Transcenta Holding Limited announced that the preclinical anti-tumor efficacy and safety results of [177Lu]Lu-TST001 have been published on European Journal of Nuclear Medicine and Molecular Imaging (EJNMMI). In this preclinical studies, [177Lu]Lu-TST001 demonstrated significant antitumor efficacy with acceptable toxicity. It exhibits strong potential for clinical translation, providing a new promising treatment option for CLDN18.2-overexpressing tumors, including gastric cancer.

This research was conducted in collaboration between Transcenta and the team of Professor Hua Zhu from Beijing Cancer Hospital. In this study, a [177Lu]Lu-TST001 radionuclide antibody conjugate was developed that targets CLDN18.2 using a DOTA-TST001 as a precursor and is labeled with 177Lu, a therapeutic radionuclide. The clear molecular imaging, favorable biodistribution, and pharmacokinetics of [177Lu]Lu-TST001 were validated in a mouse xenograft GC model.

Moreover, this study explored the short-term therapeutic efficacy of [177Lu]Lu-TST001 radioimmunotherapy (RIT) against CLDN18.2-positive tumors and determined the optimal therapeutic dose in a GC tumor model. Safety under the treatment dose of the probe was also examined. Significant therapeutic effects with acceptable short-term toxicity were achieved in the mouse model.

Osemitamab (TST001) is a high affinity humanized anti-CLDN18.2 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 CLDN18.2 targeting antibody being developed globally.

Osemitamab (TST001) was generated using Transcenta's Immune Tolerance Breaking Technology (IMTB) platform. Osemitamab (TST001) kills CLDN18.2 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) was 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.