On June 22, 2020 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, reported the presentation of new preclinical data for its folate receptor alpha (FolRα) targeting antibody-drug conjugate, STRO-002, at the 2020 American Association for Cancer Research (AACR) (Free AACR Whitepaper) Virtual Annual Meeting II from June 22-24, 2020 (Press release, Sutro Biopharma, JUN 22, 2020, View Source;301080795.html [SID1234561369]). The data, being presented by Sutro’s Chief Scientific Officer, Trevor Hallam, Ph.D., demonstrates STRO-002’s immune-modulating properties and potentiation by PD-L1 blockade.

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The results of the study showed that in FolRα positive tumor cells, STRO-002 treatment induced hallmarks of immunogenic cell death, killing tumor cells while activating immune cells, including monocytes. When combined in mouse tumor models with avelumab, an anti-human & mouse PD-L1 monoclonal antibody, the combination treatment enhanced efficacy leading to more complete responses and increased killer T cells, than either agent alone. Importantly, the data suggest that a single dose of STRO-002 when combined with a PD-1/PD-L1 blockade could provide an effective and protective anti-tumor immune response.

"These data suggest that STRO-002 can drive immune-modulatory responses that can cause complete tumor regression, tumor specific T cell activation and adaptive anti-tumor immunity," said Dr. Hallam. "The results here support the clinical evaluation of STRO-002 in combination with anti-PD1 or anti-PD-L1 agents. While we believe STRO-002 as a single agent may demonstrate clinical benefit in certain tumors resistant to checkpoint inhibitor monotherapies, we are excited at the prospect of evaluating potential additional positive impacts on cancer patients that may result from combination treatment regimens involving STRO-002 with other checkpoint inhibitors."

"An important part of our STRO-002 clinical development strategy includes evaluating these data to determine an optimal combination regimen to take into clinical trials," said Sutro Chief Medical Officer, Arturo Molina, M.D. "We anticipate evaluating STRO-002 in combination studies in addition to our single agent studies. We currently expect to initiate a STRO-002 combination clinical trial in 2021."

STRO-002 is an antibody-drug conjugate directed against FolRα, a membrane receptor glycoprotein, which is highly expressed in ovarian cancer and endometrial cancer and is composed of a FolRα antibody conjugated to a tubulin inhibitor hemiasterlin using a cleavable linker.

A Phase 1, open-label, multicenter, dose escalation trial with dose expansion of STRO-002 is ongoing, designed to identify the maximum tolerated dose, the recommended Phase 2 clinical dose, and to evaluate the safety, tolerability, and preliminary anti-tumor activity of STRO-002 in adults with advanced epithelial ovarian cancer, including fallopian or primary peritoneal cancer, and endometrial cancer. The trial is registered with clinicaltrials.gov identifier NCT03748186. Sutro discovered, developed and manufactures STRO-002 using its proprietary XpressCF+ cell-free protein synthesis technology.

Presentation Details:

Title: STRO-002, an anti-FolRα ADC, demonstrates immune-modulating properties
and potentiates PD-L1 blockade
Abstract Number: 2250
Session Title: Immune Mechanisms Invoked by Therapies 2
Date/Time: June 22, 2020, 9:00 a.m. – 6:00 p.m. EDT
Presenter: Trevor Hallam, Ph.D.

The e-poster presentation can be found on the AACR (Free AACR Whitepaper) website and is also accessible through the Clinical/Scientific Presentation and Publication Highlights page of the News section of Sutro Biopharma’s website at www.sutrobio.com on the day of the poster presentation.

Additionally, on June 24th Sutro’s partner Merck KGaA, Darmstadt, Germany, will be presenting preclinical data from the collaboration’s pre-Development Candidate, M1231, a first-in-class bispecific antibody-drug conjugate targeting EGFR and MUC1.

Presentation Details:

Title: M1231: A first-in-class bispecific antibody-drug conjugate targeting EGFR
and MUC1
Abstract Number: 5686
Session Title: Emerging Mechanisms of Resistance to Targeted Therapies
Date/Time: June 24, 2020, 10:05 a.m. – 10:15 a.m. EDT
Presenter: Jan Anderl, Ph.D.