Response to CYP3A5 genotype, but not CYP3A4*1b, CYP3A4*22, or hematocrit, predicts tacrolimus dose requirements in Brazilian renal transplant patients

摘要

We appreciate the opportunity to respond to the letter by Santoro et at, "CYP3A5 Genotype, but not CYP3A4*lb, CYP3A4+22, or Hematocrit, Predicts Tacrolimus Dose Requirements in Brazilian Renal Transplant Patients."1 Following our study in 59 Caucasian renal allograft recipients in^which we demonstrated that in vivo CYP3A4 activity (assessed by midazolam clearance), CYP3A5 genotype, and hematocrit predict 60-72% of the variability in tacrolimus dose requirements, dose-corrected trough levels (TacC0/dose), and clearance,2 Santoro et at. assessed the impact of CYP3A4 and CYP3A5 single-nucleotide polymorphisms and hematocrit on TacC0/dose in a cohort of 140 Brazilian renal recipients.