Pharmacoeconomic evaluation of voriconazole versus posaconazole for antifungal prophylaxis in acute myeloid leukaemia

Voriconazole and posaconazole are used prophylactically against invasive fungal infection (IFI) in patients with acute myeloid leukaemia (AML). The current study attempted to evaluate the economics of voriconazole versus posaconazole for prophylaxis in AML. A 6 year (2003-09) retrospective chart review of AML patients was performed at a major Australian tertiary hospital. Patients were followed through the induction stage of chemotherapy, estimating outcome probabilities and prescribing patterns of antifungal prophylaxis. Cost inputs were obtained from the latest Australian sources. A decision analytical model was developed to depict options and consequences involved in the prophylaxis, including success, survival, possible and proven IFIs, and discontinuations due to intolerance. A cost-benefit analysis and an uncertainty study through sensitivity analyses were performed. Fifty-six and 38 patients were evaluated in the voriconazole and posaconazole groups, respectively. Baseline demographic characteristics were not significantly different between the study cohorts. Posaconazole was associated with an overall cost saving of AU$17 458 (29%) per patient over voriconazole. The posaconazole group was associated with lower rate of death, as well as lower probability of discontinuation because of possible infections and intolerance to oral administration. The voriconazole group was associated with fewer proven infections. As per sensitivity analyses, results were highly robust over variations in all costs and probabilities in the model. Monte Carlo simulation suggested a 91.6% chance for posaconazole to cost less than voriconazole. This is the first economic evaluation of voriconazole versus posaconazole; where posaconazole appears to be more cost-beneficial than voriconazole as antifungal prophylaxis in AML.