Cost Effectiveness of Peginterferon α-2a Plus Ribavirin versus Interferon α-2b Plus Ribavirin as Initial Therapy for Treatment-Naive Chronic Hepatitis C

Introduction: In adults with previously untreated chronic hepatitis C (CHC), the combination of peginterferon α-2a plus ribavirin produces a higher rate of sustained virological response (SVR) than interferon α-2b plus ribavirin, but it is still unproven whether this increase is cost effective. The objective of this study was to determine if the gain in SVR with peginterferon α-2a plus ribavirin is worth the incremental cost.

Methods: We constructed a Markov model of disease progression in which cohorts of patients received peginterferon α-2a plus ribavirin or interferon α-2b plus ribavirin for 48 weeks (hepatitis C virus [HCV] genotype 1 and non-1 patients with fibrosis) or 24 weeks (genotype non-1 patients without fibrosis), and were followed for their expected lifetimes. The reference patient was a 45-year-old male with CHC without cirrhosis. The SVRs with peginterferon α-2a plus ribavirin and interferon α-2b plus ribavirin used to populate the model were 46% and 36% for patients infected with HCV genotype 1 and 76% and 61% for patients infected with HCV non-1 genotypes, respectively. QOL and costs for each health state were based on literature estimates and on Italian treatment patterns. Costs were in 2002 euros and benefits were discounted at 3%. Sensitivity analyses on key clinical and economic parameters were performed. The analysis was reported from the perspective of the Italian National Health Service.

Results: In patients infected with HCV genotype 1, peginterferon α-2a plus ribavirin increased life-years (LYs) by 0.78 years and QALYs by 0.67 years, compared with interferon α-2b and ribavirin. The incremental cost per LY and QALY gained was €9433 and €10 894, respectively. In patients infected with HCV non-1 genotypes, peginterferon α-2a plus ribavirin increased LYs by 1.17 and QALY by 1.01 years, compared with interferon α-2b plus ribavirin. The incremental cost per LY and QALY gained was €3261 and €3766, respectively. Using genotype distribution estimates, the weighted average ICER for all genotypes was €6811 per LY gained and €7865 per QALY gained.

Conclusion: Our model suggests that peginterferon α-2a plus ribavirin is cost effective compared with conventional interferon α-2b plus ribavirin for treatment of naive adults with CHC, regardless of HCV genotype, under a wide range of assumptions regarding treatment effectiveness and costs.