A commentary discusses whether isavuconazole will now replace voriconazole as standard of care for the treatment of invasive aspergillosis. It notes advantages of isavuconazole over voriconazole include:
• broader spectrum of activity (including most mucormycetes)
• once-daily dosing after the loading dose
• linear pharmacokinetics, and less interpatient variability in exposure
• water solubility (thus no need for cyclodextrin in the intravenous formulation)
• fewer CYP enzyme-mediated drug–drug interactions
The commentators note that much of the cost of treating fungal infection relates to the cost of antifungal drugs thus addition of a new antifungal drug into a hospital formulary will require demonstration of substantial clinical advantages or cost-effectiveness over existing drugs. They suggest isavuconazole will probably achieve an equivalent recommendation to voriconazole for the initial treatment of invasive aspergillosis in clinical guidelines. However, voriconazole will soon be coming off-patent in many countries (from mid 2016 in UK) and new formulations of posaconazole are now available, broadening therapeutic options and affecting cost. They add that a cost-effectiveness comparison between voriconazole and isavuconazole would be a useful addition to the scientific literature and could be modelled from the findings of this study.