SUZHOU, China, July 28, 2021, Transcenta Holding Limited ("Transcenta"), a clinical stage global biotherapeutics company with fully-integrated capabilities in discovery, development and manufacturing of antibody-based therapeutics, announces that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation to TST001, its anti-Claudin18.2 monoclonal antibody currently in Phase I clinical trial, for the treatment of patients with gastric cancer or gastroesophageal junction (GC/GEJ). According to preclinical and clinical data, TST001 displayed potent anti-tumor activities in tumor model of gastric cancer or patient of gastric cancer expressing Claudin18.2.

Gastric cancer is a rare disease in the United States, though it has a much higher incidence in Asian countries such as China and Japan. According to the National Cancer Institute's Surveillance, Epidemiology, and End Results Program, in 2018, there were an estimated 120,301 people living with gastric cancer in the United States. It is the third leading cause of cancer deaths worldwide, following only lung and colorectal cancer. At present, the treatment options of gastric cancer expressing Claudin18.2 are very limited other than surgical resection, chemotherapy and most recently immunotherapy.

Orphan Drug Designation (ODD) is granted by the FDA to drugs intended to treat rare disorders that affect fewer than 200,000 people in the U.S. The designation can provide development and commercial incentives, including eligibility for seven years of market exclusivity in the U.S. after product approval, tax credit of 50% clinical trial cost, waiver of BLA user fee, subsidies for R&D costs, protocol assistance and expedited regulatory approval pathway.

"GC/GEJ is a serious, life-limiting orphan disease in the US. At present, the treatment of GC/GEJ represents an urgent unmet clinical need globally. This ODD by the US FDA for the treatment of GC/GEJ marks an important milestone in the global development of TST001," said Dr. Michael Shi, EVP, Head of Global R&D and CMO of Transcenta. "We will expedite the development of TST001 for GC/GEJ either as single agent or combination therapy to benefit patients around the world."

About TST001

TST001 is the second Claudin18.2 targeting antibody therapeutic candidate being developed globally after Zolbetuximab (IMAB362). TST001 is a high-affinity recombinant humanized monoclonal antibody targeted Claudin18.2 generated by Transcenta's Immune Tolerance Breaking Technology (IMTB) platform. TST001 can kill Claudin18.2 expressing tumor cells by mechanisms of antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Leveraging advanced bioprocessing technology, the fucose content of TST001 was significantly reduced during the production, which further enhanced the ADCC-mediated tumor killing activity of TST001. TST001 displayed more potent anti-tumor activities than IMAB362 analog in mouse xenograft experiments. Clinical trials for TST001 are ongoing in China and US since July 2020 (NCT04396821, NCT04495296/CTR20201281).