On June 9, 2023, Sutro Biopharma, Inc. (Company) received a notice of termination from Celgene Corporation, a Bristol Myers Squibb company (BMS), of the Amended and Restated Collaboration and License Agreement, dated as of August 2, 2017, by and among the Company, Celgene Corporation and Celgene Alpine Investment Company II, LLC, as amended . The Company and Celgene Corporation originally entered into the collaboration governed by the Agreement in 2014, prior to BMS's acquisition of Celgene Corporation. Under the Agreement, the Company and BMS had been collaborating on an antibody-drug conjugate program targeting B cell maturation antigen, CC-99712.

The Company has been informed by BMS that the decision to terminate the Agreement and stop development of CC-99712 was the result of a portfolio prioritization decision. The termination of the Agreement is effective as of October 7, 2023 (the " Termination Date "). From and after the Termination Date, the Company will have sole worldwide rights to CC-99712.