FOCBP must have a negative pregnancy test =<  days prior to registration on study
Females of child-bearing potential (FOCBP) must have a negative pregnancy test within  days prior to registration on study
FOCBP must have a negative pregnancy test within  days prior to registration on study
FOCBP must have a negative pregnancy test within  days prior to registration on study; NOTE: a negative pregnancy test is also required within  days prior to first dose of pembrolizumab and therefore may need to be repeated if screening test is more than  days prior to first dose
FOCBP must have a negative serum or urine pregnancy test within  days prior to registration on study
FOCBP must have a negative pregnancy test within - days prior to receiving study drug
FOCBP must have a negative serum OR urine pregnancy test =<  days prior to registration
FOCBP must have a negative pregnancy test =<  days prior to registration on study
FOCBP must have a negative pregnancy test (either urine or serum) within  days prior to registration
FOCBP must have a negative pregnancy test within  days prior to registration\r\n* Note: FOCBP will have to have repeat pregnancy test within  hours of starting nivolumab, scheduled for cycle  day 
FOCBP must have a negative pregnancy test (serum or urine) within  days prior to registration on study
FOCBP must have a negative pregnancy test (beta-human chorionic gonadotropin [HCG] test in urine or serum) within  days prior to registration on study (Note: The test will have to be repeated if cycle  day is more than  days from registration)
FOCBP must have a negative pregnancy test =<  days prior to registration
FOCBP must have a negative pregnancy test within  days prior to registration on study
FOCBP must have a negative urine or serum pregnancy test within  days prior to registration on study.