Intravenous medication blocks programmed death 1 (PD-1) immune inhibitory pathway
TUESDAY, April 19, 2016 (HealthDay News) — Pembrolizumab (Keytruda), a programmed death 1 inhibitor, may help patients with Merkel-cell carcinoma, according to a preliminary study published online April 19 in the New England Journal of Medicine. The research was published to coincide with the annual meeting of the American Association for Cancer Research, held from April 16 to 20 in New Orleans.
Paul Nghiem, M.D., Ph.D., a professor of medicine at the University of Washington in Seattle, gave the drug to 26 patients with advanced Merkel-cell carcinoma. Of these 26 patients, 17 had tumors that carried the Merkel-cell polyomavirus. All patients received pembrolizumab every three weeks — for between four and 49 weeks.
Overall, out of 25 patients who were evaluated, 14 patients — or 56 percent — saw their cancer shrink at least partially. In four patients, all signs of the cancer disappeared. After more than six months of follow-up, the cancer remained under good control in 12 of the 14. Two patients developed signs of inflammation in the liver or heart muscle and had to discontinue the drug after only one or two doses. Yet, both patients still showed a response to the drug months after stopping it, Nghiem told HealthDay.
“In this study, first-line therapy with pembrolizumab in patients with advanced Merkel-cell carcinoma was associated with an objective response rate of 56 percent,” the authors write. “Responses were observed in patients with virus-positive tumors and those with virus-negative tumors.”
Merck, the manufacturer of pembrolizumab, and the U.S. National Cancer Institute funded the study.
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