Economic evaluation of voriconazole in the treatment of invasive aspergillosis in the Netherlands

Objective: To asses the cost-effectiveness of voriconazole in comparison to conventional amphotericin B and itraconazole for the treatment of invasive aspergillosis in the Netherlands. Methods: The cost-effectiveness of voriconazole in comparison to conventional amphotericin B or itraconazole was evaluated with a decision tree model followed by a life-time Markov model, focusing on long-term survival of patents treated for invasive aspergillosis. Efficacy after 12 weeks of treatment from clinical trials was used to estimate long-term effectiveness by extrapolating these short-term results over time. Information on medical resource consumption, treatment pathways and switch proportions were obtained from both the literature and Experts. Probabilistc analysis was used to compare the cost-effectiveness among the regimens. Results: With voriconazole, the mean cost for treating invasive aspergillosis per patient was euro32651 (2.5th percentile and 97.5th of uncertainty distribution: euro30037; euro36859), compared to euro33616 (euro30920; euro39633) for conventional amphotericin B and euro29115 (euro23537; euro61414) for itraconazole. The mean survival of patients treated with voriconazole was 174.0 life weeks (160.1; 188.8), compared to 116.1 life weeks (104.8; 128.0) for conventional amphotericin B and 150.4 life weeks (109.1; 194.4) for itraconazole. The beneficial effects of voriconazole on both cost and effectiveness compared with conventional amphotericin B resulted in a probability of 69.8% that voriconazole was a dominant treatment (i.e. less costs and longer survival). The incremental cost-effectiveness ratio of voriconazole versus itraconazole was euro150 per life week (i.e. 7800 euros per life-year gained). Depending on the willingness to pay (WTP) the probability of being cost-effective vs. itraconazole increased to a maximum probability of 70%. Conclusion: In the treatment of invasive aspergillosis, voriconazole is dominant over amphotericin B and cost-effective in comparison to itraconazole.