology related to the treatment of cardiomyopathy due to Friedreich’s Ataxia (the “Adverum Agreement”). In connection with the Adverum Agreement, the Company gained access to a portfolio of inventions, patent rights, technology, and licensed methods that the Company continues to develop, and the Company will assume all development and commercialization activities worldwide. Pursuant to the Adverum Agreement, the Company paid a one-time up-front non-refundable fee of $7.5 million, and is obligated to pay aggregate development and regulatory milestones of up to $17.5 million including a $3.5 million development milestone that was achieved and paid in the first quarter of 2023, and aggregate sales event and commercialization milestones of up to $49.0 million. The Company is obligated to pay Adverum tiered royalties ranging from high single-digits to sub teens based on annual aggregate worldwide net sales of Products (as defined in the Adverum Agreement). As of December 31, 2023, there were no research and development expenses recorded by the Company or payments made to Adverum under the terms of the Adverum Agreement other than the one-time up-front non-refundable fee of $7.5 million and the $3.5 million development milestone that was achieved and paid in the first quarter of 2023. The Adverum Agreement remains in effect until termination at the date of the last royalty term to expire. The Company can terminate the Adverum Agreement with 120 days’ written notice. The Adverum Agreement can also be terminated as a result of a patent challenge, material breach of contractual terms, or insolvency by either party. Cornell University —On May 27, 2020, the Company entered into two exclusive license agreements with Cornell University (“Cornell”) (the “Cornell First License Agreement” and the “Cornell Second License Agreement,” collectively “the Cornell License Agreements”). The Cornell First License Agreement is for the in-license of technology related to portfolios for APOE-associated Alzheimer’s disease and Anti-Tau, although the Company’s license is not restricted by such indications and it includes assignment to the Company of Cornell’s IND for the use of AAVrh10.hAPOE2 vector to treat APOE4 homozygous patients who are at risk for or have Alzheimer’s disease to support development of the Company’s LX1001 program. The Cornell Second License Agreement is for the in-license of technology related to a portfolio for Friedreich’s ataxia although the Company’s license is not restricted by such indications. Through the Cornell License Agreements, the Company gains access to a portfolio of inventions, patent rights, technology, and licensed methods that the Company continues to develop. Under the terms of the Cornell License Agreements, the Company has assumed all development and commercialization activities worldwide with respect to the licensed technology. As initial consideration for the Cornell License Agreements, the Company paid Cornell an upfront payment in cash of $0.3 million and issued $1.3 million of notes (the “Notes”). In November 2020, the Notes with outstanding principal of $1.3 million were cancelled in exchange for 1,337,610 shares of series A convertible preferred stock. As additional consideration, the Company is required to pay Cornell up to $8.4 million upon the achievement of specific clinical and regulatory milestones under the Cornell First License Agreement and up to $4.3 million in two portfolios and up to $0.6 million for a third portfolio upon the achievement of specific clinical and regulatory milestones under the Cornell Second License Agreement. In the second quarter of 2022, a clinical and regulatory milestone of $0.1 million was recognized and paid to Cornell in connection with the Cornell Second License Agreement. The Company is also required to pay Cornell a flat royalty in the mid-single-digits based on net sales of the products covered by the licenses, subject to certain adjustments. Upon expiration of the royalty term of a given licensed product in a country, the respective license becomes non-exclusive and royalty-free. In addition, each of the Cornell License Agreements may be terminated by the Company for any reason upon ninety (90) days’ advance notice to Cornell and by Cornell upon the Company’s material uncured breach, and all licenses and rights granted by either party under such agreement will concurrently terminate. During the year ended December 31, 2022, the Company incurred and paid $0.1 million and $0.1 million, respectively, of research and development expenses to Cornell in connection with the Cornell License Agreements. During the year ended December 31, 2023, the Company did not incur any research and development expenses or make any payments to Cornell in connection with the Cornell License Agreements. Stelios Therapeutics, Inc. —Stelios was an early-stage company developing novel adeno-associated AAV-based gene therapies for rare cardiac conditions including arrhythmogenic cardiomyopathy and TNNI3-associated hypertrophic cardiomyopathy. On July 16, 2021, the Company acquired 100% of the outstanding stock of Stelios that was accounted for as an asset acquisition pursuant ASC 805, Business Combinations . The Company is required to pay up to an aggregate of $20.5 million to the selling shareholders of Stelios upon the achievement of certain development milestones, including a $2.0 million development milestone that was achieved and paid in the third quarter of 2022. Regents of the University of California, San Diego —Stelios entered into exclusive worldwide license agreements on April 23, 2020, and August 6, 2020 (the “First UCSD Agreement” and the “Second UCSD Agreement”, respectively) with the Regents of UCSD to in-license