Merck announced on April 20, 2026, that the U.S. Food and Drug Administration (FDA) has granted Priority Review for two supplemental Biologics License Applications (sBLAs) for its anti-PD-1 therapy, KEYTRUDA, and its subcutaneous formulation, KEYTRUDA QLEX. These applications seek approval for the use of these therapies in combination with Padcev (enfortumab vedotin-ejfv) for the treatment of patients with muscle-invasive bladder cancer (MIBC) who are eligible for cisplatin-based chemotherapy.
The FDA grants Priority Review to applications for medicines that, if approved, would provide significant improvements in the safety or effectiveness of the treatment, diagnosis, or prevention of serious conditions. Under the Prescription Drug User Fee Act (PDUFA), the FDA aims to take action on these applications within six months, compared to the standard ten-month review cycle. The target action date for these specific applications has been set for the fourth quarter of 2026.
The submission is based on results from the Phase 3 KEYNOTE-B15 trial, also designated as EV-304. This global, randomized, open-label study evaluated the efficacy and safety of the KEYTRUDA and Padcev combination compared to the current standard of care, which typically involves cisplatin-based chemotherapy. The trial focused on the neoadjuvant setting, where treatment is administered before surgery, and the adjuvant setting, where treatment continues after surgery. The primary endpoints of the study included pathological complete response (pCR) and event-free survival (EFS).
Dr. Marjorie Green, senior vice president and head of oncology, global clinical development, Merck Research Laboratories, highlighted the importance of the regulatory milestone. She noted that the Priority Review underscores the potential of this combination to address the needs of patients with muscle-invasive bladder cancer earlier in their treatment journey. The goal of the therapy is to improve outcomes for patients before they undergo radical cystectomy, a major surgical procedure to remove the bladder.
Bladder cancer remains a significant health challenge, with approximately 82,000 new cases diagnosed annually in the United States. Muscle-invasive bladder cancer is a particularly aggressive form of the disease where the tumor has penetrated the muscular wall of the bladder, increasing the risk of metastasis. While cisplatin-based chemotherapy has been the standard of care for decades, many patients still experience disease recurrence following surgery.
This regulatory development follows the previous FDA approval of the KEYTRUDA and Padcev combination for patients with locally advanced or metastatic urothelial cancer. Padcev is an antibody-drug conjugate (ADC) directed against Nectin-4, a protein highly expressed in bladder cancer cells. By combining an immune checkpoint inhibitor with an ADC, the treatment aims to leverage two distinct mechanisms to target and eliminate cancer cells. Merck continues to collaborate with Pfizer and Astellas Pharma on the development and commercialization of this combination therapy.