Effect of treatment with ambrisentan in patients with systemic sclerosis and mild pulmonary arterial hypertension: long-term follow-up data from EDITA study

<bold>Objective:</bold> In this trial, patients with systemic sclerosis (SSc) and mild pulmonary vascular disease (PVD) treated with ambrisentan had a significant decline of pulmonary vascular resistance (PVR) but not of mean pulmonary arterial pressure (mPAP) vs. placebo after 6 months. This EDITA-ON study aimed to assess long-term effects of open label therapy with ambrisentan vs. no pulmonary arterial hypertension (PAH) therapy. <bold>Methods:</bold> Patients who participated in the EDITA study and received regular follow-up were included in EDITA-ON. Clinical data and hemodynamics during follow-up were analysed. The primary endpoint was to assess whether continued treatment with ambrisentan vs. no treatment prevented the development of PAH according to the new definition. <bold>Results:</bold> Of the 38 SSc patients included in the EDITA study four were lost to follow-up. Of the 34 remaining patients (age 55±11 years, 82.1% female subjects), 19 received ambrisentan after the termination of the blinded phase, 15 received no PAH medication. The mean follow-up time was 2.59±1.47 years, during which 29 patients underwent right heart catheterization. There was a significant improvement of mPAP in catheterised patients receiving ambrisentan vs. no PAH treatment (1.53±2.53 vs 1.91±2.98 mmHg, p=0.003). In patients without PAH treatment 4/12 patients newly developed PAH vs. 0/17 of patients receiving ambrisentan (p<0.0001). <bold>Conclusion:</bold> In SSc patients with early PVD, the development of PAH and/or deterioration was less frequent among patients receiving ambrisentan, indicating that early treatment and close follow-up could be beneficial in this high-risk group.