The AMBITION trial revealed lower risk of clinical failure events with ambrisentan and tadalafil combination as compared to monotherapy alone in adults. We aimed to describe the safety and efficacy of this combination therapy in children with PAH.
Retrospective observational study including children from 2 Pediatric PAH Centers. Demographics, symptoms, exercise capacity, hemodynamics, biomarkers, and adverse effects were collected at baseline (before start of ambrisentan and tadalafil) and early and late follow up. Wilcoxon matched-pairs signed-rank tests were used to test for statistical significance. Patients either switched from a different dual PDE5+ERA combination (group A) or received no prior PAH therapy or monotherapy(group B).
There were 29 subjects, 16F,13M; ages(6.5-13.5y median 10) with Group I PAH. All subjects reported improvement in symptoms. Statistically significant improvements in 6MWD and hemodynamics were seen at early and late follow up (14-23 months, median 19) in the entire sample and Group B (table 1). WHO FC improved in 41% and was unchanged in 59%. Two discontinued tadalafil due to headaches and none due to lack of clinical efficacy.
Combination therapy with ambrisentan and tadalafil was associated with improvement in exercise capacity and hemodynamics in children as compared to monotherapy, and had an acceptable safety profile. Based on these early data, further study of combination therapy in pediatric PAH is warranted.