Merck Increases Focus on Advanced Prostate Cancer, Expanding Immuno-Oncology Program with Three New Phase 3 Trials

Merck, known as MSD outside the United States and Canada, announced the presentation of interim data from the Phase 1b/2 KEYNOTE-365 umbrella trial investigating KEYTRUDA, Merck’s anti-PD-1 therapy, in combination with various agents for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC). These early findings show anti-tumor activity across three cohorts of the study, which investigated KEYTRUDA in combination with LYNPARZA (Cohort A, Abstract #145); docetaxel and prednisone (Cohort B, Abstract #170); and enzalutamide (Cohort C, Abstract #171) – with a safety profile consistent with each therapy alone. These results are being presented today at the 2019 Genitourinary Cancers Symposium (ASCO GU) in San Francisco. Based on the findings, Merck is initiating three new pivotal Phase 3 trials with KEYTRUDA in combination with LYNPARZA (KEYLYNK-010, NCT03834519), docetaxel and prednisone (KEYNOTE-921, NCT03834506) and enzalutamide (KEYNOTE-641, NCT03834493).

“At the core of our research program is a commitment to investigate the potential of KEYTRUDA – both as combination and monotherapy – to serve as a foundational treatment, especially for cancers where additional therapies are needed,” said Dr. Roy Baynes, senior vice president, head of global clinical development, and chief medical officer, Merck Research Laboratories. “These promising data presented at ASCO GU coupled with the significant unmet medical need in patients with metastatic castration-resistant prostate cancer, propelled us to initiate three new Phase 3 trials to further evaluate these KEYTRUDA combination regimens.”

Merck’s existing clinical development program in metastatic prostate cancer includes studies evaluating KEYTRUDA and LYNPARZA as monotherapy and in combination with other anti-cancer therapies with various mechanisms of action. Ongoing trials include the Phase 2 KEYNOTE-199 trial for KEYTRUDA monotherapy and, in collaboration with AstraZeneca, the Phase 3 trials PROfound evaluating LYNPARZA monotherapy and PROPEL evaluating LYNPARZA in combination with abiraterone as a first-line therapy in patients with mCRPC. With the initiation of KEYLYNK-010, KEYNOTE-921 and KEYNOTE-641, Merck now has the largest clinical program with an anti-PD-1 therapy in prostate cancer and the only program to evaluate overall survival (OS) as a co-primary endpoint across three Phase 3 trials.