Tolerability and Effectiveness of Extended Dosing of Liposomal Amphotericin B (L-AmB) for Primary Prophylaxis of Invasive Fungal Disease in High-risk Pediatric Patients: a Retrospective Multicenter Study

Invasive fungal disease (IFD) still represents an important cause of morbidity and mortality in immunocompromised patients, particularly in patients undergoing antineoplastic chemotherapy or allogeneic hemopoietic stem cell transplantation (allo-HSCT). In this setting children presents some differences compared to adults in terms of risk factors for IFD: different treatment schemes, age-related comorbidities, diagnostic tools with different sensitivity. International guidelines strongly recommend primary prophylaxis in children at high risk of developing IFD to reduce disease-related morbidity and mortality (patients are considered to be at high risk in the presence of an IFD incidence ≥10%). Although the risk factors are well characterized in the literature and substantially unchanged over time, the local epidemiology must be considered in the evaluation of the best prophylaxis strategy. Drugs presently recommended for antifungal prophylaxis have been poorly studied in children, anyway triazoles (mainly posaconaozle) are indicated as possible prophylactic agents also in pediatrics. However, these drugs can present important interactions with drugs important for the treatment of pediatric leukemias (e.g. vinca alkaloids and posaconazole) and sometimes they lack of specific pediatric formulations, fact that can reduce compliance because of bad taste of the available formulations (oral solutions) or difficulties in swallowing and risk of poor absorption in presence of mucositis (bulky, non-divisible pills or capsules). Liposomal amphotericin B (L-AmB) can represent a valid alternative for antifungal prophylaxis in pediatric age as its spectrum is extended to both molds and yeasts, has reduced pharmacological interactions with the antineoplastic drugs most frequently used in treatment protocols. All this despite the availability of an intravenous formulation only which may require hospital access or activation of the home care team, but which can ensure complete compliance with the treatment. L-AmB prophylaxis has been proposed with different dosages: 1 mg/kg every other day vs 2.5 mg/kg/dose twice-a-week vs 5 mg/kg/once-a-week).