Astellas initiates Phase 3 trial of ASP2138 for CLDN18.2-positive gastric cancer, advancing its oncology pipeline
Executive summary: Astellas dosed the first patient in its Phase 3 clinical trial of ASP2138 for Claudin 18.2-positive, HER2-negative gastric or gastroesophageal junction adenocarcinoma. The trial could yield a new treatment option for a difficult-to-treat gastric cancer subset and impact Astellas' oncology revenue prospects.
Who is involved: Astellas Pharma Inc., clinical trial sites, patients with Claudin 18.2-positive gastric cancer, and regulators overseeing the study.
Likely next: The company will continue patient enrollment and expects to report interim efficacy data within the next 12–18 months, followed by potential regulatory submissions if endpoints are met.
On August 24, 2026, Astellas Pharma administered the first dose of ASP2138 in a Phase 3 clinical trial enrolling patients with HER2‑negative, locally advanced unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma that tests positive for Claudin 18.2. The study is designed to compare the investigational antibody‑drug conjugate against the current standard of care, with primary endpoints focused on overall survival and progression‑free survival, alongside a safety evaluation. This marks Astellas’ latest advancement in its oncology pipeline, positioning the company among several biopharmaceutical firms that have pursued Claudin 18.2‑directed therapies for gastric cancer. The initiation of a pivotal trial underscores the continued interest in targeting Claudin 18.2, a molecule overexpressed in a subset of gastric tumors that has shown promise in earlier‑stage studies. For Astellas, a positive outcome could provide a differentiated treatment option in a disease area where therapeutic choices remain limited, potentially strengthening its competitive stance in the precision oncology market. While the trial’s full enrollment and follow‑up period will take time, interim data readouts are anticipated within the next few years, which will clarify ASP2138’s clinical benefit and inform subsequent regulatory and commercial decisions.
Timeline
- — Astellas Doses First Patient in Phase 3 Study of ASP2138 in CLDN18.2-postive and HER2-negative locally advanced unresectable or metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma (PR Newswire)
Analysis — what this means
Sectors affected
- Gastric adenocarcinoma therapeutics
- Claudin 18.2-targeted oncology
Key entities
Sources
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