Dr Galsky on the Design of the KEYNOTE-B15 Trial in MIBC

“The primary end point of the study was EFS, and that was determined by blinded, independent central review. [The] key secondary end points were OS and pCR rate.”

Matthew D. Galsky, MD, the deputy director and director of genitourinary medical oncology; codirector of the Center of Excellence for Bladder Cancer; and a professor of medicine, hematology and medical oncology, and urology, at the Mount Sinai Tisch Cancer Center, discussed the study design of the phase 3 KEYNOTE-B15/EV-304 trial (NCT04700124), which examined enfortumab vedotin-ejfv (Padcev) in combination with pembrolizumab (Keytruda) for the perioperative treatment of patients with muscle-invasive bladder cancer (MIBC) who were eligible for cisplatin-containing therapy and radical cystectomy.

KEYNOTE-B15 enrolled patients with MIBC with clinically localized disease who were eligible for cisplatin and radical cystectomy, Galsky began. Patients were randomly assigned to receive either intravenous (IV) enfortumab vedotin at 1.25 mg/kg on days 1 and 8 every 3 weeks plus IV pembrolizumab at 200 mg on day 1 every 3 weeks (n = 405); or 70 mg/m² of cisplatin and 1000 mg/m² of gemcitabine as neoadjuvant therapy (n = 403), he continued. Treatment continued for 4 cycles in both arms and was followed by radical cystectomy with pelvic lymph node dissection; patients in the investigational arm then received adjuvant enfortumab vedotin plus pembrolizumab and patients in the control arm underwent observation.

The primary end point of the trial was event-free survival per blinded independent central review, Galsky said. Overall survival and pathological complete response rate were evaluated as key secondary end points, he concluded.

Data from KEYNOTE-B15 were presented by Galsky during the 2026 Genitourinary Cancers Symposium.

Disclosures: Galsky holds consulting or advisory roles with Abbvie, Bristol-Myers Squibb, EMD Serono, Gilead Sciences, Janssen, Merck, and Pfizer. He also received research funding from AstraZeneca (Inst), Bristol-Myers Squibb (Inst), Dendreon (Inst), Genentech/Roche (Inst), Janssen Oncology (Inst), Merck (Inst), and Novartis (Inst). He has patents, royalties, or other intellectual property including: METHODS AND COMPOSITIONS FOR TREATING CANCER AND RELATED METHODS. MOUNT SINAI SCHOOL OF MEDICINE July 2012 Application number: 20120322792.