Pembrolizumab Offers Extended Survival in Advanced Melanoma Patients

Treatment with the anti–programmed death 1 (PD-1) antibody pembrolizumab yielded good long-term survival outcomes in a phase Ib trial of patients with advanced melanoma. The benefit was seen regardless of whether patients had been previously treated with ipilimumab.

“Before 2011, before ipilimumab, patients with advanced melanoma had a median survival of less than 1 year,” said Caroline Robert, MD, PhD, of the Institut Gustave-Roussy in Paris. Robert led the study (abstract 9503) that will be presented at the American Society of Clinical Oncology (ASCO) Annual Meeting, on June 6 in Chicago, and she discussed the results during a press call on Wednesday, May 18.

Pembrolizumab was granted approval for the treatment of advanced melanoma after an accelerated review in September 2014, based on data from the KEYNOTE-001 trial. The new analysis includes long-term results of that same study, involving 655 patients, 75% of whom had received prior therapies, including ipilimumab (52%).

The median overall survival (OS) in the study was 24.4 months, and the 3-year OS rate was 40%, a result Robert called “really exciting.” The 3-year OS was slightly better among patients who had not received any prior therapy, at 45%. When divided based on who had previously received ipilimumab or not, the 3-year OS was 41% in both groups.

The response rate was 33%, and the median duration response had not yet been reached; 73% of those with a response had a duration of at least 2 years. Ninety-five patients (15%) had a complete response, and 61 of those stopped treatment after the complete response; only two of those patients progressed after stopping treatment, one whom has since started a second course of pembrolizumab.

Robert called the safety profile “manageable.” Only 8% of the full cohort stopped the therapy due to a drug-related adverse event, and there were no drug-related deaths. The most common adverse events with pembrolizumab included fatigue (40%), itchiness (28%), and rash (23%).

“These long-term data we think support the durable benefit of pembrolizumab and confirm its use as one of the new standards of care for patients with advanced melanoma,” Robert concluded.

“New therapies that block the PD-1 are extending survival for many patients, and for some may offer the prospect of living longer than ever after a diagnosis with advanced melanoma,” said Don S. Dizon, MD, an ASCO spokesperson who moderated the press call, adding that it is especially impressive that these data came from a phase I trial. “In a matter of a few years, these therapies have truly transformed the outlook for patients with melanoma and many other hard-to-treat cancers.”