The impact of co-morbidity in childhood cystic fibrosis

Posaconazole Tablets in Real-Life Lung Transplantation: Impact on Exposure, Drug-Drug Interactions, and Drug Management in Lung Transplant Patients, Including Those with Cystic Fibrosis

Appropriate exposure to posaconazole (PSZ) has been limited until the recent approval of the delayed-release oral tablet formulation. Our goal was to determine the exposure obtained by using the standard dose of 300 mg once a day in lung transplant (LT) patients, including patients with cystic fibrosis (CF). PSZ trough concentrations (C0) were determined using a liquid chromatography-tandem mass spectrometry assay. Indicative thresholds of interest were <0.7 mg/liter for prophylaxis and 1 to 3 mg/liter for cure. The tacrolimus (TRL) and everolimus (ERL) C0 measured during PSZ exposure were also collected. The interaction with proton-pump inhibitors (PPI) was evaluated. We recorded the results for 21 CF patients with LT (CFLT patients), 11 non-CF patients with LT (NCFLT patients), and 27 nontransplant (NT) patients in pneumology departments. The weights of the NCFLT, CFLT, and NT patients were 59.2 ± 8.4, 48.8 ± 8.4, and 63.7 ± 16.6 kg, respectively (P = 0.001* [asterisk means that statistical test is significant]), and the PSZ C0 exposures for these patients were 1.9 ± 1.5, 1.1 ± 0.8, and 2.4 ± 1.8 mg/liter, respectively (P < 0.00001*). More than 60% of the concentrations were in the therapeutic range. In CFLT patients, the administration of one 300-mg PSZ tablet quickly achieved an exposure similar to that achieved with the PSZ oral suspension formulation (OSF) administered 3 or 4 times a day for several months. The TRL C0/dose ratio (C0/D) was 7.4 ± 4.4 mg/liter with PSZ tablets, whereas it was 4.6 ± 0.8 mg/liter with the PSZ oral solution (P = 0.034*). The ERL C0/D was similar with both formulations. PPI had no impact on the PSZ concentration (1.49 ± 1.07 mg/liter without PPI versus 1.33 ± 1.17 mg/liter with PPI; P = 0.4134*). Despite the high levels of exposure, PSZ remained well tolerated (one case of diarrhea and one case of fatigue were reported). PSZ tablet administration allows satisfactory exposure, even in CFLT patients, with a dosage lower than that of the PSZ OSF. This once-a-day formulation was not impacted by PPI, which are extensively used in CF patients.