0000950170-24-055069 | 10-Q | XBRL Viewer

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Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, value per share	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common stock, value per share	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common Stock, Shares Issued	83,819,862	81,969,693
Common stock, shares outstanding	83,819,862	81,969,693

Fair value of financial instruments

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Fair value of financial instruments

5. fair value of financial instruments

The Company’s financial instruments that are measured at fair value on a recurring basis consist of money market funds, marketable securities, and a derivative liability (success payment liability) pursuant to the Company's license agreement with the President and Fellows of Harvard College ("Harvard") and The Broad Institute, Inc. ("Broad"), which license agreement is referred to herein as the Harvard/Broad License Agreement. The following tables set forth the fair value of the Company’s financial instruments by level within the fair value hierarchy:


	As of March 31, 2024
(in thousands)	Fair value		Level 1		Level 2		Level 3
Assets
Money market funds	$	83,801	$	83,801	$	—	$	—
Marketable securities:
U.S. treasury bills and notes		217,192		—		217,192		—
U.S. agency securities		244,975		—		244,975		—
Total assets	$	545,968	$	83,801	$	462,167	$	—
Liabilities
Success payment liability	$	2,642	$	—	$	—	$	2,642
Total liabilities	$	2,642	$	—	$	—	$	2,642


	As of December 31, 2023
(in thousands)	Fair value		Level 1		Level 2		Level 3
Assets
Money market funds	$	120,987	$	120,987	$	—	$	—
Marketable securities:
U.S. treasury bills and notes		148,107		—		148,107		—
U.S. agency securities		269,663		—		269,663		—
Total assets	$	538,757	$	120,987	$	417,770	$	—
Liabilities
Success payment liability	$	2,720	$	—	$	—	$	2,720
Total liabilities	$	2,720	$	—	$	—	$	2,720

Cash Equivalents—Cash equivalents of $83.8 million and $121.0 million as of March 31, 2024 and December 31, 2023, respectively, consisted of money market funds and are classified within Level 1 of the fair value hierarchy because they are valued using quoted market prices in active markets.

Marketable Securities—The Company measures its marketable securities at fair value on a recurring basis and classifies those instruments within Level 2 of the fair value hierarchy. Marketable securities are classified within Level 2 of

the fair value hierarchy because pricing inputs are other than quoted prices in active markets, which are either directly or indirectly observable as of the reporting date, and fair value is determined through the use of models or other valuation methodologies.

Success Payment Liability—The Company is obligated to pay to Harvard and Broad tiered success payments in the event its average market capitalization exceeds specified thresholds for a specified period of time ascending from a mid-ten digit dollar amount to $10.0 billion, or sale of the Company for consideration in excess of those thresholds. In the event of a change of control or a sale of the Company, the Company is required to pay success payments in cash within a specified period following such event. Otherwise, the success payments may be settled at the Company’s option in either cash or shares of its common stock, or a combination of cash and shares of its common stock. The maximum aggregate success payments that could be payable by the Company is $31.3 million.

The success payment liability is stated at fair value and is considered Level 3 because its fair value measurement is based, in part, on significant inputs not observed in the market. The Company used a Monte Carlo simulation model, which models the value of the liability based on several key variables, including probability of event occurrence, timing of event occurrence, as well as the value of the Company’s common stock.

The Company remeasured the liability at fair value with corresponding decreases of $0.1 million and $0.7 million recorded to other income for the three months ended March 31, 2024 and 2023, respectively.

The primary inputs used in valuing the success payment liability at March 31, 2024 and December 31, 2023 were as follows:


	At March 31, 2024			At December 31, 2023
Fair value of common stock (per share)	$	13.28		$	13.94
Equity volatility		83	%		83	%

The reconciliation of change in the fair value of financial instruments based on Level 3 inputs for the three months ended March 31, 2024 is as follows:


(in thousands)	Success payment liability
Balance at December 31, 2023	$	2,720
Change in fair value		(78	)
Balance at March 31, 2024	$	2,642

The reconciliation of change in the fair value of financial instruments based on Level 3 inputs for the three months ended March 31, 2023 is as follows:


(in thousands)	Success payment liability
Balance at December 31, 2022	$	2,885
Change in fair value		(738	)
Balance at March 31, 2023	$	2,147

- 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

Net loss per share - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Success payment liability	$ 2,642	$ 2,720

Common Stock	3 Months Ended
Mar. 31, 2024
Preferred Stock [Abstract]
Common Stock	10. Common stock In July 2022, the Company entered into an Open Market Sale Agreement (the "Sales Agreement") with Jefferies LLC ("Jefferies") as the agent pursuant to which the Company is entitled to offer and sell, from time to time at prevailing market prices, shares of the Company’s common stock. The Company agreed to pay Jefferies a commission of up to 3.0% of the aggregate gross sale proceeds of any shares sold by Jefferies under the Sales Agreement. During the three months ended March 31, 2024, the Company sold 1,766,835 shares of its common stock under the Sales Agreement for aggregate net proceeds of $22.4 million, after deducting commissions and offering expenses payable by the Company. As of March 31, 2024, the Company sold 4,547,688 shares of its common stock under the Sales Agreement for aggregate net proceeds of $86.0 million, after deducting commissions and offering expenses payable by the Company. In July 2023, in connection with the execution of the Lilly Agreement, the Company and Lilly also entered into the Lilly Stock Purchase Agreement, pursuant to which the Company sold 1,552,795 shares of common stock to Lilly at a price of $19.32 per share, for an aggregate purchase price of $30.0 million. In December 2023, the Company completed a follow-on public offering of common stock, pursuant to which the Company issued and sold 14,375,000 shares of its common stock, including 1,875,000 shares of its common stock sold pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a public offering price of $10.00 per share. The Company received net proceeds of approximately $134.7 million after deducting underwriting discounts and offering expenses of approximately $9.0 million. In December 2023, the Company also completed a private placement pursuant to a stock purchase agreement with Lilly for the sale and issuance of 2,296,317 shares of common stock at a purchase price of $10.00 per share for an aggregate purchase price of $23.0 million.

Common Stock

3 Months Ended

Mar. 31, 2024

Preferred Stock [Abstract]

Common Stock

10. Common stock

In July 2022, the Company entered into an Open Market Sale Agreement (the "Sales Agreement") with Jefferies LLC ("Jefferies") as the agent pursuant to which the Company is entitled to offer and sell, from time to time at prevailing market prices, shares of the Company’s common stock. The Company agreed to pay Jefferies a commission of up to 3.0% of the aggregate gross sale proceeds of any shares sold by Jefferies under the Sales Agreement. During the three months ended March 31, 2024, the Company sold 1,766,835 shares of its common stock under the Sales Agreement for aggregate net proceeds of $22.4 million, after deducting commissions and offering expenses payable by the Company. As of March 31, 2024, the Company sold 4,547,688 shares of its common stock under the Sales Agreement for aggregate net proceeds of $86.0 million, after deducting commissions and offering expenses payable by the Company.

