In patients with HCV infection who did not have a sustained response to peginterferon plus ribavirin, the addition of telaprevir to this combination therapy was more effective than combination therapy alone. Adverse events with telaprevir included rash and anemia. Approximately 60% of patients who are infected with hepatitis C virus (HCV) genotype 1 are not cured by 48 weeks of peginterferon alfa combined with ribavirin. 1 Such patients fall into one of three categories: those who have no response to therapy, which is defined as a reduction of less than 2 log 10 in HCV RNA levels after 12 weeks of therapy 2 ; those who have a partial response, which is defined as a reduction of at least 2 log 10 in a patient who has always had detectable serum HCV RNA during therapy; and those who have a relapse, . . .