William Kevin Kelly, DO
Formal discussant of the CheckMate 650 trial, William Kevin Kelly, DO, Professor of Medical Oncology at the Sidney Kimmel Cancer Center and Jefferson Health in Philadelphia, commented on the combination therapy’s toxicity. “The discontinuation of study drug was significant. An important issue is whether the drug was tolerable or not in this population,” he said, “as only a small percentage of patients in both cohorts actually received the four planned treatment cycles. Just one-third of patients got to maintenance dose,” he pointed out. “It was discontinued for toxicity by 50% in cohort 1 and 44% in cohort 2.”
As Dr. Kelly emphasized, studies of nivolumab/ipilimumab in patients with different cancer types suggest that the regimen is better tolerated. In particular, more patients with melanoma and kidney cancer were able to receive the full regimen, whereas just 33% of patients with metastatic castration-resistant prostate cancer in cohort 1 and 24% of those in cohort 2 received the planned four treatments.
“For some reason, patients with prostate cancer are not tolerating this dosing regimen of nivolumab and ipilimumab as well as the other populations,” he said. “Optimal dose regimens need to be explored. As I teach all my fellows, if you can’t get the drug(s) in, it is not going to work,” he added. ■
DISCLOSURE: Dr. Kelly has received honoraria from Sanofi; is a consultant/advisor for Janssen Oncology; and has received institutional research funding from Novartis, Janssen Oncology, and Sanofi.
In contrast with melanoma, lung cancer, and kidney cancer, immune checkpoint inhibitor therapy has been disappointing in prostate cancer thus far. Because of success in treating other tumor types, interest remains high in exploring the effect of immunotherapy with checkpoint inhibition in prostate...