In July 2023, in connection with the execution of the Lilly Agreement, the Company and Lilly also entered into the Lilly Stock Purchase Agreement, pursuant to which the Company sold 1,552,795 shares of common stock to Lilly at a price of $19.32 per share, for an aggregate purchase price of $30.0 million.

In December 2023, the Company completed a follow-on public offering of common stock, pursuant to which the Company issued and sold 14,375,000 shares of its common stock, including 1,875,000 shares of its common stock sold pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a public offering price of $10.00 per share. The Company received net proceeds of approximately $134.7 million after deducting underwriting discounts and offering expenses of approximately $9.0 million.

In December 2023, the Company also completed a private placement pursuant to a stock purchase agreement with Lilly for the sale and issuance of 2,296,317 shares of common stock at a purchase price of $10.00 per share for an aggregate purchase price of $23.0 million.

Stock-based compensation - Schedule of Stock Option Activity (Details)
$ / shares in Units, $ in Thousands

3 Months Ended

Mar. 31, 2024

USD ($)

$ / shares

Share-Based Payment Arrangement [Abstract]

Number of options, Outstanding, Beginning balance | shares

9,924,878

Number of options, Granted | shares

2,639,100

Number of options, Exercised | shares

(76,044)

Number of options, Forfeited | shares

(140,987)

Number of options, Outstanding, Ending balance | shares

12,346,947

Number of options, Exercisable | shares

5,412,030

Number of options, Expected to vest | shares

6,934,917

^[1]

Weighted average exercise price, Beginning balance | $ / shares

$ 16.98

Weighted average exercise price, Granted | $ / shares

12.76

Weighted average exercise price, Exercised | $ / shares

3.95

Weighted average exercise price, Forfeited | $ / shares

22.03

Weighted average exercise price, Ending balance | $ / shares

16.1

Weighted average exercise price, Exercisable | $ / shares

13.77

Weighted average exercise price, Expected to vest | $ / shares

$ 17.91

^[1]

Weighted average remaining contractual life (in years), Outstanding

8 years 1 month 6 days

Weighted average remaining contractual life (in years), Exercisable

6 years 10 months 24 days

Weighted average remaining contractual life (in years), Expected to vest

9 years

^[1]

Aggregate intrinsic value, Outstanding | $

$ 34,374

^[2]

Aggregate intrinsic value, Exercisable | $

28,776

^[2]

Aggregate intrinsic value, Expected to vest | $

$ 5,598

^[1],[2]

[1]	This represents the number of unvested options outstanding as of March 31, 2024 that are expected to vest in the future.
[2]	The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of the common stock for the options that were in the money as of March 31, 2024.

Related Party Transactions - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Related Party Transaction [Line Items]
Research and development expenses	$ 48,376	$ 47,110

Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Schedule of Fair Value of Financial Instruments, Assets and Liabilities

The following tables set forth the fair value of the Company’s financial instruments by level within the fair value hierarchy:


	As of March 31, 2024
(in thousands)	Fair value		Level 1		Level 2		Level 3
Assets
Money market funds	$	83,801	$	83,801	$	—	$	—
Marketable securities:
U.S. treasury bills and notes		217,192		—		217,192		—
U.S. agency securities		244,975		—		244,975		—
Total assets	$	545,968	$	83,801	$	462,167	$	—
Liabilities
Success payment liability	$	2,642	$	—	$	—	$	2,642
Total liabilities	$	2,642	$	—	$	—	$	2,642


	As of December 31, 2023
(in thousands)	Fair value		Level 1		Level 2		Level 3
Assets
Money market funds	$	120,987	$	120,987	$	—	$	—
Marketable securities:
U.S. treasury bills and notes		148,107		—		148,107		—
U.S. agency securities		269,663		—		269,663		—
Total assets	$	538,757	$	120,987	$	417,770	$	—
Liabilities
Success payment liability	$	2,720	$	—	$	—	$	2,720
Total liabilities	$	2,720	$	—	$	—	$	2,720

Schedule of Fair Value Liabilities Measured on Recurring Basis

The primary inputs used in valuing the success payment liability at March 31, 2024 and December 31, 2023 were as follows:


	At March 31, 2024			At December 31, 2023
Fair value of common stock (per share)	$	13.28		$	13.94
Equity volatility		83	%		83	%

Schedule of Reconciliation of Changes in Fair Value of Financial Instruments

The reconciliation of change in the fair value of financial instruments based on Level 3 inputs for the three months ended March 31, 2024 is as follows:


(in thousands)	Success payment liability
Balance at December 31, 2023	$	2,720
Change in fair value		(78	)
Balance at March 31, 2024	$	2,642

The reconciliation of change in the fair value of financial instruments based on Level 3 inputs for the three months ended March 31, 2023 is as follows:


(in thousands)	Success payment liability
Balance at December 31, 2022	$	2,885
Change in fair value		(738	)
Balance at March 31, 2023	$	2,147

Income Taxes (Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 106	$ 0
Effectice Income Tax Rate	(0.20%)	0.00%
Effective income tax rate, Change in enacted tax rate, Percent	21.00%	21.00%

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Cash and cash equivalents	$ 144,200	$ 206,180	$ 83,746
Restricted cash	4,774		4,824
Total cash, cash equivalents and restricted cash	$ 148,974	$ 210,954	$ 88,570	$ 120,236

Net loss per share (Tables)

3 Months Ended

Mar. 31, 2024

Earnings Per Share [Abstract]

Potential Common Shares, Based on Amounts Outstanding at Period End were Excluded From the Computation of Diluted Net Loss Per Share Attributable to Common Stockholders

The Company excluded the following potential common shares, presented based on amounts outstanding at period end, from the computation of diluted net loss per share for the period indicated because including them would have had an anti-dilutive effect:


	As of March 31,
	2024		2023
Unvested restricted stock units		2,103,658		977,525
Outstanding options to purchase common stock		12,346,947		9,872,169
Total		14,450,605		10,849,694

