ECONOMIC EVALUATION OF VORICONAZOLE VERSUS CASPOFUNGIN FOR THE TREATMENT OF INVASIVE ASPERGILLOSIS IN BELGIUM

OBJECTIVE:To perform an economic evaluation of voriconazole versus caspofungin in first line treatment of invasive aspergillosis (IA). These 2 antifungal drugs have a more favorable toxicity profile than the conventional amphotericin B and have a lower cost than the expensive liposomal/lipid formulation of amphotericin B. No head-to-head comparative study was conducted with voriconazole and caspofungin in IA. Based on the clinical trials of both antifungals, a conservative approach of similar efficacy has been considered. METHODS: The analysis is based on a simplified cost-minimization model with results from the National Health system RIZIV/INAMI perspective (year 2008). Only limited direct costs were considered, namely the drug cost over the episode of treatment. Treatment duration and patients' weight were key parameters. Their values were obtained from the Belgian observational VORIBEL study (Pfizer data on file) for voriconazole treatment. Treatment duration for caspofungin was derived from the EORTC study where almost 50% of the patients were recruited in Belgian centres. Mean cost and incremental cost were calculated. Univariate sensitivity analyses were carried out on weight, treatment duration as well as on route of administration. RESULTS: In invasive aspergillosis, the weighted cost per episode of fungal infection was 11.996 (sic) with voriconazole treatment (voriconazole IV followed by oral voriconazole) and 13.657 (sic) with caspofungin treatment (intravenous caspofungin only). The incremental saving with voriconazole treatment was 1.661 (sic) per patient. The cost-saving results of voriconazole were confirmed with varying treatment duration within realistic range. 41% of the patients in the VORIBEL study were fully treated with oral formulation. For these patients a saving of 6.375 (sic) was achieved with the use of oral voriconazole. CONCLUSION: Voriconazole is a cost-saving option compared with caspofungin in the treatment of invasive aspergillosis