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 patients 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. Probabilistic analysis was used to compare the cost-effectiveness among the regimens. RESULTS With voriconazole, the mean cost for treating invasive aspergillosis per patient was E32 651 (2.5th percentile and 97.5th of uncertainty distribution: E30 037; E36 859), compared to E33 616 (E30 920; E39 633) for conventional amphotericin B and E29 115 (E23 537; E61 414) 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 E150 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.