materials and intellectual property related to gene therapies for arrhythmogenic right ventricular cardiomyopathy and hypertrophic cardiomyopathy, respectively. The First UCSD Agreement and the Second UCSD Agreement relate to the Company’s development efforts for its LX2021 and LX2022 programs, respectively. In connection with the First UCSD Agreement and the Second UCSD Agreement, the Company gained access to inventions, patent rights, technology, and licensed methods that it continues to develop, and it has assumed all worldwide development and commercialization activities with respect to the licensed technologies. The First UCSD Agreement and Second UCSD Agreement required Stelios to pay one-time up-front non-refundable cash fees of $20,000 for each agreement and requires the Company to pay aggregate development and commercialization milestones of up to $4.8 million and $2.4 million, respectively, and low- to mid-single digit royalties and low-single digit royalties, respectively, based on aggregate net sales. The only research and development expenses incurred by Stelios or the Company and payments made to the Regents of UCSD through December 31, 2023 under the terms of the First UCSD Agreement and the Second UCSD Agreement were the one-time up-front non-refundable cash fees of $20,000 for each agreement. The Company has the right to terminate the First UCSD Agreement and the Second UCSD Agreement at any time upon sixty (60)-days’ written notice to the Regents of UCSD. On October 4, 2021, the Company entered into an exclusive worldwide license agreement (the “Third UCSD Agreement” and collectively with the First UCSD Agreement and the Second UCSD Agreement, the “UCSD Agreements”) with the Regents of UCSD to in-license materials and intellectual property related to LX2020, a gene therapy for arrhythmogenic right ventricular cardiomyopathy. In connection with the Third UCSD Agreement, the Company gained access to inventions, patent rights, technology, and licensed methods that it continues to develop, and it has assumed all worldwide development and commercialization activities with respect to the licensed technology. The Third UCSD Agreement required the Company to pay a one-time up-front non-refundable cash fee of $20,000 and requires the Company to pay aggregate development and commercialization milestones of up to $4.0 million, and low-to mid-single digit royalties based on aggregate net sales. The only research and development expenses incurred by the Company and payments made to the Regents of UCSD under the terms of the Third UCSD Agreement were the one-time up-front non-refundable cash fee of $20,000. The Company has the right to terminate the Third UCSD Agreement at any time upon sixty (60)-days’ written notice to the Regents of UCSD. On December 3, 2021, the Company entered into two sponsored research agreements with the Regents of UCSD (collectively, the “UCSD SRAs”) for the Company’s LX2020, LX2021 and LX2022 programs in connection with the UCSD Agreements. Under the terms of the UCSD SRAs, the Company has the first rights to obtain non-exclusive or exclusive, sublicensable, royalty-bearing, perpetual and transferable worldwide licenses in any resulting inventions owned by the Regents of UCSD or resulting jointly owned inventions between the Company and the Regents of UCSD, and the Company retains the rights to any resulting inventions owned by the Company. The UCSD SRAs each have a two-year term and may be terminated early by the Company at any time upon the giving of thirty (30) days’ written notice to the Regents of UCSD. The total costs to be invoiced to the Company over the terms of the UCSD SRAs are $5.6 million, of which $1.6 million and $2.3 million were recorded in research and development expenses during the years ended December 31, 2023 and December 31, 2022, respectively. The Company made payments totaling $0.4 million and $2.8 million to the Regents of UCSD during the years ended December 31, 2023 and December 31, 2022, respectively. The Company has paid a cumulative total of $3.2 million to the Regents of UCSD as of December 31, 2023, in connection with the UCSD SRAs. Weill Cornell Medical College —On February 2, 2021, the Company entered into a Research Collaboration Agreement with Weill Cornell Medical College (“WCM” and the “WCM Agreement”) in conjunction with the Cornell License Agreements entered on May 27, 2020. The Company committed to fund scientific research at WCM to investigate further and potentially enhance the technology licensed to the Company pursuant to the License Agreements. Under the terms of the WCM Agreement, each WCM invention, joint invention, and related joint results for which an Improvement, as defined in the WCM Agreement, applies and the Company has made an election to amend the Cornell License Agreements, the Company has the first option to negotiate in good faith with WCM for royalty- bearing, worldwide license, under Cornell patent rights, Cornell rights, and Cornell’s interest in joint patent rights, to develop, make, have made, use, offer for sale, sell, have sold, and import derived products in the field. During the years ended December 31, 2023 and December 31, 2022 the Company incurred $1.0 million and $6.1 million, respectively, of research and development costs in connection with the WCM Agreement. During the years ended December 31, 2023 and December 31, 2022 the Company paid $2.1 million and $5.5 million, respectively, to WCM in connection with the WCM Agreement. Cumulatively, the Company has incurred and paid total research and development costs of $9.9 to WCM in connection with the WCM Agreement as of December 31, 2023. The WCM Agreement expired in accordance with its terms in January 2024.

