RESULTS	Overall survival was significantly longer in the group receiving ipilimumab plus dacarbazine than in the group receiving dacarbazine plus placebo ( 11.2 months vs. 9.1 months , with higher survival rates in the ipilimumab-dacarbazine group at 1 year ( 47.3 % vs. 36.3 % ) , 2 years ( 28.5 % vs. 17.9 % ) , and 3 years ( 20.8 % vs. 12.2 % ) ( hazard ratio for death , 0.72 ; P < 0.001 ) .\