Fair value of financial instruments - Summary of Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets
Total assets	$ 545,968	$ 538,757
Liabilities
Total liabilities	2,642	2,720
Success Payment Liability
Liabilities
Total liabilities	2,642	2,720
U.S. Treasury Bills and Notes
Assets
Total assets	217,192	148,107
U.S. Agency Securities
Assets
Total assets	244,975	269,663
Level 1
Assets
Total assets	83,801	120,987
Liabilities
Total liabilities	0	0
Level 1 \| Success Payment Liability
Liabilities
Total liabilities	0	0
Level 1 \| U.S. Treasury Bills and Notes
Assets
Total assets	0	0
Level 1 \| U.S. Agency Securities
Assets
Total assets	0	0
Level 2
Assets
Total assets	462,167	417,770
Liabilities
Total liabilities	0	0
Level 2 \| Success Payment Liability
Liabilities
Total liabilities	0	0
Level 2 \| U.S. Treasury Bills and Notes
Assets
Total assets	217,192	148,107
Level 2 \| U.S. Agency Securities
Assets
Total assets	244,975	269,663
Level 3
Assets
Total assets	0	0
Liabilities
Total liabilities	2,642	2,720
Level 3 \| Success Payment Liability
Liabilities
Total liabilities	2,642	2,720
Level 3 \| U.S. Treasury Bills and Notes
Assets
Total assets	0	0
Level 3 \| U.S. Agency Securities
Assets
Total assets	0	0
Money Market Funds
Assets
Total assets	83,801	120,987
Money Market Funds \| Level 1
Assets
Total assets	83,801	120,987
Money Market Funds \| Level 2
Assets
Total assets	0	0
Money Market Funds \| Level 3
Assets
Total assets	$ 0	$ 0

Collaboration and License Agreements

3 Months Ended

Mar. 31, 2024

Collaboration and License Agreements [Abstract]

Collaboration and License Agreements

9. Collaboration and license agreements

The Company's significant collaboration and license agreements are disclosed in Note 9, "Collaboration and license agreements," to the audited consolidated financial statements for the year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K filed with the SEC on February 27, 2024. Since the date of those financial statements, there have been no changes to its collaboration and license agreements, except as noted below.

Vertex agreement

In July 2022, the Company entered into a Strategic Collaboration and License Agreement (the “Vertex Agreement”) with Vertex Pharmaceuticals Incorporated (“Vertex”) for an exclusive, four-year worldwide research collaboration focused on developing in vivo gene editing candidates toward an undisclosed target for the treatment of a single liver disease.

During the three months ended March 31, 2024 and 2023, the Company recognized $3.0 million and $1.4 million of revenue, respectively, associated with the Vertex Agreement related to research services performed during the period. As of March 31, 2024, the Company has recorded $20.0 million as non-current deferred revenue. Costs incurred relating to the Company’s collaboration programs under the Vertex Agreement consist of internal and external research costs, which primarily include: salaries and benefits, and preclinical research studies. These costs are included in research and development expenses in the Company’s condensed consolidated statements of operations during the three months ended March 31, 2024 and March 31, 2023.

Lilly agreement

In June 2023, the Company entered into a Research and Collaboration Agreement (the “Lilly Agreement”) with Eli Lilly and Company ("Lilly") for an exclusive, five-year worldwide research collaboration initially focused on advancing the Company’s discovery-stage in vivo gene editing lipoprotein(a) program.

In the three months ended March 31, 2024, the Company achieved a research and development milestone under the Lilly Agreement which triggered a $5.0 million payment that was received in the same period. Upon achievement of the milestone, the Company updated the transaction price and allocated the $5.0 million milestone to the research and development activities under the Lilly Agreement (the “Lilly Research Services”). During the three months ended March 31, 2024, the Company recorded a cumulative catch-up of $0.2 million for the portion of the milestone that was satisfied in prior periods.

During the three months ended March 31, 2024, the Company recognized $2.7 million of revenue associated with the Lilly Agreement related to the Lilly Research Services performed during the period, inclusive of the cumulative catch-up related to the milestone achieved in March 2024. As of March 31, 2024, the Company has recorded $31.7 million of long-term deferred revenue and $1.5 million of short-term deferred revenue, of which $28.5 million related to the unexercised material rights and the remaining $4.7 million related to the Lilly Research Services and will be recognized over the period of service.

Costs incurred relating to the Company’s collaboration programs under the Lilly Agreement consist of internal and external research costs, which primarily include: salaries and benefits, and preclinical research studies. These costs are included in research and development expenses in the Company’s consolidated statements of operations during the three months ended March 31, 2024.

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Collaborations Revenue	$ 5,695	$ 1,404
Operating expenses:
Research and development	48,376	47,110
General and administrative	14,163	12,553
Total operating expenses	62,539	59,663
Loss from operations	(56,844)	(58,259)
Other income:
Change in fair value of success payment liability	78	738
Interest and other income, net	8,136	5,546
Total other income, net	8,214	6,284
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest, Total	(48,630)	(51,975)
Provision for income taxes	$ (106)	$ 0
Net loss per common share , basic	$ (0.59)	$ (0.84)
Net loss per common share , diluted	$ (0.59)	$ (0.84)
Weighted-average common shares used in net loss per share attributable to common stockholders, basic	83,132,960	61,787,403
Weighted-average common shares used in net loss per share attributable to common stockholders, diluted	83,132,960	61,787,403
Comprehensive Loss:
Net loss	$ (48,736)	$ (51,975)
Other comprehensive (loss) gain:
Unrealized (loss) gain on marketable securities	(772)	457
Comprehensive loss	$ (49,508)	$ (51,518)

Fair value of financial instruments - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 83,800		$ 121,000
Common Stock, Shares Issued	83,819,862		81,969,693
Issuance of common stock, value	$ 84		$ 82
Other Expense
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success Payment Liability, Payable	100	$ 700
Harvard and Board
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, payable	10,000,000
Harvard \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, payable	$ 31,300

Stock-based compensation - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Jan. 01, 2024
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance	14,242,655
Share-Based Payment Arrangement, Expense	$ 10,341	$ 8,024
Twent Eighteen \| Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance	6,885,653
ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase in common stock capital shares, reserved for future issuance			819,697
2021 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance			4,098,485
Stock available for issuance under ESPP	2,096,889
Shares available for future grant	3,731,207
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation cost	$ 82,400
Weighted average period over which unrecognized compensation is expected to be recognized	2 years 9 months 18 days
RSU \| 2024 Inducement Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance	4,000,000
RSU \| 2021 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for future grant	1,179,470
Vesting period	4 years
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation cost	$ 28,900
Weighted average period over which unrecognized compensation is expected to be recognized	3 years 6 months
Restricted Stock \| 2024 Inducement Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for future grant	3,846,700

