Caspofungin: an echinocandin antifungal agent

The mainstays of treatment for nosocomial fungal infections have been amphotericin B and azole derivatives. Caspofungin acetate is a new echinocandin antifungal agent with a mechanism of action that targets a structural component of the fungal cell wall.

This article describes the pharmacologic properties and potential clinical usefulness of caspofungin.

Relevant information was identified through searches of MEDLINE (1966-September 2001). Iowa Drug Information Service (1966-September 2001), and International Pharmaceutical Abstracts (1970-September 2001), as well as meeting abstracts of the Infectious Diseases Society of America and the Interscience Conference on Antimicrobial Agents and Chemotherapy (1996-2001), using the terms caspofungin, MK-0991, pneumocandin, echinocandin, candin, and beta-(1,3)-glucan inhibitor.

In vitro, caspofungin exhibits antifungal activity against an array of clinically important yeasts and molds, including Candida and Aspergillus spp. The proposed susceptibility breakpoint for caspofungin against Candida spp, the most common cause of nosocomial fungal infections, is a minimum inhibitory concentration of < or =1 microg/mL. In humans, caspofungin has a volume of distribution of 9.67 L, is extensively bound to albumin (97%), has a plasma elimination half-life of 9 to 11 hours, and is metabolized to inactive metabolites in the liver. Dose adjustment based on age, sex, race, or renal function does not appear to be necessary, although patients with moderate hepatic insufficiency (Child-Pugh score 7-9) should receive a lower maintenance dose. The results of clinical trials, although somewhat preliminary, suggest that caspofungin is effective in the treatment of esophageal and oropharyngeal candidiasis and invasive aspergillosis. When combined with other antifungal agents, caspofungin produces a synergistic or additive effect against a variety of clinically important fungi. The most commonly reported adverse events with caspofungin have included fever, infusion-related reactions, headache, nausea, elevations in liver transaminase levels, and histamine-type reactions. The recommended dosage in adults is 70 mg IV on day 1 followed by 50 mg/d, with the duration of treatment depending on the severity of the patient's underlying condition and the clinical response.

Although additional studies are needed, caspofungin appears to be a promising agent for the treatment of patients with difficult-to-treat or life-threatening fungal infections.