Efficacy of high doses of liposomal amphotericin B in the treatment of experimental aspergillosis.

Objective: Differences in efficacy between deoxycholate amphotericin B (d-AmB) and escalating doses of liposomal amphotericin B (L-AmB) were evaluated in a model of invasive pulmonary aspergillosis in persistently steroid-immunosuppressed rats.

Methods: Animals were infected intratracheally with a conidial suspension of a clinical isolate of Aspergillus fumigatus and randomized to receive intravenously 5% dextrose, 1 mg/kg/day of d-AmB or 3, 5 or 10 mg/kg/day of L-AmB.

Results: All the antifungal treatments improved survival, although no differences were found among the groups, perhaps because of treatment-related toxicity. In animals surviving long enough to receive at least five doses of antifungal treatment, there were significant reductions in paired lung weight in the 5 and 10 mg/kg/day L-AmB groups as compared with the controls (P=0.004 and 0.001, respectively) and with the 3 mg/kg/day L-AmB group (P=0.007 and 0.002, respectively). Significant decreases in fungal biomass, measured indirectly by chitin quantification, were found only in the 10 mg/kg/day L-AmB group as compared with controls (P=0.003), d-AmB (P=0.007) and 3 mg/kg/day L-AmB (P=0.001).

Conclusion: Infusion of L-AmB doses as high as 10 mg/kg/day may be a good therapeutic option for the management of invasive pulmonary aspergillosis developing in the context of steroid immunosuppression, although further studies are needed to assess this approach.