Anidulafungin: advantage for the newcomer?

Anidulafungin is the most recently approved compound of the echinocandin antifungal class. Its mode of action is the noncompetitive inhibition of -(1,3)-D-glucan synthesis. Potent fungicidal activity has been demonstrated against many Candida spp., including non-albicansCandida spp. and fluconazole-resistant strains, as well as fungistatic activity against Aspergillus spp. Owing to low oral bioavailability, it can only be administered intravenously. Anidulafungin is not metabolized by the liver and renal clearance is negligible, thus rendering dosage adjustments in patients with impaired hepatic or renal function unnecessary. Due to lack of interference with the cytochrome P450 pathway, it displays minimal drug-drug interaction. Anidulafungin has been approved by the US FDA for the treatment of esophageal and invasive candidiasis after clinical trials demonstrated its noninferiority to fluconazole. In September 2007, anidulafungin gained EMEA approval for the treatment of invasive candidiasis in adult non-neutropenic patients. For those with invasive or noninvasive candidiasis with resistance or intolerance to fluconazole in particular, as well as those requiring antifungal medication, that anidulafungin does not interact with concomitant medication means it may be regarded as a safe and efficacious treatment option. Promising results from animal models and experience with the other echinocandins indicate several potential lines of investigation: invasive aspergillosis, prophylaxis and treatment of transplant patients, and empirical treatment in patients with febrile neutropenia. Significant differences in clinical efficacy or safety favoring anidulafungin over the other echinocandins are yet to be discovered.