Background and objectives: Effective management of immunosuppressants is extemely important to improve prognosis of heart transplant recipients. We aim to investigate the effects of cytochrome P450 (CYP) 3A5 (rs776746) single nucleotide polymorphisms (SNPs) on serum tacrolimus concentrations/doses (C/Ds, ng/mL per mg/kg) and long-term prognosis in Chinese heart transplant recipients.
Methods: We detected the CYP3A5 SNPs of 203 consecutive Chinese heart transplant recipients between August 2005 and July 2012, and 55 of them who received tacrolimus-based immunosuppressive therapy were enrolled in this study. The tacrolimus C/Ds at 1, 3, 6, 12, 24 and 36 months after transplantation were routinely calculated. X-ray-guided endomyocardial biopsies (EMBs) were performed at 1, 3 and 6 months after heart transplantion to evaluate acute rejection degrees. All participants were then followed up annually until May 2018. The designed primary endpoint was all-cause mortality.
Results: In 55 heart transplant recipients (43 males and 12 females), CYP3A5 non-expressors (CYP3A5*3/*3, n = 40) had significantly higher tacrolimus C/Ds than expressors (CYP3A5*1/*3, n = 15) at all time points (P < 0.001). Chi-squared test showed no significant differences in EMB-proven acute rejections between the two groups within 6 months after heart transplantion. The median follow-up period was 94.7 months, and eight patients died. Kaplan-Meier analysis showed CYP3A5 expressors tend to have higher mortality than non-expressors (20% vs 12.5%, log-rank: P = 0.314).
Conclusions: CYP3A5 SNPs affect tacrolimus pharmacokinetics in Chinese heart transplant recipients, and non-expressors have higher tacrolimus C/Ds. In addition, expressors tend to have a worse long-term prognosis than non-expressors.