Pharmacokinetic and pharmacogenetic analysis of immunosuppressive agents after laparoscopic sleeve gastrectomy

Background: Severe obesity has been shown to limit access to renal transplantation in patients with end-stage renal disease (ESRD). Laparoscopic sleeve gastrectomy (LSG) has been performed in the ESRD population to assist in achieving waitlist and transplant eligibility. Little is known about how LSG impacts the bioequivalence of tacrolimus products and immunosuppression pharmacokinetics. Methods: This was a prospective, open-label, single-dose, crossover, two-period pharmacokinetic (PK) study. The purpose of this study was to assess single-dose PK of immediate-release tacrolimus (IR-TAC), extended-release tacrolimus (ER-TAC), and mycophenolic acid (MPA) in adult ESRD patients post-LSG. Results: Twenty-three subjects were included in the 24-hour PK assessments. The ratio of geometric means between ER-TAC and IR-TAC was 103.5% (90% CI; 89.6%-119.6%) for AUC(0-24) and 92.5% (90% CI; 80.4%-106.4%) for C-max. PK parameters were similar between ER-TAC and IR-TAC, except for C-min (P=.004) and C-max (P=.04). MPA AUC(0-24) was similar when given with either ER-TAC or IR-TAC (P=.32). Patients expressing CYP3A5* 1 genotypes had lower tacrolimus AUC0-24 values vs those with CYP3A5* 3/* 3 (IR-TAC P<.001; ER-TAC P=.008). Genotype did not impact MPA PK. Conclusion: Dose modification of immunosuppressants post-LSG may not be necessary aside from standard therapeutic drug monitoring.