Astellas And Pfizer Announces Topline Results From Interim Analysis Of Phase 3 EV-304 Clinical Trial For PADCEV In Combination With Keytruda; Trial Met Its Primary Endpoint

• PADCEV plus Keytruda is the first and only regimen without platinum-based chemotherapy to improve event-free and overall survival when used before and after surgery in cisplatin-eligible patients with muscle-invasive bladder cancer
• Positive EV-304 data, combined with the recent unprecedented results from the EV-303 trial, highlight the potential of this combination to become a new platinum-free standard of care in an earlier stage of bladder cancer
• Results from the Phase 3 EV-304 trial will be presented at an upcoming medical meeting and discussed with global health authorities for potential regulatory filings

TOKYO and NEW YORK, Dec. 17, 2025 /PRNewswire/ -- Astellas Pharma Inc. (TSE: 4503, President and CEO: Naoki Okamura, "Astellas") and Pfizer Inc. (NYSE:PFE) today announced positive topline results from an interim analysis of the Phase 3 EV-304 clinical trial (also known as KEYNOTE-B15) for PADCEV™ (enfortumab vedotin), a Nectin-4 directed antibody-drug conjugate, in combination with Keytruda® (pembrolizumab), a PD-1 inhibitor. This pivotal study is evaluating the combination as neoadjuvant and adjuvant treatment (before and after surgery) versus standard of care neoadjuvant chemotherapy (gemcitabine and cisplatin) in patients with muscle-invasive bladder cancer (MIBC) who are eligible for cisplatin-based chemotherapy. The trial met its primary endpoint, demonstrating clinically meaningful and statistically significant improvements in event-free survival (EFS), and overall survival (OS), a key secondary endpoint.