Participants received a total of four infusions, at three-week intervals, a much shorter course of therapy than currently available, the study authors said.
"With melanoma there are few approved options for therapy and when we use agents like chemotherapy, people are on drugs forever and there's [only] a short-term benefit," explained Dr. Kari Kendra, a medical oncologist with the Ohio State University Comprehensive Cancer Center - Arthur G. James Cancer Hospital and Richard J. Solove Research Institute in Columbus. "With immune modulators like IL-2 or ipilimumab, there's a potential for durable responses."
There was essentially no difference in median survival between the groups taking ipilimumab with or without gp100: about 10 months. This compared with only 6.4 months for those taking gp100 alone, a 68 percent improvement.
"The gp100 vaccine didn't seem to add much to the treatment," Hodi said.
But receiving the IV infusion again if the melanoma looked like it was coming back also provided some benefit, Hodi said.
Fifteen percent of patients receiving ipilimumab experienced serious side effects, compared to only 3 percent receiving gp100 on its own. There were 14 deaths related to the drugs used in the study, and seven of the patients died from problems with their immune system, the researchers reported.
The researchers are now focusing their attention on the patients who survived sometimes as long as six years.
"We're looking at predictive biomarkers to see why some get a greater benefit than others," Hodi said.
Ipilimumab is not yet FDA-approved, so there's no price tag associated with it, although Kendra said she "would
All rights reserved