The effect of CYP3A inhibitors and inducers on the pharmacokinetics of telaprevir in healthy volunteers

Abstract

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Telaprevir is a hepatitis C virus protease inhibitor for the treatment of genotype 1 chronic hepatitis C in adult patients with compensated liver disease. In vitro studies indicated that CYP3A was the major cytochrome P‐450 (CYP) isozyme involved in the metabolism of telaprevir. It is important to understand the potential for drug–drug interactions of telaprevir when it is co‐administered with CYP3A inhibitors or inducers. WHAT THIS STUDY ADDS • CYP3A inducers, rifampicin and efavirenz, can reduce telaprevir exposure to varying degrees based on their potency. After a single dose, telaprevir exposure is increased when ketoconazole, a strong CYP3A inhibitor, is co‐administered. However, at steady‐state, telaprevir exposure is less likely to be affected by CYP3A inhibitors. AIM To evaluate the effects of ketoconazole, rifampicin and efavirenz on the pharmacokinetics of telaprevir in healthy volunteers. METHOD Results from three clinical studies are described. (1) Volunteers received a single 750 mg dose telaprevir with and without a single 400 mg dose ketoconazole. (2) Volunteers received (a) 1250 mg telaprevir followed by three 750 mg doses given every 8 h and (b) four 1250 mg telaprevir doses given every 8 h, with a single 400 mg dose ketoconazole given with the fourth dose of telaprevir. (3) Volunteers received either a single 750 mg dose telaprevir with or without 600 mg once daily rifampicin, or 750 mg every 8 h telaprevir with and without 600 mg once daily efavirenz. RESULTS A single 400 mg dose of ketoconazole increased single dose telaprevir exposure: the geometric least‐squares mean ratio (GLSMR, with 90% confidence limits) was 1.24 (1.10, 1.41) for Cmax and 1.62 (1.45, 1.81) for AUC(0,∞). However, after multiple doses of telaprevir, there was no discernible effect of ketoconazole on telaprevir exposure. Co‐administration of rifampicin at steady‐state markedly reduced single dose telaprevir exposure with GLSMRs of 0.14 (0.11, 0.18) for Cmax and 0.08 (0.07, 0.11) for AUC(0,∞), whereas efavirenz had a smaller effect on telaprevir exposure when both drugs were co‐administered at steady‐state, with GLSMRs of 0.91 (0.81, 1.02) for Cmax, 0.53 (0.44, 0.65) for Cmin, and 0.74 (0.65, 0.84) for AUC(0,8 h). CONCLUSION CYP3A inducers, rifampicin and efavirenz, can reduce telaprevir exposure to varying degrees based on their potency. The effect of ketoconazole as an inhibitor of telaprevir metabolism is more pronounced after a single dose of telaprevir than after repeated administration.

Application of Micropatterned Cocultured Hepatocytes to Evaluate the Inductive Potential and Degradation Rate of Major Xenobiotic Metabolizing Enzymes

“…PBPK modeling using Simcyp was used to predict the free steady-state C max of rifampin after oral dosing. The simulated C max of rifampin at the 600-mg dose is similar to reported clinical C max of rifampin at 600 mg (Garg et al, 2013). The change in midazolam AUC after treatment with varying oral doses of rifampin was reported in Kharasch et al (2011).…”

Validation of a sensitive LC/MS/MS method for the determination of telaprevir and its R‐isomer in human plasma

“…The overall average of telaprevir-R/total ratio was 33.9%, but this ratio increased from 24% at the first dose to 40% at steady state. Observed telaprevir and telaprevir-R concentrations in these 150 samples were within the range of published values from 249 to 4882 ng/mL (Sarrazin et al, 2007;Marcellin et al, 2011;Garg et al, 2013). Method reproducibility was demonstrated by reanalyzing incurred samples (n = 15).…”

“…A difference of 30% between the two analyses was allowed for the incurred analysis. Additionally, the concentrations from this methodology were compared with those arising from previous analytical methods (Sarrazin et al, 2007;Marcellin et al, 2011;Garg et al, 2013).…”

Effect of the CYP3A inhibitor ketoconazole on the PXR-mediated induction of CYP3A activity

“…The measured concentrations of ketoconazole were also in the range of previously published data [25,26].…”