Effect of CYP3A5*1 expression on tacrolimus required dose after liver transplantation: A systematic review and meta-analysis.

We systematically collected eligible data to measure the effect of CYP3A5*1 expression on personalized tacrolimus therapy. Six databases were searched for studies on adult liver transplant recipients and donors of liver graft which reported tacrolimus dose requirement, trough blood concentration, and/or concentration/dose (C/D) ratio in expressers and nonexpressers of CYP3A5*1. Eligible data were pooled by meta-analysis. Sixteen observational studies (1309 recipients, 1044 donors of liver graft) were included in the analyses. Tacrolimus C/D ratio was lower, and the dose was higher in recipient expressers of CYP3A5*1 and/or carriers of expresser liver graft at 1-4 weeks and 2-4, 6, and 12 months post-transplantation. Tacrolimus blood concentration was lower at the first two weeks. Pair expressers were affected by about twofold, and the effect was different between ethnic groups. CYP3A5*1 expression in recipients increased tacrolimus required dose by 0.023 at first, 0.022 at third, and 0.012 mg/kg/day at sixth month. Its expression in graft tissue increased tacrolimus required dose by 0.024 at first, 0.035 at third, and 0.032 mg/kg/day at sixth month. Considering CYP3A5*1 polymorphism can be helpful in individualization of tacrolimus efficient dose prior to administration, and it can remove initial high-risk lag time (over/underdose period before reaching target blood level) at first few days post-transplantation.