Cost-effectiveness analysis of combination antifungal therapy with voriconazole and anidulafungin versus voriconazole monotherapy for primary treatment of invasive aspergillosis in Spain

Echinocandins - structure, mechanism of action and use in antifungal therapy

With increasing number of immunocompromised patients as well as drug resistance in fungi, the risk of fatal fungal infections in humans increases as well. The action of echinocandins is based on the inhibition of β-(1,3)-d-glucan synthesis that builds the fungal cell wall. Caspofungin, micafungin, anidulafungin and rezafungin are semi-synthetic cyclic lipopeptides. Their specific chemical structure possess a potential to obtain novel derivatives with better pharmacological properties resulting in more effective treatment, especially in infections caused by Candida and Aspergillus species. In this review we summarise information about echinocandins with closer look on their chemical structure, mechanism of action, drug resistance and usage in clinical practice. We also introduce actual trends in modification of this antifungals as well as new methods of their administration, and additional use in viral and bacterial infections.

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

Background

Invasive mould diseases are associated with high morbidity, mortality and economic impact. Its treatment is often started prior to differential pathogen diagnosis. Isavuconazole is approved for treatment of invasive aspergillosis (IA) and invasive mucormycosis (IM) when amphotericin‐B is not indicated.

Objectives

To estimate the cost‐effectiveness of isavuconazole vs voriconazole for the treatment of adult patients with possible IA prior to differential pathogen diagnosis, in Spain.

Methods

A decision tree analysis was performed using the Spanish Healthcare System perspective. Among all patients with possible IA, it was considered that 7.81% actually had IM. Costs for laboratory analysis, management of adverse events, hospitalisation and drugs per patient, deaths and long‐term effects in life years (LYs) and quality‐adjusted LYs (QALYs) were considered. Efficacy data were obtained from clinical trials and utilities from the literature. Deterministic and probabilistic sensitivity analyses (PSA) were conducted.

Results

In patients with possible IA and when compared to voricanozole, isavuconazole showed an incremental cost of 4758.53€, besides an incremental effectiveness of +0.49 LYs and +0.41 QALYs per patient. The Incremental Cost Effectiveness Ratio was 9622.52€ per LY gained and 11,734.79€ per QALY gained. The higher cost of isavuconazole was due to drug acquisition. Main parameters influencing results were mortality, treatment duration and hospitalisation days. The PSA results showed that isavuconazole has a probability of being cost‐effective of 67.34%, being dominant in 24.00% of cases.

Conclusions

Isavuconazole is a cost‐effective treatment compared to voriconazole for patients with possible IA for a willingness to pay threshold of 25,000€ per additional QALY.

Combination Antifungal Therapy for Invasive Aspergillosis Revisited

Invasive aspergillosis (IA) causes significant morbidity and mortality among immunocompromised hosts. Combination therapy with mold-active triazoles and echinocandins has been used with the hope of improving outcomes over monotherapy, especially in the setting of refractory disease. Herein, I update our prior systematic review and meta-analysis on combination therapy for salvage IA in the context of the recently published randomized clinical trial of combination therapy for primary IA. Clinicians should consider combination antifungals for IA in refractory disease despite immune reconstitution when there are concerns for resistance or pharmacokinetic variability.