UGT1A3 and Sex Are Major Determinants of Telmisartan Pharmacokinetics—A Comprehensive Pharmacogenomic Study

Abstract

To investigate how variability in multiple pharmacokinetic genes associates with telmisartan exposure, we determined telmisartan single-dose (40 mg) pharmacokinetics and sequenced 379 genes in 188 healthy volunteers. Intronic UGT1A variants showed the strongest associations with the area under the plasma concentration-time curve from zero hours to infinity (AUC0–∞) and peak plasma concentration (Cmax) of telmisartan. These variants were strongly linked with the increased function UGT1A3*2 allele, suggesting that it is the causative allele underlying these associations. In addition, telmisartan plasma concentrations were lower in men than in women. The UGT1A3*2 was associated with a 64% and 63% reduced AUC0-∞ of telmisartan in UGT1A3*2 heterozygous and homozygous men, respectively (P = 1.21 × 10−16 and 5.21 × 10−8). In women, UGT1A3*2 heterozygosity and homozygosity were associated with 57% (P = 1.54 × 10−11) and 72% (P = 3.31 × 10−15) reduced AUC0-∞, respectively. Furthermore, a candidate gene analysis suggested an association of UGT1A3*3 and the SLCO1B3 c.767G>C missense variant with telmisartan pharmacokinetics. A genotype score, which reflects the effects of sex and genetic variants on telmisartan AUC0–∞, associated with the effect of telmisartan on diastolic blood pressure. These data indicate that sex and UGT1A3 are major determinants and suggest a role for OATP1B3 in telmisartan pharmacokinetics.