 SOUTH SAN FRANCISCO, Calif., Sept. 30, 2021 PRNewswire -- Sutro Biopharma, Inc. NASDAQ: STRO, a clinical-stage drug discovery, development and manufacturing company focused on the application of precise protein engineering and rational design to create next-generation cancer and autoimmune therapeutics, today announced that Merck, known as MSD outside the United States and Canada, has extended the research term for the first cytokine derivative program under the 2018 Merck Agreement, for an additional two years. 