To initiate TranStar 301 global Phase III pivotal trial of Osemitamab (TST001) in combination with Nivolumab and chemotherapy for the first-line treatment of patients with HER2 negative, CLDN18.2 expressing locally advanced or metastatic gastric or gastroesophageal (G/GEJ) adenocarcinoma. In addition, we are in the process of EU and FDA regulatory interaction.

Gastric cancer (GC) is the 4th leading cause of cancer death worldwide, accounting for about 7.7% of all cancer related mortality. The five year survival rate for gastric cancer is still around 30%. Nivolumab, an anti-PD-1 antibody, has been approved globally for the first line treatment of patients with advanced or metastatic HER2-negative G/GEJ cancer.

Osemitamab (TST001) is a second generation humanized CLDN18.2 targeting antibody with enhanced ADCC. It has shown anti-tumor activities in preclinical models with a broad range of CLDN18.2 expression. Recently, the Company presented efficacy data of Osemitamab (TST001) in combination with CAPOX as the first-line treatment of G/GEJ cancer at 2023 ASCO annual meeting and 2023 ESMO GI. Among 64 patients with CLDN18.2 positive (defined as: IHC membrane staining ≥10% tumor cells with ≥1+ intensity per LDT assay, selecting approximately 55% of the screened patients) were treated, 49 at the dose of 6mg/kg. The data showed that the estimated median progression-free survival was 9.5 months from all dose groups, consistent across all CLDN18.2 expression levels, with a median duration of response of 9.9 months.

Preclinical studies have demonstrated synergistic anti-tumor activities between Osemitamab (TST001) and anti-PD-1 antibodies in CLDN18.2 expressing tumor models. Recently Transcenta has reported that 82 patients had been enrolled in TranStar 102 to assess the safety and efficacy of Osemitamab (TST001) in combination with Nivolumab and CAPOX. So far, the combination is well tolerated.

TranStar 301 is a global randomized, double-blind, placebo-controlled Phase III trial designed to evaluate Osemitamab (TST001) in combination with Nivolumab plus chemotherapy as the first-line treatment for patients with locally advanced or metastatic HER2 negative, CLDN18.2 expressing G/GEJ adenocarcinoma.

"We are actively progressing our plans to develop Osemitamab (TST001) in combination with Nivolumab and chemotherapy as first-line treatment for CLDN18.2 expressing G/GEJ adenocarcinomas in a large multinational Phase III clinical trial. CDE and MFDS approvals are exciting milestones, with several others coming soon. We are looking forward to sharing more information as it becomes available." said Dr. Caroline Germa, Transcenta's Executive Vice President, Global Medicine Development and Chief Medical Officer.