Plasma letrozole concentrations in postmenopausal women with breast cancer are associated with CYP2A6 genetic variants, body mass index, and age.

ABSTRACT: The associations between plasma letrozole concentrations and CYP2A6 and CYP3A5 genetic variants were tested in the Exemestane and Letrozole Pharmacogenomics (ELPH) trial. ELPH is a multicenter, open-label prospective clinical trial in women randomly assigned (n≈250 in each arm) to receive 2 years of treatment with either oral letrozole (2.5 mg/day) or oral exemestane (25 mg/day). CYP2A6 and CYP3A showed effects on letrozole metabolism in vitro. DNA samples were genotyped for variants in the CYP2A6 and CYP3A5 genes. Plasma letrozole concentrations showed high interpatient variability (>10-fold) and were associated significantly with CYP2A6 genotypes (P<0.0001), body mass index (BMI) (P<0.0001), and age (P=0.0035). However, CYP3A5 genotypes showed no association with plasma letrozole concent

SUBMITTER: Desta Z 

PROVIDER: S-EPMC3667657 | biostudies-literature | 2011 Nov

REPOSITORIES: biostudies-literature