Pharmacokinetics and safety of posaconazole intravenous solution and powder for oral suspension in children with neutropenia: an open-label, sequential dose-escalation trial

Abstract

Posaconazole is approved for use in adults as an intravenous (IV) solution and two different oral formulations (a suspension and an improved bioavailability tablet). Data on the pharmacokinetics (PK), dosing and safety of posaconazole in children are limited. A novel powder for oral suspension (PFS) offers the bioavailability of the tablet formulated for weight-based dosing in children. A non-randomised, open-label, sequential dose-escalation, phase 1b trial evaluated the PK and safety of posaconazole IV and PFS in children aged 2 to 17 years with documented or expected neutropenia (ClinicalTrials.gov, NCT02452034; MSD protocol number, MK-5592-P097). Participants received posaconazole IV 3.5, 4.5 or 6.0 mg/kg/d for ≥10 days, with an option to switch to posaconazole PFS at the identical dose for ≤18 days. The target exposure was a mean within-dose cohort average steady-state plasma concentration (Cavg) of ~1200 ng/mL, with ~90% of participants achieving Cavg between 500 and 2500 ng/mL. Doses of 4.5 and 6.0 mg/kg/d achieved the PK target of ~90% of participants with a Cavg ≥500 ng/mL. PFS resulted in lower posaconazole exposures than IV across age groups at all doses. Posaconazole IV and PFS were well tolerated and had safety profiles similar to those reported for adults. Posaconazole PK following IV and PFS administration was well characterised by the data and enable selection of appropriate paediatric doses. Both formulations were well tolerated without dose-, exposure- or age-related differences in the safety profiles.