The 2023 Stock Option and Incentive Plan (2023 Plan) was adopted by the board of directors, approved by the Company’s stockholders on July 4, 2023, and became effective on July 13, 2023, replacing the 2017 Equity Incentive Plan. The number of shares initially reserved for issuance under the 2023 Plan was 2,585,968. The number of shares will automatically increase each January 1, by (i) 4% of the outstanding number of shares of the Company’s Series A common stock on the immediately preceding December 31 or (ii) a lesser number of shares as determined by the compensation committee of the board of directors. In accordance with the 2023 Plan, the shares reserved for issuance automatically increased by 855,016 shares on January 1, 2024, by 1,226,994 shares on January 1, 2025 and by 1,278,164 shares on January 1, 2026. As of June 30, 2026, the aggregate maximum number of shares reserved for issuance under the 2023 Plan was 5,946,142, of which 141,151 shares were available for future grants. Option grants issued under the 2023 Plan are exercisable for up to 10 years from the date of issuance.

In March 2024, the Company established a pool of 1,000,000 shares of Series A common stock (Inducement Pool) from which equity grants in the form of options and restricted stock units may be issued as inducement for new employees to accept employment offers from the Company or for individuals returning to employment after a bona fide period of non-employment with the Company. Inducement Pool grants are granted outside of the 2023 Plan and do not require approval from the Company’s stockholders pursuant to the Nasdaq inducement grant exception in accordance with Nasdaq Listing Rule 5635(c)(4). In February 2025, the Company increased the number of shares available for issuance by 300,000 shares, and further by 100,000 shares in April 2026 and by 525,000 shares in May 2026, increasing the total number of shares available for issuance under the Inducement Pool to 1,925,000 shares. As of June 30, 2026, 677,558 shares were available for future grants from the Inducement Pool.

Stock options

The Company grants stock options which consist of (i) time-based options, which vest and become exercisable, subject to the participant’s continued employment or service through the applicable vesting date and (ii) performance-based options, which vest based on performance measures against predetermined objectives that include successful completion of qualified equity offerings or announced topline results for clinical trials and positive clinical results over a specified performance period. The Company’s time-based options have various vesting schedules that range from vesting immediately to vesting over a four-year period.

During the six months ended June 30, 2026 and 2025, the weighted average grant-date fair value per share of stock options granted was $4.93 and $3.77, respectively. The total intrinsic value of stock options exercised during the six months ended June 30, 2026 and 2025, was approximately $40,000 and de minimis, respectively. Additionally, during the six months ended June 30, 2026 and 2025, cash received from the exercise of stock options was approximately $0.1 million and $1,000, respectively.

As of June 30, 2026, there was $13.6 million of unrecognized compensation expense, which is expected to be recognized over a remaining weighted-average period of 2.9 years.

Valuation assumptions

The expected term is determined using the simplified method, which represents the average of the contractual term of the options and the weighted-average expected vesting period. The risk-free interest rate is determined by reference to the United States Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the option. The expected stock volatility rate is based on the volatility rates of comparable publicly held companies over a period equal to the expected term of the option. The Company also utilizes its limited available historical volatility, to a lesser weight, in its expected stock volatility calculation. The Company utilizes a dividend yield of zero based on the fact that the Company has never paid cash dividends to stockholders and has no current intentions to pay cash dividends.

Restricted stock units

The Company’s restricted stock units generally vest over a four-year period in equal amounts on an annual basis, provided the employee remains continuously employed with the Company. The fair value of the restricted stock units is equal to the closing price of the Company’s Series A common stock on the grant date.

As of June 30, 2026, the total unrecognized compensation expense related to unvested restricted stock units was $3.1 million, which is expected to be recognized over a remaining weighted-average period of 2.7 years.

Performance stock units

A performance stock unit (PSU) represents one equivalent share of the Company’s Series A common stock to be issued after achievement of the performance goals specified in the grant. The Company estimates the fair value of PSUs as of the grant date based upon the expected likelihood of achievement of the performance goals specified in the grant and the closing price of its Series A common stock on the date of grant. The Company recognizes stock-based compensation expense over the requisite service period, if it is probable that the performance goal will be achieved.

In May 2026, the Company granted 616,800 PSUs which are subject to a performance and a service condition to certain of its employees (the 2026 PSU Awards). The 2026 PSU Awards will vest upon the achievement of certain regulatory milestones, whereas one-third of such earned portion shall vest upon the Compensation Committee’s determination of the achievement of each regulatory milestone and the remaining two-thirds will vest in two equal installments on the first and second anniversaries of the achievement date. The Company will begin recognizing compensation cost on the date that the performance condition becomes probable, with an initial recording of the cumulative expense that would have been recognized if the PSU expense had been recognized on a straight-line basis since the date of grant. The remaining unrecognized compensation cost will then be expensed prospectively on a straight-line basis over the remaining service period. As of June 30, 2026, the Company has not recognized any stock-based compensation expense related to the 2026 PSU Awards as the Company does not yet consider achievement of the performance metric to be probable. As of June 30, 2026, the total unrecognized compensation expense related to the unvested 2026 PSU Awards was $4.5 million.

Employee stock purchase plan

The 2023 Employee Stock Purchase Plan (the ESPP) was adopted by the board of directors in July 2023 with an initial total of 215,497 shares of Series A common stock reserved for issuance. Under the ESPP plan, the amount of shares reserved automatically increases each January 1 through January 1, 2033, by the least of (i) 215,497 shares of Series A common stock, (ii) 1% of the outstanding number of shares of the Company’s Series A common stock on the immediately preceding December 31 or (iii) such lesser number of shares of Series A common stock as determined by the administrator of the ESPP. In accordance with the ESPP, the shares reserved for issuance automatically increased by 213,754 shares on January 1, 2024, by 215,497 shares on January 1, 2025 and by 215,497 shares on January 1, 2026. As of June 30, 2026, the aggregate maximum number of shares reserved for issuance under the ESPP was 860,245, of which 844,174 shares remain available for future issuance. During the three and six months ended June 30, 2026, 16,071 shares were issued under the ESPP. There were no shares issued under the ESPP during the three and six months ended June 30, 2025.