The FDA has granted accelerated approval to Keytruda (pembrolizumab) for the treatment of patients with advanced or unresectable melanoma who are no longer responding to other drugs. Melanoma occurs when cancer cells form in the skin cells that make the pigment responsible for color in the skin.
Keytruda has become the first approved drug that blocks a cellular pathway known as PD-1, which restricts the body’s immune system from attacking melanoma cells. It is intended for use following treatment with ipilimumab, a type of immunotherapy. For melanoma patients whose tumors express a gene mutation called BRAF V600, Keytruda is intended for use after treatment with and a BRAF inhibitor, a therapy that blocks activity of BRAF gene mutations.
Keytruda marks the 6th new melanoma treatment approved since 2011, with the five prior drugs being ipilumab (2011), peginterferon alfa-2b (2011), vemurafenib (2011), dabrafenib (2013), and trametinib (2013).
Keytruda’s efficacy was established in 173 clinical trial participants with advanced melanoma whose disease progressed after prior treatment. All participants were treated with Keytruda, either at the recommended dose of 2 mg/kg or at a higher dose of 10 mg/kg. In the half of the participants who received Keytruda at the recommended dose of 2 mg/kg, approximately 24% had their tumors shrink. This effect lasted at least 1.4 to 8.5 months and continued beyond this period in most patients. A similar percentage of patients had their tumor shrink at the 10 mg/kg dose.
Keytruda’s safety was established in the trial population of 411 participants with advanced melanoma. The most common side effects of Keytruda were fatigue, cough, nausea, itchy skin (pruritus), rash, decreased appetite, constipation, joint pain (arthralgia) and diarrhea. Keytruda also has the potential for severe immune-mediated side effects. In the 411 participants with advanced melanoma, severe immune-mediated side effects involving healthy organs, including the lung, colon, hormone-producing glands and liver, occurred uncommonly.
Keytruda is marketed by Merck & Co., based in Whitehouse Station, New Jersey.