Merck has announced the closure of KEYNOTE-598, a phase 3 study evaluated pembrolizumab plus ipilimumab versus pembrolizumab monotherapy as a first-line treatment for patients with non–small cell lung cancer (NSCLC) whose tumors express PD-L1.
According to a press release issued by the company, the study was terminated following a recommendation from an independent Data Monitoring Committee that the risk-to-benefit profile of pembrolizumab plus ipilimumab did not support continued investigation. Interim results suggested that treatment with the combination did not provoke a clinically meaningful improvement in overall survival or progression-free survival over pembrolizumab monotherapy.
In addition, treatment with pembrolizumab plus ipilimumab was associated with a greater proportion of grade 3-5 adverse events, serious adverse events, and adverse events resulting in discontinuation or death.
“We conducted KEYNOTE-598 in order to explicitly explore whether combining our anti–PD-1 therapy with ipilimumab provided additional benefits beyond treatment with pembrolizumab alone in the metastatic NSCLC setting. It is very clear that in this study, the addition of ipilimumab did not add clinical benefit but did add toxicity,” said Roy Baynes, MD, PhD, senior vice president, head of global clinical development and chief medical officer, Merck, in the press release. “Pembrolizumab monotherapy remains a standard of care for the treatment of certain patients with metastatic NSCLC whose tumors express PD-L1.”
The Data Monitoring Committee recommended that patients assigned ipilimumab discontinue treatment.
The randomized, double-blind KEYNOTE-598 study enrolled patients with metastatic NSCLC whose tumors express PD-L1 (tumor proportion score ≥ 50%), with no EGFR or ALK genomic alterations. Merck plans to submit data from the study for presentation at an upcoming scientific meeting.