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# Merck Discontinues Keytruda Prostate Cancer Trial
- URL: https://www.fdaweb.com/merck-discontinues-keytruda-prostate-cancer-trial/
- Published: 2023-02-28T12:00:00.000Z
- Updated: 2026-09-14T18:17:30.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5153869

Merck says it is discontinuing the Phase 3 KEYNOTE-641 trial evaluating Keytruda (pembrolizumab) in combination with enzalutamide and androgen deprivation therapy (ADT) for treating patients with metastatic castration-resistant prostate cancer, based on the recommendation of an independent data monitoring committee. An interim analysis found that the combination therapy did not demonstrate an improvement in radiographic progression-free survival or overall survival (OS), which are the primary endpoints, compared to placebo plus enzalutamide and ADT.

The company also announced that another Phase 3 trial, KEYNOTE-789, evaluating Keytruda in combination with pemetrexed plus platinum-based chemotherapy did not meet its dual primary endpoint of OS for treating patients with metastatic nonsquamous non-small cell lung cancer, with epidermal growth factor receptor-genomic tumor mutations, who have previously progressed on a tyrosine kinase inhibitor. “At the final analysis of the study, there was an improvement in OS for patients who received Keytruda plus pemetrexed with platinum-based chemotherapy compared to pemetrexed with platinum-based chemotherapy; however, these results did not meet statistical significance per the pre-specified statistical plan,” Merck says. “At an earlier interim analysis, the trial’s other dual primary endpoint, progression-free survival was tested and showed an improvement in the Keytruda arm compared to chemotherapy alone, but these results did not reach statistical significance.”