Susan Keown of Fred Hutch News Service reports on what appears to be a critical breakthrough in helping advanced Merkel Cell Carcinoma patients survive longer than heretofore possible. Ms. Keown reports that the study evidences that pembrolizumab interferes in one of the complex interactions between tumor-specific immune cells, or T cells (top) and tumor cells. Specifically, trial participants with advanced Merkel cell carcinoma received a drug designed to interfere in the interaction between cell components called PD-1 and PD-L1, at left, a “braking” system that tamps down the immune response. Based on these findings, reported in the Journal of Clinical Oncology, more than two-thirds of people with the advanced form of rare skin cancer are on track to survive at least two years after starting the immunotherapy drug on the landmark clinical trial. A profound shift when thinking of Merkel Cell Carcinoma (MCC), just a few years ago, MCC patients only option was chemotherapy. As many as three-quarters would die within that two-year timeframe based on previous studies.
Investigator Dr. Martin “Mac” Cheever of Fred Hutchinson Cancer Research Center are thrilled. The multisite trial tested the immune-boosting drug pembrolizumab (Keytruda)—also known as a checkpoint inhibitor because it blocks checkpoint—brakes, essentially—that keep the immune system from mounting a cancer-killing response as Ms. Keown reports for prominent investigational center Fred Hutch in Seattle. They report that the trial enrolled 50 patients. Once receiving pembrolizumab, 28 patients either experienced the cancer shrink or even disappear. This reports Fred Hutch, is an unusually high rate of response for a solid-tumor cancer. There are severe side effects, hence risks including one death out of the 50 patients.
The U.S. FDA approved pembrolizumab for MMC in December 2018 based on this trial. The Fred Hutch team was a pivotal driver in this study. However, because of early results as far back as 2015, the drug has been a standard of care for MCC patients. Guidelines were established based on the preliminary results of the first clinical trials.