Caspofungin (
Cancidas, Merck & Co. Inc.) is the first
echinocandin antifungal agent to gain FDA-approval for use in the US. It has excellent clinical activity against Candida spp. and Aspergillus spp. but lacks significant activity against Cryptococcus neoformans.
Caspofungin may have some activity against dimorphic fungi such as Histoplasma capsulatum and Coccidioides immitis, but no clinical data is available for treatment of these
infections.
Caspofungin has demonstrated poor activity against most filamentous fungi in vitro. Several clinical trials have demonstrated its efficacy in the treatment of oropharyngeal, oesophageal and
invasive candidiasis, as well as invasive
aspergillosis. As a result of
caspofungin's unique mechanism of action, and the high morbidity and mortality of
invasive fungal infections, there is considerable interest in using this new
antifungal agent as part of a combination antifungal
therapy. In vitro studies and small case series indicate that
caspofungin does not appear to be antagonistic when combined with other antifungals, such as
itraconazole,
voriconazole or
amphotericin B against Aspergillus spp.
Caspofungin exerts concentration-dependent killing effects in many different in vitro and animal models of
disseminated fungal infection. The usual daily dose is 50 mg/day i.v. following a 70 mg i.v. loading dose. However, higher
caspofungin doses have been safely administered and up to 70 mg/day can be administered for patients who fail to respond to lower doses.
Caspofungin has an excellent safety profile with reduced toxicities, compared to other licensed
antifungal agents.
Fever,
thrombophlebitis,
headache and liver
enzyme elevations were the most common
drug-related side effects reported in clinical trials so far. Additional data are needed to document its safety in long-term use, and with higher doses in patients with
invasive fungal infections.
Caspofungin is a promising agent as first-line
therapy for
invasive candidiasis, and as
salvage therapy for invasive
aspergillosis. However, more clinical data are needed to define its role as primary
therapy for invasive
aspergillosis, and its role in combination antifungal
therapy.