Accrued expenses

3 Months Ended

Mar. 31, 2024

Payables and Accruals [Abstract]

Accrued expenses

6. Accrued expenses

Accrued expenses consisted of the following:


(in thousands)	March 31, 2024		December 31, 2023
Employee compensation and related benefits	$	5,617	$	12,342
Accrued external research and development expenses		7,909		4,856
Professional fees		2,127		1,492
License and milestone payments		—		500
Other		899		988
Total	$	16,552	$	20,178

Marketable securities - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Marketable Securities [Line Items]
Remaining contractual maturities of marketable securities term	12 months	12 months
Unrealized losses on marketable securities	$ 0.5	$ 0.1

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net loss	$ (48,736)	$ (51,975)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	1,632	1,127
Non-cash lease expense	1,768	1,632
Net amortization of premium (accretion of discount) on marketable securities	(3,967)	(3,855)
Stock-based compensation	10,341	8,024
Change in fair value of success payments liabilities	(78)	(738)
Changes in operating assets and liabilities:
Collaboration receivable	168	1,404
Prepaid expenses and other assets	(672)	(2,353)
Accounts payable	(3,306)	1,485
Accrued expenses and other liabilities	(3,649)	(2,283)
Operating lease liabilities	(1,234)	(1,564)
Deferred revenue	4,651	0
Net cash used in operating activities	(43,082)	(49,096)
Cash flows from investing activities:
Purchases of property and equipment	(433)	(3,375)
Purchases of marketable securities	(164,190)	(133,755)
Maturities of marketable securities	122,991	152,522
Net cash (used in) provided by investing activities	(41,632)	15,392
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs	22,484	1,987
Proceeds from exercise of stock options	301	116
Payment of equity offering costs	(51)	(65)
Net cash provided by financing activities	22,734	2,038
Decrease in cash, cash equivalents and restricted cash	(61,980)	(31,666)
Cash, cash equivalents and restricted cash—beginning of period	210,954	120,236
Cash, cash equivalents and restricted cash—end of period	148,974	88,570
Supplemental disclosure of noncash investing and financing activities:
Property and equipment additions included in accounts payable and accrued expenses	$ 545	$ 1,657

Leases - Summary of Supplemental Cash Flow Information Related to Operating Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash paid for amounts included in the measurements of lease liabilities [Abstract]
Operating cash flows related to operating leases	$ 2,641	$ 3,148

Income Taxes

3 Months Ended

Mar. 31, 2024

Income Tax Disclosure [Abstract]

Income Taxes

13. Income taxes

The income tax provision was $0.1 million for the three months ended March 31, 2024. There was no income tax provision recorded for the three months ended March 31, 2023.The Company's effective income tax rate was (0.2)% for the three months ended March 31, 2024 and de minimus for the three months ended March 31, 2023. The increase in provision for income taxes primarily relates to an increase in state income taxes based on gross interest income.

The effective income tax rate for the three months ended March 31, 2024 and 2023 differed from the 21% federal statutory rate primarily due to the valuation allowance maintained against the Company’s net deferred tax assets.

- 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
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

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

Leases (Tables)

3 Months Ended

Mar. 31, 2024

Leases [Abstract]

Components of Operating Lease Cost

The components of operating lease cost were as follows:


	Three months ended March 31,
(in thousands)	2024		2023
Operating lease costs	$	3,234	$	3,222
Variable lease costs		1,057		879
Total	$	4,291	$	4,101

Supplemental Cash Flow Information Related to Operating Leases

Supplemental cash flow information related to operating leases was as follows:


	Three months ended March 31,
(in thousands)	2024		2023
Cash paid for amounts included in the measurements of lease liabilities:
Operating cash flows related to operating leases	$	2,641	$	3,148

Schedule of Future Minimum Lease Commitments under Non-Cancellable Leases

Future minimum commitments under non-cancellable leases as of March 31, 2024 were as follows:


Years ending December 31,	Amount
	(in thousands)
Remainder of 2024	$	7,948
2025		10,895
2026		11,210
2027		11,534
2028		11,868
Thereafter		49,881
Total lease payments	$	103,336
Less: interest		(29,662	)
Present value of operating lease liabilities	$	73,674

Stock-based compensation

3 Months Ended

Mar. 31, 2024

Share-Based Payment Arrangement [Abstract]

Stock-based compensation

11. Stock-based compensation

The 2018 Equity Incentive Plan (the “2018 Plan”), adopted by the board of directors in August 2018 provided for the grant of qualified incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock and restricted stock units to the Company’s employees, officers, directors, advisors, and outside consultants for the issuance or purchase of shares of the Company’s common stock. The maximum number of shares of common stock that were authorized for issuance under the 2018 Plan was 6,885,653.

In June 2021, the Company's board of directors adopted, and the Company's stockholders approved, the 2021 Stock Incentive Plan (the “2021 Plan”), which became effective on June 16, 2021. The 2021 Plan provides for the grant of incentive stock options and nonstatutory stock options, stock appreciation rights, restricted and unrestricted stock and stock units, performance awards, and other share-based awards to the Company's employees, directors, advisors and outside consultants. The shares reserved for issuance pursuant to the 2021 Plan are subject to an annual increase through January 1, 2031.

On January 1, 2024, 4,098,485 shares of the Company's common stock were added to the amount reserved for issuance under the 2021 Plan. As of March 31, 2024, the Company had reserved 14,242,655 shares of the Company's common stock for issuance of stock options, restricted stock, and restricted stock units, of which 3,731,207 remained available for future grant under the 2021 Plan. Upon effectiveness of the 2021 Plan, the Company ceased granting additional awards under the 2018 Plan.

In February 2024, the board of directors adopted the 2024 Inducement Stock Incentive Plan (the “Inducement Plan”). The Inducement Plan provides for the grant of nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards to persons who (a) were not previously an employee or director or (b) are commencing employment with the Company following a bona fide period of non-employment, in either case, as an inducement material to such person’s entry into employment with the Company and in accordance with the requirements of the Nasdaq Stock Market Rule 5635(c)(4). As of March 31, 2024, the Company had reserved 4,000,000 shares of the Company’s common stock for issuance of nonstatutory stock options and restricted stock unit awards, of which 3,846,700 remained available for future grant under the Inducement Plan.

