Pharmacist intervention in treatment of patients with genotype 1 chronic hepatitis C.

Chronic hepatitis C infection affects nearly 300 million people worldwide. It is one of the main causes of chronic liver disease and the most common indication for liver transplantation.1-5 There are 6 major strains or genotypes of hepatitis C virus (HCV). These genotypes have different geographic distributions, with the type 1 genotype (HCV-1) most common in the United States (accounting for about 75% of cases)6 and in Spain where it is responsible for 60%-70% of all cases of chronic hepatitis C.7 The most effective initial therapy for patients with this disorder is the combination of interferon alfa-2b with ribavirin.8,9 More recently, there has been a modification of interferon alfa-2b with the addition of a polyethylene glycol molecule to interferon (peginterferon) to produce a biologically active molecule with a longer half-life than the natural molecule, and more favorable pharmacokinetics; these characteristics allow for convenient once-weekly dose administration.6,10,11 In 2001, an important randomized clinical trial was published with peginterferon alfa-2b plus ribavirin in combination therapy administered over 24-48 weeks as a function of the infective virus genotype. The results of the trial indicated sustained viral response (SVR) of 42% in patients infected with HCV-1 and 54% in the sample overall.12 Experience gained from clinical trials indicates that HCV genotypes 2 and 3 are highly susceptible to current combination therapy regimens, whereas genotype 1 has a lower response rate to interferon-based therapies. The recommended length of treatment for HCV-1 is 48 weeks.13 Because genotype 1 is both the most prevalent type and is associated with a lower viral response rate and greater potential liver-related morbidity and mortality,7 it is important to know the outcome of treatment of HCV-1 in studies conducted in routine clinical practice.14 Although HCV genotype is the main determinant of response of therapy, additional factors, such as adherence to recommended dose and duration of treatment, significantly influence the probability of achieving SVR. A retrospective analysis documented that patients who receive more than 80% of their interferon doses and more than 80% of their ribavirin doses for more than 80% of the duration of therapy (the 80/80/80 rule) had significantly higher SVR, compared with patients with worse adherence. This effect was more apparent in patients infected with HCV-1 than in those infected with Pharmacist Intervention in Treatment of Patients With Genotype 1 Chronic Hepatitis C