Abstract
Venous thromboembolism (VTE) is more frequent in infants than in older children. Treatment
guidelines in children are adapted from adult VTE data, but do not currently include
direct oral anticoagulant use. Dabigatran etexilate (DE) use in the paediatric population
with VTE therefore requires verification. We investigated the pharmacokinetic/pharmacodynamic
(PK/PD) relationship, safety and tolerability of DE oral liquid formulation (OLF)
in infants with VTE (aged < 12 months) who had completed standard anticoagulant treatment
in an open-label, phase IIa study. Patients received a single-dose of DE OLF (based
on an age- and weight-adjusted nomogram) yielding an exposure comparable to 150 mg
in adults. The PK end point was plasma concentration of total dabigatran; PD end points
included activated partial thromboplastin time (aPTT), ecarin clotting time (ECT)
and diluted thrombin time (dTT). Safety end points included incidence of all bleeding
and other adverse events (AEs). Ten patients were screened; eight entered the study
(age range, 41–169 days). The geometric mean (gMean) total dabigatran plasma concentrations
2 hours post-dose (around peak concentrations) were 120 ng/mL with a geometric coefficient
of variation (gCV) of 62.1%. The gMean at 12 hours post-dosing was 60.4 ng/mL (gCV
30%). PK/PD relationship was linear for ECT and dTT (R
2 = 0.858 and 0.920, respectively), while total dabigatran concentration and aPTT showed
a non-linear correlation. There were no deaths, treatment discontinuations or treatment-related
AEs. In conclusion, DE was well tolerated without any treatment-related AEs in infants.
The observed PK/PD relationships were comparable with the established profile in older
patients with VTE.
Keywords
dabigatran etexilate - paediatrics - pharmacokinetics - pharmacodynamics - venous
thromboembolism
