In November 2023, the Company's board of directors adopted the 2023 Incentive Award Plan (the “2023 Plan”). On January 1, 2024, the shares of common stock authorized for issuance under the 2023 Plan increased by 2,060,277 shares and as of March 31, 2024, a total of 4,220,719 shares of common stock were available for future issuance under the 2023 Plan.

Stock option activity for the three months ended March 31, 2024 was as follows:


	Number of Options			Weighted-Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2023		3,720,455		$	7.61		9.49	$	57,821
Granted		1,831,369			25.08
Exercised		(5,595	)		4.59
Cancelled and forfeited		(97,953	)		12.46
Outstanding at March 31, 2024		5,448,276		$	13.40		9.37	$	53,607
Vested and expected to vest, March 31, 2024		5,448,276		$	13.40		9.37	$	53,607
Exercisable at March 31, 2024		460,603		$	8.42		8.23	$	6,604

Aggregate intrinsic value in the above table is calculated as the difference between the exercise price of the options and the Company’s estimated fair value of its common stock as of March 31, 2024 and December 31, 2023.

The aggregate intrinsic value of options exercised during the three months ended March 31, 2024 was $0.1 million. The estimated weighted-average grant-date fair value of options granted during the three months ended March 31, 2024 was $20.40 per share. No options were granted or exercised during the three months ended March 31, 2023. As of March 31, 2024, there was $52.3 million of unrecognized stock-based compensation related to stock options, which is expected to be recognized over a weighted-average period of 3.5 years.

The following table summarizes the Company’s restricted stock activity.


	Number of Awards			Weighted-Average Grant Date Fair Value
Unvested as of December 31, 2023		239,699		$	0.93
Vested		(55,501	)		1.01
Unvested as of March 31, 2024		184,198		$	0.91

No restricted stock was issued or repurchased during the three months ended March 31, 2024. The Company issued 1,874 shares of restricted stock and repurchased 4,698 shares or restricted stock during the three months ended March 31, 2023.

The purchase price of the restricted stock awards is the fair value of common stock as determined by the board of directors at the issuance date. The shares generally vest monthly over four years from the grant date.

The Company recorded $0.1 million as a share repurchase liability for restricted stock awards in accrued expenses and other current liabilities on the unaudited condensed balance sheets as of March 31, 2024 and December 31, 2023.

As of March 31, 2024, unrecognized stock-based compensation expense related to outstanding unvested restricted stock awards was $49,000, which is expected to be recognized over a weighted-average period of 2.0 years.

Total stock-based compensation expense recorded in the unaudited condensed statements of operations and comprehensive loss was as follows:


	Three months ended March 31,
	2024		2023
	(in thousands)
General and administrative	$	2,240	$	16
Research and development		1,664		15
Total stock-based compensation expense	$	3,904	$	31

On November 14, 2023, the Company's board of directors adopted the 2023 Employee Stock Purchase Plan (the “ESPP”) which became effective immediately. On January 1, 2024, the number of shares of common stock authorized for issuance under the ESPP increased automatically by 412,055 shares and as of March 31, 2024, a total of 798,780 shares were available for future issuance under the ESPP. There were no shares issued under the ESPP during the three months ended March 31, 2024.