Evaluation of the potency of telaprevir and its metabolites as inhibitors of renal organic cation transporters, a potential mechanism for the elevation of serum creatinine.

Telaprevir-based triple therapy is a highly effective treatment for chronic hepatitis C. However, adverse reactions include reversible and dose-dependent elevation of serum creatinine levels. We speculated that this effect reflects inhibition of the renal organic cation transporters hOCT2, hMATE1, and hMATE2-K by telaprevir or its metabolites (VRT-127394 and VRT-0922061). Telaprevir, VRT-127394, and VRT-0922061 showed negligible or weak effects on hOCT2 at concentrations of ≥20 µM, but inhibited hMATE1 by 35, 38, and 53% and hMATE2-K by 47, 45, and 61% at 100 µM, respectively. Telaprevir or its metabolites (10 µM) did not affect basal-to-apical transport of MPP(+) across monolayers of hOCT2-hMATE1 double-transfected MDCKII cells, whereas pyrimethamine, a potent inhibitor of hMATE1, markedly inhibited MPP(+) transport. Taken together, inhibition of hOCT2, hMATE1, and hMATE2-K is unlikely to be clinically relevant because unbound plasma concentrations of telaprevir and its metabolites reach only 2 µM following oral administration of a dose of 750 mg telaprevir. Hence, elevated serum creatinine during telaprevir therapy may not be related to direct inhibition of renal organic cation transporters.