Stock-based compensation expense recorded in the Company's condensed consolidated statements of operations and comprehensive loss is as follows:


	Three months ended March 31,
(in thousands)	2024		2023
Research and development	$	5,625	$	4,489
General and administrative		4,716		3,535
Total stock-based compensation expense	$	10,341	$	8,024

Stock options

The following table provides a summary of stock option activity during the three months ended March 31, 2024:


	Number of options			Weighted average exercise price per share		Weighted average remaining contractual life (in years)		Aggregate intrinsic value(2) (in thousands)
Outstanding at December 31, 2023		9,924,878		$	16.98
Granted		2,639,100			12.76
Exercised		(76,044	)		3.95
Forfeited		(140,987	)		22.03
Outstanding at March 31, 2024		12,346,947		$	16.10		8.1	$	34,374
Exercisable at March 31, 2024		5,412,030		$	13.77		6.9	$	28,776
Expected to vest after March 31, 2024(1)		6,934,917		$	17.91		9.0	$	5,598

(1)

This represents the number of unvested options outstanding as of March 31, 2024 that are expected to vest in the future.

(2)

The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of the common stock for the options that were in the money as of March 31, 2024.

As of March 31, 2024, there was $82.4 million of unrecognized stock-based compensation expense related to unvested stock options, which is expected to be recognized over a weighted-average period of approximately 2.8 years.

Restricted stock units

During the three months ended March 31, 2024, the Company granted 1,179,470 restricted stock units under the 2021 Plan and Inducement Plan. These restricted stock units vest annually over a four-year period.

A summary of the status of and change in unvested restricted stock units as of March 31, 2024 was as follows:


	Shares			Weighted- average grant date fair value per share
Unvested restricted stock units as of December 31, 2023		964,511		$	19.92
Restricted stock units granted		1,179,470		$	12.78
Restricted stock units vested		(7,290	)	$	32.86
Restricted stock units forfeited		(33,033	)	$	19.80
Unvested restricted stock units as of March 31, 2024		2,103,658		$	15.88

As of March 31, 2024, there was $28.9 million of unrecognized stock-based compensation expense related to restricted stock units that are expected to vest. These costs are expected to be recognized over a weighted-average remaining vesting period of approximately 3.5 years.

2021 Amended and Restated Employee Stock Purchase Plan

In June 2021, the board of directors adopted, and the Company's stockholders approved, the 2021 Employee Stock Purchase Plan, (the "ESPP"), as amended and restated, which became effective on June 16, 2021. The shares reserved for issuance pursuant to the ESPP are subject to an annual increase through January 1, 2031. On January 1, 2024, 819,697 shares of common stock were added to the amount reserved for sale under the ESPP. As of March 31, 2024, 2,096,889 shares remained available for issuance under the ESPP.

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Leases

3 Months Ended

Mar. 31, 2024

Leases [Abstract]

Leases

7. Leases

The Company’s operating lease activity is comprised of non-cancelable facility leases for office and laboratory space in Boston, Massachusetts.

The Company has also entered into multiple contract research and contract manufacturing service agreements with third parties which contain embedded leases within the scope of ASC Topic 842, “Leases”. The embedded leases are considered short term leases, as the contractual terms are 12 months or less. Accordingly, no lease liability or right of use asset has been recorded, and the Company has recognized $1.9 million and $0.2 million of short term lease costs associated with the embedded leases during the three months ended March 31, 2024 and 2023, respectively.

The components of operating lease cost were as follows:


	Three months ended March 31,
(in thousands)	2024		2023
Operating lease costs	$	3,234	$	3,222
Variable lease costs		1,057		879
Total	$	4,291	$	4,101

Supplemental cash flow information related to operating leases was as follows:


	Three months ended March 31,
(in thousands)	2024		2023
Cash paid for amounts included in the measurements of lease liabilities:
Operating cash flows related to operating leases	$	2,641	$	3,148

As of March 31, 2024, the Company’s operating leases were measured using a weighted-average incremental borrowing rate of 7.89% over a weighted-average remaining lease term of 8.8 years.

Future minimum commitments under non-cancellable leases as of March 31, 2024 were as follows:


Years ending December 31,	Amount
	(in thousands)
Remainder of 2024	$	7,948
2025		10,895
2026		11,210
2027		11,534
2028		11,868
Thereafter		49,881
Total lease payments	$	103,336
Less: interest		(29,662	)
Present value of operating lease liabilities	$	73,674

Subsequent Events

3 Months Ended

Mar. 31, 2024

Subsequent Events [Abstract]

Subsequent Events

14. Subsequent events

The Company evaluated all subsequent events and determined there are no material recognized or unrecognized subsequent events requiring disclosure.

Stock-based compensation - Summary of the Restricted Stock Units (Details) - Two Thousand And Twenty One Stock Incentive Plan [Member]	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested RSUs, beginning balance, Unvested \| shares	964,511
Restricted stock units granted \| shares	1,179,470
Restricted stock units vested \| shares	(7,290)
Restricted stock units forfeited \| shares	(33,033)
Unvested RSUs, ending balance, unvested \| shares	2,103,658
Weighted-Average Grant Date Fair Value Per Share, beginning balance, Unvested \| $ / shares	$ 19.92
Weighted-Average Grant-Date Fair Value, Granted \| $ / shares	12.78
Weighted-Average Grant-Date Fair Value, forfeited \| $ / shares	19.8
Weighted-Average Grant Date Fair Value Per Share, Vested \| $ / shares	32.86
Weighted-Average Grant Date Fair Value Per Share, ending balance, Unvested \| $ / shares	$ 15.88

Marketable Securities

3 Months Ended

Mar. 31, 2024

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

3. Marketable securities

Marketable securities by security type consisted of the following:


	March 31, 2024
(in thousands)	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
U.S. treasury bills and notes	$	217,458	$	—	$	(266	)	$	217,192
U.S. agency securities		245,209		33		(267	)		244,975
Total	$	462,667	$	33	$	(533	)	$	462,167


	December 31, 2023
(in thousands)	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
U.S. treasury bills and notes	$	147,978	$	144	$	(15	)	$	148,107
U.S. agency securities		269,520		277		(134	)		269,663
Total	$	417,498	$	421	$	(149	)	$	417,770

The remaining contractual maturities of all marketable securities were less than 21 months as of March 31, 2024 and 24 months as of December 31, 2023.The gross unrealized losses on the Company’s marketable securities of $0.5 million and $0.1 million as of March 31, 2024 and December 31, 2023, respectively, were caused by interest rate increases which resulted in the decrease in market value of these securities. Because the decline in fair value is attributable to changes in interest rates and not credit quality, and because the Company does not intend to sell the investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases, which may be maturity, the Company did not consider those marketable securities to be impaired at March 31, 2024 or December 31, 2023. None of the Company’s marketable securities have been in a continuous unrealized loss position for 12 months or greater as of March 31, 2024 or December 31, 2023.

