Under the terms of its stock option plans, the Company’s board of directors may grant stock options to employees, directors and consultants. The Company issued stock options under the 2015 Equity Incentive Plan, as amended (the “2015 plan”) until September 2024, when the 2024 Equity Incentive Plan (“2024 Plan”) was adopted. There are no remaining shares available to be granted under the 2015 Plan. There were 4,533,794 and 3,514,033 stock options outstanding under the 2015 Plan and 2024 Plan, respectively, as of June 30, 2025.

The 2024 Plan authorizes the award of incentive stock options (“ISOs”), which are intended to qualify for tax treatment under Section 422 of the U.S. Internal Revenue Code of 1986, as amended, and nonqualified stock options, Restricted Stock Awards, Stock Appreciation Rights, Restricted Stock Units, (each as defined in the 2024 Plan), performance awards and stock bonus awards. The 2024 Plan initially reserved 3,650,000 shares of the Company's common stock, which includes any reserved shares not issued or subject to outstanding grants under the 2015 Plan on the effective date of the 2024 Plan, for issuance pursuant to awards granted under our 2024 Plan. The number of shares reserved for issuance under the 2024 Plan will increase automatically on January 1 of each of the first ten calendar years during the term of the 2024 Plan by the number of shares equal to the lesser of 5% of the aggregate number of all classes of the Company's common stock and the total number of shares of the Company's common stock subject to any pre-funded warrants, in each case, as issued and outstanding as of the immediately preceding December 31, or a number as may be determined by the Company's board of directors. Pursuant to the 2024 Plan, ISOs may be granted only to employees of the Company. The Company may grant all other types of awards to its employees, directors and consultants.

As of June 30, 2025, 2,131,869 shares were available for future grants under the 2024 Plan. The terms of the agreements are determined by the board of directors. The Company’s stock options have a maximum term of 10 years and vest based on the terms in the agreements, generally over 4 years.

The following table summarizes the stock option activity for the six months ended June 30, 2025:


	Shares Available to Grant			Number of Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value (in thousands)
Balance-December 31, 2024		3,039,972			5,384,142		$	9.61		7.8	$	1,022
Change in authorized shares		1,755,582			—			—
Granted		(2,894,646	)		2,894,646			4.38
Exercised		—			—			—
Forfeited/expired		230,961			(230,961	)		10.08
Balance-June 30, 2025		2,131,869			8,047,827		$	7.72		8.4	$	271
Vested and Exercisable-June 30, 2025					2,994,408		$	8.46		7.0	$	265

There were no stock options exercised during the six months ended June 30, 2025. The intrinsic value of the stock options that were exercised during the six months ended June 30, 2024 was nil.

The weighted-average grant date fair value of stock options granted during the six months ended June 30, 2025 and 2024 was $3.66 and $7.11, respectively, and were estimated on the date of grant using a Black-Scholes option pricing model with the following weighted-average assumptions:


	Six months ended June 30,
	2025			2024
Risk-free interest rate		4.4	%		4.6	%
Expected term of stock options (in years)	6.0			6.0
Expected stock price volatility		108.0	%		110.2	%
Estimated dividend yield		—			—

Stock-based compensation expense recorded as research and development and general and administrative expenses in the statements of operations and comprehensive loss is as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2025		2024		2025		2024
Research and development	$	790	$	478	$	1,578	$	776
General and administrative		2,439		1,080		4,600		1,634
Total stock-based compensation expense	$	3,229	$	1,558	$	6,178	$	2,410

As of June 30, 2025, there was $29.4 million of unrecognized compensation cost that is expected to be recognized over a weighted average period of 2.9 years.

In September 2024, the Company adopted the 2024 Employee Stock Purchase Plan (the “2024 ESPP”). The 2024 ESPP enables eligible employees to purchase shares of the Company's common stock with accumulated payroll deductions. The Company has initially reserved 330,000 shares of its common stock for sale under the 2024 ESPP. The aggregate number of shares issued over the term of the 2024 ESPP, subject to stock-splits, recapitalizations or similar events, may not exceed 3,300,000 shares of the Company's common stock. The number of shares reserved for issuance under the 2024 Plan will increase automatically on January 1 of each of the first ten calendar years during the term of the 2024 Plan by the number of shares equal to the lesser of 1% of the aggregate number of all classes of the Company's common stock and the total number of shares of the Company's common stock subject to any pre-funded warrants, in each case, as issued and outstanding as of the immediately preceding December 31, or a number as may be determined by the Company's board of directors. As of June 30, 2025, there were a total of 688,500 shares available for future purchase under the 2024 ESPP.