Bosentan in Systemic Sclerosis

The effect of bosentan on digital ulcers (DU) was studied in two randomized placebo-controlled trials (RAPIDS-1 and RAPIDS-2). A limitation of these studies was the heterogeneous study population. More importantly, there were no endpoints that assessed changes in vasculopathy and / or perfusion. Laser Doppler imaging has been shown to effectively demonstrate blood flow restrictions in the hands of patients with Systemic Sclerosis (SSc). The relation between blood flow restriction in the hands measured by laser Doppler imaging and the extent of DU disease has not been studied. The current study will attempt to demonstrate this relation. In addition, the impact of bosentan on the blood flow in the hands, in a defined cohort of SSc-DU patients with a history of DU within the past 2 years and a clinically relevant reduction of blood flow in the hands, will be assessed.