Capital Stock - Additional Information (Details) - USD ($)				12 Months Ended
	Mar. 11, 2024	Nov. 07, 2023	Nov. 02, 2023	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Authorized capital stock				510,000,000
Common stock shares authorized				500,000,000	18,125,051
Preferred stock shares authorized				10,000,000
Common stock, par value per share				$ 0.0001	$ 0.0001
Preferred stock, par value per share				$ 0.0001
Common stock, shares issued				26,668,485	1,648,734
Common stock shares issued upon early exercise of unvested stock options				22,107
Dividends, common stock, cash				$ 0
Proceeds from issuance of common stock		$ 100,300,000
Convertible preferred stock, shares outstanding		143,653,545			143,653,545
Common Stock
Class of Stock [Line Items]
Number of common shares issued and sold				10,139,656
Number of shares issued during the period upon conversion of convertible securities				14,456,364
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares outstanding		85,495,722		0	85,495,722
Number of shares issued during the period upon conversion of convertible securities		8,070,027
Series A Convertible Preferred Stock \| Common Stock
Class of Stock [Line Items]
Number of shares issued during the period upon conversion of convertible securities		8,070,027
Series B Convertible Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares outstanding		58,157,823		0	58,157,823
Series B Convertible Preferred Stock \| Common Stock
Class of Stock [Line Items]
Number of shares issued during the period upon conversion of convertible securities		6,386,337
Series B Convertible Preferred Stock \| Antidilutive Securities
Class of Stock [Line Items]
Number of shares issued during the period upon conversion of convertible securities		896,764
IPO \| SAFE
Class of Stock [Line Items]
Underwriting discounts, commissions and offering expenses				$ 113,000
IPO \| Common Stock
Class of Stock [Line Items]
Number of common shares issued and sold		9,090,910
Underwriting discounts, commissions and offering expenses		$ 11,300,000
Offering price per share		$ 11
IPO \| Common Stock \| SAFE
Class of Stock [Line Items]
Number of common shares on conversion of debt instrument			411,815
Over-Allotment Option \| Common Stock
Class of Stock [Line Items]
Number of common shares issued and sold		1,048,746
Subsequent Event \| Private Placement \| Common Stock
Class of Stock [Line Items]
Number of common shares issued and sold	6,278,905
Offering price per share	$ 15.13
Gross proceeds from private placement	$ 95,000,000

