Zhejiang Doral Biotechnology Announces Clinical Trial Collaboration with MSD to Evaluate DR30303 in Combination with KEYTRUDA® for Gastric and Gastroesophageal Junction Cancer

HangzhouDecember 16, 2022/PR Newswire/ --Hangzhou, Zhejiang Province, China [December 9, 2022],Zhejiang Doer Biologics Co., Ltd. ("Doer Biologics"), a clinical-stage biopharmaceutical company developing innovative biotherapeutics for metabolic diseases and cancer,TodayAnnouncementEntered into a clinical trial collaboration agreement with MSD (MSD is the corporate name of Merck & Co., Inc. in Kenilworth, NJ, USA) to explore Doer Biologics' anti-Claudin18.2 antibody DR30303 in combination with MSD’s PD-1 inhibitor KEYTRUDA.^®(Clinical trial of pembrolizumab) in combination therapy for patients with gastric cancer or gastroesophageal junction cancer.

According to the agreement, Doer Biologics will conduct clinical trials based on the clinical protocol agreed upon and finalized by both parties to evaluate DR30303 and KEYTRUDA.^®Safety and Efficacy of Combined Therapy in Claudin18.2-Positive, Locally Advanced Unresectable or Metastatic Gastric Cancer or Gastroesophageal Junction Cancer (GC/GEJ) Patients.

Dr. Huang Yanshan, founder and CEO of Doer Biologics, stated: "DR30303 is a humanized anti-Claudin18.2 single-domain antibody Fc fusion protein (VHH-Fc) developed by Doer Biologics based on its proprietary SMART-VHHBody platform. We believe DR30303 exhibits strong affinity and highly selective binding to Claudin18.2, while enhancing antibody-dependent cellular cytotoxicity (ADCC) activity, with a lower risk of immunogenicity. Its smaller molecular weight may allow DR30303 to penetrate more quickly and deeply into solid tumors. We believe DR30303 has the potential to be a best-in-class anti-Claudin."in18.2 antibody." Dr. Yongliang Fang, Chief Operating Officer of Doer Biologics, commented: "DR30303 has demonstrated good safety in the ongoing monotherapy trial and shown encouraging anti-tumor signals in patients with Claudin18.2-positive solid tumors. We are very pleased to explore DR30303 in combination with KEYTRUDA.^®Combined treatment for Claudin18.2-positive gastric cancer or gastroesophageal junction cancer (GC/GEJ) patients.

KEYTRUDA^®Is a registered trademark, with the trademark owner being Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc. located in Rahway, New Jersey, USA.

AboutDR30303

DR30303 is a humanized anti-Claudin18.2 single-domain antibody Fc fusion protein (VHH-Fc) developed by Doer Biologics based on its proprietary SMART-VHHBody platform. Due to the tumor specificity of Claudin18.2 and its abnormally high expression in gastric cancer and pancreatic cancer, it has become an extremely attractive target for cancer treatment. DR30303 exhibits strong high-selectivity binding to the Claudin18.2 target, with enhanced antibody-dependent cellular cytotoxicity (ADCC) activity achieved through Fc engineering modifications. Additionally, T-cell epitope prediction based on algorithms indicates a lower risk of immunogenicity. Preclinical studies have shown that DR30303 demonstrates potent anti-tumor activity both as a monotherapy and in combination with chemotherapy drugs or PD-1 inhibitors across various mouse tumor models, while also displaying favorable pharmacokinetic properties.