Jeffrey S. Weber, MD, PhD, Director of the Donald A. Adam Comprehensive Melanoma Research Center at the Moffitt Cancer Center and Research Institute in Tampa, Florida, formally discussed the prembrolizumab study at the ASCO Annual Meeting. He called the response rate and the ongoing responses “impressive,” and the 1-year 69% overall survival rate “outstanding” and “promising,” though cautioned, “It’s still early days for pembrolizumab,” as many patients were just enrolled in the past year.

He noted that two dosing regimens—2 mg/kg every 2 weeks and 10 mg/kg every 2 weeks—look “equally effective,” and the higher dose was associated with slightly more toxicity.  He noted that the 12% rate of grade 3/4 adverse events seemed high, and questioned whether this might be an error of how the toxicity was reported compared to other trials. Overall, he commented, pembrolizumab has “an excellent toxicity profile.”

“Is pembrolizumab better than nivolumab? That is still an open question,” he maintained. “Overall, this study [demonstrated] slightly better outcomes; nonetheless, the record for overall survival and response rate were outstanding, and the drug looks very promising.” ■

Disclosure: Dr. Weber reported no potential conflicts of interest.