Pharmacokinetics of micafungin in HIV positive patients with confirmed esophageal candidiasis.

Esophageal candidiasis (EC) is a common and serious complication in patients infected with the human immunodeficiency virus (HIV). Micafungin has been shown to have dose-related efficacy and to be well tolerated in patients with HIV and EC. This analysis of data from a randomized, double-blind study examined pharmacokinetic parameters of micafungin (dosed at 50, 100, and 150 mg/day) and its metabolites in a subset of patients with HIV and EC. Micafungin exhibited linear, predictable pharmacokinetics, similar to the previous observations in healthy control subjects. Micafungin peak plasma concentration and exposure were increased with dose, while half-life and clearance remained consistent with increasing dose. Plasma concentrations of the metabolites M-1, M-2, and M-5 remained low throughout the study (24 h exposure ≤14% relative to micafungin at end of therapy for each). No differences in micafungin pharmacokinetic parameters were observed according to the sex or race of the patients. The high systemic exposures associated with micafungin 100 and 150 mg/day relative to micafungin 50 mg/day were found to directly correlate with endoscopic clearance. These data provide evidence that the pharmacokinetics of micafungin underlie the dose-related efficacy in patients with HIV and EC.