- Males who are sexually active with WOCBP must agree to follow instructions for method(s) of contraception for a period of 90 days (duration of sperm turnover) plus the time required for the investigational drug to undergo five half lives. The terminal half lives of nivolumab and ipilimumab are up to 25 days and 18 days, respectively. Males who receive nivolumab combined with ipilimumab who are sexually active with WOCBP must continue contraception for 31 weeks (90 days plus the time required for nivolumab to undergo five half-lives) after the last dose of investigational drug.