There was a small but statistically significant decrease in CrCl from baseline in the active arm , compared to placebo , which was first observed at week 4 ( mean change : -2.4 vs. -1.1 ml/min ; P = 0.02 ) , persisted through the last on-treatment visit ( mean change : +0.3 vs. +1.8 ml/min ; P = 0.02 ) , and resolved after stopping pre-exposure prophylaxis ( mean change : -0.1 vs. 0.0 ml/min ; P = 0.83 ) .