Merck: Advanced melanoma patients treated with MK-3475 showed 81% survival at 1 year

Patients with advanced melanoma had an overall survival rate of 81% at 1 year across all monotherapy doses of an investigational anti-PD-1 immunotherapy, Merck has announced.

The first overall survival data were from a cohort of 135 patients with advanced melanoma in an ongoing phase 1B study of MK-3475, a highly selective, anti-PD-1 immunotherapy designed to restore the immune system’s ability to recognize and target cancer cells by selectively achieving dual ligand blockade (PD-L1 and PD-L2) of the PD-1 protein, according to a press release. The research was to be presented at the Society for Melanoma Research Congress in Philadelphia.

“The objective response rate (patients who had either complete or partial response) across all doses improved with longer duration of follow-up; at the time of this analysis, the objective response rate was 41% (9% complete response rate) as evaluated by a blinded central review committee using RECIST 1.1 (Response Evaluation Criteria in Solid Tumors),” the release said.

The majority of responses to MK-3475 occurred within 12 weeks of treatment; however, partial to complete response continued after 6 months of therapy and as late as 70 weeks, Merck said. Median response duration or median overall survival has not yet been reached for all doses evaluated.

MK-3475 is being evaluated in more than 1,000 patients with late-stage cancers, predominantly lung and melanoma, in the multicenter, open-label trial. Dosing regimens include 10 mg/kg every 2 weeks, 10 mg/kg every 3 weeks or 2 mg/kg every 3 weeks. Overall response rate is the primary endpoint; progression-free survival and overall survival are considered secondary endpoints.

“New agents are needed for patients with advanced melanoma,” researcher Caroline Robert, MD, PhD, head of dermatology at Gustave Roussy, Cancer Campus, Grand Paris, said in the release. “I am excited by the results seen for MK-3475 as a single agent and believe these findings support further study both as a monotherapy and in combination in various solid tumors.”

MK-3475 was granted an FDA breakthrough therapy designation — awarded to expedite the approval process of drugs used to treat life-threatening or serious diseases that “may demonstrate substantial improvement over existing therapies” — in April, Merck said.

For more information:

Robert C. Updated Clinical Efficacy and Safety of MK-3475 (Anti-PD-1 Monoclonal Antibody) in Advanced Melanoma. Presented at: Society for Melanoma Research; Nov. 17-20, 2013; Philadelphia.