Transcenta Presented Safety / Tolerability and Preliminary Anti-tumor Activity Data in Gastric and Pancreatic Cancers of TST001 Monotherapy from China Phase I Clinical Trial at the 2022 International Gastric Cancer Congress

SUZHOU,China,March 10,2022 -- 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 Transcenta has presented the safety/tolerability and preliminary anti-tumor activity data in gastric and pancreatic cancers of TST001 China phase I clinical trial as a poster presentation at the 2022 International Gastric Cancer Congress (IGCC).

The primary objectives of this phase I study (NCT04495296) are to evaluate the safety and tolerability,to identify MTD and recommended phase 2 dose (RP2D) in patients with advanced or metastatic solid tumors who progressed on or after standard treatments. Secondary objectives include the assessment of pharmacokinetic parameter,immunogenicity,and preliminary anti-tumor activity.

In the dose escalation phase,patients without preselection of tumor Claudin18.2 expression were given increasing doses of TST001 intravenously every 3 weeks (Q3W) using a 3+3 design. As of November 23rd,2021,11 patients had been treated at the dose levels of 3,6,and 10 mg/kg Q3W. 9 patients were DLT evaluable with no DLT reported and MTD has not been reached. TST001 demonstrated a roughly linear PK profile as both Cmax and AUC increased proportionally across the dose range following the first dose. No drug accumulation was observed in Q3W cohort. 10 mg/kg Q3W was designated as RP2D for further expansion study and additional patients with Claudin18.2 overexpression were enrolled into the expansion phase at the 10 mg/kg Q3W dose. The most common AEs (>20%) included nausea,vomiting,anemia,hypoalbuminemia,abdominal distension,constipation. In terms of efficacy,one patient in the 6 mg/kg Q3W dose-escalation cohort who progressed on multiple lines of chemotherapies,anti-PD1 and anti-VEGF therapies achieved a confirmed partial response at week 12. Post the data cut-off date,additional confirmed PRs were observed at recommended phase 2 dose in the newly enrolled monotherapy expansion cohorts including gastric cancer and pancreatic cancer patients with Claudin18.2 expression. One pancreatic cancer patient with medium-low Claudin 18.2 expression achieved 82% tumor reduction at 12 weeks post-treatment. Enrollment of patients for the monotherapy expansion cohorts is ongoing and full data will be updated and reported in future medical conference.

In this Phase 1 clinical study,TST001 demonstrated a manageable & tolerable safety profile in patients with advanced solid tumors and preliminary anti-tumor activity in a heavily pretreated gastric and pancreatic cancer patient expressing Claudin18.2.

"Claudin18.2 is an ideal target with great anti-tumor potential for cancer treatment. TST001,a high affinity Claudin18.2 humanized antibody,is safe and displayed promising anti-tumor activity in Claudin18.2 over-expressing gastric and pancreatic cancer patients." said Dr. Michael Shi,EVP,Head of Global R&D and CMO of Transcenta,"We will continue to characterize the safety and anti-tumor activities of the monotherapy in various Claudin18.2 expressing solid tumors as well as combination therapy with standard of care for first line gastric cancer. We believe TST001 could offer new and more effective treatment options for gastric cancer patients."

"Gastric cancer is one of the highly prevalent malignant tumor types in China. In recent years,Claudin18.2 has emerged as a promising cancer treatment target for gastric cancer beyond HER2 and PD-L1. TST001 is the second most advanced global program targeting Claudin 18.2 and has shown promising signals of anti-tumor activities with manageable safety profile. I look forward to the start of the global phase III registration-enabling trial for testing TST001 as the treatment for first line gastric cancer," said Professor Lin Shen from Beijing Cancer Hospital.

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,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.comand https://www.linkedin.com/company/transcenta.

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