The Company adopted the 2019 Plan in June 2019 pursuant to which the Company could issue incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units (“RSUs”), and other stock-based awards. Recipients of stock options or stock appreciation rights shall be eligible to purchase shares of the Company’s common stock at an exercise price equal to the estimated fair market value of such stock on the date of grant. The exercise price could be less than fair market value if the stock award was granted pursuant to an assumption or substitution for another stock award in the event of a merger or sale of the Company. The maximum term of options granted under the 2019 Plan is ten years, and stock options typically vest over a four-year period. The Board could assign vesting terms to the stock option grants as deemed appropriate. The Company has the option to repurchase any unvested shares at the original purchase price upon any voluntary or involuntary termination. At the discretion of the Board, unvested shares held by employees may accelerate vesting in the event of a change of control of the Company unless assumed or substituted by the acquirer or surviving entity.

As of December 31, 2022, there were no shares authorized to be issued and the remaining shares available for issuance under the 2019 Plan were made available for issuance under the 2022 Plan at the time of adoption described below. No further shares will be issued under the 2019 Plan. As of December 31, 2021, there were 3,077,023 shares authorized to be issued and 2,194,906 shares reserved for future issuance under the 2019 Plan.

In October 2022, the Board adopted, and in November 2022 its stockholders approved, the 2022 Plan, which became effective immediately prior to and contingent upon the execution of the underwriting agreement related to the Company’s IPO. The 2022 Plan allows the Company to make equity-based and cash-based incentive awards to its officers, employees, directors, and consultants. The 2022 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock awards, RSUs and other stock-based awards. The number of shares initially reserved for issuance under the 2022 Plan is 5,606,723, which is the sum of: (i) 2,555,271 new shares, plus (ii) the number of shares that remained available for issuance under the 2019 Plan at the time the 2022 Plan became effective and (iii) up to 2,148,679 shares of common stock subject to awards granted under the 2019 Plan that, after the effective date of the 2022 Plan, expire or otherwise terminate without having been exercised in full or are forfeited to or repurchased. In addition, the number of shares reserved and available for issuance under the 2022 Plan will automatically increase on January 1, 2023 and each January 1 thereafter, by five percent of the aggregate number of shares of common stock of all classes issued and outstanding on the immediately preceding December 31 or such lesser number of shares of common stock as determined by the compensation committee.

The shares of common stock underlying any awards under the 2022 Plan and the 2019 Plan that are forfeited, canceled, held back upon exercise or settlement of an award to satisfy the exercise price or tax withholding, reacquired by the Company prior to vesting, satisfied without the issuance of stock, expire, or are otherwise terminated (other than by exercise) will be added back to the shares of common stock available for issuance under the 2022 Plan.

As of December 31, 2022, there were 518,636 shares reserved for future issuance under the 2022 Plan.

In October 2022, the Board adopted, and in November 2022 its stockholders approved, the 2022 ESPP, which became effective immediately prior to and contingent upon the execution of the underwriting agreement related to the Company’s IPO. A total of 215,000 shares of common stock were initially reserved for issuance under this plan. The number of shares of common stock that may be issued under the 2022 ESPP shall cumulatively increase beginning on January 1, 2023 and each January 1 thereafter through January 1, 2032, by one percent of the outstanding number of shares of common stock on the immediately preceding December 31 or such lesser number of shares as determined by the compensation committee.

No shares of the Company's common stock were issued and no stock-based compensation expense was recognized during the year ended December 31, 2022 related to the 2022 ESPP.

In November 2022, in connection with the IPO, the Company issued certain directors and employees, including its executive officers, stock options to purchase an aggregate of 1,097,168 shares of its common stock with an exercise price equal to the IPO price of $12.50 per share, under the 2022 Plan. The Company estimated that the aggregate grant-date fair value of the options granted in connection with the IPO was $10.0 million, which is expected to be recognized as stock-based compensation expense over the vesting period of three to four years.