Stock-Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

9. Stock-based Compensation

In February 2021, the Company adopted the 2021 Equity Incentive Plan (the “2021 Plan”) for the issuance of stock options to the Company’s key directors, officers, employees and consultants, as a means to secure the benefits arising from capital stock ownership. In connection with the Company’s IPO in November 2023, the Company adopted the 2023 Equity Incentive Plan (the “2023 Plan”) and the 2023 Employee Stock Purchase Plan (the “2023 ESPP” and collectively with the 2021 Plan and 2023 Plan, the “Plans”). The purposes of the Plans are to promote the alignment of the interests of key directors, officers, employees, and consultants with the success of the Company and to provide compensation opportunities to attract, retain and motivate directors, officers, employees, and consultants of the Company.

The Company’s Board of Directors adopted the 2023 Plan and the 2023 ESPP in October 2023, and the Company’s stockholders approved the 2023 Plan and the 2023 ESPP in October 2023. In connection with the IPO, the Company’s 2023 Equity Incentive Plan (the “2023 Plan”) and its 2023 Employee Stock Purchase Plan (the “2023 ESPP”) became effective. Upon the effectiveness of the 2023 Plan and the 2023 ESPP:

•

582,699 shares of common stock reserved for future issuance under the 2021 Plan ceased to be available for issuance and were added to, and became available for issuance under, the 2023 Plan, and no further grants will be made under the 2021 Plan;

•

1,803,980 shares of common stock were reserved for future issuance under the 2023 Plan, in addition to the shares of common stock reserved for issuance under the 2021 Plan that were added to the shares reserved under the 2023 Plan; and

•

238,600 shares of common stock were reserved for future issuance under the 2023 ESPP.

The maximum number of shares of common stock that may be issued under the 2023 Plan is 4,737,000 shares, which is approximately the sum of (i) 1,803,980 new shares, plus (ii) the 2021 Plan’s available reserve, plus (iii) the number of returning shares, if any, upon the cancellation or forfeiture of equity awards that are outstanding under the 2021 Plan. In addition, the number of shares of common stock reserved for issuance under the 2023 Plan will automatically increase on January 1 of each year, beginning on January 1, 2024, and continuing through and including January 1, 2033, by 5% of the total number of shares of common stock outstanding on December 31 of the immediately preceding calendar year, or a lesser number of shares determined by the Company’s Board of Directors prior to the applicable January 1. The number of shares of common stock reserved for issuance under the 2023 ESPP will automatically increase on January 1 of each calendar year, beginning on January 1, 2024 and continuing through and including January 1, 2033, by the lesser of (i) 1% of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year, (ii) 477,200 shares and (iii) a number of shares determined by the Company’s Board of Directors. Shares subject to purchase rights granted under the 2023 ESPP that terminate without having been exercised in full will not reduce the number of shares available for issuance under the 2023 ESPP.

As of December 31, 2023, 2,293,816 shares and 238,600 shares were available for future issuance under the 2023 Plan and 2023 ESPP, respectively. No shares have been issued under the 2023 ESPP through December 31, 2023.

Stock option activity

Stock options granted under the 2021 Plan generally (i) are subject to requisite service requirements, (ii) vest over a four-year period with 25% of the options granted vesting after one year and the remainder vesting in equal monthly installments over the following 36 months, and (iii) allow for early exercise subject to repurchase. Stock options granted under the 2021 Plan to certain of the Company’s

non-employees

vest in equal monthly installments over a four-year period or vested upon the achievement of a certain milestone event. The Company has not repurchased any shares of common stock issued pursuant to the early exercise of stock options granted under the 2021 Plan through December 31, 2023.

