Caspofungin versus amphotericin B for candidemia: a pharmacoeconomic analysis

In a randomized, comparative, clinical trial, caspofungin was found to be as effective as amphotericin B deoxycholate (ampho B) for treating candidemia (favorable outcomes in 71.7% and 62.8% of patients, respectively) and exhibited a generally better safety profile, particularly with respect to impaired renal function (IRF) (P = 0.02).

The goal of this study was to examine whether cost savings generated from the reduced rates of IRF observed in the clinical trial would be enough to offset the higher acquisition cost of caspofungin relative to ampho B.

We developed an economic model in which 100 hypothetical patients with candidemia were treated with caspofungin or ampho B. Rates of IRF and duration of drug therapy were taken from the clinical trial. Information on the cost of treating IRF was obtained through a search of MEDLINE using the terms amphotericin and cost, amphotericin and resource, amphotericin and hospital, and amphotericin and toxicity; and the medical subject headings kidney failure, acute/drug therapy; kidney failure, acute/epidemiology; kidney failure, acute/etiology; kidney/drug effects; cost of illness; costs and cost analysis; kidney failure, acute, and economics; and kidney failure, acute/economics. In addition, the Web site was searched for relevant references, and the Merck publication alert system was used. Antifungal drug costs were estimated using data from IMS Health. Costs were reported in year-2003 US dollars.

In the base case, the model projected that using caspofungin instead of ampho B would result in substantially lower treatment costs for IRF, which would more than offset the higher drug acquisition cost (cost-offset percentage, 122%), leading to a net mean savings of 758.60 US dollars per patient. These results were not very sensitive to the difference in daily drug cost, but were sensitive to the mean cost attributable to treating IRF. As that varied, the cost-offset percentage varied from 61% (substantial cost offset) to 183% (cost savings).

The results of this economic model suggest that, based only on differences in drug acquisition cost and renal toxicity, the use of caspofungin instead of ampho B in patients with candidemia may be a cost-saving strategy from the perspective of a hospital.