Factors Influencing the Safety and Efficiency of Antifungal Prophylaxis with Posaconazole in Children with Hematological Diseases: From Genetics to Polypharmacotherapy

Dose Optimisation of Posaconazole and Therapeutic Drug Monitoring in Pediatric Patients

Experience in the clinical use of posaconazole (PCZ) in pediatric patients is limited, and no specific dose recommendations exist. This study aimed to investigate an appropriate dosing regimen, and assess the exposure-response relationships of PCZ in children. We reviewed the medical records of inpatients aged <18 years who subjected to PCZ concentrations monitoring. Clinical data, PCZ dosing and monitoring data were collected. A total of 375 PCZ trough concentrations (C _min) from 105 pediatric patients were included. For children receiving PCZ for prophylaxis, the median doses required to achieve the therapeutic range at the ages of <6, 6-12 and >12 years were 14.80, 14.52 and 12.90 mg/kg/day, respectively (p = 0.001); and for those receiving PCZ for treatment, the median doses were 23.50, 20.96 and 15.38 mg/kg/day, respectively (p = 0.001). Among children taking PCZ for prophylaxis, 12% developed a proven or probable breakthrough IFIs; the median PCZ concentrations were significantly lower than those children with successful treatment response (0.43 versus 1.20 μg mL^-1; p < 0.001). 79.2% patients taking PCZ for treatment had a positive clinical response, and the median PCZ concentrations were significantly higher than those children with disease progression (1.06 versus 0.53 μg mL^-1; p = 0.024). No association between C _min values and hepatotoxicity was observed. Factors such as age, CRP, ALT and co-administration with proton pump inhibitors exhibited significant effects on PCZ C _min. It is necessary to adjust the dosing regimens based on PCZ C _min to individualize antifungal therapy and provide guidelines for dose adjustment in children.

Antifungal Prophylaxis With Posaconazole in Immunocompromised Children Younger Than 13 Years

OBJECTIVE

Prophylaxis with posaconazole (PP) is effective in the prevention of invasive fungal infections in immunocompromised adult patients. However, evaluation of its effectiveness and safety in children is limited. The aim of the study was to describe the use of posaconazole as antifungal prophylaxis in children.

METHODS

We reviewed the medical records of immunocompromised patients younger than 13 years with hematologic diseases and post hematopoietic stem cell transplant (HSCT) who received antifungal PP at the Instituto Nacional de Salud del Niño San Borja (INSN-SB) in Lima, Peru, from January 2014 to December 2018.

RESULTS

Fifty-six courses of PP were identified in 47 patients with a median age of 7.5 years (IQR, 4-10), 51.6% (n = 24) of whom were female. The main underlying medical conditions were aplastic anemia (n = 19, 33.9%), acute lymphoblastic leukemia (n = 18, 32.1%), acute myeloid leukemia (n = 14, 25.0%), and 34.1% had undergone HSCT. The median dose of posaconazole was 13.62 mg/kg/day (IQR, 12.0-16.8), and the median duration of PP was 24 days (IQR, 16-82). Gastrointestinal symptoms included abdominal pain (17.9%), nausea (16.1%), diarrhea (7.1%), and vomiting (3.6%). Elevated alanine aminotransferase and aspartate aminotransferase levels were observed in 9/35 patients (25.7%) and 10/51 (19.6%) patients, respectively. Five cases of breakthrough fungal infection were identified (8.9%).

CONCLUSIONS

Patients younger than 13 years who received PP showed an increase in transaminase values, and the development of breakthrough fungal infections.