Cost-Effectiveness of Combination Peginterferon alpha-2a and Ribavirin Compared With Interferon alpha-2b and Ribavirin in Patients With Chronic Hepatitis C

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Abstract
Sustained virological response (SVR) is the primary objective in the treatment of chronic hepatitis C (CHC). Results from a recent clinical trial of patients with previously untreated CHC demonstrate that the combination of peginterferon α-2a and ribavirin produces a greater SVR than interferon α-2b and ribavirin combination therapy. However, the cost-effectiveness of peginterferon α-2a plus ribavirin in the U.S. setting has not been investigated. A Markov model was developed to investigate cost-effectiveness in patients with CHC using genotype to guide treatment duration. SVR and disease progression parameters were derived from the clinical trials and epidemiologic studies. The impact of treatment on life expectancy and costs were projected for a lifetime. Patients who had an SVR were assumed to remain virus-free for the rest of their lives. In genotype 1 patients, the SVRs were 46% for peginterferon α-2a plus ribavirin and 36% for interferon α-2b plus ribavirin. In genotype 2/3 patients, the SVRs were 76% for peginterferon α-2a plus ribavirin and 61% for interferon α-2b plus ribavirin. Quality of life and costs were based on estimates from the literature. All costs were based on published U.S. medical care costs and were adjusted to 2003 U.S. dollars. Costs and benefits beyond the first year were discounted at 3%. In genotype 1, peginterferon α-2a plus ribavirin increases quality-adjusted life expectancy (QALY) by 0.70 yr compared to interferon α-2b plus ribavirin, producing a cost-effectiveness ratio of $2,600 per QALY gained. In genotype 2/3 patients, peginterferon α-2a plus ribavirin increases QALY by 1.05 yr in comparison to interferon α-2b plus ribavirin. Peginterferon α-2a combination therapy in patients with HCV genotype 2 or 3 is dominant (more effective and cost saving) compared to interferon α-2b plus ribavirin. Results weighted by genotype prevalence (75% genotype 1; 25% genotype 2 or 3) also show that peginterferon α-2a plus ribavirin is dominant. Peginterferon α-2a and ribavirin remained cost-effective (below $16,500 per QALY gained) under sensitivity analyses on key clinical and cost parameters. Peginterferon α-2a in combination with ribavirin with duration of therapy based on genotype, is cost-effective compared with conventional interferon α-2b in combination with ribavirin when given to treatment-naïve adults with CHC.