UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

SUTRO BIOPHARMA, INC.

(Exact name of registrant as specified in its charter)

111 Oyster Point Blvd.

South San Francisco, California, 94080

(Address of principal executive offices) (Zip Code)

(650) 881-6500

(Registrant’s telephone number, including area code)

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 1.01 Entry into a Material Definitive Agreement.

On April 18, 2022 Sutro Biopharma, Inc. (the “Company”) entered into amendment No. 1 (the “Amendment”) to its licensing agreement (the “Tasly License Agreement”) with Tasly Biopharmaceuticals Co., Ltd. (“Tasly”) regarding Tasly’s exclusive license to develop and commercialize STRO-002 in Greater China, consisting of China, Hong Kong, Macau and Taiwan. Pursuant to the Amendment, the initial payment due by Tasly was amended to $25 million, and a $15 million payment will be placed in escrow by Tasly in the second quarter of 2022 and become payable to the Company upon satisfaction of certain regulatory milestones. The Amendment also added an additional regulatory milestone payment to the Tasly License Agreement, providing potential payments totaling up to $350 million related to development, regulatory and commercialization milestones, beyond the payments described above, and made certain other ministerial edits.

The foregoing description of the Amendment is qualified in its entirety by reference to the Amendment, a copy of which will be filed as an exhibit to the Company’s Quarterly Report on Form 10-Q for the quarter ending June 30, 2022.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.