ABCB1 genetics predicts tacrolimus response in patients with ulcerative colitis. Running head: Tacrolimus Pharmacogenetics in IBD

Objectives: Tacrolimus (TAC) is effective in steroid refractory ulcerative colitis (UC) but non-response and unpredictable adverse events are major limitations in clinical practice. In transplantation medicine genetic variants related to TAC metabolism (e.g., cytochrome P450 3A) ad TAC transport (e.g. P-glycoprotein/ABCB1) have been repeatedly associated with interindividual variability in response to tacrolimus. We aimed, for the first time, to elucidate the contribution of those polymorphisms to TAC response in the largest cohort of UC patients studied so far. Methods: The study population comprises 89 patient…