Merck Announces Positive Results from KEYNOTE-905 Trial for Muscle-Invasive Bladder Cancer Treatment

Merck announces topline results from KEYNOTE-905 trial, a Phase 3 study in patients with muscle-invasive bladder cancer. Keytruda plus Padcev demonstrated a statistically significant and clinically meaningful improvement in event-free survival, overall survival, and pathologic complete response rate compared to surgery alone. The safety profile of the combination was consistent with the known safety profiles of each agent. No new safety signals were identified. The results will be shared with regulatory authorities worldwide and presented at an upcoming medical meeting.

Merck (NYSE: MRK) has announced positive topline results from the Phase 3 KEYNOTE-905 trial, which evaluated the efficacy of KEYTRUDA (pembrolizumab) plus Padcev (enfortumab vedotin-ejfv) in patients with muscle-invasive bladder cancer (MIBC) who are ineligible for cisplatin-based chemotherapy. The study demonstrated a statistically significant and clinically meaningful improvement in event-free survival (EFS), overall survival (OS), and pathologic complete response (pCR) rate compared to surgery alone.

The trial, known as EV-303, enrolled 595 patients who were randomized to receive either KEYTRUDA alone or in combination with Padcev, either preoperatively or postoperatively, followed by surgery (radical cystectomy). The primary objective of the study was to compare EFS between the combination therapy and surgery alone, which was achieved with statistically significant results. Additionally, the combination therapy showed improvements in OS and pCR rate compared to surgery alone.

Dr. Christof Vulsteke, MD, PhD, the principal investigator of the trial, stated, "This is the first time a systemic treatment approach has significantly extended survival over standard-of-care surgery in this population, demonstrating the potential of this combination to address a critical unmet need."

The safety profile of the combination therapy was consistent with the known safety profiles of each agent, with no new safety signals identified. The companies plan to share these results with regulatory authorities worldwide and will present the data at an upcoming medical meeting.

This trial marks a significant advancement in the treatment of MIBC, particularly for patients who are ineligible for cisplatin-based chemotherapy. Merck is continuing to evaluate the combination therapy in additional Phase 3 studies, including KEYNOTE-866, KEYNOTE-992, and KEYNOTE-B15, to further explore its potential benefits in various stages of bladder cancer.

References:
[1] Merck. (2025). Merck Announces Positive Topline Results from KEYNOTE-905 Trial in Patients with Muscle-Invasive Bladder Cancer. Retrieved from [https://www.merck.com/news/keytruda-pembrolizumab-plus-padcev-enfortumab-vedotin-ejfv-significantly-improved-event-free-and-overall-survival-and-pathologic-complete-response-rate-for-certain-patients-with-muscle/](https://www.merck.com/news/keytruda-pembrolizumab-plus-padcev-enfortumab-vedotin-ejfv-significantly-improved-event-free-and-overall-survival-and-pathologic-complete-response-rate-for-certain-patients-with-muscle/)