PRINCETON, N.J. and SUZHOU, China, April 10, 2024 -- 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 it has presented 4 posters highlighting study results from ongoing trials related to Osemitamab (TST001) and TST003 at AACR Annual Meeting 2024,  including development of Claudin 18.2 IHC 14G11 pharmDx as a clinical trial assay for the clinical development of anti-Claudin 18.2 monoclonal antibody Osemitamab (TST001) in G/GEJ adenocarcinoma; the safety, tolerability and pharmacokinetics profile of Osemitamab (TST001) administered as monotherapy or in combination with nivolumab or standard of care in patients with locally advanced or metastatic solid tumors (TranStar101: a Phase I/IIa clinical trial); prevalence of Claudin 18.2 expression in gastric/gastroesophageal junction adenocarcinoma by Transcenta proprietary CLDN 18.2 assay from US and Chinese patients from Transtar101 and Transtar102 clinical trials, as well as a first-in-human, open-label, multi-center phase 1 study of TST003, a GREM 1 inhibitor, in subjects with locally advanced or metastatic solid tumors.

The Annual Meeting of AACR was held from April 5 to 10, 2024 at the San Diego Convention Center, California, USA. It is the focal point of the cancer research community, where scientists, clinicians, other health care professionals, survivors, patients, and advocates gather to share the latest advances in cancer science and medicine. From population science and prevention; to cancer biology, translational, and clinical studies; to survivorship and advocacy; the AACR Annual Meeting highlights the work of the best minds in cancer research from institutions all over the world.

A brief summary of the presentations is as follows:

Title: Development of Claudin 18.2 IHC 14G11 pharmDx as a Clinical Trial Assay for the clinical development of anti-Claudin 18.2 monoclonal antibody Osemitamab (TST001) in gastric and gastroesophageal junction adenocarcinoma

First Author: H. Alderson, Agilent Technologies, Inc.

Session Category: Clinical Research

Session Title: Predictive Biomarkers 2

Session Date and Time: Monday April 8, 2024, 9:00 AM - 12:30 PM

Location: Poster Section 44

Poster Board Number: 2535

Full poster:

https://www.transcenta.com/ch/uploadfile/yushangweb_file/2024040714321266123dec03e93.pdf

Title: A Phase I/IIa clinical trial (TranStar101) to evaluate the safety, tolerability and pharmacokinetics of Osemitamab (TST001) administered as monotherapy or in combination with nivolumab or standard of care in US patients with locally advanced or metastatic solid tumors

First Author: Yelena Janjigian, Memorial Sloan Kettering Cancer Center

Session Category: Clinical Trials

Session Title: Phase 0 and Phase I Clinical Trials

Session Date and Time: Monday Apr 8, 2024, 1:30 PM - 5:00 PM

Location: Poster Section 49

Poster Board Number: 11

Full poster:

https://www.transcenta.com/ch/uploadfile/yushangweb_file/20240407135928661236407f153.pdf

Title: Prevalence of Claudin 18.2 expression in gastric/gastroesophageal junction adenocarcinoma among patients in TranStar101 and TranStar102 clinical trials

First Author: Li Shen, Suzhou Transcenta Therapeutics Co., Ltd

Session Category: Clinical Research

Session Title: Biomarkers in Clinical Trials

Session Date and Time: Monday Apr 8, 2024, 1:30 PM - 5:00 PM

Location: Poster Section 40

Poster Board Number: 7

Full poster:

https://www.transcenta.com/ch/uploadfile/yushangweb_file/202404071409276612389739561.pdf

Title: A first-in-human, open-label, multi-center phase 1 study of TST003, a GREM 1 inhibitor, in subjects with locally advanced or metastatic solid tumors

First Author:Ismael Rodriguez Rivera, NEXT Oncology

Session Category: Experimental and Molecular Therapeutics

Session Title: Novel Biologic Therapies and Therapeutic Targets

Session Date and Time: Tuesday Apr 9, 2024, 1:30 PM - 5:00 PM

Location: Poster Section 27

Poster Board Number: 25

Full poster:

https://www.transcenta.com/ch/uploadfile/yushangweb_file/202404071350026612340a8722b.pdf

About Osemitamab (TST001)

Osemitamab (TST001) is a high affinity humanized anti-CLDN 18.2 monoclonal antibody with enhanced antibody-dependent cellular cytotoxicity ("ADCC"). It has shown potent anti-tumor activities in tumor xenograft models. Osemitamab (TST001) is the second most advanced CLDN 18.2 targeting antibody being developed globally. Osemitamab (TST001) was generated using Transcenta's Immune Tolerance Breaking Technology (IMTB) platform. Osemitamab (TST001) kills CLDN 18.2 expressing tumor cells by mechanisms of ADCC. Leveraging advanced bioprocessing technology, the fucose content of Osemitamab (TST001) was significantly reduced during the production, which further enhanced NK cells mediated ADCC activity of Osemitamab (TST001). Clinical trials for Osemitamab (TST001) are ongoing in the U.S. and China (NCT05190575, NCT04396821, NCT04495296, NCT05608785 / CTR20201281). Osemitamab (TST001) has been granted Orphan Drug Designation in the U.S. by FDA for the treatment of patients with gastric or gastroesophageal junction (G/GEJ) and pancreatic cancer.

About TST003

TST003 is a high affinity monoclonal antibody targeting Gremlin1, a member of the TGF-β superfamily. Gremlin1 protein is a highly conserved secreted protein and has shown to play important roles during embryonic development and promote epithelial mesenchymal transition. Gremlin1 is upregulated in multiple solid tumors. TST003 has demonstrated promising single agent and combination activities in patient-derived xenograft tumor models from the difficult-to-treat solid tumors resistant to checkpoint inhibitors including castration resistant prostate cancer and microsatellite stable colorectal cancer.