The board of directors of the Company announced that it has presented updated efficacy data from the expansion cohort of the TranStar102 of Osemitamab (TST001) plus CAPOX chemotherapy study as the first-line treatment of advanced G/GEJ Cancer at the ESMO Congress 2023 in Madrid, Spain. The updated data continued to show encouraging efficacy from previously disclosed data in patients with CLDN18.2 expression 10%, 1+ per the LDT assay used to select patients. Two additional posters were presented: one on preclinical data supporting the triple combination of Osemitamab, nivolumab and chemotherapy over Osemitamab and chemotherapy including in PD-L1 negative tumors; and one detailing the clinical pharmacology explorations supporting the recommended Phase III dose.

Study Design. Cohort C from Transtar102 study (NCT04495296) was designed to explore the safety and efficacy of Osemitamab plus CAPOX as first-line treatment in advanced G/GEJ cancer. 20 patients of the 49 patients had progression of disease or death, with an estimated median progression-free survival (PFS) of 14 months.

The median overall survival (OS) was not reached because of the limited number of events, the 12-month survival rate for the overall population of cohort-C (64 patients, all doses) was 88.9% (95% CI: 74.2, 95.4). This further supports the Phase III trial strategy of combining Osemitamab with nivolumab and treatment in 1L CLDN18.2 positive G/GEJ cancer which the Company received FDA clearance recently. F favorable and Manageable Safety Profile.

The safety profile of these 49 patients was mainly characterized by manageable on-target-off-tumor effects, including nausea, hypo albuminemia, and vomiting, most of them were grade 1 or 2 and occurred during the first 2 cycles. In addition, preclinical data presented at the congress (#1560P) showed significant upregulation of PD-L1 in gastric cancer cells and increased TIL infiltration into tumor upon treatment with Osemitamab (TST001). The combination of anti-CLDN18.2 Osemitamab (tST001) with PD1 inhibitor nivolumab andotherapy resulted in significant synergy including in a CLDN18.2 positive/PD-L1 negative PDX model of gastric cancer.

Leveraging advanced bioprocessing technology, the fucose content of Osemitamab was significantly reduced during the production, which further enhanced NK cells mediated ADCC activity of Osemitamab. Clinical trials for Osemitamab (tST001) are ongoing in the U.S. and China (NCT05190575, NCT04396821, NCT04495296, NCT05190575, NCT05190575), NCT04396821,NCT04495296, NCT04495296, and chemotherapy resulted in significant synergy including in an CLDN18.2 positive and PDX model of gastric Cancer. Leveraging advanced biOProcessing technology, the Fucose content of Ose mitamab (TST001).