Introduction: In adults with previously untreated chronic hepatitis C (CHC), the combination of peginterferon alpha-2a plus ribavirin produces a higher rate of sustained virological response (SVR) than interferon alpha-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 alpha-2a plus ribavirin is worth the incremental cost.
Methods: We constructed a Markov model of disease progression in which cohorts of patients received peginterferon alpha-2a plus ribavirin or interferon alpha-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 alpha-2a plus ribavirin and interferon alpha-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 alpha-2a plus ribavirin increased life-years (LYs) by 0.78 years and QALYs by 0.67 years, compared with interferon alpha-2b and ribavirin. The incremental cost per LY and QALY gained was euro9433 and euro10 894, respectively. In patients infected with HCV non-1 genotypes, peginterferon alpha-2a plus ribavirin increased LYs by 1.17 and QALY by 1.01 years, compared with interferon alpha-2b plus ribavirin. The incremental cost per LY and QALY gained was euro3261 and euro3766, respectively. Using genotype distribution estimates, the weighted average ICER for all genotypes was euro6811 per LY gained and euro7865 per QALY gained.
Conclusion: Our model suggests that peginterferon alpha-2a plus ribavirin is cost effective compared with conventional interferon alpha-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.