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 AUC_τ and C_max, 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.