Astellas Pharma has initiated a Phase 3 clinical trial for ASP2138, an investigational bispecific antibody targeting Claudin 18.2 (CLDN18.2)-positive, HER2-negative gastric and gastroesophageal junction (GEJ) cancers.
The randomized, double-blind, placebo-controlled study will enroll approximately 570 adult patients with locally advanced unresectable or metastatic adenocarcinoma. Participants will receive either ASP2138 combined with chemotherapy and pembrolizumab or a placebo plus chemotherapy, with or without pembrolizumab, as a first-line treatment.
The trial’s co-primary endpoints are overall survival and progression-free survival. Secondary endpoints include objective response rate and duration of response. The company has dosed the first patient under the trial identifier NCT07673887, registered on ClinicalTrials.gov.
ASP2138 is designed to bind to CLDN18.2 on tumor cells and CD3-positive T cells, facilitating T-cell-mediated anti-tumor activity. Current standard-of-care therapies for advanced gastric and GEJ cancers, excluding CLDN18.2-directed treatments, demonstrate median progression-free survival of six to seven months.
Tadaaki Taniguchi, Astellas’ Chief Research and Development Officer, said the initiation marks a key milestone for ASP2138 and the company’s broader efforts in CLDN18.2-targeted oncology. The trial aligns with Astellas’ strategic plan to launch five or more Phase 3 or pivotal studies by fiscal year 2027.
