FDA Grants Accelerated Approval to Pembrolizumab for MCC

Earlier this week, the FDA granted accelerated approval to pembrolizumab (Keytruda) for adult and pediatric patients with recurrent locally advanced or metastatic Merkel cell carcinoma (MCC). The indication was approved under the accelerated approval pathway due to tumor response rate and durability of response.

The approval was based on data from the Cancer Immunotherapy Trials Network (CITN)’s CITN-09/KEYNOTE-017 trial. The phase 2, nonrandomized, multicenter, open-label trial enrolled 50 patients with recurrent locally advanced or metastatic MCC who had not received prior systemic therapy.

“Merkel cell carcinoma is an aggressive and fast-growing form of skin cancer that has historically been challenging to treat… [We] are pleased to provide an important new therapeutic option for Merkel cell carcinoma patients,” said Scott Ebbinghaus, MD, vice president, clinical research, Merck Research Laboratories, in a statement.

Patients were administered pembrolizumab 2 mg/kg every 3 weeks until unacceptable toxicity or disease progression that was symptomatic, was rapidly progressive, required urgent intervention, occurred with a decline in performance status, or was confirmed at least 4 weeks later with repeat imaging. Patients who did not demonstrate disease progression were treated for up to 24 months. Researchers assessed tumor status at 13 weeks, followed by every 9 weeks for the first year and every 12 weeks thereafter.

The investigators found that pembrolizumab as a monotherapy demonstrated an objective response rate of 56% (95% CI, 41%-70%), with a complete response rate of 24% (95% CI, 13%-38%) and a partial response rate of 32% (95% CI, 20%-47%). In total, 96% of responding patients experienced a durability of response for 6 months or longer, and 54% experienced a durability of response for 12 months or longer.

“The CITN-09-KEYNOTE-017 trial demonstrates that first-line treatment with anti-PD1 therapy provides a meaningful advance for Merkel cell carcinoma patients who have historically had a poor long-term prognosis,” said Paul Nghiem, MD, PhD. “A few years ago, patients with Merkel cell carcinoma did not have treatment options beyond chemotherapy. As a practicing physician I am pleased that this approval provides another option for patients facing this rare and challenging disease.”