Economic Evaluation of Voriconazole versus Caspofungin for the Treatment of Invasive Aspergillosis in Spain

Abstract and Introduction

Abstract

Background and objective: Invasive fungal infections are becoming increasingly prevalent and are more frequently the aetiological agents responsible for nosocomial infections. Since mid-2002, two new antifungal drugs — voriconazole, a third-generation azole, and caspofungin, a member of a new class of drugs called echinocandins — have been marketed in Spain. Both drugs have greater efficacy (because of their specific mechanisms of action), more favourable toxicity profiles and are much less costly than liposomal amphotericin B. The objective of this study was to conduct an economic evaluation of voriconazole versus caspofungin for the treatment of invasive aspergillosis in Spain.
Methods: This was a cost-minimisation analysis (2006 costs) from the hospital perspective. Duration of treatment and bodyweight of patients were obtained from the Fungcost study and the incidence of adverse events was obtained from different published sources. Only direct costs were considered. Mean expected cost and incremental cost were calculated, and univariate and bivariate (bodyweight/treatment duration) sensitivity analyses were conducted.
Results: The mean expected cost per episode was €6041.93 (intravenous treatment acquisition cost €5524.75) for voriconazole and €7174.05 (intravenous treatment acquisition cost €6672.80) for caspofungin in invasive aspergillosis; the incremental cost was €1132.18. Results were robust for any treatment duration and sensitive to bodyweights <103.42kg.
Conclusion: Voriconazole is a more cost-effective option than caspofungin in invasive aspergillosis in patients with a bodyweight <103.42kg.

Introduction

Invasive fungal infections are becoming increasingly prevalent and are more frequently the aetiological agents responsible for nosocomial infections.^[1] Despite therapeutic and diagnostic advances in recent years, invasive fungal infections are still associated with unacceptable morbidity and mortality rates and we are still far from being in a similar situation to that pertaining to management of bacterial diseases.^[2]

The predominant fungal pathogens are Candida spp. and Aspergillus spp. Although the prevalence of Aspergillus spp. is much lower than that of Candida spp., Aspergillus has a mortality rate as high as 85% in many studies,^[3,4,5,6] and up to 90% in the case of bone marrow transplant patients.^[7]

Invasive aspergillosis occurs almost exclusively in immunocompromised patients (AIDS, cancer, diabetes, transplant, surgical, major trauma and burn patients). Intensification of chemotherapy and the increasing number of transplants, as well as the emergence of new immunosuppressant drugs, is leading to the appearance of these infections in patients in whom they were previously uncommon (e.g. leukaemia and lymphoma patients).^[8] Pulmonary aspergillosis is unquestionably the most common clinical presentation of invasive aspergillosis, followed at some distance by sinusitis, infection of the tracheobronchial tree and infection of the CNS.^[9]

The search for new molecules for the treatment of these diseases has intensified in recent years because of the limited pharmacotherapeutic arsenal available and the emergence of resistance to currently existing drugs. The main cause for the rise in resistance to antifungal agents is the large increase in their use in recent years. Administration of antifungal agents against resistant fungi stimulates their proliferation by eliminating potential nonresistant competitors.^[10,11]

Until some years ago, amphotericin B in its different forms (conventional, lipid and liposomal) was the treatment of choice for aspergillosis. The lipid formulations of amphotericin reduce the problems of intolerance and toxicity (primarily nephrotoxicity) associated with conventional amphotericin ^[12,13,14] but result in a large increase in the cost^[15] of treatments and have certain limitations, such as an inability to cross the brain-blood barrier, which makes them ineffective for the treatment of fungal infections located in the CNS.

Since mid-2002, two new antifungal drugs — voriconazole, a third-generation azole, and caspofungin, a member of a new class of drugs called echinocandins — have been marketed in Spain. Both have greater efficacy (as a result of their specific mechanisms of action), more favourable toxicity profiles and a much lower cost than liposomal amphotericin B.^[16,17,18]

Because of the progressive growth in healthcare expenditure and the limited availability of resources, it is important to determine the costs of these new therapies, as well as the factors that may influence their use. Few studies have been carried out to date on this subject and it is important to note that drug costs are different in Spain, both because of variations in prices and because of the different treatment regimens used.^[19]

The objective of this study was to perform an economic evaluation of voriconazole and caspofungin, both recently marketed in Spain, for the treatment of invasive aspergillosis. The study was designed to reflect patterns of treatment of this infection in the Spanish healthcare setting,^[19] in order to identify, from the perspective of the National Health System (hospital level), the most cost-effec-tive treatment option for use in routine clinical practice.

Clin Drug Invest. 2007;27(3):197-205. © 2007  Adis Data Information BV

Cite this: Economic Evaluation of Voriconazole versus Caspofungin for the Treatment of Invasive Aspergillosis in Spain - Medscape - Mar 01, 2007.