SOUTH SAN FRANCISCO, CA, USA I April 8, 2022 I Sutro Biopharma, Inc. (“Sutro” or the “Company”) (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 therapeutics, today announced new nonclinical data for its folate receptor alpha (FolRα) targeting antibody-drug conjugate (ADC) STRO-002, in an e-poster session, at the American Association for Cancer Research (AACR) Annual Meeting 2022, being held virtually and in New Orleans from April 8-13, 2022.

STRO-002 is an ADC designed to target FolRα, which is currently in Phase 1 clinical trials for the treatment of ovarian and endometrial cancers. In the e-poster session presented at AACR, studies in vitro demonstrate STRO-002’s ability to induce hallmarks of immunogenic cell death. Studies in vivo show that pre-administration of STRO-002 to FolRα-expressing tumor cells confers anti-tumor immunity as demonstrated by both rejection of the primary tumor and significant protection after a tumor re-challenge. Further, in vivo induction of immunogenic cell death extended to a complementary anti-tumor mechanism in combination with a checkpoint inhibitor (avelumab) in re-challenged animals. Additionally, when STRO-002 was administered in combination with an anti-VEGF antibody (bevacizumab), the tumor growth was significantly inhibited.

Nonclinical studies using endometrial and non-small cell lung cancer (NSCLC) patient derived xenograft models with diverse levels of FolRα expression demonstrated robust STRO-002 activity, with the degree of efficacy correlating with FolRα levels. Similar activity was also seen in cells with moderate to low levels of FolRα expression. In the NSCLC model, a STRO-002 dose of 10 mg/ml resulted in significant and long-term responses.

“These nonclinical data provide insight into STRO-002’s immunogenic cell death properties and reveal its potential to elicit host immune system engagement and potentiate efficacy in a targeted and dependent manner,” said Trevor Hallam, Ph.D., President of Research and Chief Scientific Officer at Sutro. “The potent cytotoxic and immune stimulatory properties of STRO-002 through immunogenic cell death may also enhance activity in indications that are thought to have lower levels of FolRα such as in non-small cell lung cancer and endometrial cancers.”

The data is being presented as an e-poster at the AACR Annual Meeting, with details as follows:

Abstract: #5591
Session: OPO.IMO2.01 – Preclinical Immunotherapy
Title: Anti-FolRα ADC STRO-002 induces immunogenic cell death (ICD) to enhance anti-tumor activity
Presenter: Kristin Bedard, Ph.D., Vice President of Discovery at Sutro Biopharma

The poster is accessible through the Clinical/Scientific Presentation and Publication Highlights page of the News section of the company’s website at www.sutrobio.com.

 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.

Sutro’s proprietary and integrated cell-free protein synthesis platform XpressCF® and site-specific conjugation platform XpressCF+™ led to the discovery of STRO-001 and STRO-002, Sutro’s first two internally-developed ADCs. STRO-001 is a CD74-targeting ADC currently under investigation in a Phase 1 clinical trial for patients with advanced B-cell malignancies and was granted Orphan Drug Designation by the FDA for multiple myeloma. STRO-002, a folate receptor alpha (FolRα)-targeting ADC, is currently being investigated in a Phase 1 clinical trial for patients with ovarian and endometrial cancers and was granted Fast Track designation by the FDA for ovarian cancer. A third product candidate, CC-99712, a BCMA-targeting ADC, which is part of Sutro’s collaboration with Bristol Myers Squibb, formerly Celgene Corporation, is enrolling patients for its Phase 1 clinical trial of patients with multiple myeloma and has received Orphan Drug Designation from the FDA. A fourth product candidate, M1231, a MUC1-EGFR, bispecific ADC, which is part of Sutro’s collaboration with Merck KGaA, Darmstadt, Germany, known as EMD Serono in the U.S. and Canada (EMD Serono), is enrolling patients for its Phase 1 clinical trial of patients with metastatic solid tumors, non-small cell lung cancer (NSCLC) and esophageal squamous cell carcinoma. These four product candidates resulted from Sutro’s XpressCF® and XpressCF+™ technology platforms. Bristol Myers Squibb and EMD Serono have worldwide development and commercialization rights for CC-99712 and M1231, respectively, for which Sutro is entitled to milestone or contingent payments and tiered royalties.

Sutro is dedicated to transforming the lives of cancer patients by creating medicines with improved therapeutic profiles for areas of unmet need. To date, Sutro’s platform has led to ADCs, bispecific antibodies, cytokine-based immuno-oncology therapies, and vaccines directed at precedented targets in clinical indications where the current standard of care is suboptimal.

Sutro’s platform allows it to accelerate discovery and development of potential first-in-class and best-in-class molecules through rapid and systematic evaluation of protein structure-activity relationships to create optimized homogeneous product candidates. In addition to developing its own oncology pipeline, Sutro is collaborating with select pharmaceutical and biotechnology companies to discover and develop novel, next-generation therapeutics.

Follow Sutro on Twitter, @Sutrobio, and at www.sutrobio.com to learn more about our passion for changing the future of oncology.

SOURCE: Sutro Biopharma