In addition, in November 2022, the Company granted certain employees, including its executive officers, an aggregate of 1,768,632 RSUs under the 2022 Plan. Based on an assumed fair value of $12.50 per share, which was the IPO price, the Company estimated that the aggregate grant-date fair value of the RSUs granted in connection with the IPO was $22.1 million, which is expected to be recognized as stock-based compensation expense over the vesting period of three to four years.

The Company has granted stock options with service-based vesting conditions. Stock options typically vest over four years and have a maximum term of ten years. The Company typically grants stock options to employees and non-employees at exercise prices deemed by the Board to be equal to the fair value of the common stock at the time of grant.

The assumptions that the Company used in the Black-Scholes option-pricing model to determine the grant date fair value of stock options granted were as follows:


	December 31, 2022	December 31, 2021
Risk-free interest rate range	2.69% - 4.15%	0.49% - 1.33%
Dividend yield	0.00%	0.00%
Expected life of options (years)	5.8 - 6.1	5.0 - 6.2
Volatility rate range	71.06% - 82.54%	70.77% - 79.18%
Fair value of common stock range	$3.63 - $12.50	$1.04 - $3.88

The following table summarizes the Company’s stock option activity for the year ended December 31, 2022:


	Number of Shares			Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2021		881,611		$	1.60		9.18	$	2,008
Granted		2,516,310			7.74
Exercised		(25,039	)		0.94
Forfeited or canceled		(71,947	)		2.55
Outstanding as of December 31, 2022		3,300,935		$	6.29		9.26	$	18,346
Vested and expected to vest as of December 31, 2022		3,300,935		$	6.29		9.26	$	18,346
Vested and exercisable as of December 31, 2022		726,847		$	2.14		8.38	$	6,822

The aggregate intrinsic value of options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the common stock as of the end of the reporting period. The aggregate intrinsic value of options exercised during the year ended December 31, 2022 was $0.1 million. There was no aggregate intrinsic value of options exercised during the year ended December 31, 2021.

The weighted-average grant date fair value of the Company’s stock options granted during the year ended December 31, 2022 and 2021 was $5.52 and $1.04 per option, respectively. As of December 31, 2022 and 2021, there was $13.0 million and $0.4 million,

respectively, of unrecognized stock-based compensation expense related to stock option grants. As of December 31, 2022 and 2021, the Company expects to recognize this amount over a weighted-average period of 3.3 years and 2.6 years, respectively.

The total fair value of options vested during the years ended December 31, 2022 and 2021, was $0.5 million and $0.5 million, respectively.

The Company has granted RSUs with service vesting based conditions. Unvested shares of restricted common stock may not be sold or transferred by the holder. They are legally issued and outstanding. These restrictions lapse accordingly to the time-based vesting of each award.

A summary of the RSU activity during the year ended December 31, 2022 is as follows:


	Restricted Stock Units		Weighted-Average Grant Date Fair Value
Unvested at December 31, 2021		—	$	—
Granted		1,787,152		12.49
Vested		—		—
Forfeited		—		—
Unvested at December 31, 2022		1,787,152	$	12.49

The Company granted RSUs under the 2022 Plan, 25% of which vest on the first anniversary of the vesting start date, and the remaining restricted stock units vest in equal quarterly installments for 12 quarters thereafter. No RSUs vested during the year ended December 31, 2022.

The weighted-average grant date fair value of the Company’s RSUs granted during the year ended December 31, 2022 was $12.49 per RSU. As of December 31, 2022, there was $21.4 million of unrecognized stock-based compensation expense related to RSUs, which is expected to be recognized over a weighted-average period of 3.1 years.

Stock-based compensation expense included in the Company’s consolidated statements of operations and comprehensive loss is as follows (in thousands):


	Year Ended December 31,
	2022		2021
Research and development	$	789	$	411
General and administrative		1,396		86
Total stock-based compensation expense	$	2,185	$	497