Cost effectiveness of tenofovir disoproxil fumarate for the treatment of chronic hepatitis B from a Canadian public payer perspective.

INTRODUCTION Previous research has demonstrated that tenofovir disoproxil fumarate (DF) is the most cost-effective nucleos(t)ide treatment for chronic hepatitis B (CHB) in the UK, Spain, Italy and France. However, to our knowledge, no published studies have yet evaluated the cost effectiveness of any treatments for CHB in a Canadian setting, where relative prices and management of CHB differ from those in Europe. AIM Our objective was to determine the cost effectiveness of tenofovir DF compared with other nucleos(t)ide therapies licensed for CHB in Canada from the perspective of publicly funded healthcare payers. METHODS A Markov model was used to calculate the costs and benefits of nucleos(t)ide therapy in three groups of patients with hepatitis B e antigen (HBeAg)-positive and -negative CHB: nucleos(t)ide-naive patients without cirrhosis; nucleos(t)ide-naive patients with compensated cirrhosis; and lamivudine-resistant patients. Disease progression was modelled as annual transitions between 18 disease states. Transition probabilities, quality of life and costs were based on published studies. Health benefits were measured in QALYs. The reference year for costs was 2007 and costs and outcomes were discounted at 5% per annum. RESULTS First-line tenofovir DF was the most effective nucleos(t)ide strategy for managing CHB, generating 6.85-9.39 QALYs per patient. First-line tenofovir DF was also the most cost-effective strategy in all patient subgroups investigated, costing between $Can43,758 and $Can48,015 per QALY gained compared with lamivudine then tenofovir. First-line tenofovir DF strongly dominated first-line entecavir. Giving tenofovir DF monotherapy immediately after lamivudine resistance developed was less costly and more effective than any other active treatment strategy investigated for lamivudine-resistant CHB, including second-line use of adefovir or adefovir + lamivudine. Probabilistic sensitivity analysis demonstrated 50% confidence that first-line tenofovir DF is the most cost-effective nucleos(t)ide strategy for treatment-naive patients with CHB, at a $Can50,000 per QALY threshold, and confirmed that first-line tenofovir DF has the highest expected net benefits. CONCLUSIONS First-line tenofovir DF appears to be the most cost-effective nucleos(t)ide treatment for both cirrhotic and non-cirrhotic CHB patients in Canada, providing that society is willing to pay at least $Can48,015 per QALY gained, although sensitivity analyses highlighted uncertainty around the results.