SUZHOU, China, June 1, 2022，Transcenta Holding Limited ("Transcenta") (HKEX: 06628), a clinical stage biopharmaceutical company with fully-integrated capabilities in discovery, research, development and manufacturing of antibody-based therapeutics, announces that clinical data for the dose-escalation part of the Phase I study of TST001 in combination with CAPOX as the first line treatment of advanced and metastatic G/GEJ cancer has been published on the ASCO's website: https://conferences.asco.org/am/attend.

The data showed that TST001 in combination with CAPOX as the first line treatment of patients with advanced and metastatic G/GEJ cancer is well tolerated and encouraging preliminary anti-tumor activities have been observed. The recruitment for the current cohort is ongoing, and the safety and efficacy of the combination of TST001+CAPOX as first line treatment for patients with advanced and metastatic G/GEJ cancer will be further evaluated.

TST001（Claudin18.2）
Abstract Number: 4062
Session Date and Time: June 4, 2022, 8:00 AM-11:00 AM CDT
Title: A Phase I Study of TST001, a High Affinity Humanized Anti-Claudin18.2 Monoclonal Antibody, in Combination with Capecitabine and Oxaliplatin (CAPOX) as a First Line Treatment of Advanced G/GEJ Cancer
First author: Professor Jifang Gong, Peking University Cancer Hospital and Research Institute
Presentation Format: Poster

The study aimed to evaluate the safety, tolerability and preliminary efficacy of TST001 in combination with CAPOX as the first line treatment of patients with advanced G/GEJ cancer. (ClinicalTrials.gov Identifier: NCT04495296). Chinese patients with advanced G/GEJ cancer who had not received prior systemic treatment were enrolled regardless of Claudin18.2 expression in the dose escalation phase following 3+3 design; the safety and efficacy profile was being further evaluated in the dose expansion phase.

As of April 5, 2022, 14 patients had been dosed with TST001 at 1, 3, 6 or 8 mg/kg plus CAPOX Q3W in the dose escalation phase, and 12 patients at 6 mg/kg Q3W in the expansion phase. No subject experienced dose-limiting toxicity. Treatment-emergent adverse events (TEAEs) were mostly grade 1-2, including nausea, hypoalbuminemia, anemia, vomiting, and AST increased. Among the 9 subjects in the dose-escalation phase without Claudin18.2 selection who had measurable lesions and had received at least one posttreatment tumor assessments, 5 achieved partial response and 3 achieved stable disease as the best overall response per RECIST1.1.

"Claudin18.2 has been validated as a novel target and promising anti-tumor activity has been observed in the phase II FAST clinical trial of IMAB362." said Professor Lin Shen from Beijing Cancer Hospital. "According to efficacy and safety results from trials thus far, TST001 showed manageable safety profile and encouraging anti-tumor activities in Claudin18.2 expressing treatment naïve gastric cancer patients. I am looking forward to further evaluating this combo therapy in a randomized global multi-center phase III registration trial in Claudin18.2 positive gastric cancer patients."

"From the dose-escalation phase, we are very pleased to show that TST001 is well tolerated and displayed encouraging clinical response in combination with chemotherapy in Claudin18.2 unselected first line gastric cancer patients." said Dr. Michael Shi, EVP, Head of Global R&D and CMO of Transcenta. "We will continue to evaluate the safety and efficacy of this combination and plan to initiate a multi-center global registration enabling trial in Claudin18.2 positive first line gastric cancer patients. The development will be supported by our proprietary Claudin18.2 companion diagnostic kit being developed in parallel and strong in-house CMC capabilities. We believe that TST001 in combination with chemotherapy could provide a novel option for the treatment of Claudin18.2 positive gastric cancer patients globally."

About TST001

TST001 is a high affinity humanized anti-Claudin18.2 monoclonal antibody with enhanced antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) activities and potent anti-tumor activities in tumor xenograft models. TST001 is the second Claudin18.2 targeting antibody therapeutic candidate being developed globally. TST001 is generated using Transcenta's Immune Tolerance Breaking Technology (IMTB) platform. TST001 kills 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 NK cells mediated ADCC activity of TST001. Clinical trials for TST001 are ongoing in China and US (NCT04396821, NCT04495296/CTR20201281). TST001 was granted Orphan Drug Designation in the US by FDA for the treatment of patients with gastric cancer or gastroesophageal junction (GC/GEJ).

About Transcenta Holding Limited

Transcenta (HKEX: 06628) is a clinical stage biopharmaceutical company with fully integrated capabilities in antibody-based biotherapeutics discovery, research, development and manufacturing.

Transcenta has established global footprint, with Headquarters and Discovery, Clinical 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 and Los Angeles, US. Transcenta has also initiated the construction of the Group Headquarters and the second high-end biopharmaceutical facility with ICB as its core technology in Suzhou Industrial Park. Transcenta is developing ten therapeutic antibody molecules for oncology and selected non-oncology indications including bone and kidney disorders.

For more information, please visit www.transcenta.com and https://www.linkedin.com/company/transcenta.

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