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Sustained Symptomatic, Functional, and Hemodynamic Benefit With the Selective Endothelin-A Receptor Antagonist, Sitaxsentan, in Patients With Pulmonary Arterial Hypertension

A 1-Year Follow-up Study

      Study objectives:

      To examine the long-term efficacy and safety of the selective endothelin-A receptor (ET-A) antagonist, sitaxsentan sodium, after 1 year of therapy in patients with pulmonary arterial hypertension (PAH).

      Design:

      The study was a Canadian, open-label extension of at least 1-year total of active therapy (sitaxsentan, 100 mg/d), following a preceding, blinded, 12-week placebo controlled trial of sitaxsentan (placebo, or sitaxsentan, 100 mg/d or 300 mg/d), which had then been followed by a blinded active-therapy continuation study (sitaxsentan, 100 mg/d or 300 mg/d).

      Patients:

      Eleven patients with PAH were enrolled. The condition of one patient worsened at 7 months of therapy, and the patient transferred to epoprostenol therapy. The remaining 10 patients (idiopathic [n = 3], connective tissue disease [n = 3], congenital heart disease [n = 4]) completed the evaluation after 1 year of active therapy.

      Interventions:

      The end points of the study included the 6-min walk test, World Health Organization (WHO) functional class, and cardiopulmonary hemodynamic parameters.

      Results:

      After 1 year of sitaxsentan therapy, there were significant improvements in 6-min walk distance (50-m treatment effect), WHO functional class, and hemodynamics, as compared to baseline. There were no serious adverse events, and no instances of hepatotoxicity or bleeding.

      Conclusion:

      Long-term selective ET-A blockade with sitaxsentan sodium is safe and may improve exercise capacity, functional class, and hemodynamics in patients with PAH.

      Key words

      Abbreviations:

      CI (confidence interval), CTD (connective tissue disease), ET (endothelin), ET-A (endothelin-A receptor), ET-B (endothelin-B receptor), PAH (pulmonary arterial hypertension), PH (pulmonary hypertension), Ppa (pulmonary arterial pressure), PVR (pulmonary vascular resistance), STRIDE (Sitaxsentan To Relieve Impaired Exercise), WHO (World Health Organization)
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