TRANSCENTA-B (06628) announced that the company's board of directors is pleased to share updated efficacy analysis from the I/II phase clinical trial (TranStar102) of osemitamab in combination with nivolumab and CAPOX as first-line treatment for gastric or gastroesophageal junction adenocarcinoma (G cohort), based on CLDN18.2 and PD-L1 expression. The findings were presented as a poster (Abstract #299P) at the European Society for Medical Oncology Asia Congress 2025 (ESMO Asia 2025) in Singapore.

The new analysis further supports the encouraging clinical benefits demonstrated by the osemitamab triple therapy. With a median follow-up of 25.8 months, among 26 patients with CLDN18.2 expression ≥40% (≥2+) and known PD-L1 CPS, the median progression-free survival (mPFS) reached 16.6 months, with an objective response rate (ORR) of 68% and a median duration of response (mDoR) of 18 months. Notably, in both PD-L1 CPS <1 and ≥1 subgroups, patients with higher CLDN18.2 expression showed better PFS than those with lower expression, indicating that osemitamab's potential therapeutic benefit is consistent regardless of PD-L1 expression levels. The safety profile remained consistent with previously reported data at ASCO 2025.

"Exploratory efficacy analyses continue to demonstrate favorable clinical benefits with osemitamab in combination with standard treatment," said Professor Lin Shen, principal investigator of the study and Director of the Department of Gastrointestinal Oncology and Phase I Clinical Trials at Peking University Cancer Hospital. "The consistent benefit across different PD-L1 subgroups is particularly noteworthy, suggesting this regimen may offer clinically meaningful improvements for a broad population of advanced gastric or gastroesophageal junction adenocarcinoma patients."

"We are encouraged by the sustained strong clinical benefit signals from this study, further validating osemitamab's potential to deliver substantial benefits for patients in need of more effective treatment options," said Dr. Chuan Qi, Executive Vice President of Global Clinical Development at TRANSCENTA. "Additionally, the updated data continue to confirm the favorable safety and tolerability of osemitamab combined with nivolumab and CAPOX as a first-line treatment for advanced gastric or gastroesophageal junction adenocarcinoma."