TRANSCENTA-B (06628) will present inspiring efficacy data for OSEMITAMAB (TST001) triple therapy for first-line treatment of gastric or gastroesophageal junction adenocarcinoma at ESMO 2024.

TRANSCENTA-B (06628) announced that updated research data on the combination of Osemitamab (TST001) with Nivolumab and CAPOX as first-line treatment for advanced gastric or gastroesophageal junction adenocarcinoma (TranStar102) has been released. The data from this cohort have continued to show encouraging efficacy since being presented at the ASCO 2024 conference. The research results indicate that, among patients with known levels of CLDN18.2 and PD-L1 expression, patients with high/medium CLDN18.2 expression had a median progression-free survival (mPFS) of 14.2 months and a confirmed objective response rate of 68%. The majority of patients had a PD-L1 CPS <5. Compared to a control group of patients with very low/no CLDN18.2 expression, the triple therapy reduced the risk of disease progression or death by 50% in the group of patients with high/medium CLDN18.2 expression (regardless of CPS expression level) (HR=0.505, 95% CI 0.244-1.045). This data further confirms the synergistic mechanism between the CLDN18.2 targeted drug and the checkpoint inhibitor reported by the company at the ESMO 2023 conference, showing that the CLDN18.2 targeted antibody can induce PD-L1 expression and T cell infiltration even in gastric cancer tumor cells with low or no PD-L1 expression. As of the data cut-off date, with a limited number of events, the median overall survival has not yet been reached, and the 12-month survival rate for the overall population in this cohort (82 patients) was 73.8% (95% CI: 62.0-82.4%). Previous studies have shown that regardless of the level of PD-L1 expression, the combination of Zolbetuximab and CAPOX can improve the median progression-free survival of CLDN18.2-positive patients from 6.80 months to 8.21 months (HR=0.687 (95% CI, 0.544-0.866) (Source: Shah, Manish A et al. Nature Medicine 2023 Aug 29 (8): 2133-2141)). Updated data from the Cohort-G study shows that Osemitamab (TST001) combined with Nivolumab and CAPOX is significantly more effective than the treatment regimens of Nivolumab combined with CAPOX or Zolbetuximab combined with CAPOX. The updated data was presented in poster format (abstract #1419p) at the ESMO 2024 conference held in Barcelona, Spain on September 16, 2024. "The updated data from the Cohort-G trial shows that the combination of Osemitamab (TST001) with Nivolumab and CAPOX as first-line treatment for advanced gastric or gastroesophageal junction adenocarcinoma is promising in terms of efficacy. The confirmed objective response rate and median progression-free survival of patients with high/medium CLDN18.2 expression and known PD-L1 expression levels compared to patients without CLDN18.2 expression confirm the synergistic effect between Osemitamab (TST001) and checkpoint inhibitors, demonstrating the potential of the triple therapy and the possibility of benefitting patients with low PD-L1 expression," said Dr. Caroline Germa, Global Head of Drug Development and Chief Medical Officer of the company. "The data from the Cohort-G study presented at the 2024 European Society for Medical Oncology (ESMO) conference provides compelling evidence of clinical benefits of the triple therapy. Significant improvements in progression-free survival and objective response rates are particularly pronounced in patients with high/medium CLDN18.2 expression and low PD-L1 expression levels, highlighting the potential of this treatment regimen," said Professor Lin Shen, Director of the Department of Digestive Tumors and Phase I Clinical Trials Unit at Peking University Cancer Hospital and the principal investigator of this study. "We are excited about the positive impact this therapy could have on patients."