Martin Cheever

More than two-thirds of people with an advanced form of a rare skin cancer are on track to survive at least two years after starting an immunotherapy drug on a landmark clinical trial, researchers reported Wednesday in the Journal of Clinical Oncology.

That’s a profound shift for this deadly cancer, Merkel cell carcinoma, or MCC. Just a few years ago, patients with advanced MCC would invariably receive chemotherapy, the previous standard of care. As many as 75 percent would die within that timeframe, previous studies have shown.

The investigators are “thrilled” that so many of the trial participants are doing well, compared with what historical data would predict, said Martin “Mac” Cheever of Fred Hutchinson Cancer Research Center, one of the leaders of this first-of-its-kind study.

Martin "Mac" Cheever
Martin “Mac” Cheever is a professor of medicine (oncology) at the University of Washington School of Medicine. Credit: Robert Hood / Fred Hutch News Service

The multisite trial tested an immune-boosting drug called pembrolizumab (Keytruda), also known as a checkpoint inhibitor because it blocks a checkpoint that keep the immune system from mounting a cancer-killing response.