On June 24, 2026 Merck (NYSE: MRK), known as MSD outside of the United States and Canada, reported that KEYTRUDA (pembrolizumab), Merck’s anti-PD-1 therapy, in combination with Padcev (enfortumab vedotin-ejfv), an antibody-drug conjugate (ADC), is approved in the European Union (EU), as neoadjuvant treatment and then continued after radical cystectomy (RC) as adjuvant treatment, for adults with resectable muscle-invasive bladder cancer (MIBC) who are ineligible for cisplatin-containing chemotherapy. This approval, which also covers KEYTRUDA SC [known as KEYTRUDA QLEXTM (pembrolizumab and berahyaluronidase alfa-pmph) in the U.S.], makes this combination the first and only PD-1 inhibitor plus ADC regimen available for these patients in the EU.

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This approval is based on results from the pivotal Phase 3 KEYNOTE-905 trial (also known as EV-303), which was conducted in collaboration with Pfizer and Astellas. In the study, KEYTRUDA plus Padcev, as perioperative treatment, demonstrated statistically significant and clinically meaningful improvements in event-free survival (EFS), overall survival (OS) and pathologic complete response (pCR) rate versus surgery alone in patients with MIBC who are not eligible for or declined cisplatin-based chemotherapy. KEYTRUDA plus Padcev reduced the risk of EFS events by 60% (HR=0.40 [95% CI, 0.28-0.57]; p<0.0001) versus surgery alone. Median EFS was not reached (NR) (95% CI, 37.3-NR) for KEYTRUDA plus Padcev versus 15.7 months (95% CI, 10.3-20.5) for surgery alone. KEYTRUDA plus Padcev also reduced the risk of death by 50% (HR=0.50 [95% CI, 0.33-0.74]; p=0.0002) versus surgery alone. Median OS was NR (95% CI, NR-NR) for KEYTRUDA plus Padcev versus 41.7 months (95% CI, 31.8-NR) for surgery alone. The trial demonstrated a statistically significant difference in pCR rate (57.1% [95% CI: 49.3, 64.6] vs. 8.6% [95% CI: 4.9, 13.8]; p<0.0001). The approval follows a positive recommendation from the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP), received in May 2026.

"Patients with resectable muscle-invasive bladder cancer who are ineligible for cisplatin‑containing chemotherapy face an aggressive disease and few effective therapies, with surgery alone as the longstanding standard of care," said Professor Christof Vulsteke, head of Integrated Cancer Center Ghent (IKG) and Clinical Trial Unit Oncology Ghent and KEYNOTE-905 principal investigator. "Based on robust data from the KEYNOTE-905 trial, this approval marks a turning point in bladder cancer care. It introduces a potentially practice-changing perioperative treatment option that may significantly improve outcomes and extend survival for this underserved patient population across the European Union."

"For patients with resectable muscle-invasive bladder cancer in Europe, this approval represents a meaningful advance after years of limited progress in the field," said Dr. Marjorie Green, senior vice president and head of oncology, global clinical development, Merck Research Laboratories. "As the first PD-1 inhibitor plus antibody-drug conjugate regimen approved in this setting, this treatment is poised to address a crucial unmet need, reflecting our continued commitment to delivering innovative KEYTRUDA-based therapies to patients with bladder cancer worldwide."

This approval authorizes marketing of this KEYTRUDA treatment regimen for this indication in all 27 EU member states, as well as Iceland, Liechtenstein and Norway. Timing for commercial availability of KEYTRUDA for this indication in individual EU countries will depend on multiple factors, including the completion of national reimbursement procedures.

In November 2025, KEYTRUDA and KEYTRUDA QLEX, each in combination with Padcev, were approved by the U.S. Food and Drug Administration (FDA), as neoadjuvant treatment and then continued after cystectomy as adjuvant treatment, for the treatment of adult patients with MIBC who are ineligible for cisplatin-based chemotherapy.

About KEYNOTE-905/EV-303

KEYNOTE-905, also known as EV-303, is an open-label, randomized, multi-arm, controlled Phase 3 trial (ClinicalTrials.gov, NCT03924895) evaluating perioperative KEYTRUDA, with or without Padcev, versus surgery alone in patients with MIBC who are either not eligible for or declined cisplatin-based chemotherapy. The trial enrolled 595 patients who were randomized to receive either:

Arm A: Three cycles of neoadjuvant KEYTRUDA, followed by surgery to remove the bladder (RC), followed by 14 cycles of adjuvant KEYTRUDA;
Arm B: Surgery alone;
Arm C: Three cycles of neoadjuvant KEYTRUDA plus enfortumab vedotin, followed by surgery to remove the bladder (RC), followed adjuvantly by six cycles of KEYTRUDA plus enfortumab vedotin and then eight cycles of KEYTRUDA alone.
The primary objective of this trial is to compare EFS between arm C and arm B, defined as the time from randomization to the first occurrence of any of the following events: progression of disease that precludes RC surgery or failure to undergo RC surgery in participants with residual disease, gross residual disease left behind at the time of surgery, local or distant recurrence as assessed by imaging and/or biopsy or death due to any cause. The key secondary objectives are to compare OS and the difference in pCR rate between arm C and arm B, as well as EFS, OS and the difference in pCR rate between arm A and arm B. The study remains ongoing to test hypotheses between arm A and arm B.

About bladder cancer

Bladder cancer is the ninth most common cancer worldwide, diagnosed in more than 614,000 patients each year globally. In Europe, it is estimated there were approximately 224,700 patients diagnosed with bladder cancer and more than 70,300 deaths from the disease in 2022. According to some clinical practice guidelines, about 25% of newly diagnosed bladder cancer cases are MIBC. The standard of care for patients with MIBC has been neoadjuvant cisplatin-based chemotherapy followed by surgery, which is shown to prolong survival. However, up to half of patients with MIBC are not eligible to receive cisplatin and face limited treatment options, typically undergoing surgery alone.

(Press release, Merck & Co, JUN 24, 2026, View Source [SID1234668935])