"After taking pembrolizumab, 66 patients had their tumors shrink substantially and stabilize, instead of continuing to grow. Among them were 18 patients whose t

"After taking pembrolizumab, 66 patients had their tumors shrink substantially and stabilize, instead of continuing to grow. Among them were 18 patients whose tumors vanished and have not returned." BUT "Just 4 percent of cancer patients have the type of genetic aberration susceptible to pembrolizumab. [But that adds up to a lot of patients: as many as 60,000 each year in the United States alone, the study’s investigators estimated.]" and from the abstract of the paper itself: "Objective radiographic responses were observed in 53% of patients and complete responses were achieved in 21% of patients."