Stock options granted under the 2023 Plan generally (i) are subject to requisite service requirements, and (ii) vest over a four-year period with 25% of the options granted vesting after one year and the remainder vesting in equal monthly installments over the following 36 months.


	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Grant Date Fair Value		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding as of December 31, 2022		1,916,194		$	4.64	$	3.00		8.65	$	20,130
Granted		1,227,954			13.63		9.89
Exercised		(11,916	)		4.27		2.75				—
Forfeited		(500,542	)		9.36		6.67
Expired		(215,950	)		3.73		2.38

Outstanding as of December 31, 2023		2,415,740		$	8.32	$	5.80		7.83	$	13,689

Vested options outstanding and exercisable as of December 31, 2022		661,239		$	3.75	$	2.39		8.55	$	7,540
Unvested options outstanding and exercisable as of December 31, 2022		1,254,955		$	5.12	$	3.32		8.70	$	12,590
Vested options outstanding and exercisable as of December 31, 2023		933,200		$	5.68	$	3.53		6.78	$	7,552
Unvested options outstanding and exercisable as of December 31, 2023		1,482,540		$	9.98	$	7.22		8.49	$	6,137

The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock.

The total grant date fair values of options vested during the years ended December 31, 2023 and December 31, 2022 was $2.4 million and $1.6 million, respectively, including $0.1 million for a total of 342,404 stock options granted to certain nonemployees that vested upon the achievement of a certain milestone event during the year ended December 31, 2022.

The Company estimated the fair value of options granted using a Black-Scholes option pricing model with the following assumptions presented on a weighted average basis (not stated in thousands):


	Year Ended December 31,
	2023			2022
Risk-free interest rate		3.43	%		2.76	%
Expected term (in years)		5.78			6.03
Expected volatility		67.59	%		73.36	%
Expected dividend yield		0.00	%		0.00	%

The expected dividend yields are 0.00% as the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future.

Stock-based compensation expense

Stock-based compensation expense was classified as follows in the Company’s consolidated statements of operations and comprehensive loss:


	Year Ended December 31,
	2023		2022
Research and development expense	$	1,751	$	966
General and administrative expense		1,292		815

Total stock-based compensation expense	$	3,043	$	1,781

As of December 31, 2023 there was $9.8 million of unrecognized stock-based compensation expense related to unvested stock options estimated to be recognized over a weighted-average period of 2.97 years.

Subsequent Events - Additional Information (Details) - Common Stock - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Mar. 11, 2024	Dec. 31, 2023
Subsequent Event [Line Items]
Number of common shares issued and sold		10,139,656
Private Placement \| Subsequent Event
Subsequent Event [Line Items]
Number of common shares issued and sold	6,278,905
Offering price per share	$ 15.13
Gross proceeds from private placement	$ 95.0

Accrued Expenses and Other Current Liabilities (Tables)

12 Months Ended

Dec. 31, 2023

Accrued Liabilities and Other Liabilities [Abstract]

Summary of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following:


	December 31, 2023		December 31, 2022
Accrued research and development expenses	$	6,384	$	4,755
Accrued payroll expenses		242		796
Accrued professional fees		1,078		629
Other current liabilities		169		240

Total accrued expenses and other current liabilities	$	7,873	$	6,420

Commitments and Contingencies - Additional Information (Details) - Third Parties for Pharmaceutical Manufacturing and Research Activities	12 Months Ended
	Dec. 31, 2023
Maximum
Loss Contingencies [Line Items]
Termination notice period (in days)	60 days
Minimum
Loss Contingencies [Line Items]
Termination notice period (in days)	30 days

