Melanoma patients treated using Bristol-Myers Squibb’s (BMS) human CTLA-4 mAb candidate, ipilimumab, survived significantly longer than those receiving a gp100 cancer vaccine, according to new Phase III results. Results were presented at ASCO and also published in the June 5 issue of The New England Journal of Medicine in a paper titled “Improved Survival with Ipilimumab in Patients with Metastatic Melanoma.”
The Phase III study included 676 patients with inoperable, late-stage metastatic melanoma tumors. It showed that while patients treated using the gp100 vaccine alone had a median overall survival of 6.4 months, those treated using ipilimumab had a median survival of 10.1 months. Adding the gp100 vaccine to ipilimumab had no extra benefits, with median overall survival of 10 months.
The proportion of patients still alive after a year was 25% for the gp100 vaccine cohort, 46% for the group receiving ipilimumab alone, and 44% for the combination therapy cohort. Two-year survival for patients receiving the gp100 vaccine was 14% compared to 24% for the ipilimuma monotherapy group and 22% for the combination group. Ipilimumab therapy also led to a 36% reduction in the risk of progression compared with gp100 alone.
Ipilimumab did demonstrate some serious and potentially fatal side effects, as seen in previous trials, BMS notes. The most common adverse events related to the study drugs were immune-related events, which occurred in approximately 60% of patients treated with ipilimumab and 32% of those given gp100. Grade 3 or 4 immune-related adverse events occurred in 10 to 15% of patients treated with ipilimumab and in 3% treated with gp100 alone.
There were 14 deaths related to the study drugs (2.1%), and seven were associated with immune-related adverse events. Writing in the NEJM, the researcher team, led by F. Stephen Hodi, M.D, of the Dana Farber Cancer Institute, concluded, “adverse events can be severe, long-lasting, or both, but most are reversible with appropriate treatment.”