SUZHOU, China, August 18, 2021, Transcenta announced that it held an investigator meeting successfully for TST001 Phase I clinical trial study on August 14. Professors Lin Shen and Jifang Gong from Beijing Cancer Hospital, Professor Weijian Guo from Fudan University Shanghai Cancer Center and other investigators from more than 40 hospitals nationwide attended the meeting and participated in the project discussion. Dr. Xueming Qian, CEO of Transcenta, Dr. Michael Shi, EVP, Head of Global R&D and CMO of Transcenta, and members of TST001-1002 project team attended the meeting.

The investigators concluded that the current clinical data of TST001 supports the initiation of the expansion phase study. Transcenta announced that the first patient of the Phase IIa clinical trial was successfully dosed on August 17, 2021.

Claudin 18.2 is a pan-cancer target and is highly expressed in gastric cancer, pancreatic cancer, gallbladder and biliary tract cancer, esophageal cancer and only highly expressed in normal gastric epithelial cells. The result of IMAB362 Phase II trial FAST validated Claudin18.2 as a novel target with high potential for anti-tumor efficacy. TST001 is a second-generation humanized antibody targeting Claudin18.2 developed by Transcenta in house, and it has higher affinity and more enhanced NK cells mediated ADCC activity than IMAB362.

Transcenta initiated a Phase I clinical trial of TST001 in the US and China in August 2020, led by Professor Lin Shen from Beijing Cancer Hospital, to evaluate its safety, tolerability, pharmacokinetics and preliminary efficacy. The Phase I single-agent dose escalation trial (0.3-10 mg/kg Q3W) has been completed in China. During the trial, a gastric cancer patient heavily pre-treated with therapies (including chemotherapies, PD-1 immunotherapy and anti-VEGF inhibitor) achieved partial response after 6 weeks of treatment with 6 mg/kg (Q3W) and the partial response was confirmed at 12 weeks post-treatment. TST001 also demonstrated a favorable safety profile with no additional drug-induced SAE other than nausea and vomiting. Recently, the US Food and Drug Administration (FDA) has granted Orphan Drug Designation to TST001 for the treatment of gastric cancer and gastroesophageal junction cancer.

The Phase IIa clinical trial of TST001 is an open-label, single-arm, multi-center study. It is designed to further evaluate the safety, tolerability, and anti-tumor efficacy in patients with multiple solid tumors expressing Claudin18.2 including gastric cancer. These patients will be screened using an immunohistochemistry assay developed by Transcenta and validated by central lab that specifically detects Claudin18.2 but not Claudin 18.1.

Professor Lin Shen from Beijing Cancer Hospital commented, "During the dose escalation phase of the TST001 trial, we have observed promising anti-tumor activity of TST001. TST001 is the second leading Claudin18.2-targeting monoclonal antibody worldwide following Zolbetuximab (IMAB362) of Astellas and is also the fastest-moving program in China. Now, we have gained experience on safety and preliminary efficacy on single agent and combination therapy. We look forward to advancing this program aggressively to bring more effective treatments to gastric cancer patients worldwide."

Dr. Michael Shi, EVP, Head of Global R&D and CMO of Transcenta said, "When initiating TST001 project, we set very high differentiation criteria for binding affinity, in vitro and in vivo efficacy, antibody developability. Currently we have hit the goals in all aspects. This investigator meeting marks the official initiation of the multicenter Phase IIa clinical trial. We will work with many centers in China to further expand single-agent escalation / expansion studies and combination therapy to bring benefits to cancer patients around the world in the future." 

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).