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 121,466	$ 77,335
Prepaid expenses	2,825	2,342
Other current assets	3	371
Total current assets	124,294	80,048
Restricted cash	3,252	3,253
Property and equipment, net	1,056	998
Lease right-of-use assets—finance, net	1,763	2,069
Lease right-of-use assets—operating	9,442	10,708
Total assets	139,807	97,076
Current liabilities:
Accounts payable	3,794	2,678
Taxes payable	157	506
Accrued expenses and other current liabilities	7,873	6,420
Accrued bonuses	2,810	1,911
Current portion of lease liabilities—finance	518	547
Current portion of lease liabilities—operating	2,087	2,287
Total current liabilities	17,239	14,349
Non-current liabilities
Non-current portion of lease liabilities—finance	1,247	1,648
Non-current portion of lease liabilities—operating	7,786	9,000
Total liabilities	26,272	24,997
Commitments and contingencies (Note 12)
Stockholders' equity (deficit):
Common stock, $0.0001 par value, 500,000,000 shares authorized as of December 31, 2023; 26,668,485 shares issued and 26,646,378 shares outstanding as of December 31, 2023; 18,125,051 shares authorized as of December 31, 2022; 1,648,734 shares issued and 1,607,185 shares outstanding as of December 31, 2022	3	0
Additional paid-in capital	295,372	2,492
Accumulated deficit	(181,840)	(115,446)
Total stockholders' equity (deficit)	113,535	(112,954)
Total liabilities, preferred stock and stockholders' equity (deficit)	139,807	97,076
Series A Convertible Preferred Stock
Non-current liabilities
Convertible preferred stock	0	85,268
Series B Convertible Preferred Stock
Non-current liabilities
Convertible preferred stock	$ 0	$ 99,765

Capital Stock - Schedule of Common Stock Reserved for Future Issuances (Details) - shares	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Total shares of common stock reserved for future issuance	4,948,156	16,476,313
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Total shares of common stock reserved for future issuance	0	8,070,027
Series B Convertible Preferred Stock
Class of Stock [Line Items]
Total shares of common stock reserved for future issuance	0	5,489,573
2021 Plan and 2023 Plan
Class of Stock [Line Items]
Total shares of common stock reserved for future issuance	2,293,816	1,000,519
2021 Plan and 2023 Plan \| Common Stock
Class of Stock [Line Items]
Total shares of common stock reserved for future issuance	2,415,740	1,916,194
2023 ESPP
Class of Stock [Line Items]
Total shares of common stock reserved for future issuance	238,600	0

- Definition

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

+ References

+ Details

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Use of Estimates

tions use

Cash and Cash Equivalents and Restricted Cash

as non-current in

the Company’s consolidated balance sheet according to the timing of maturity, and is associated with collateral for letters of credit issued in connection with its operating

lease right-of-use and

finance

lease right-of-use assets

Net Loss per Share

Net Loss per Share—

The Company follows the

two-class

method when computing net income (loss) per common share as the Company has issued shares that meet the definition of participating securities. The

two-class

holders

non-forfeitable

dividend rights in the event a dividend is paid on common stock. There is no allocation required under the

two-class

method during periods of loss since the participating securities do not have a contractual obligation to share in the losses of the Company.

te 9), were excluded from the computation of diluted net loss per common share because including them would have had an anti-dilutive ef

fect as the Company reported net losses for those periods.

Deferred Offering Costs

expe

nses in the consolidated statement of operations and comprehensive loss. The Company had no deferred offering costs recorded as of December 31, 2023 or December 31, 2022.

Accounts Receivable and Allowance for Doubtful Accounts

mulative

cash receipts if there remains additional award money to be collected.

Classification of Convertible Preferred Stock

—Until the closing of the Company’s IPO on November 7, 2023, the holders of the series A and series B convertible preferred stock had certain liquidation rights in the event of a

d stock

Grant Revenue

ents r

Research and Development

General and Administrative

General and Administrative—

manage

Stock Based Compensation Expense

Stock Based Compensation Expense—

The Company accounts for stock-based payment awards granted to employees

and non-employees as

for non-employee awards

is the date of grant without changes in the fair value of the award. Stock-based compensation costs

for non-employees are

mitte

additional paid-in capital

in the Company’s consolidated balance sheet, which is relieved to

additional paid-in capital

Income Taxes

—Prior to November 20, 2020, the Company was an LLC entity and elected to be treated under the Partnership provisions of the Internal Revenue Code. Accordingly, the LLC entity was not viewed as

a tax-paying entity

in any jurisdiction and all income and deductions of the LLC entity flowed through to the individual members and therefore no income tax

es were

recorded by the Company. On November 20, 2020, the Company converted to a C Corporation.

