The effect of CYP3A5 genetic polymorphisms on adverse events in patients with ulcerative colitis treated with tacrolimus

Abstract

Background: Tacrolimus is an immunosuppressive agent, used in the remission induction therapy of ulcerative colitis (UC).

Aims: We investigated the correlation between CYP3A5 genetic polymorphisms and the adverse events in patients with UC. The pharmacokinetics of tacrolimus after oral administration were also analyzed.

Methods: We enrolled 29 hospitalized patients with UC received oral tacrolimus. Genotyping for CYP3A5 A6986G (rs776746) was performed using Custom TaqMan^® SNP genotyping assays. Adverse events, concentration and dose (C/D) ratios and clinical outcomes were investigated.

Results: CYP3A5 expressers and non-expressers were 16 and 13, respectively. C/D ratios of CYP3A5 expressers were significantly lower compared to non-expressers. The response rate in CYP3A5 non-expressers was relatively higher in the early phase of treatment compared to expressers, but not statistically significant. The incidence of overall adverse events was significantly higher in CYP3A5 expressers than in non-expressers (P=0.034, chi-squared test). In particular, the incidence of nephrotoxicity was significantly higher in CYP3A5 expressers compared to non-expressers (P=0.027, chi-squared test). All of the nephrotoxicity were reversible and resolved by discontinuation or dose reduction of tacrolimus.

Conclusion: The adverse events especially nephrotoxicity were frequently observed in CYP3A5 expressers. CYP3A5 expressers should be paid attention to the onset of nephrotoxicity.

Keywords: Adverse events; Nephrotoxicity; Single nucleotide polymorphism.