[Clinical use of telaprevir: stopping rules, predicting response, treatment length, and management of adverse effects].

Triple combination therapy with pegylated interferon, ribavirin and telaprevir is currently considered the gold standard for the treatment of chronic hepatitis C virus (HCV) infection. The most important features are an increase in rates of sustained viral response (74-79% vs 46% with pegylated interferon and ribavirin), as well as the possibility of early cessation of ineffective therapy due to the application of futility rules at weeks 4 and 12 (HCV-RNA > 1,000 UI/ml), and the possibility of selecting candidates for the shortest treatments due to the clinical significance of extended rapid viral response (undetectable HCV-RNA at weeks 4 and 12 of triple therapy). Treatment length is mainly based on the stage of fibrosis and prior response to pegylated interferon and ribavirin. Thus, in both treatment-naïve patients and patients with recurrence after pegylated interferon therapy, the duration of treatment is 24 or 48 weeks (unless cirrhosis is present), depending on the presence of extended rapid viral response, while in cirrhotic patients and null responders, treatment length is 48 weeks. The main adverse effects of telaprevir therapy are anemia and skin rash. If these effects occur, the main measures that should be adopted are reduction of the ribavirin dose in anemia, and close monitoring and treatment cessation in skin rash, depending on its spread and severity.