The Company accounts for income taxes under the asset and liability method pursuant to ASC 740,

Income Taxes

The Company records interest and penalties related to uncertain tax positions in the provision for income taxes.

Fair Value Measurements

Level 1

—Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

Level 2

Level 3

—Inputs are unobservable inputs for the asset or liability.

Concentrations of Credit Risk

—Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and restricted cash. The Company’s cash and

Segment Information

—The Company manages its operations as a

single

segment for the purposes of assessing performance and allocating resources. The Company is focused on preclinical and clinical stage gene therapies, and speci

ficall

y on hereditary and acquired diseases of high unmet need. The Company’s chief operating decision maker (“CODM”) reviews the Company’s financial informati

on on

an aggregated basis for purposes of assessing performance and allocating resources. All assets are held in the United States. The Company has not earned any product revenue through December 31, 2023.

Property and Equipment

Costs for capital assets not yet placed into service are capitalized

as construction-in-progress and

lease right-of-use assets.

The following is the summary of property and equipment and related accumulated depreciation as of December 31, 2023, and December 31, 2022 (years not stated in thousands):


	Useful Life		December 31, 2023			December 31, 2022
Internal use software		3 years	$	296		$	245
Furniture and fixtures		5 years		380			375
Lab equipment		7 years		514			279
Leasehold improvements		7 years		247			232

Total property and equipment				1,437			1,131
Less: accumulated depreciation and amortization				(381	)		(133	)

Total property and equipment, net			$	1,056		$	998

Leases

—In accordance with ASC 842,

Leases

a right-of-use asset

The Company enters into contracts that contain both lease

and non-lease components. Non-lease components

may include maintenance, utilities, and other operating costs. The Company combines the lease

and non-lease components

of fixed costs in its lease arrangements as a single lease component. Variable costs, such as utilities or maintenance costs, are not included in the measurement

of right-of-use assets

and lease liabilities, but rather are expensed when the event determining the amount of variable consideration to be paid occurs.

Operating

lease right-of-use assets

right-of-use

lease right-of-use assets

Certain of the Company’s leases include options to extend or terminate the lease. The amounts determined for the

Company’s right-of-use assets

and lease liabilities generally do not assume that renewal options or early-termination provisions, if any, are exercised, unless it is reasonably certain that the Company will exercise such options.

Recent Accounting Pronouncements Not Yet Adopted

Recent Accounting Pronouncements Not Yet Adopted—

In December 2023, the FASB issued ASU No.

2023-09,

Income Taxes

(Topic 740). ASU

No. 2023-09

requires disaggregation of the effective tax rate reconciliation into standard categories, enhances disclosure of income taxes paid, and modifies other income

tax-related

disclosures. ASU

No. 2023-09

will be effective for t

he Co

mpany starting in annual periods in 2025, with early adoption permitted. The Company is currently assessing the impact of adopting this guidance on its consolidated financial statements.

In November 2023, the FASB issued ASU No.

2023-07,

Segment Reporting—Improving Reportable Segment Disclosures

(Topic 280). ASU

No. 2023-07

also requires all annual disclosures currently required by Topic 280 to be included in interim periods. ASU

No. 2023-07

Leases - Reconciliation of Remaining Equipment Finance Lease Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
2024	$ 531
2025	579
2026	579
2027	357
2028	11
Thereafter	0
Total lease payments	2,057
Less: imputed interest	(292)
Total finance lease liabilities	1,765
Included in the consolidated balance sheet:
Current portion of lease liabilities—finance	518	$ 547
Non-current portion of lease liabilities—finance	$ 1,247	$ 1,648