Astellas Launches Phase III Trial of Claudin 18.2/CD3 Bispecific Antibody ASP2138 in Gastric Cancer

▎Armstrong

On June 29, 2026, Astellas registered a Phase III clinical trial on ClinicalTrials.gov for the first-line treatment of locally advanced or recurrent gastric cancer with the Claudin18.2/CD3 bispecific antibody ASP2138 in combination with chemotherapy ± PD-1 antibody.

This Phase III clinical trial plans to enroll 570 patients with advanced gastric cancer and is expected to be completed in February 2031.

Astellas has established a comprehensive portfolio around Claudin 18.2, acquiring Ganymed in 2016 to obtain Vyloy, subsequently collaborating with Xencor to develop the Claudin 18.2/CD3 bispecific antibody ASP2138, and later licensing in Evopoint Biosciences’ novel Claudin 18.2 ADC, XNW27011. While Vyloy has been approved for marketing, it is effective only in patients with high Claudin 18.2 expression. ASP2138 holds the potential to expand treatment to all Claudin 18.2-positive populations, whereas XNW27011 offers the prospect of chemotherapy-free regimens and is also suitable forAll Claudin 18.2-positive populations.

Summary

The R&D competition for Claudin18.2 is particularly intense, encompassing various drug modalities such as monoclonal antibodies (mAbs), T-cell engagers (TCEs), antibody-drug conjugates (ADCs), and CAR-T therapies. Astellas’ Claudin18.2 monoclonal antibody and Kineta’s Claudin18.2 CAR-T therapy have both been approved for market launch, while Innovent Biologics and CHIATAI TIANQING have submitted marketing applications for their respective Claudin18.2 ADCs.