Accrued expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Employee compensation and related benefits	$ 5,617	$ 12,342
Accrued external research and development expenses	7,909	4,856
Professional fees	2,127	1,492
License and milestone payments	0	500
Other	899	988
Total	$ 16,552	$ 20,178

Net loss per share - Potential Common Shares, Based on Amounts Outstanding at Period End were Excluded From the Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	14,450,605	10,849,694
Unvested restricted stock units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	2,103,658	977,525
Outstanding Options To Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	12,346,947	9,872,169

Property and Equipment, net - Schedule of Property and Equipment, net (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property Plant And Equipment [Line Items]
Total property and equipment	$ 33,048	$ 32,897
Less accumulated depreciation	(12,024)	(10,392)
Property and equipment, net	21,024	22,505
Lab equipment
Property Plant And Equipment [Line Items]
Total property and equipment	29,002	28,851
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	726	726
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	2,323	2,323
Computer Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	$ 997	$ 997

Leases - Summary of Components of Operating Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Lease, Cost [Abstract]
Operating lease costs	$ 3,234	$ 3,222
Variable lease costs	1,057	879
Total	$ 4,291	$ 4,101

Accrued Expenses (Tables)

3 Months Ended

Mar. 31, 2024

Payables and Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses consisted of the following:


(in thousands)	March 31, 2024		December 31, 2023
Employee compensation and related benefits	$	5,617	$	12,342
Accrued external research and development expenses		7,909		4,856
Professional fees		2,127		1,492
License and milestone payments		—		500
Other		899		988
Total	$	16,552	$	20,178

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2024

Accounting Policies [Abstract]

Cash, Cash Equivalents and Restricted Cash

Cash, cash equivalents and restricted cash

Restricted cash represents collateral provided for letters of credit issued as security deposits in connection with the Company’s leases of its corporate facilities. A reconciliation of the cash, cash equivalents, and restricted cash reported within the condensed consolidated balance sheet that sum to the total of the same amounts shown in the condensed consolidated statement of cash flows is as follows:


	March 31,		March 31,
(in thousands)	2024		2023
Cash and cash equivalents	$	144,200	$	83,746
Restricted cash		4,774		4,824
Total cash, cash equivalents and restricted cash	$	148,974	$	88,570

Net loss per share

3 Months Ended

Mar. 31, 2024

Earnings Per Share [Abstract]

Net loss per share

12. Net loss per share

The Company’s potential dilutive securities, which include unvested restricted stock units and common stock options, have been excluded from the computation of diluted net loss per share as the effects would be anti-dilutive. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at period end, from the computation of diluted net loss per share for the period indicated because including them would have had an anti-dilutive effect:


	As of March 31,
	2024		2023
Unvested restricted stock units		2,103,658		977,525
Outstanding options to purchase common stock		12,346,947		9,872,169
Total		14,450,605		10,849,694

Property and equipment, net

3 Months Ended

Mar. 31, 2024

Property, Plant and Equipment [Abstract]

Property and equipment, net

4. Property and equipment, net

Property and equipment, net, consisted of the following:


(in thousands)	March 31, 2024			December 31, 2023
Lab equipment	$	29,002		$	28,851
Leasehold improvements		726			726
Furniture and fixtures		2,323			2,323
Computer equipment		997			997
Total property and equipment		33,048			32,897
Less accumulated depreciation		(12,024	)		(10,392	)
Property and equipment, net	$	21,024		$	22,505

The following table summarizes depreciation expense incurred:


	Three months ended March 31,
(in thousands)	2024		2023
Depreciation expense	$	1,632	$	1,127

Fair value of financial instruments - Schedule of Fair Value Liabilities Measured on Recurring Basis (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of common stock (per share)	$ 13.28	$ 13.94
Equity Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity volatility	83.00%	83.00%

Nature of the Business and Basis of Presentation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended
	Dec. 31, 2023	Jul. 31, 2022	Mar. 31, 2024
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Sale of stock, number of shares issued in transaction			1,766,835
Common Stock, Shares, Issued	81,969,693		83,819,862
Commission On Aggregate Gross Sale Proceeds		3.00%
Common Stock, Capital Shares Reserved for Future Issuance			14,242,655
Investment Banking, Advisory, Brokerage, and Underwriting Fees and Commissions, Total	$ 9.0
Net proceeds from sale of common stock			$ 22.4
Cash, cash equivalents, and marketable securities			$ 606.4
Public offering [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Sale of stock, number of shares issued in transaction	14,375,000
Common Stock, Shares, Issued	1,875,000
Common Stock Offering Price Per Share	$ 10
Net proceeds from sale of common stock	$ 134.7

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (48,736)	$ (51,975)

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
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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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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/exampleRef
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-URI https://asc.fasb.org//1943274/2147480167/946-830-55-10

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2024

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of significant accounting policies

The Company's significant accounting policies are disclosed in Note 2, "Summary of significant accounting policies," in the audited consolidated financial statements for the year ended December 31, 2023, and notes thereto, included in the Company’s Annual Report on Form 10-K filed with the SEC on February 27, 2024. Since the date of those financial statements, there have been no changes to the Company's significant accounting policies.

Cash, cash equivalents and restricted cash


	March 31,		March 31,
(in thousands)	2024		2023
Cash and cash equivalents	$	144,200	$	83,746
Restricted cash		4,774		4,824
Total cash, cash equivalents and restricted cash	$	148,974	$	88,570

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Stockholders' Equity [Abstract]
Issuance of common stock from At-the-Market offering	$ 747	$ 126

Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2024

Investments, Debt and Equity Securities [Abstract]

Schedule of Marketable Securities by Security

Marketable securities by security type consisted of the following:


	March 31, 2024
(in thousands)	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
U.S. treasury bills and notes	$	217,458	$	—	$	(266	)	$	217,192
U.S. agency securities		245,209		33		(267	)		244,975
Total	$	462,667	$	33	$	(533	)	$	462,167


	December 31, 2023
(in thousands)	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
U.S. treasury bills and notes	$	147,978	$	144	$	(15	)	$	148,107
U.S. agency securities		269,520		277		(134	)		269,663
Total	$	417,498	$	421	$	(149	)	$	417,770

Property and equipment, net (Tables)

3 Months Ended

Mar. 31, 2024

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment, net

Property and equipment, net, consisted of the following:


