Astellas Pharma has initiated a Phase 3 clinical trial of ASP2138, an investigational bispecific antibody, for the treatment of adults with locally advanced unresectable or metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma.
The randomized, double-blind, placebo-controlled study will enroll approximately 570 participants across multiple countries. ASP2138 targets Claudin 18.2 (CLDN18.2)-positive and HER2-negative tumors, a subset associated with poor prognosis in advanced gastric cancer. The trial will assess the drug in combination with chemotherapy and pembrolizumab, comparing it against placebo plus chemotherapy with or without pembrolizumab as a first-line treatment.
The primary endpoints are overall survival and progression-free survival. Current standard-of-care treatments for advanced gastric and GEJ cancers typically yield median progression-free survival of six to seven months with non-CLDN18.2 directed therapies. ASP2138 is designed to bind to CLDN18.2 on tumor cells and CD3-positive T cells, facilitating T-cell-mediated anti-tumor activity.
Tadaaki Taniguchi, Chief Research and Development Officer at Astellas, stated that the first patient dosed in the Phase 3 study represents a key milestone for ASP2138 and the company’s broader efforts in CLDN18.2-targeted therapies. The trial is part of Astellas’ strategic plan to initiate five or more Phase 3 or pivotal studies by fiscal year 2027.
