12. STOCK-BASED COMPENSATION

2019 Equity Incentive Plan

During 2019, the Company adopted the 2019 Equity Incentive Plan, as amended (the “2019 Plan”). Under the 2019 Plan, there were 19,758,924 shares of common stock issuable upon the exercise of outstanding stock options as of June 30, 2026 that were previously granted to employees, officers, directors, consultants, and advisors. Options typically vest over four years and have a maximum term of 10 years. Concurrent with the IPO in February 2026, all unissued shares reserved for grant under the 2019 Plan ceased to be available, with future issuances intended to be made under the 2026 Equity Incentive Plan.

2026 Equity Incentive Plan

During the six months ended June 30, 2026, in connection with the Company's IPO, the Company adopted the 2026 Equity Incentive Plan, as amended (the “2026 Plan”). The 2026 Plan initially provided for the issuance of up to 11,852,719 shares of common stock, and is expected to be increased annually at a rate of four percent of the then outstanding number of shares of common stock, or such lesser amount as may be determined by the board of directors, plus the number of shares available from forfeitures and cancellations under the 2019 Plan. As of June 30, 2026, there were 7,232,136 shares of common stock available for issuance to employees, officers, directors, consultants, and advisors in the form of non-qualified and incentive stock options, restricted stock awards, and other stock-based awards. Options typically vest over four years and have a maximum term of 10 years.

Stock Option Valuation

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 Company utilized the Black-Scholes OPM to estimate the fair value of stock options awarded to employees, officers, directors, consultants and advisors. The Black-Scholes OPM requires several key assumptions. The assumptions that the Company used to determine the grant-date fair value of options granted to employees, non-employees and directors were as follows, presented on a weighted-average basis:

As of June 30, 2026, there was $87.0 million of unrecognized compensation expense, related to unvested time-based stock options that will be recognized over a weighted-average remaining term of 2.8 years.

Prior to January 1, 2024, the Company issued stock options covering shares 631,665 of common stock subject to the performance condition of entering into one or more strategic transactions pursuant to which the Company has the right to receive, in the aggregate, at least $200.0 million in specified payments. During the year ended December 31, 2022, the vesting of stock options covering 157,916 shares of stock with this performance condition was accelerated following the signing of the Amgen Collaboration Agreement in recognition of performance that did not otherwise achieve the performance condition. During the year ended December 31, 2025, the vesting of stock options covering 157,916 shares of common stock with this performance condition was accelerated following the signing of the Novartis Collaboration Agreement in recognition of performance that did not otherwise achieve the performance condition. The balance of 315,833 shares of common stock underlying these stock options remains outstanding. No stock-based compensation expense has been recorded on the remaining unvested stock options as the performance conditions are not deemed probable of occurrence.

During the year ended December 31, 2024, the Company issued stock options covering 65,832 shares of common stock subject to the performance condition of entering into one or more strategic transactions pursuant to which the Company has the right to receive, in the aggregate, at least $50.0 million in specified payments. Additionally, the Company issued stock options covering 65,832 shares of common stock subject to the performance condition of entering into one or more strategic transactions pursuant to which the Company has the right to receive, in the aggregate, at least $100.0 million in specified payments. These stock option grants covering an aggregate of 131,664 shares of common stock expired without the performance conditions having been deemed satisfied and were forfeited as of January 1, 2026.