Therapeutic drug monitoring of telaprevir in chronic hepatitis C patients receiving telaprevir-based triple therapy is useful for predicting virological response.

OBJECTIVES This prospective, pharmacokinetic study was done to investigate the impact of telaprevir plasma trough concentration (Ctrough) in the early stage of treatment on the response to telaprevir-based triple therapy for chronic hepatitis C patients. METHODS Participants were 70 chronic hepatitis C patients infected with genotype 1. All patients received 12 week triple therapy that included telaprevir (2250 mg/day), pegylated interferon-α2b (pegylated-IFNα2b) (60-150 μg/week) and ribavirin (600-1000 mg/day) followed by a 12 week dual therapy that included pegylated-IFNα2b and ribavirin. Plasma telaprevir Ctrough was determined by a validated assay using HPLC at days 3, 7 and 14. The study was registered as a clinical trial on the University Hospital Medical Information Network (ID 000009656). RESULTS The rates of undetectable hepatitis C virus RNA at week 4 [rapid virological response (RVR)] and at 24 weeks after therapy [sustained virological response (SVR)] were 71.4% and 82.9%, respectively. Of the patients with RVR, 90% achieved SVR. The mean telaprevir Ctrough levels at days 3, 7 and 14 of SVR patients (2.748, 2.733 and 2.999 μg/mL, respectively) were significantly higher than those of non-SVR patients (1.616, 1.788 and 2.314 μg/mL, respectively) (all P < 0.05). Multiple logistic regression analysis of possible predictors of SVR extracted higher telaprevir Ctrough at day 3 (OR 1.012 by 0.001 μg/mL, P < 0.0001) and interleukin 28B (rs8099917) TT allele (OR 6.16 versus non-TT alleles, P < 0.0001). CONCLUSIONS Therapeutic drug monitoring of telaprevir in the early stage of treatment is useful in clinical practice for predicting the virological response of patients receiving telaprevir-based triple therapy.