Transcenta Provides Program Update for Anti-Claudin18.2 Monoclonal Antibody TST001 and Reports Promising Early Anti-Tumor Responses in Patients with Gastric Cancer

Transcenta Holding Limited, a clinical stage global biotherapeutics company with fully-integrated capabilities in discovery, development and manufacturing of antibody-based therapeutics, announces that promising anti-tumor responses have been observed in the ongoing TST001 (anti-Claudin18.2 monoclonal antibody) trials.

TST001 is currently in dose-escalation study as monotherapy in both US and China. In addition, Transcenta initiated combination study with chemotherapies in second line (paclitaxel) and first line (CAPOX) setting for gastric cancer in April and May 2021, respectively. Over forty patients have been evaluated and data from patients treated with the current doses of either TST001 alone or in combination with chemotherapies supports that TST001 is safe.

Promising early anti-tumor activities have also been observed from these studies. One heavily pretreated late-line gastric cancer patient out of the three patients at 6 mg/kg dose cohort in the monotherapy dose-escalation study achieved partial response according to RECIST1.1 criteria after 6 weeks of treatment. In addition, the patient also had rapid and significant tumor biomarker reduction post-TST001 treatment. The patient previously failed multiple lines of chemotherapies, PD-1 immunotherapy and anti-VEGF inhibitor. In addition, in the TST001 plus CAPOX combination study in first-line gastric cancer, a patient in the first dosing cohort achieved partial response after 6 weeks of treatment according to the RECIST1.1 criteria.

With these data, Transcenta plans to complete the ongoing dose-escalation study and initiate Phase 2a monotherapy studies in Q4 2021 in Claudin18.2-expressing solid tumors including gastric cancer, pancreatic cancer and other tumor types. Detailed data from the TST001 Phase 1a study will be submitted for presentation in a future medical conference.

"Recently, Claudin18.2 has emerged to be an exciting target for the treatment of gastric cancer. The ability of TST001 to induce significant anti-tumor activities in patient failed multiple previous treatments at 6mg/kg during dose-escalation indicated that TST001 is a very promising anti-Claudin18.2 targeting agent. I look forward to seeing even better anti-tumor responses in gastric cancer patients expressing high levels of Claudin18.2 at higher dose and in combination therapies." said Professor Lin Shen from Beijing Cancer Hospital.

"From the clinical studies, we are very excited to observe positive efficacy signals in heavily pre-treated late-line gastric cancer patients with high expression of Claudin18.2 who failed all available classes of front-line, second-line and third-line standard therapies in gastric cancer. In addition, we are quickly advancing TST001 in earlier lines of gastric cancer development in combination with chemotherapies and immunotherapies. The preliminary safety and efficacy of TST001 monotherapy and its combination with chemotherapies showed that TST001 has great potential for patients whose tumor expressed Claudin18.2. I look forward to additional clinical data in the future that will further reinforce TST001's efficacy and safety profiles, and accelerate our clinical development programs in multiple tumor types targeting Claudin18.2." said Dr. Michael Shi, EVP, Head of Global R&D and CMO of Transcenta.

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).

About Transcenta Holding Limited.

Transcenta is a clinical stage global biotherapeutics company that fully integrates antibody-based biotherapeutics discovery, development and manufacturing. Transcenta has established global footprint, with Headquarter and Discovery and Translational Research Center in Suzhou, Process and Product Development Center and Manufacturing Facility in Hangzhou, and Clinical Development Centers in Beijing, Shanghai and Guangzhou in China and in Princeton, US, and External Partnering Center in Boston, US. Transcenta is developing nine therapeutic antibody molecules for oncology and selected non-oncology indications including bone and kidney disorders. Upon the latest financing, the company has raised over $342 million from globally prominent investors.