Key Highlights
- FDA accepted priority review for two supplemental Biologics License Applications covering KEYTRUDA and KEYTRUDA QLEX, both used alongside Padcev.
- The submissions focus on muscle-invasive bladder cancer (MIBC) patients who qualify for cisplatin-based chemotherapy treatment.
- FDA established August 17, 2026 as the target action date for its decision.
- Both applications rely on Phase 3 KEYNOTE-B15 trial results demonstrating enhanced survival outcomes.
- Approval would establish the first perioperative treatment option for MIBC patients across all cisplatin eligibility categories.
Merck has secured another significant regulatory milestone for KEYTRUDA, its flagship oncology treatment, after receiving priority review designation from the FDA for bladder cancer applications.
The pharmaceutical company disclosed Monday that federal regulators accepted two supplemental Biologics License Applications for KEYTRUDA (pembrolizumab) and KEYTRUDA QLEX (pembrolizumab and berahyaluronidase alfa-pmph). Each application proposes using the therapy alongside Padcev (enfortumab vedotin-ejfv) for muscle-invasive bladder cancer patients who meet criteria for cisplatin-based chemotherapy.
Regulators scheduled August 17, 2026 as the Prescription Drug User Fee Act target action date.
The FDA reserves priority review designation for therapeutic candidates that demonstrate potential for substantial improvements when treating serious medical conditions. This classification accelerates the evaluation process to approximately six months rather than the conventional ten-month timeline.
Trial Results Supporting the Applications
The regulatory submissions draw upon evidence from the Phase 3 KEYNOTE-B15 clinical trial. This research demonstrated superior survival results among muscle-invasive bladder cancer patients receiving the combined KEYTRUDA and Padcev regimen.
While Merck withheld detailed trial statistics from Monday’s statement, the FDA’s priority review designation indicates regulators view the evidence as potentially transformative for clinical practice.
Current FDA-approved indications for KEYTRUDA combined with Padcev encompass adult patients with locally advanced or metastatic urothelial cancer across the United States, European Union, Japan, and additional markets worldwide.
These new regulatory submissions seek to extend treatment availability into earlier disease stages — specifically the muscle-invasive phase — where therapeutic goals typically focus on achieving cure.
Pioneering Treatment Classification
Regulatory approval would establish KEYTRUDA and KEYTRUDA QLEX combined with Padcev as the inaugural perioperative therapies for MIBC patients across all cisplatin eligibility categories.
This represents a clinically significant development. Present regulatory approvals cover the combination therapy for MIBC patients who cannot receive cisplatin-based chemotherapy. These new applications would incorporate patients who qualify for cisplatin treatment — substantially expanding the addressable patient population.
Perioperative therapy describes treatment administered before and after surgical intervention, which represents standard medical practice for muscle-invasive bladder cancer management. Entering this treatment setting with priority review status positions Merck favorably from a regulatory standpoint as the August decision date approaches.
KEYTRUDA QLEX delivers pembrolizumab through subcutaneous administration, allowing injection beneath the skin rather than requiring intravenous infusion. This formulation may provide practical advantages compared to traditional IV delivery methods.
Merck’s equity price increased 3.13% during Monday’s trading session following the announcement. Investment analysts tracking the company’s oncology development portfolio will closely monitor the August 17 target date.

