Advanced Melanoma Immunotherapy May Change Treatment of Disease

Keytruda acts by allowing T cells to recognize and attack cancer cells.

A first in class immunotherapy approved last week offers significant hope to patients with metastatic melanoma.

The anti-PD-1 immunotherapy pembrolizumab (Keytruda) acts by allowing T cells to recognize and attack cancer cells.

The drug previously received accelerated approval for metastatic melanoma, but was only administered to patients who no longer respond to ipilimumab. Both drugs act similarly in binding to the immune molecule CTLA-4, which blocks T cell activity.

A comparison of Keytruda and ipilimumab showed less severe adverse events, improved tumor response, improved response duration, and extended survival from treatment with Keytruda.

"We are delighted that we found that pembrolizumab is superior to ipilimumab as first-line therapy by improving responses and survival," said co-developer Dr. Antoni Ribas, of the UCLA Jonsson Comprehensive Cancer. "With today's approval by the FDA, physicians will be able to identify patients who are candidates for receiving pembrolizumab as first-line therapy."

In a clinical trial, 834 patients with metastatic melanoma were randomized to receive Keytruda or ipilimumab. Researchers assessed treatment responses by progression-free survival and overall survival (OS), and also assessed the overall response rate to treatment and safety.

After 6 months, 45% of patients in the Keytruda group responded to therapy compared with 26% in the ipilimumab group, which represents a 42% improvement in progression free survival for patients on Keytruda.

At 1 year, OS in the Keytruda group was 74% and 68% across 2 study groups, compared with 58% among patients administered ipilimumab. The tumor response rate was 33% in the Keytruda group compared with 12% in the ipilimumab group.

Furthermore, adverse events were found in 12% of patients administered Keytruda compared with 20% of patients administered ipilimumab.