Study of Ambrisentan With Antifibrotic Agent Combination Therapy in Diffuse Systemic Sclerosis

Systemic sclerosis is a chronic autoimmune connective tissue disorder with no universally accepted disease modifying regimen. Recruiting patients for systemic sclerosis treatment studies is difficult due to the limited availability of such patients and furthermore the use of a placebo arm is often deemed unethical due to the poor survival of diffuse systemic sclerosis patients. Long-term controlled trials examining functional outcomes and survival from novel therapeutic agents for systemic sclerosis are often difficult to undertake because of costs, rarity of the disease and ethical issues with the use of a true placebo. Open label single center studies while inferior to multicenter placebo controlled studies, have helped establish the benefits of certain pharmaceutical agents in systemic sclerosis, and while not universally accepted as disease modifying agents, have been used with some success to treat systemic sclerosis. The hypothesis on which we are basing this study is that an endothelin receptor antagonist and disease modifying agent with antifibrotic properties will have additive influence on fibrosis, inhibit cellular and humoral hyperactivity and interfere with smooth muscle proliferation in the vessel wall. The combination of these two agents will also be the first regimen to address the heterogeneity of scleroderma manifestations including ILD, pulmonary arterial hypertension and skin manifestations