In 2015, the Company established the 2015 Plan, under which the Company may grant options and restricted stock to its employees and certain non-employees. As of September 30, 2024, there were 992,459 shares of common stock subject to outstanding awards under the 2015 Plan. In 2022, the Company established the 2022 Plan, under which the Company may grant options, restricted stock units, restricted stock, stock appreciation rights, dividend equivalents and other stock and cash-based awards to its employees and certain non-employees. As of September 30, 2024, there were 3,404,697 shares of common stock subject to outstanding awards under the 2022 Plan.

On January 11, 2024, the Company’s board of directors and stockholders approved the 2024 Equity Incentive Plan (the 2024 Plan), which became effective on the date immediately preceding the date on which the Company’s registration statement was declared effective by the SEC. The 2024 Plan replaced the 2022 Plan, as the Company’s board of directors has determined to not make additional grants under the 2022 Plan following the closing of the offering. However, the 2015 and 2022 Plan will continue to govern outstanding equity awards granted under the 2015 and 2022 Plans. The 2024 Plan allows the Company to make equity-based and cash-based incentive awards to its officers, employees, directors and consultants. The number of shares initially available for issuance under awards granted pursuant to the 2024 Plan is (1) 8,246,565 shares, plus (2) any shares subject to outstanding awards under the 2015 Plan and 2022 Plan as of the effective date of the 2024 Plan that become available for issuance under the 2024 Plan thereafter in accordance with its terms. As of September 30, 2024, there were 806,007 shares of common stock subject to outstanding awards and 7,711,327 shares of common stock remaining and available for issuance under the 2024 Plan.

The Company may grant options to purchase authorized but unissued shares of the Company’s common stock. Options granted under the 2015 Plan, 2022 Plan and 2024 Plan include incentive stock options that can be granted only to the Company’s employees and non-statutory stock options that can be granted to the Company’s employees, consultants, advisors and directors.

The exercise prices, vesting and other restrictions of the awards granted under the 2015 Plan, 2022 Plan and 2024 Plan are determined by the Board, except that no stock option may be issued with an exercise price less than the fair market value of the common stock at the date of the grant or have a term in excess of ten years. Options granted under the 2015 Plan, 2022 Plan and 2024 Plan are exercisable in whole or in part at any time subsequent to vesting.

The following table provides the assumptions used in determining the fair value of option awards for the three and nine months ended September 30, 2024 and 2023:


	Three Months Ended September 30,		Nine Months Ended September 30,
	2024	2023	2024	2023
Expected volatility	77.34% - 77.74%	81.8% - 82.1%	77.34% - 84.50%	81.4% - 83.7%
Risk-free interest rate	3.46% - 4.15%	4.33% - 4.35%	3.46% - 4.62%	3.58% - 4.35%
Expected dividend yield	0%	0%	0%	0%
Expected term (in years)	6.1	5.3 - 6.11	6.05 - 6.1	4.95 - 6.11

The weighted average grant-date fair value of the options granted was $17.14 and $3.22 per share for the nine months ended September 30, 2024 and 2023, respectively. The fair value of shares vested during the nine months ended September 30, 2024 and 2023 was $4.27 and $2.02 per share, respectively. The fair value of shares exercised during the nine months ended September 30, 2024 and 2023 was $2.07 and $1.47 per share, respectively.

The following table summarizes stock option activity for the nine months ended September 30, 2024 (in thousands, except share and per share amounts):


	Number of Outstanding Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
						(Years)
Balance at December 31, 2023		5,532,871		$	4.12		8.55	$	40,290
Granted		806,007		$	24.03
Exercised		(872,520	)	$	2.07
Forfeited/Expired		(263,195	)	$	4.69
Balance at September 30, 2024		5,203,163		$	7.52		7.96	$	157,184
Vested and expected to vest at September 30, 2024		5,203,163		$	7.52		7.96	$	157,184
Exercisable at September 30, 2024		1,896,514		$	3.15		6.51	$	65,574

The Company recorded stock-based compensation expense related to stock options of $2.0 million and $0.4 million for the three months ended September 30, 2024 and 2023, respectively, and $5.1 million and $0.8 million for the nine months ended September 30, 2024 and 2023, respectively. As of September 30, 2024, the Company had an aggregate $21.9 million of gross unrecognized stock-based compensation expense related to unvested options to be recognized over a weighted average period of 3.1 years.

Stock-based compensation expense related to stock options and the 2024 Employee Stock Purchase Plan (see Note 9) recorded in the accompanying statements of operations for the three and nine months ended September 30, 2024 and 2023 was as follows (in thousands):


	Three Months Ended September 30,				For the Nine Months Ended September 30,
	2024		2023		2024		2023
Research and development	$	901	$	238	$	2,223	$	430
General and administrative		1,748		156		4,189		320
Total stock-based compensation expense	$	2,649	$	394	$	6,412	$	750

The Company has not recognized and does not expect to recognize in the near future, any tax benefit related to employee stock-based compensation expense as a result of the full valuation allowance related to its net deferred tax assets.