SUZHOU, China, Mar. 3, 2023, 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, today announces that the study results of its CLDN18.2-targeting Immuno-PET probe [89Zr]Zr-DFO-TST001 for non-invasive imaging in gastrointestinal tumors have been published on Journal of Pharmaceutical Analysis.

The study, led by Professor Hua Zhu and his team from Beijing Cancer Hospital. The study successfully prepared and evaluated the 89Zr labeled GMP grade anti-CLDN18.2 recombinant humanized antibody TST001 as molecular imaging probe. [89Zr]Zr-DFO-TST001 exhibited good specificity at the cellular level and rapid tumor accumulation which remained positive from 24 to 96 hours. It provides a promising non-invasive imaging tool for detecting the treatment effects of therapeutic antibodies in humans in real time and for the screening and efficacy evaluation of patients targeted for CLDN18.2 therapy in the future.

Clinical studies indicated that the CLDN18.2 expression level was correlated with drug efficacy, showing more clinical benefit in patients with CLDN18.2 high expression in tumors. Therefore, patient selection based on CLDN18.2 expression level becomes critical for CLDN18.2-targeted therapies. At present, the main detection method of CLDN18.2 protein expression is immunohistochemistry (IHC). IHC is invasive, and requires endoscopic biopsy, and the sampling site and number are limited. Due to the heterogeneous nature of tumor, the CLDN18.2 distribution and dynamic changes in expression levels in patients cannot be fully reflected in real-time. Molecular imaging can be used as a non-invasive diagnostic tool to detect the expression and distribution of CLDN18.2 in the lesion using the radioactive signal emitted by the radiotracer, thereby help to screen patients with potential benefit to therapy, evaluate the efficacy of CLDN18.2 targeted therapy, and guide the accurate diagnosis and treatment of tumors.

“This study successfully achieved the development, quality control and Micro-PET imaging clinical evaluation of GMP-grade monoclonal nuclide probes targeting CLDN18.2, providing a new path for the development of ZR-89-labeled tumor targeting monoclonal antibodies. In cell and animal models, [89Zr]Zr-DFO-TST001 specifically recognizes and targets the CLDN18.2 receptor/tissue. With the increasingly popular PET/CT examination equipment, the probe is expected to be used for screening patients with potential benefit to therapy, localizing of systemic lesions and efficacy evaluation” said Prof. Hua Zhu from Beijing Cancer Hospital.

“We are fortunate to have the opportunity to collaborate with leading colleges and institutes on the development of a CLDN18.2-targeting Immuno-PET Probe for gastrointestinal tumors. Optimizing the selection of patients in a non-invasive way is key to improve the overall benefit risk of CLDN18.2 targeted treatments. This technology also opens up innovative ways of monitoring treatment outcomes. We look forward to further development of this approach and potential use in the clinics.” said Dr. Xueming Qian, CEO of Transcenta.

The study results were jointly carried out by

• NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals, Peking University Cancer Hospital & Institute

• School of Basic Medical Sciences, Southwest Medical University

• Suzhou Transcenta Therapeutics Co., Ltd, Suzhou

• Institute of Biomedical Engineering, Peking University Shenzhen Graduate School

• Guizhou University Medicine College

Original article: https://www.sciencedirect.com/science/article/pii/S2095177923000357

About TST001 (Osemitamab)

TST001 (Osemitamab) is a high affinity humanized anti- CLDN18.2 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 (Osemitamab) is the second most advanced CLDN18.2 targeting antibody being developed globally. TST001 (Osemitamab) is generated using Transcenta's Immune Tolerance Breaking Technology (IMTB) platform. TST001 (Osemitamab) kills CLDN18.2 expressing tumor cells by mechanisms of ADCC and CDC. Leveraging advanced bioprocessing technology, the fucose content of TST001 (Osemitamab) was significantly reduced during the production, which further enhanced NK cells mediated ADCC activity of TST001 (Osemitamab). Clinical trials for TST001 (Osemitamab) are ongoing in the U.S. and China (NCT04396821, NCT04495296/CTR20201281). TST001 (Osemitamab) was granted Orphan Drug Designation in the U.S. by FDA for the treatment of patients with gastric or gastroesophageal junction (G/GEJ) cancer.

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 Princeton, US and in Beijing, Shanghai and Guangzhou of China, 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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