Caspofungin (
MK-0991;
L-743,872) belongs to the
echinocandin family, a new class of
antifungal agents that act on the fungal cell wall by inhibiting
glucan synthesis. Data in vitro, and experimental studies, have demonstrated that
caspofungin has antifungal activity against yeasts of the genus Candida (including isolates resistant to
azoles and
amphotericin B), several species of filamentous fungi, including Aspergillus, and certain dimorphic fungi, such as Histoplasma, Blastomyces and Coccidioides. In vitro and in animals,
caspofungin shows additive or synergic antifungal activity with
amphotericin B and
triazoles. It also possesses activity against Pneumocystis carinii. Clinical trials have shown
caspofungin to be well tolerated and effective in invasive
aspergillosis in patients refractory or intolerant to standard treatment (45% favourable responses), in oropharyngeal and oesophageal
candidiasis (67-93% favourable responses with an efficacy similar to those of
amphotericin B and
fluconazole), and in
invasive candidiasis with efficacy equivalent to that of
amphotericin B, and better tolerability. The results of these first clinical trials were promising, and led to the approval of
caspofungin for invasive
aspergillosis after failure of, or intolerance to, standard
therapy. Further studies are required to define the exact role of
caspofungin in the antifungal armamentarium.