Trial Investigating Pembrolizumab for Hormone-Sensitive Prostate Cancer Discontinued

Merck has made the decision to end the KEYNOTE-991 trial (ClinicalTrials.gov Identifier: NCT04191096). The phase 3 study was evaluating pembrolizumab (Keytruda^®), a programmed death receptor-1 (PD-1)-blocking antibody, in combination with enzalutamide (Xtandi^®), an androgen receptor inhibitor, and androgen deprivation therapy (ADT) in patients with metastatic hormone-sensitive prostate cancer.

Findings from a planned interim analysis showed that treatment with the pembrolizumab combination did not result in an improvement in overall survival or radiographic progression free survival, the study’s primary endpoints, when compared with placebo plus enzalutamide and ADT.

While no new safety signals were identified in the trial, a higher incidence of serious adverse events was observed in the pembrolizumab combo arm vs the control arm.

Data from KEYNOTE-991 will be presented at an upcoming meeting.

Reference

Merck announces KEYNOTE-991 trial evaluating Keytruda^® (pembrolizumab) plus enzalutamide and androgen deprivation therapy in patients with metastatic hormone-sensitive prostate cancer to stop for futility. News release. January 25, 2023. https://www.businesswire.com/news/home/20230124006084/en/Merck-Announces-KEYNOTE-991-Trial-Evaluating-KEYTRUDA%C2%AE-pembrolizumab-Plus-Enzalutamide-and-Androgen-Deprivation-Therapy-in-Patients-With-Metastatic-Hormone-Sensitive-Prostate-Cancer-to-Stop-for-Futility.