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

Background: In the EDITA 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 six months. The EDITA-ON study aimed to assess long-term effects of open label therapy with ambrisentan vs. no pulmonary arterial hypertension (PAH) therapy.

Methods: Patients who participated in the EDITA study and received regular follow-up were included in EDITA-ON. Clinical, echocardiographic, laboratory, exercise and hemodynamic parameters 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.

Results: Of 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 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 6/12 patients had PAH vs. 1/17 of patients receiving ambrisentan (p < 0.0001).

Conclusion: 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. Future trials in this field are needed to confirm these results.