Cost-effectiveness analysis of isavuconazole versus voriconazole for the treatment of patients with possible invasive aspergillosis in Sweden

Abstract

BackgroundVoriconazole is well established as standard treatment for invasive aspergillosis (IA). In 2017, isavuconazole, a new antifungal from the azole class, with a broader pathogen spectrum, was introduced in Sweden. A model has therefore been developed to compare the cost-effectiveness of isavuconazole and voriconazole in the treatment of possible IA in adults in Sweden.MethodsThe cost-effectiveness of isavuconazole versus voriconazole was evaluated using a decision-tree model. Patients with possible IA entered the model, with 6% assumed to actually have mucormycosis. It was also assumed that pathogen information would become available during the course of treatment for only 50% of patients, with differential diagnosis unavailable for the remainder. Patients who were considered unresponsive to first-line treatment were switched to second-line treatment with liposomal amphotericin-B. Data and clinical definitions included in the model were taken from the published randomised clinical trial comparing isavuconazole with voriconazole for the treatment of IA and other filamentous fungi (SECURE) and the single-arm, open-label trial and case-control analysis of isavuconazole for the treatment of mucormycosis (VITAL). A probabilistic sensitivity analysis was used to estimate the combined parameter uncertainty, and a deterministic sensitivity analysis and a scenario analysis were performed to test the robustness of the model assumptions. The model followed a Swedish healthcare payer perspective, therefore only considering direct medical costs.ResultsThe base case analysis showed that isavuconazole resulted in an incremental cost-effectiveness ratio (ICER) of 174,890 Swedish krona (SEK) per additional quality adjusted life-year (QALY) gained. This was mainly due to the efficacy of isavuconazole against IA and mucormycosis, as opposed to voriconazole, which is only effective against IA. Sensitivity and scenario analyses of the data showed that the average ICER consistently fell below the willingness to pay (WTP) threshold of 1,000,000 SEK. The probability of isavuconazole being cost-effective at a WTP of 170,000 SEK per QALY gained was 50% and at a WTP of 500,000 SEK per QALY gained was 100%.ConclusionsThis model suggests that the treatment of possible IA with isavuconazole is cost-effective compared with treatment with voriconazole from a Swedish healthcare payer perspective.Electronic supplementary materialThe online version of this article (10.1186/s12879-019-3683-2) contains supplementary material, which is available to authorized users.

The cost-effectiveness of isavuconazole compared to the standard of care in the treatment of patients with invasive fungal infection prior to differential pathogen diagnosis in the United Kingdom

“…In terms of cost-effectiveness, the US model estimated that isavuconazole was dominant in terms of the incremental cost per death avoided and the incremental cost per responder. A Swedish model published in 2019 assessed the cost-effectiveness of isavuconazole vs voriconazole for the treatment of patients who, at the point of treatment initiation, did not have a confirmed differential diagnosis between IA and mucormycosis, in terms of incremental cost per QALY based on data from the SECURE trial, and case-control analysis between the VITAL study and FungiScope registry 41 . The Swedish model results also favored the use of isavuconazole with 0.3 more QALYs per patient than voriconazole at an incremental cost of 52,191 Swedish krona (SEK), resulting in an ICER of 174,890 SEK per additional QALY gained.…”

“…A US cost-effectiveness evaluation found isavuconazole to be a cost-effective treatment option relative to voriconazole in hospitalized patients with IA 40 . Another cost-effectiveness analysis took a Swedish healthcare payer perspective and found treatment of possible IA (at the point of treatment initiation, a differential diagnosis between IA and mucormycosis had not been achieved) with isavuconazole to be cost-effective compared with voriconazole 41 . Furthermore, cost-minimization models in Italy 42 , Germany 43 , and the UK 44 estimated that isavuconazole is cost-saving relative to liposomal amphotericin B (L-AMB) followed by posaconazole in the treatment of mucormycosis and of invasive mold disease in general 45 .…”

The cost‐effectiveness of isavuconazole compared to voriconazole, the standard of care in the treatment of patients with invasive mould diseases, prior to differential pathogen diagnosis in Spain

“…Several economic analyses of isavuconazole vs voriconazole for the treatment of IA have been conducted in different countries: in hospitalised patients with IA in the United States 17 and in patients with possible IA in Sweden 18 and the UK 19 . Cost‐minimisation models of isavuconazole vs L‐AMB followed by posaconazole for the treatment of IM have been also performed in Italy, 20 Germany 21 and the UK 22 .…”

Isavuconazole: Mechanism of Action, Clinical Efficacy, and Resistance

“…All studies found that isavuconazole was cost-saving when compared to voriconazole. These cost savings included the cost of the drug, the cost of adverse events, and hospital readmissions [ 34 , 35 , 36 ].…”