The Company grants stock-based incentive awards pursuant to the 2021 Equity Incentive Plan (the “2021 Plan”), the 2019 Equity Incentive Plan (the “2019 Plan”), the 2022 Equity Incentive Plan (the “2022 Plan”) and the 2022 Equity Inducement Plan (the “2022 Inducement Plan”). As of June 30, 2026, there were 3,700,580 shares, 264,673 shares, 572,454 shares and 334,056 shares, respectively, available for future issuance under the 2021 Plan, 2019 Plan, 2022 Plan and 2022 Inducement Plan.

The following table summarizes stock option activity for the six months ended June 30, 2026 (in thousands, except share and per share amounts):


	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value
Outstanding at January 1, 2026		12,468,296		$	3.99		7.8	$	595
Granted(1)		3,711,138			1.50
Exercised		(28,706	)		1.64
Expired		(1,093	)		1.97
Forfeited		(347,835	)		2.21
Outstanding at June 30, 2026		15,801,800		$	3.45		6.8	$	17,918
Options exercisable June 30, 2026		10,353,420		$	4.39		5.4	$	10,140

(1) Includes 250,956 performance stock options granted during the six months ended June 30, 2026, which vest only upon closing of qualified financing. As of June 30, 2026, the performance stock options are not fully vested.

The aggregate intrinsic value is calculated as the difference between the exercise price of all outstanding and exercisable stock options and the fair value of the Company’s common stock of $3.01 per share as of June 30, 2026. The aggregate intrinsic value of stock options exercised during the three and the six months ended June 30, 2026 was $0.1 million. No stock options were exercised during the three months and the six months ended June 30, 2025.

The Company has an aggregate $5.8 million of gross unrecognized stock-based compensation expense as of June 30, 2026, remaining to be amortized over a weighted average period of 2.9 years.

The weighted-average grant-date fair value of options granted during the three months ended June 30, 2026 and 2025 was $1.82 and $0.78 per share respectively, and the six months ended was $1.06 and $0.78 per share respectively, and was calculated using the following key input assumptions in the Black-Scholes option-pricing model:


	Three Months Ended June 30,		Six Months Ended June 30,
	2026	2025	2026	2025
Expected volatility	99.68%	99.43% - 101.51%	98.78% - 103.00%	93.92% - 101.51%
Risk-free interest rate	4.13%	3.75% - 4.11%	3.86% - 4.13%	3.75% - 4.45%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Expected term (in years)	6.08	5.25 - 6.08	5.27 - 6.08	5.00 - 6.08

The following table summarizes restricted stock units activity for the six months ended June 30, 2026:


	Number of Units			Weighted Average Grant Date Fair Value
Outstanding at January 1, 2026		1,634,519		$	2.61
Granted		143,708			1.38
Forfeited		(117,849	)		0.12
Vested and settled		(381,049	)		2.35
Outstanding at June 30, 2026(1)		1,279,329		$	2.78

(1) Includes 886,081 RSUs which are vested but not settled at June 30, 2026.

During the six months ended June 30, 2026, the Company issued 334,934 shares of its common stock from the settlement of 381,049 restricted common units, with the remaining shares withheld for taxes. The Company has an aggregate $1.13 million of gross unrecognized restricted stock-based compensation expense as of June 30, 2026, remaining to be amortized over a weighted average period of 1.7 years.

During the three months ended June 30, 2026, the Company issued 381,067 shares of common stock as other awards under the 2021 Plan to the former Chief Executive Officer (CEO), as part of a separation agreement between the company and former CEO, and the compensation cost has been recorded within general and administrative expense.

The following table summarizes the total stock-based compensation expense for the three and six months ended June 30, 2026 and 2025, respectively (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
General and administrative	$	5,077	$	2,446	$	5,932	$	4,955
Research and development		451		569		806		1,691
Total	$	5,528	$	3,015	$	6,738	$	6,646