Comparative adherence of macitentan versus ambrisentan and bosentan in Australian patients with pulmonary arterial hypertension: a retrospective real-world database study.

Aim: Bosentan, ambrisentan, and macitentan are endothelin receptor antagonists (ERAs), currently available in Australia for treatment of pulmonary arterial hypertension (PAH). This study assessed the comparative adherence of these ERAs for PAH in Australian patients.

Methods: This retrospective, observational study used data for adults with PAH from the Services Australia 10% Pharmaceuticals Benefits Scheme (PBS) dataset (01/2006-10/2020). The primary outcome was treatment adherence (i.e. receiving ≥80% of ERA doses over 12 months). Secondary outcomes were time to treatment change (add-on or switch) and overall survival.

Results: The study included 436 patients who took bosentan (n = 200), ambrisentan (n = 69), or macitentan (n = 167). Treatment adherence was significantly greater in patients who received macitentan (65.3%) versus ambrisentan (56.5%) and bosentan (58.0%), with odds ratios (ORs; 95% CI) of 0.51 (0.30-0.88; p = 0.016) for bosentan versus macitentan and 0.48 (0.24-0.96; p = 0.037) for ambrisentan versus macitentan. The median time to treatment change was 47.2 and 43.4 months for bosentan and ambrisentan, respectively (not calculated for macitentan because of insufficient duration of data).

Limitations and conclusions: Real-world data for Australian patients with PAH showed that treatment adherence for ERAs was suboptimal. Adherence was higher for macitentan compared with ambrisentan and bosentan.