KENILWORTH, N.J.--(BUSINESS WIRE)--

Merck Announces KEYNOTE-598 Trial Evaluating KEYTRUDA® (pembrolizumab) in Combination With Ipilimumab Versus KEYTRUDA Monotherapy in Certain Patients With Metastatic Non-Small Cell Lung Cancer To Stop for Futility and Patients to Discontinue Ipilimumab

Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced that it will be stopping KEYNOTE-598, a Phase 3 trial investigating KEYTRUDA, Merck’s anti-PD-1 therapy, in combination with ipilimumab (Yervoy®), compared with KEYTRUDA monotherapy, for the first-line treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors express PD-L1 (tumor proportion score [TPS] ≥50%) with no EGFR or ALK genomic tumor aberrations. Merck is discontinuing the study following the recommendation of an independent Data Monitoring Committee (DMC), which determined the benefit/risk profile of the combination did not support continuing the trial. At an interim analysis, the combination of KEYTRUDA and ipilimumab showed no incremental benefit in overall survival (OS) or progression-free survival (PFS), the study’s dual primary endpoints, compared with KEYTRUDA alone and crossed futility boundaries. No new safety signals for KEYTRUDA monotherapy were observed, however the combination of KEYTRUDA and ipilimumab was associated with a higher incidence of grade 3-5 adverse events (AEs), serious AEs, and AEs leading to discontinuation or death, compared with KEYTRUDA monotherapy. Merck will inform study investigators of the recommendation from the DMC and the DMC is advising that patients in the study discontinue treatment with ipilimumab/placebo. Data from this study will be submitted for presentation at an upcoming scientific congress and communicated to regulatory agencies.

“We conducted KEYNOTE-598 in order to explicitly explore whether combining our anti-PD-1 therapy, KEYTRUDA, with ipilimumab provided additional benefits beyond treatment with KEYTRUDA alone in the metastatic non-small cell lung cancer setting,” said Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories. “It is very clear that in this study, the addition of ipilimumab did not add clinical benefit but did add toxicity. KEYTRUDA monotherapy remains a standard of care for the treatment of certain patients with metastatic non-small cell lung cancer whose tumors express PD-L1.”

While the combination of an anti-PD-1 therapy plus ipilimumab has been approved in certain indications, studies supporting these approvals have, for the most part, not compared the combination directly with anti-PD-1 monotherapy. Bristol Myers Squibb has reported topline results of CheckMate-915, a Phase 3 study in adjuvant melanoma that directly compared treatment with ipilimumab in combination with an anti-PD-1 therapy versus the anti-PD-1 therapy alone. In two separate news releases issued over the last year, the company announced the study did not meet its co-primary endpoints in the all-comer population or in patients whose tumors expressed PD-L1