FDA Approves Breakthrough Melanoma Therapy

Pembrolizumab is the first drug approved that blocks the PD-1 cellular pathway.

The FDA granted approval today for a breakthrough therapy in the treatment of melanoma.

Pembrolizumab (Keytruda) provides a new option for patients with advanced or unresectable melanoma following a lack of response to other medications. The treatment was approved through the FDA’s breakthrough therapy designation after it was found to offer substantial improvement over other available treatments during a preliminary clinical evaluation.

“Keytruda is the sixth new melanoma treatment approved since 2011, a result of promising advances in melanoma research,” said Richard Pazdur, MD, director of the Office of Hematology and Oncology Products for the FDA Center for Drug Evaluation and Research in a press release. “Many of these treatments have different mechanisms of action and bring new options to patients with melanoma.”

Pembrolizumab acts as an inhibitor of the PD-1 cellular pathway, which prevents the immune system from attacking melanoma cells. The medication is to be used following treatment with the immunotherapy ipilimumab.

In melanoma patients with tumors that express the BRAF V600 gene mutation, the combination therapy blocks the activity of BRAF gene mutations.

In a clinical trial of 173 participants with advanced melanoma who didn’t respond to prior treatment, participants were treated with pembrolizumab at the recommended dose of 2 mg/kg or at a higher dose of 10 mg/kg. In the half of the patients who received pembrolizumab at the recommended dose of 2 mg/kg, approximately 24% had their tumors shrink.

The reduced tumors lasted from 1.4 to 8.5 months and extended beyond that period in most patients, while a similar percentage of patients had their tumors shrink at the 10-mg/kg dose.

A safety evaluation of the drug was conducted in 411 advanced melanoma patients. The most common adverse events were fatigue, cough, nausea, itchy skin, rash, decreased appetite, constipation, joint pain, and diarrhea, the FDA said.

Severe immune-mediated side effects were uncommon but could affect healthy organs such as the lungs, the colon, hormone-producing glands, and the liver.