For stock options requiring an assessment of value during the three months ended March 31, 2026 and 2025, the fair value of each stock option award was estimated using the Black-Scholes option-pricing model utilizing the following assumptions:


		March 31, 2026
Risk-free interest rate		3.92% - 3.98%
Expected dividend yield		0%
Expected volatility		88.60% - 89.63%
Expected life		5.50 to 6.25 years

		March 31, 2025
Risk-free interest rate		4.05% - 4.46%
Expected dividend yield		0%
Expected volatility		86.46% - 87.69%
Expected life		5.50 to 6.25 years

A summary of stock option activity for the three months ended March 31, 2026 is as follows:


	Number of Shares*			Weighted Average Exercise Price*		Weighted Average Remaining Contractual Life (in Years)
Stock options outstanding at December 31, 2025		424,910		$	116.68		6.79
Granted		6,960			10.10		—
Exercised		—			—		—
Forfeited		(113,196	)		28.65		—
Expired		(2,662	)		151.41		—
Stock options outstanding at March 31, 2026		316,012			145.57		5.06
Stock options exercisable at March 31, 2026		264,067		$	167.61		4.32

(*) Retroactively adjusted to reflect the one-for-thirty (1-for-30) reverse stock split, which was effective on April 23, 2026. See Note 2.

The aggregate intrinsic value of exercisable but unexercised in-the-money stock options at March 31, 2026 was zero based on a weighted average exercise price of $167.61 per share. The aggregate intrinsic value of options is calculated as the difference of the market close price of $6.90 on March 31, 2026, and the weighted average exercise price of $167.61, with a weighted average remaining contractual term of 4.32 years.

Stock-based compensation for the three months ended March 31, 2026 and 2025 was included in the Company’s condensed consolidated statements of operations as follows:


	Three Months Ended March 31,
(in thousands)	2026		2025
General and administrative	$	19	$	695
Research and development		29		643
Total stock-based compensation	$	48	$	1,338

As of March 31, 2026, total unrecognized stock-based compensation expense was $1.1 million, which is expected to be recognized as an operating expense in the Company’s condensed consolidated statements of operations over the weighted average remaining period of 3.23 years.

During the three months ended March 31, 2026 and 2025, the Company granted stock options to purchase 7.0 thousand shares of common stock with a weighted average grant date fair value of $10.10 per share and stock options to purchase 63.0 thousand shares of common stock with a weighted average grant date fair value of $29.70 per share, respectively.