(in thousands)	March 31, 2024			December 31, 2023
Lab equipment	$	29,002		$	28,851
Leasehold improvements		726			726
Furniture and fixtures		2,323			2,323
Computer equipment		997			997
Total property and equipment		33,048			32,897
Less accumulated depreciation		(12,024	)		(10,392	)
Property and equipment, net	$	21,024		$	22,505

Schedule of Depreciation Expense

The following table summarizes depreciation expense incurred:


	Three months ended March 31,
(in thousands)	2024		2023
Depreciation expense	$	1,632	$	1,127

Marketable securities - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Marketable Securities [Line Items]
Amortized Cost	$ 462,667	$ 417,498
Gross unrealized gains	33	421
Gross unrealized losses	(533)	(149)
Fair value	462,167	417,770
U.S. Treasury Bills and Notes [Member]
Marketable Securities [Line Items]
Amortized Cost	217,458	147,978
Gross unrealized gains	0	144
Gross unrealized losses	(266)	(15)
Fair value	217,192	148,107
U.S. Agency Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	245,209	269,520
Gross unrealized gains	33	277
Gross unrealized losses	(267)	(134)
Fair value	$ 244,975	$ 269,663

Property and Equipment, net - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 1,632	$ 1,127

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance at Dec. 31, 2022	$ 550,932	$ 62	$ 895,801	$ (694)	$ (344,237)
Beginning Balance (in shares) at Dec. 31, 2022		61,730,816
Exercise of stock options	116		116
Exercise of stock options (in shares)		29,010
Issuance of common stock from At-the-Market offering, net of issuance costs of $126	1,922		1,922
Issuance of common stock from At-the-Market offering, net of issuance costs of $126, (in shares)		103,184
Unrealized loss on marketable securities	457			457
Stock-based compensation	8,024		8,024
Net loss	(51,975)				(51,975)
Ending Balance at Mar. 31, 2023	509,476	$ 62	905,863	(237)	(396,212)
Ending balance (in shares) at Mar. 31, 2023		61,863,010
Beginning Balance at Dec. 31, 2023	$ 599,502	$ 82	1,143,453	272	(544,305)
Beginning Balance (in shares) at Dec. 31, 2023	81,969,693	81,969,693
Vesting of restricted common stock (in shares)		7,290
Exercise of stock options	$ 301		301
Exercise of stock options (in shares)	76,044	76,044
Issuance of common stock from At-the-Market offering, net of issuance costs of $126	$ 22,433	$ 2	22,431
Issuance of common stock from At-the-Market offering, net of issuance costs of $126, (in shares)		1,766,835
Unrealized loss on marketable securities	(772)			(772)
Stock-based compensation	10,341		10,341
Net loss	(48,736)				(48,736)
Ending Balance at Mar. 31, 2024	$ 583,069	$ 84	$ 1,176,526	$ (500)	$ (593,041)
Ending balance (in shares) at Mar. 31, 2024	83,819,862	83,819,862

Stock-based compensation (Tables)

3 Months Ended

Mar. 31, 2024

Share-Based Payment Arrangement [Abstract]

Summary of Stock Based Compensation Expense

Stock-based compensation expense recorded in the Company's condensed consolidated statements of operations and comprehensive loss is as follows:


	Three months ended March 31,
(in thousands)	2024		2023
Research and development	$	5,625	$	4,489
General and administrative		4,716		3,535
Total stock-based compensation expense	$	10,341	$	8,024

Schedule of Stock Option Activity

The following table provides a summary of stock option activity during the three months ended March 31, 2024:


	Number of options			Weighted average exercise price per share		Weighted average remaining contractual life (in years)		Aggregate intrinsic value(2) (in thousands)
Outstanding at December 31, 2023		9,924,878		$	16.98
Granted		2,639,100			12.76
Exercised		(76,044	)		3.95
Forfeited		(140,987	)		22.03
Outstanding at March 31, 2024		12,346,947		$	16.10		8.1	$	34,374
Exercisable at March 31, 2024		5,412,030		$	13.77		6.9	$	28,776
Expected to vest after March 31, 2024(1)		6,934,917		$	17.91		9.0	$	5,598

(1)

This represents the number of unvested options outstanding as of March 31, 2024 that are expected to vest in the future.

(2)

Schedule of Status and Change in Unvested Restricted Stock

A summary of the status of and change in unvested restricted stock units as of March 31, 2024 was as follows:


	Shares			Weighted- average grant date fair value per share
Unvested restricted stock units as of December 31, 2023		964,511		$	19.92
Restricted stock units granted		1,179,470		$	12.78
Restricted stock units vested		(7,290	)	$	32.86
Restricted stock units forfeited		(33,033	)	$	19.80
Unvested restricted stock units as of March 31, 2024		2,103,658		$	15.88

License Agreements

3 Months Ended

Mar. 31, 2024

License Agreement [Abstract]

License Agreement

8. License agreements

The Company's significant license agreements are disclosed in Note 8, "License agreements," to the audited consolidated financial statements for the year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K filed with the SEC on February 27, 2024. Since the date of those financial statements, there have been no changes to its license agreements.

Fair value of financial instruments - Schedule of Reconciliation of Changes in Fair Value of Financial Instruments (Details) - Success Payment Liability - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 2,720	$ 2,885
Changes in fair value	(78)	(738)
Ending balance	$ 2,642	$ 2,147

Nature of the Business and Basis of Presentation

3 Months Ended

Mar. 31, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of the Business and Basis of Presentation

1. Nature of the business and basis of presentation

Organization

Verve Therapeutics, Inc. (the “Company” or “Verve”) is a clinical-stage genetic medicines company pioneering a new approach to the care of cardiovascular disease, transforming treatment from chronic management to single-course gene editing medicines. The Company was incorporated on March 9, 2018 as Endcadia, Inc., a Delaware corporation, and began operations shortly thereafter. In January 2019, the Company amended its certificate of incorporation to change its name to Verve Therapeutics, Inc. The Company’s principal offices are located in Boston, Massachusetts.

Liquidity and capital resources

Since its inception, the Company has devoted its efforts principally to research and development and raising capital. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry including, but not limited to, technical risks associated with the successful research, development and manufacturing of product candidates, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Current and future programs will require significant research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company expects that its cash, cash equivalents and marketable securities of $606.4 million as of March 31, 2024 will be sufficient to fund its operations and capital expenditure requirements beyond the next 12 months from the date of issuance of these financial statements. The Company will need additional financing to support its continuing operations and pursue its growth strategy. Until such time as the Company can generate significant revenue from product sales, if ever, it expects to finance its operations through a combination of equity offerings, debt financings, collaborations, strategic alliances and licensing arrangements. The Company may be unable to raise additional funds or enter into such other agreements when needed on favorable terms or at all. The inability to raise capital as and when needed could have a negative impact on the Company’s financial condition and its ability to pursue its business strategy. The Company will need to generate significant revenue to achieve profitability, and it may never do so.

