SOUTH SAN FRANCISCO, CA, USA I August 25, 2020 I 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 oncology therapeutics, today announced that it has achieved a clinical supply milestone under its collaboration and license agreement with the healthcare division of Merck KGaA, Darmstadt, Germany and is entitled to receive a milestone payment. The candidate, M1231, was discovered using Sutro’s XpressCF® and XpressCF+™ drug discovery and manufacturing technologies and includes a proprietary linker-warhead also discovered by Sutro. M1231 is a MUC1-EGFR bispecific antibody drug conjugate (ADC) for the treatment of solid tumors and relies on the strand-exchange engineered domain (SEED) platform from Merck KGaA, Darmstadt, Germany to generate bispecific antibody-like molecules.

The milestone was achieved with the delivery of GMP clinical trial supply to Merck KGaA, Darmstadt, Germany for the Phase 1 clinical trial testing of M1231 pursuant to a 2014 license agreement. As part of the agreement, Sutro will manufacture M1231 for early clinical supply and is eligible for further milestones and royalties. Merck KGaA, Darmstadt, Germany will be responsible for filling and finishing the drug product, in addition to its clinical development and commercialization.

“Reaching the clinical supply milestone in our collaboration with Merck KGaA, Darmstadt, Germany underscores our continued commitment to deliver novel therapies to patients with cancer,” said Bill Newell, Sutro’s Chief Executive Officer. “M1231 bispecific ADC was generated with Sutro’s XpressCF® and XpressCF+™ drug discovery and manufacturing technologies which enabled the use of iterative optimization through cell-free protein synthesis and site-specific conjugation with the goal of an improved therapeutic window. Through our continued collaboration with Merck KGaA, Darmstadt, Germany, we hope to move closer to bringing new treatment options to cancer patients.”

“M1231 is the first bispecific ADC targeting both MUC1 and EGFR.  By combining XpressCF+™ technology with the SEED antibody platform, Merck KGaA, Darmstadt, Germany and Sutro in collaboration have developed a unique next generation ADC that has the potential to increase the therapeutic window by selectively targeting tumors that co-express two different tumor antigens.,” said Trevor Hallam, PhD, Sutro’s Chief Scientific Officer.

“We look forward to working with Merck KGaA, Darmstadt, Germany to apply our proprietary GMP manufacturing platform to supply M1231 for the early clinical studies,” said Shabbir Anik, PhD, Sutro’s Chief Technical Officer.

Under the terms of the 2014 license agreement, Sutro and Merck KGaA, Darmstadt, Germany have collaborated to discover and develop ADCs utilizing Sutro’s cell-free protein synthesis and site-specific conjugation platforms, XpressCF® and Xpress CF+™. Further financial details are not being disclosed.

About Sutro Biopharma
Sutro Biopharma, Inc., located in South San Francisco, is a clinical-stage drug discovery, development and manufacturing company. Using precise protein engineering and rational design, Sutro is advancing next-generation oncology therapeutics.

SOURCE: Sutro Biopharma