Pembrolizumab Approved for Merkel Cell Carcinoma by the FDA
Posted: Thursday, December 20, 2018
The U.S. Food and Drug Administration (FDA) recently granted accelerated approval to pembrolizumab (Keytruda) for adult and pediatric patients with recurrent locally advanced or metastatic Merkel cell carcinoma.
The FDA’s approval was based on Cancer Immunotherapy Trials Network protocol 9 (CITN-09), also known as KEYNOTE-017, a multicenter, nonrandomized, open-label trial that enrolled 50 patients with recurrent locally advanced or metastatic Merkel cell carcinoma who had not received prior systemic therapy for advanced disease. Patients received pembrolizumab at 2 mg/kg every 3 weeks.
The major efficacy outcome measures were overall response rate and response duration, assessed by blinded independent central review per Response Evaluation Criteria in Solid Tumors, version 1.1. The overall response rate was 56%, with a complete response rate of 24%. The median response duration was not reached. Among the 28 patients with responses, 96% had response durations of more than 6 months, and 54% had response durations of more than 12 months.
The most common adverse reactions associated with single-agent pembrolizumab reported in at least 20% of treated patients were fatigue, musculoskeletal pain, decreased appetite, pruritus, diarrhea, nausea, rash, pyrexia, cough, dyspnea, constipation, pain, and abdominal pain.
The recommended pembrolizumab dose for Merkel cell carcinoma is 200 mg administered as a 30-minute intravenous infusion every 3 weeks for adults; 2 mg/kg (to a maximum of 200 mg) administered as a 30-minute intravenous infusion every 3 weeks for pediatric patients up to age 18.