Merck's Dual-Drug Combo Gets FDA Green Light for Advanced Bladder Cancer

Merck just scored a major win: the FDA approved a first-of-its-kind combo treatment pairing KEYTRUDA (a PD-1 inhibitor) with Padcev (an antibody-drug conjugate) for muscle-invasive bladder cancer patients who can’t tolerate cisplatin chemotherapy.

Why this matters: Roughly 50% of patients relapse after surgery alone. This new regimen offers a real alternative for the cisplatin-ineligible crowd—a population with serious unmet medical needs.

The data looks solid:

• 60% reduction in event-free survival risks vs. surgery alone
• 50% improvement in overall survival
• 57.1% pathologic complete response rate (vs. 8.6% with surgery only)
• Based on Phase 3 KEYNOTE-905 trial with 25.6-month median follow-up

Two delivery options: KEYTRUDA comes as IV infusion, while the newly approved KEYTRUDA QLEX (launched September) is a subcutaneous injection combining pembrolizumab with berahyaluronidase alfa—giving patients more flexibility.

The catch: Immune-mediated side effects like pneumonitis, colitis, and hepatitis observed in patients, consistent with PD-1 inhibitor profiles. At least 20% experienced adverse reactions during treatment.

Stock performance: MRK closed Friday at $97.76 (up 2.94%). KEYTRUDA alone generated $8.1B in Q3 2025 sales—a 10% YoY jump. Over the past year, MRK has ranged from $73.31 to $105.07.

This approval could reshape bladder cancer treatment protocols for cisplatin-ineligible patients, marking the first PD-1 inhibitor + ADC combination for this indication.