The Food and Drug Administration (FDA) granted accelerated approval to Keytruda (pembrolizumab) for the treatment of adult and pediatric patients with recurrent locally advanced or metastatic Merkel cell carcinoma (MCC), according to the agency.
The approval was based on results from the multicenter, non-randomized, open-label phase 2 KEYNOTE-017 trial – designed to evaluate a dose of 2 mg/kg of Keytruda every three weeks in 50 patients with recurrent locally advanced or metastatic MCC who had not received prior systemic therapy for their advanced disease.
Overall response rate and response duration served as the primary efficacy endpoints.
Keytruda demonstrated an overall response rate of 56 percent, including a complete response rate of 24 percent. Median response duration was not reach.
Among the 28 patients who experienced a response, 96 percent had responses that lasted more than six months, and 54 percent had responses for more than a year.
The most common side effects included fatigue, musculoskeletal pain, decreased appetite, pruritus, diarrhea, nausea, rash, pyrexia, cough, dyspnea, constipation, pain and abdominal pain.
The FDA noted that this indication is approved under accelerated approval based on tumor response rate and durability of response, and that continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials.
Keytruda is an anti-PD-1 therapy designed to increase the immune system’s ability to detect and fight tumor cells by blocking the interaction between PD-1 and its ligands (a molecule that binds to another usually larger molecule), thereby activating T lymphocytes which may affect both tumor cells and healthy cells.