Median recurrence-free survival was 261 months ( 95 % CI 193-393 ) in the ipilimumab group versus 171 months ( 95 % CI 134-216 ) in the placebo group ( hazard ratio 075 ; 95 % CI 064-090 ; p = 00013 ) ; 3-year recurrence-free survival was 465 % ( 95 % CI 415-513 ) in the ipilimumab group versus 348 % ( 301-395 ) in the placebo group .