Merck's Keytruda Improves Melanoma PFS In Phase 2 Study

Merck reported positive results from a pivotal Phase 2 study of anti-PD-1 therapy Keytruda (pembrolizumab) as treatment for ipilimumab-refractory advanced melanoma.

Pembrolizumab, branded as Keytruda, is a humanized monoclonal antibody (mAb) that keeps ligands PD-L1 and PD-L2 from interacting with PD-1. This induces the PD-1 pathway-mediated inhibition of the immune response, including anti-tumor immune response. Merck has received two Breakthrough Therapy Designations from the U.S. Food and Drug Administration (FDA) for pembrolizumab as treatment for advanced non-small cell lung cancer (NSCLC) and advanced or unresectable melanoma.

In the global, randomized, pivotal Phase 2 study KEYNOTE-002, pembrolizumab met the trial’s primary endpoint by significantly enhancing progression-free survival (PFS) of patients with ipilimumab-refractory advanced melanoma versus chemotherapy. No significant variations were recorded between pembrolizumab doses in PFS pre-specified analyses. Secondary endpoints of the trial included safety, overall response rate, and duration of response. Notably, pembrolizumab out performed chemotherapy, with overall response rates coming in 5 to 6 times higher. The median duration of the follow-up analysis of the trials’ interim data was 10 months. Assessment of overall survival, a co-primary endpoint in the study, is planned at the scheduled pre-specified analyses in 2015.

“These findings demonstrate KEYTRUDA was superior to chemotherapy in helping more patients with ipilimumab-refractory advanced melanoma achieve progression-free survival. The comparative efficacy and safety data from the pivotal KEYNOTE-002 study validate and extend the findings from our earlier study in these difficult-to-treat patients, and we look forward to sharing data on overall survival at a future congress,” said Dr. Eric Rubin, VP of global clinical development for oncology at Merck Research Laboratories.

Merck presented the previously announced findings, including pre-specified analyses of ORR, duration of response, safety and health-related quality of life (HRQoL), at the Society of Melanoma Research (SMR) 2014 International Congress currently being held in Zurich, Switzerland.