STRO · Sutro Biopharma, Inc.

The option shall vest, subject to the reporting person's provision of service to the issuer on each vesting date, as to 8.33% of the total award monthly, with the first tranche vesting on July 5, 2026, and the award shall be fully vested and exercisable on the earlier of (i) the date of the issuer's 2027 annual stockholders meeting or (ii) June 5, 2027.

The option shall vest, subject to the reporting person's provision of service to the issuer on each vesting date, as to 8.33% of the total award monthly, with the first tranche vesting on July 5, 2026, and the award shall be fully vested and exercisable on the earlier of (i) the date of the issuer's 2027 annual stockholders meeting or (ii) June 5, 2027.

The option shall vest, subject to the reporting person's provision of service to the issuer on each vesting date, as to 8.33% of the total award monthly, with the first tranche vesting on July 5, 2026, and the award shall be fully vested and exercisable on the earlier of (i) the date of the issuer's 2027 annual stockholders meeting or (ii) June 5, 2027.

The option shall vest, subject to the reporting person's provision of service to the issuer on each vesting date, as to 8.33% of the total award monthly, with the first tranche vesting on July 5, 2026, and the award shall be fully vested and exercisable on the earlier of (i) the date of the issuer's 2027 annual stockholders meeting or (ii) June 5, 2027.

The option shall vest, subject to the reporting person's provision of service to the issuer on each vesting date, as to 8.33% of the total award monthly, with the first tranche vesting on July 5, 2026, and the award shall be fully vested and exercisable on the earlier of (i) the date of the issuer's 2027 annual stockholders meeting or (ii) June 5, 2027.

The option shall vest, subject to the reporting person's provision of service to the issuer on each vesting date, as to 8.33% of the total award monthly, with the first tranche vesting on July 5, 2026, and the award shall be fully vested and exercisable on the earlier of (i) the date of the issuer's 2027 annual stockholders meeting or (ii) June 5, 2027.

The option shall vest, subject to the reporting person's provision of service to the issuer on each vesting date, as to 8.33% of the total award monthly, with the first tranche vesting on July 5, 2026, and the award shall be fully vested and exercisable on the earlier of (i) the date of the issuer's 2027 annual stockholders meeting or (ii) June 5, 2027.

The option shall vest, subject to the reporting person's provision of service to the issuer on each vesting date, as to 8.33% of the total award monthly, with the first tranche vesting on July 5, 2026, and the award shall be fully vested and exercisable on the earlier of (i) the date of the issuer's 2027 annual stockholders meeting or (ii) June 5, 2027.

For avoidance of doubt, the reporting person elected to satisfy tax withholding liabilities in cash in lieu of withholding shares.

The reported total includes 250 shares of Common Stock acquired by the reporting person in one or more transactions with the Issuer pursuant to its employee stock purchase plan, which transactions are exempt pursuant to Rules 16a3(f)(1)(i)(B) and 16b3(c).

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The award vested or vests annually as to 1/4th of the total award, subject to the reporting person's continued service to the Issuer on each vesting date, with the first tranche vested on June 2, 2026.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 4, 2023, subject to continued service through each vesting date.

Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of restricted stock units; does not represent a sale by the reporting person.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 4, 2023, subject to continued service through each vesting date.

Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of restricted stock units; does not represent a sale by the reporting person.

1/48 of the total option award shall vest monthly, subject to the reporting person's continued service to the Issuer on each vesting date, with the first tranche vesting on April 1, 2026.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs shall vest as to 1/4 of the total award annually, with the first tranche vesting on March 1, 2027, subject to continued service through each vesting date.

Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of restricted stock units; does not represent a sale by the reporting person.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs shall vest as to 1/4 of the total award annually, with the first tranche vesting on March 1, 2027, subject to continued service through each vesting date.

Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of restricted stock units; does not represent a sale by the reporting person.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs shall vest as to 1/4 of the total award annually, with the first tranche vesting on March 1, 2027, subject to continued service through each vesting date.

1/48 of the total option award shall vest monthly, subject to the reporting person's continued service through each vesting date, with the first tranche vesting on April 1, 2026.

1/48 of the total option award shall vest monthly, subject to the reporting person's continued service through each vesting date, with the first tranche vesting on April 1, 2026.

1/48 of the total option award shall vest monthly, subject to the reporting person's continued service through each vesting date, with the first tranche vesting on April 1, 2026.

Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of RSUs; does not represent a sale by the reporting person.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs shall vest as to 1/4 of the total award annually, with the first tranche vesting on March 1, 2027, subject to continued service through each vesting date.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 2, 2026, subject to continued service through each vesting date.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 2, 2026, subject to continued service through each vesting date.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 2, 2026, subject to continued service through each vesting date.

Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of restricted stock units; does not represent a sale by the reporting person.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 1, 2024, subject to continued service through each vesting date.

Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of RSUs; does not represent a sale by the reporting person.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 1, 2025, subject to continued service through each vesting date.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 1, 2025, subject to continued service through each vesting date.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 1, 2024, subject to continued service through each vesting date.

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 1, 2025, subject to continued service through each vesting date.

Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of restricted stock units; does not represent a sale by the reporting person.

The option shall vest as to 16.67% of the total award monthly, subject to the reporting person's continued service to the issuer on each vesting date, with the first tranche vesting on January 23, 2026.

1/48 of the total option award shall vest monthly, subject to the reporting person's continued service to the issuer on each vesting date, with the first tranche vesting on January 23, 2026.

The option shall vest as to 16.67% of the total award monthly, subject to the reporting person's continued service to the issuer on each vesting date, with the first tranche vesting on January 23, 2026.

1/48 of the total option award shall vest monthly, subject to the reporting person's continued service to the issuer on each vesting date, with the first tranche vesting on January 23, 2026.