Antifungal therapy in children: an update

Invasive Aspergillosis in Pediatric Leukemia Patients: Prevention and Treatment

The purpose of this article is to review and update the strategies for prevention and treatment of invasive aspergillosis (IA) in pediatric patients with leukemia and in patients with hematopoietic stem cell transplantation. The major risk factors associated with IA will be described since their recognition constitutes the first step of prevention. The latter is further analyzed into chemoprophylaxis and non-pharmacologic approaches. Triazoles are the mainstay of anti-fungal prophylaxis while the other measures revolve around reducing exposure to mold spores. Three levels of treatment have been identified: (a) empiric, (b) pre-emptive, and (c) targeted treatment. Empiric is initiated in febrile neutropenic patients and uses mainly caspofungin and liposomal amphotericin B (LAMB). Pre-emptive is a diagnostic driven approach attempting to reduce unnecessary use of anti-fungals. Treatment targeted at proven or probable IA is age-dependent, with voriconazole and LAMB being the cornerstones in >2yrs and <2yrs age groups, respectively.

Advances in the Treatment of Mycoses in Pediatric Patients

The main indications for antifungal drug administration in pediatrics are reviewed as well as an update of the data of antifungal agents and antifungal policies performed. Specifically, antifungal therapy in three main areas is updated as follows: a) Prophylaxis of premature neonates against invasive candidiasis; b) management of candidemia and meningoencephalitis in neonates; and c) prophylaxis, empiric therapy, and targeted antifungal therapy in children with primary or secondary immunodeficiencies. Fluconazole remains the most frequent antifungal prophylactic agent given to high-risk neonates and children. However, the emergence of fluconazole resistance, particularly in non-albicans Candida species, should be considered during preventive or empiric therapy. In very-low birth-weight neonates, although fluconazole is used as antifungal prophylaxis in neonatal intensive care units (NICU's) with relatively high incidence of invasive candidiasis (IC), its role is under continuous debate. Amphotericin B, primarily in its liposomal formulation, remains the mainstay of therapy for treating neonatal and pediatric yeast and mold infections. Voriconazole is indicated for mold infections except for mucormycosis in children >2 years. Newer triazoles-such as posaconazole and isavuconazole-as well as echinocandins, are either licensed or under study for first-line or salvage therapy, whereas combination therapy is kept for refractory cases.

Therapeutic strategies for invasive fungal infections in neonatal and pediatric patients: an update

INTRODUCTION

Invasive fungal infections (IFIs) in neonatal and pediatric patients are still associated with high morbidity and mortality, increased length of hospital stay and high healthcare cost. Two key components are prerequisite to combat pediatric IFIs; first, definition of the 'at-risk' populations that could benefit the most from prophylactic treatment and second, prompt initiation of effective antifungal therapy.

AREAS COVERED

In this article, updated prevention and targeted therapeutic approaches for IFIs in neonates and immunocompromised children are reviewed. Furthermore, European and American guidelines concerning IFI treatment in neonates and children are compared.

EXPERT OPINION

IFIs in neonates and children present substantial differences from adults in respect to their epidemiology, pharmacokinetics of antifungal agents and dosing as well as absence of interventional Phase III and IV clinical trials for guidance of evidence-based decisions. In the therapeutic armamentarium of these age groups, although amphotericin B formulations remain widely indicated, azoles with broader spectrum activity as well as echinocandins have been added in the updated antifungal treatment algorithm. Recent European guidelines (ESCMID and ECIL) contain specific recommendations for pediatric patients with IFIs. In both age groups, definitive updated guidance for prophylaxis and more importantly targeted treatment need to be further evaluated by large, multicenter, randomized controlled trials.

Deoxycholate amphotericin B and nephrotoxicity in the pediatric setting

Since the introduction of amphotericin B as an antifungal agent, the morbidity and mortality of pediatric patients with mycotic infections have increased, primarily because of the increased immunocompromised patients. Despite the fact that deoxycholate amphotericin B was once the primary drug used for mycotic infections, its administration to children older than neonates is currently controversial because of its nephrotoxic effects. Three lipid-associated formulations have been developed and have reportedly shown similar efficacy and fewer nephrotoxic effects in adults than conventional amphotericin B, but the conclusions from comparative studies in children evaluating the nephrotoxicity risks of the 4 agents are controversial. Nevertheless, guidelines favor liposomal or lipid complex amphotericin B when polyene antifungal therapy is recommended in this age group. However, high acquisition costs often preclude their prescription in economically poor regions. Thus, physicians must consider all of these factors when determining the most cost-effective polyene antifungal treatment for their pediatric patients. This is particularly pertinent in developing countries where resources are scarce. Adjuvant sodium supplementation has been reported to be effective in protecting kidney function in extremely low birth weight infants prescribed deoxycholate amphotericin B. Further pharmacokinetic and pharmacodynamic studies of the drug in children could also provide information for rational dosing regimens designed to decrease nephrotoxicity. Conventional amphotericin B, with appropriate kidney protective measures, still plays a role in the treatment of empiric invasive mycotic infections in most pediatric patients. Liposomal and lipid complex amphotericin B should be reserved for those receiving long-term nephrotoxic agents or with altered renal function or disease. Antifungal susceptibility, renal compromise and the clinical status of the patient should determine treatment for culture-proven infections. Under the current cost limitations, undertaking and evaluating low-cost, kidney-sparing, deoxycholate amphotericin B treatments for children should be a primary concern.