Background To insert a drug into the Hospital Pharmaceutical Formulary (HPF) it is necessary to carry out a drug-economic analysis. The health economics study offers analysis tools such as Net Monetary Benefit (NMB) and Incremental Cost-Effectiveness Ratio (ICER) are useful in making these decisions. Nowadays, the prescription medication for the treatment of aspergillosis is voriconazole with consolidated effectiveness and safety.

Purpose Evaluate the cost effectiveness of isavuconazole versus voriconazole, in order to introduce isavuconazole in place of Voriconazole into the HPF.

Material and methods We analysed data from the ‘SECURE’ trial, a non-inferiority study of isavuconazole versus voriconazole, from which we extrapolated the success rates of the two drugs after a short time frame (42 days). According to our analysis, neither of the two treatments dominates the other, making it necessary to evaluate ICER and NMB, through a BIA. We built up a decision tree, considering success and both deaths from therapeutic failure and other causes. Hospitalisation, cost of drugs and adverse events (AE) costs were derived from rate tables of Italian hospital care. To calculate NMB (difference in effectiveness multiplied by willingness to pay (WTP), less difference in costs) and to value the ICER obtained, we selected two different WTP thresholds, from NICE guidelines: €30 000 and €50 000.

Results According to our analysis, neither of the two treatments dominates the other, making it necessary to evaluate ICER and NMB. Success rates of isavuconazole and voriconazole were 84.88% and 81.09% respectively. Considering all the success and failure probabilities we calculated a cost of €3,610.89 for Isavuconazole and €2,249.67 for voriconazole, resulting in an ICER ratio of €35,925.07. Considering the second threshold value (€50,000), which is above ICER value, we obtained a positive NMB (€533.78) which permitted the introduction of isavuconazole into the HPF. The €30 000 thresholds, on the contrary, results in a negative and unfavourable NMB (-€224. 22).

Conclusion According to our analysis into NMB and ICER values, the introduction of isavuconazole in the HPF is cost effective if we consider a €50,000 WTP threshold.

Reference and/or Acknowledgements 1. Maertens, et al. Isavuconazole versus voriconazole for primary treatment of invasive mould disease caused by Aspergillus and other filamentous fungi (SECURE): a phase 3, randomised-controlled, non-inferiority trial 2016.

No conflict of interest