Prognostic Association of Liposomal Amphotericin B Doses Above 5 mg/kg/d in Mucormycosis: A Nationwide Epidemiologic and Treatment Analysis in Japan

Background. Mucormycosis is a potentially fatal fungal infection, and there is limited information on its precise epidemiology and treatment practices, including the optimal dosage of liposomal amphotericin B.Methods. A retrospective, multicenter, nationwide analysis of 82 proven and probable cases of mucormycosis was performed. Cases between 2015 and 2022 were collected from 51 hospitals in Japan by hematologists and infectious disease specialists. The study included the epidemiology, treatment details, and association between the dose of liposomal amphotericin B and the outcome.Results. The lungs were the most commonly involved organ (70.7% of cases), and 35.4% of patients had disseminated disease. Rhizopus spp., Cunninghamella spp., and Mucor spp. were the most common organisms. Mortality at 4 weeks was 41.5%. The survivors had a shorter duration of neutropenia (P = .006) and less persistent hyperglycemia (P = .023). The site of infection and species of Mucorales had no detectable effect on survival. Survival did not differ between patients receiving liposomal amphotericin B at 5 mg/kg/d relative to those receiving >5 mg/kg/d (P = .625). Using Cox proportional hazards models and adjusting for confounders, the hazard ratio for the influence of >5 mg/kg/d liposomal amphotericin B on 4-week survival was 0.86 (95% CI, 0.28-2.68; P = .796) compared with 5 mg/kg/d.Conclusions. This study provides important insights into the precise epidemiology and treatment practices of mucormycosis. Treatment with liposomal amphotericin B at doses higher than 5 mg/kg/d did not improve outcomes relative to 5 mg/kg/d.