Pharmacogenomic associations in ABCB1 and CYP3A5 with acute kidney injury and chronic kidney disease after myeloablative hematopoietic cell transplantation

Renal disease is a major complication in patients following myeloablative allogeneic hematopoietic cell transplantation (HCT). Post-HCT patients receive immunosuppressive regimens containing calcineurin inhibitor (CNIs), cyclosporine or tacrolimus, for graft-versus-host disease prophylaxis. In this retrospective trial, we investigated pharmacogenomic associations in the multidrug resistance (ABCB1) and cytochrome P450 3A5 (CYP3A5) genes and acute kidney injury (AKI) and chronic kidney disease (CKD) in a cohort of 121 patients. ABCB1 and CYP3A5 are responsible for the renal disposition of CNIs, which are known to be nephrotoxic. AKI was defined as doubling of baseline serum creatinine during the first 100 days post-HCT, and CKD as at least one glomerular filtration rate <60ml/min/m² between 6 and 18 months post-HCT. Patients were genotyped for CYP3A5*1>*3 and ABCB1 single nucleotide polymorphisms (SNPs) (1199G>A, 1236C>T, 2677G>T/A and 3435C>T). Odds ratios were calculated using logistic regression. Haplotype estimation and univariate association analyses were performed because of strong ABCB1 linkage disequilibrium (LD). AKI occurred in 48 of 121 patients (39.7%) and CKD in 16 of 66 patients (24.2%). No pharmacogenomic associations were found between ABCB1 and CYP3A5 SNPs and the incidences of AKI or CKD. The degree of LD(r²) between ABCB1 SNPs was estimated as follows: 2677G>T/3435C>T (0.44), 1236C>T/ 3435C>T (0.42) and 1236C>T/2677G>T (0.72). ABCB1 1199G>A showed no LD to other SNPs (<0.05). No associations were found between the most common ABCB1 haplotypes and AKI or CKD. Since no significant pharmacogenomic associations were observed, tailoring CNIs dosing based on these genotypes is unlikely to lower significantly the risk of renal injury following myeloablative HCT.