Use of Pembrolizumab in First-Line Treatment of Merkel Cell Carcinoma
Posted: Thursday, March 7, 2019
Compared with chemotherapy, treatment with pembrolizumab may provide better outcomes for patients with advanced Merkel cell carcinoma. A study conducted by Suzanne L. Topalian, PhD, of Johns Hopkins Kimmel Cancer Center and Bloomberg–Kimmel Institute for Cancer Immunotherapy, and colleagues found that patients demonstrated improved progression-free survival with pembrolizumab compared with chemotherapy, although response durability and overall survival data are limited. Their findings were published in the Journal of Clinical Oncology.
“This is the earliest trial of immunotherapy as a front-line therapy for Merkel cell carcinoma, and it was shown to be more effective than what would be expected from traditional therapies, like chemotherapy,” said Dr. Topalian in a Johns Hopkins Medicine press release.
This multicenter phase II trial focused on 50 patients with advanced Merkcel cell carcinoma who had not received prior systemic therapy. Of these patients, 64% had Merkel cell polyomavirus–positive tumors. Patients received pembrolizumab at 2 mg/every 3 weeks for up to 2 years.
More than half of the patients (56%) responded to treatment, with a complete response noted in 24% and a partial response observed in 32%. Both patients with and without the Merkel cell polyomavirus responded well to pembrolizumab, with an objective response rate of 59% and 53%, respectively. For some patients, (24%) the tumor completely disappeared. The median progression-free survival was 16.8 months. In patients with PD-L1–positive tumors, there appeared to be a trend toward improvement in both progression-free and overall survival.
There were grade 3 or higher treatment-related adverse events in 14 of the 50 patients. Half of those participants discontinued treatment as a result, and one treatment-related death was reported.
Disclosure: The study authors’ full disclosures can be found at ascopubs.org.