Basis of presentation

The accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). 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 Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations.

The unaudited condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of the Company’s management, the accompanying unaudited condensed consolidated financial statements contain all adjustments that are necessary to present fairly the Company’s financial position as of March 31, 2024, the results of its operations and other comprehensive loss for the three months ended March 31, 2024 and 2023, stockholders’ equity for the three months ended March 31, 2024 and 2023 and cash flows for the three months ended March 31, 2024 and 2023. Such adjustments are of a normal and recurring nature. The results for the three months ended March 31, 2024 are not necessarily indicative of the results for the year ending December 31, 2024, or for any future period. These interim financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2023, and the notes thereto, included in the Company’s Annual Report on Form 10-K filed with the SEC on February 27, 2024.

Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2024

Accounting Policies [Abstract]

Reconciliation of Cash, Cash Equivalents and Restricted Cash

A reconciliation of the cash, cash equivalents, and restricted cash reported within the condensed consolidated balance sheet that sum to the total of the same amounts shown in the condensed consolidated statement of cash flows is as follows:


	March 31,		March 31,
(in thousands)	2024		2023
Cash and cash equivalents	$	144,200	$	83,746
Restricted cash		4,774		4,824
Total cash, cash equivalents and restricted cash	$	148,974	$	88,570

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2024	May 02, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Entity Registrant Name	VERVE THERAPEUTICS, INC.
Entity Central Index Key	0001840574
Trading Symbol	VERV
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		83,965,493
Entity Interactive Data Current	Yes
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common stock, par value $0.001 per share
Entity File Number	001-40489
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-4800132
Entity Address, Address Line One	201 Brookline Avenue, Suite 601
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02215
City Area Code	617
Local Phone Number	603-0070
Document Quarterly Report	true
Document Transition Report	false

License Agreements - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Research And Development Arrangement Contract To Perform For Others [Line Items]
Research and development expenses	$ 48,376	$ 47,110
Common Stock, Shares Issued	83,819,862		81,969,693
Issuance of common stock, value	$ 84		$ 82

Collaboration And License Agreements (Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue, current	$ 1,473		$ 0
Deferred Revenue, Noncurrent	$ 31,700
Shares issued and sold	1,766,835
Vertex Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue, revenue recognized	$ 3,000	$ 1,400
Amount of deferred costs related to long-term contracts	20,000
Lilly Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue, revenue recognized	2,700
Amount of deferred costs related to long-term contracts	28,500
Deferred revenue, remaining research services	4,700
Lilly Agreement [Member] \| Stock Purchase Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Fixed transaction price	5,000
Research and development milestone payments	5,000
Commercial milestone payments	$ 200

Stock-based compensation - Summary of Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 10,341	$ 8,024
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	5,625	4,489
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 4,716	$ 3,535

- 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
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-1D

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-URI https://asc.fasb.org//1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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

Leases - Summary of Future Minimum Commitments under Non-Cancellable Operating Leases (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
Remainder of 2024	$ 7,948
2025	10,895
2026	11,210
2027	11,534
2028	11,868
Thereafter	49,881
Total lease payments	103,336
Less: interest	(29,662)
Present value of operating lease liabilities	$ 73,674

Leases - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Lessee, Lease, Description [Line Items]
Increase in operating lease liability	$ (1,234)	$ (1,564)
Operating lease incremental borrowing rate	7.89%
Weighted average remaining lease term	8 years 9 months 18 days
Operating Lease, Payments	$ 2,641	3,148
ASC 842
Lessee, Lease, Description [Line Items]
Short-Term Lease, Cost	$ 1,900	$ 200

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Operating lease liability	$ 73,674
Operating lease right-of-use assets	$ 83,527	$ 85,295

Common Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions				3 Months Ended
	Dec. 31, 2023	Jul. 31, 2023	Jul. 31, 2022	Mar. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common Stock, Par Value	$ 0.001			$ 0.001
Common Stock, Shares Issued	81,969,693			83,819,862
Shares issued and sold				1,766,835
Sale of Stock, Consideration Received on Transaction				$ 22.4
Commission On Aggregate Gross Sale Proceeds			3.00%
Underwriting discounts and offering expenses	$ 9.0
Sales Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common Stock, Par Value	$ 10	$ 19.32
Common Stock, Shares Issued	2,296,317
Sales Agreement [Member] \| Common Stock [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Shares issued and sold				4,547,688
Sale of Stock, Consideration Received on Transaction				$ 86.0
Public Offering [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common Stock, Shares Issued	1,875,000
Shares issued and sold	14,375,000
Common Stock Offering Price Per Share	$ 10
Sale of Stock, Consideration Received on Transaction	$ 134.7
Lilly Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common Stock, Shares Issued		1,552,795
Stock Purchase Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Agreegate Purchase Price	$ 23.0	$ 30.0

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 144,200	$ 206,180
Marketable securities	462,167	417,770
Collaboration receivable	5,767	5,897
Prepaid expenses and other current assets	8,192	8,102
Total current assets	620,326	637,949
Property and equipment, net	21,024	22,505
Restricted cash	4,774	4,774
Operating lease right-of-use assets	83,527	85,295
Other long term assets	2,706	2,165
Total assets	732,357	752,688
Current liabilities:
Accounts payable	3,049	6,636
Accrued expenses	16,552	20,178
Deferred revenue, current	1,473	0
Lease liability, current portion	10,220	10,192
Total current liabilities	31,294	37,006
Long-term lease liability	63,454	64,715
Success payment liability	2,642	2,720
Deferred revenue, non-current	51,733	48,556
Other long term liabilities	165	189
Total liabilities	149,288	153,186
Commitments and contingencies (See Note 7 and Note 8)
Stockholders' equity
Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.001 par value; 200,000,000 shares authorized, 83,819,862 and 81,969,693 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively	84	82
Additional paid-in capital	1,176,526	1,143,453
Accumulated other comprehensive income (loss)	(500)	272
Accumulated deficit	(593,041)	(544,305)
Total stockholders equity	583,069	599,502
Total liabilities and stockholders' equity	$ 732,357	$ 752,688