Previously approved for the treatment of several other cancers, including lung, cervical, gastric, liver, head and neck, bladder, and certain types of lymphoma, pembrolizumab (Keytruda®, Merck & Co., Inc.) is now approved for both adult and pediatric patients with recurrent locally advanced or metastatic Merkel cell carcinoma (MCC), a rare skin cancer affecting about 2,000 patients per year. Merkel cell carcinoma is aggressive and challenging to treat, and patients with advanced disease have 10-year survival rates of only 20% to 49%.
Accelerated approval was granted based on a multicenter, non-randomized, open-label study known as Cancer Immunotherapy Trials Network (CITN)-09 or KEYNOTE-017 (NCT02267603). In this trial, 50 patients with recurrent locally advanced or metastatic MCC who had not yet received systemic treatment for advanced disease were given pembrolizumab 2 mg/kg every three weeks through intravenous (IV) infusion.
The primary end points of the study were overall response rate and response duration. The overall response rate was 56%, with 24% of patients achieving a complete response. The median response duration was not reached.
"The CITN-09/KEYNOTE-017 trial demonstrates that first-line treatment with anti–PD-1 therapy provides a meaningful advance for Merkel cell carcinoma patients who have historically had a poor long-term prognosis," commented the study's lead investigator, Paul T. Nghiem, MD, PhD, Professor of Dermatology at the University of Washington School of Medicine in Seattle and Affiliate Investigator at Fred Hutchinson Cancer Research Center. "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."
The most common side effects, reported in at least 20% of patients receiving pembrolizumab, include fatigue, musculoskeletal pain, decreased appetite, pruritus, diarrhea, nausea, rash, pyrexia, cough, dyspnea, constipation, pain, and abdominal pain.
For adult patients with MCC, the recommended dose is 200 mg every three weeks administered over 30-minute IV infusion, and for pediatric patients with MCC, the recommended dose is 2 mg/kg of pembrolizumab administered over 30-minute IV infusion.
For More Information
Clinicaltrials.gov (2018). Pembrolizumab in treating patients with advanced Merkel cell cancer. NLM identifier: NCT02267603.
KEYTRUDA® (pembrolizumab) prescribing information (2018). Merck. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/125514s034lbl.pdf