BACKGROUND: Invasive Aspergillosis(IA) is a serious invasive fungal infection(IFI), usually affecting immunocomprised patients. In the Netherlands, voriconazole(VOR) is the recommended primary targeted antifungal agent and is used for the vast majority of IA patients. After unsuccessful first line treatment with VOR, Caspofungin(CASP) and liposomal amphotericin B(L-AMB) are two most commonly used agents. In a previously published study, CASP was dominant over L-AMB, as a targeted salvage antifungal therapy option after VOR for IA treatment in the Netherlands. However, trial data used as input might not reflect the real world effectiveness of treatment strategies. OBJECTIVES: The objective of this study is to conduct a cost-effectiveness analysis of the most common targeted antifungal treatment sequences for IA in the Netherlands, using real-world data from a national registry. METHODS: A previously developed decision analytical model was adapted to carry out the cost-effectiveness analysis that compares L-AMB vs. CASP as a 2nd line treatment strategy after unsuccessful treatment with VOR. Findings from the analysis of the national patient registry informed the model structure, treatment patterns, duration/dosage of treatments, events and their probabilities. The model estimates both survival during infectious disease episode as well as life years saved(LYS) after short-term survival. Extensive sensitivity analyses were conducted to assess the robustness of the results.  RESULTS: Short term survival, life expectancy and cost outcomes for using L-AMB and CASP in the 2^ndline seem to be similar, after an unsuccessful primary therapy with VOR. There is a slight benefit in terms of LYS and costs for L-AMB. The analysis results are sensitive to statistical uncertainty due to the low number of patients in the registry. CONCLUSIONS: An updated analysis after more data is collected would strengthen reliability/validity of the analysis, and would make it feasible to apply statistical matching methods to adjust for possible confounding by treatment choice.