Second Amendment to the Exclusive Patent License and Research Collaboration Agreement

Exhibit 10.2

Execution Copy

Second Amendment to the

Exclusive Patent License and Research Collaboration Agreement

This Second Amendment to the Exclusive Patent License and Research Collaboration Agreement between the Parties, effective as of July 23, 2018, and as subsequently amended by Amendment #1, effective as of August 26, 2020 (the “Agreement”), is entered into and effective as of the date of last signature below ("Amendment #2") by and between SUTRO BIOPHARMA, INC., a corporation organized and existing under the laws of Delaware (“Sutro”), and MERCK SHARP & DOHME CORP., a corporation organized and existing under the laws of the State of New Jersey (“Merck”).

WHEREAS, the Parties desire to amend the Agreement to (i) extend the Research Program Term for the First Research Program in order for the Parties to research and conduct certain preclinical activities for Additional Molecules (as defined below) and (ii) agree to certain additional milestone payments related to PCC Approval by such Additional Molecule, all as more fully set forth below;

NOW, THEREFORE, in consideration of the mutual promises and covenants contained herein, the Parties agree as follows:

1.Expansion of First Research Program. Section 2.1.1 of the Agreement is amended by adding the following sentences to the end thereof:

“The Parties wish to expand the Research Plan for the First Research Program to enable continued research and preclinical activities to support certain cytokine derivative molecules, including SP10784 (“Additional Molecules”; each such molecule an “Additional Molecule”). The high-level activities to be undertaken by the Parties during the Extended Research Program Term (as defined below) for the Additional Molecules are set forth in the amended Research Plan for the First Research Program which is attached hereto as Schedule 2.1, Part A. Sutro and Merck agree that the Joint Research Committee shall review the Research Plan activities for the Additional Molecules and determine when such Research Plan activities are completed pursuant to Section 2.4.2 of the Agreement.

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2.Extension of First Research Program Term. Section 2.1.5.1 of the Agreement is amended by adding the following sentences to the end thereof:

“Notwithstanding the foregoing and the first extension of the First Research Program Term as set forth in the letter agreement, dated March 9, 2020, between the Parties, the Research Program Term for the First Research Program shall be extended until March 31, 2022 and up to sixty (60) days thereafter in the event the Joint Research Committee requires additional time to make a PCC recommendation for the Additional Molecule pursuant to Section 2.1.1.1 and/or to enable PCC Approval by Merck pursuant to Section 2.1.1.2 (“Extended Research Program Term”). Further, upon the achievement of PCC Approval by the Additional Molecule, the Research Program Term for the First Research Program shall be automatically extended from March 31, 2022 or such date up to sixty (60) days thereafter, until the earlier of (i) achievement of Process Development Lock by the Additional Molecule as determined by the Joint Research Committee and (ii) December 31, 2023 (“Subsequent Extended Research Program Term).”

3.Payments. Section 7.3.1 of the Agreement is hereby deleted and replaced with the following 7.3.1 and 7.3.1.1:

“7.3.1 One-Time Research Milestones on a per Research Program basis. The one-time research milestone payments set forth in the table below shall be made for each Research Program under this Agreement. In addition, the Parties understand and agree that, prior to the effective date of Amendment #2 to this Agreement, Merck timely paid the one-time research milestone payments below for the First Research Program and that further one-time research milestone payments below shall only be made for other applicable Research Programs under this Agreement.

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4.Except as expressly amended hereby, all of the terms and conditions of the Agreement remain in full force and effect. Terms not defined in this Amendment #2 shall have the meaning given such definitions in the Agreement.

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IN WITNESS WHEREOF, the Parties hereto have executed this Amendment #2 as of the date of last signature below.

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AMENDMENT TO THE RESEARCH PLAN FOR FIRST RESEARCH PROGRAM (SCHEDULE 2.1)

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