Bosentan Pharmacokinetics in Pediatric Patients with Pulmonary Arterial Hypertension: Comparison of Dried Blood Spot and Plasma Analysis.

FUTURE-3, a phase III pediatric pharmacokinetic (PK) trial conducted to compare 2 bosentan dosing regimens in 64 patients with pulmonary arterial hypertension, offered the opportunity to compare dried blood spot (DBS)-derived data to plasma data. Bosentan PK parameters obtained with both methods were compared by the geometric mean ratio (GMR; DBS/plasma) and its 90% CI after correction for the blood-to-plasma partition ratio (0.6). Bosentan GMRs were 1.10 (1.03, 1.16) and 1.12 (1.04, 1.20) for AUCτ and Cmax, respectively. Bosentan concentrations measured by DBS were therefore good estimations of bosentan plasma concentrations. DBS can be considered a valid alternative to bosentan assessed in plasma.