Some oral antivirals are more cost-effective than others for the treatment of chronic hepatitis B

Abstract

In their letter referring to our study “Modeling the cost-effectiveness of different oral antiviral therapies in patients with chronic hepatitis B”, Mantovani and de Portu claim that the presentation of our results is inappropriate. We beg to disagree. First, the aim of our study, as is stated in the introduction, was to assess the cost-effectiveness of various antiviral drugs [[1]Buti M. Brosa M. Casado M.A. Rueda M. Esteban R. Modeling the cost-effectiveness of different oral antiviral therapies in patients with chronic hepatitis B.J Hepatol. 2009; 51: 640-646Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar]. The “no therapy” strategy was included because a considerable number of patients with chronic hepatitis B have their treatment deferred for different reasons. Secondly, as direct comparisons between antiviral treatments are not available then indirect comparison remains the only approach to evaluate cost-effectiveness of any anti-HBV therapy. The limitations of indirect treatment comparisons in cost assessment are well recognized. For this reason, modeling techniques are especially appropriate and indicated to compare the data from different sources [[2]Claxton K. Scupher M. McCabe C. Briggs A. Akehurst R. Buxton M. et al.Probabilistic sensitivity analysis for NICE technology assessment: not an optional extra.Health Econ. 2005; 14: 339-347Crossref PubMed Scopus (326) Google Scholar]. Indeed, modeling techniques allow extrapolation of short/medium-term results from clinical trials to long-term effectiveness outcomes, which is what we did in our model, in line with previous studies [3Rajendra A. Wong J.B. Economics of chronic hepatitis B and hepatitis C.J Hepatol. 2007; 47: 608-617Abstract Full Text Full Text PDF PubMed Scopus (20) Google Scholar, 4Kanwal F. Gralnek I.M. Martin P. Dulai G.S. Farid M. Spiegel B.M. Treatment alternatives for chronic hepatitis B virus infection: a cost-effectiveness analysis.Ann Intern Med. 2005; 142: 821-831Crossref PubMed Scopus (115) Google Scholar]. In addition, the probabilistic sensitivity analysis helps the reader to better understand eventual differences between the compared options even if the primary data, virological response rates, do not derive from head-to-head studies comparing different antiviral options, as occurs in chronic hepatitis B treatment. The robustness of our model was exhaustively tested in the probabilistic analysis, and the expected variability was analysed within the Monte Carlo simulation. Finally, the basic cost-effectiveness results depicted in Figures 1 and 2 of the manuscript [[1]Buti M. Brosa M. Casado M.A. Rueda M. Esteban R. Modeling the cost-effectiveness of different oral antiviral therapies in patients with chronic hepatitis B.J Hepatol. 2009; 51: 640-646Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar] clearly show that a number of treatment options are dominated by others (in some cases by more than one option) [[1]Buti M. Brosa M. Casado M.A. Rueda M. Esteban R. Modeling the cost-effectiveness of different oral antiviral therapies in patients with chronic hepatitis B.J Hepatol. 2009; 51: 640-646Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar]. Thus, the only incremental cost-effectiveness ratios (ICERs) to be calculated are those of the more effective options relative to immediately less effective options, performing a standard incremental cost-effectiveness analysis. In our study, ICERs are shown for tenofovir vs. lamivudine and no treatment (Table 5 of the manuscript [[1]Buti M. Brosa M. Casado M.A. Rueda M. Esteban R. Modeling the cost-effectiveness of different oral antiviral therapies in patients with chronic hepatitis B.J Hepatol. 2009; 51: 640-646Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar]), and the only ICERs omitted are those of lamivudine vs. no treatment in both HBeAg-positive and HBeAg-negative patients. In our opinion, the only real contribution of the letter by Mantovani and de Portu is when they point out that lamivudine is a cost-effective option in relation to “no treatment”. This is a well-known fact that has little current relevance, since lamivudine is not a recommended first-line option in the treatment of chronic hepatitis B infection.