A Study to Evaluate the Efficacy of an Oral Medication in the Treatment and Prevention of Digital Ulcers in Patients With Systemic Sclerosis (Scleroderma).

Inclusion Criteria: * Diagnosis of limited or diffuse systemic sclerosis (SSc) according to American College of Rheumatology or LeRoy criteria * Age greater than 18 years of age * At least one digital ulcer located on the volar or lateral surface at or distal to the proximal interphalangeal joints * At least one new DU that developed within 12 weeks prior to screening * Vasodilator therapies, including calcium channel blockers, alpha-1-antagonists, ACE-inhibitors, nitroglycerin, and angiotensin receptor blockers, are permitted as long as the doses are stable for 2 weeks prior to screening and throughout the study * Treatment with omeprazole or other proton pump inhibitors must be stable for 2 weeks prior to screening and throughout the study Exclusion Criteria: * Patients with pulmonary arterial hypertension, NYHA Class III or IV * Patients who are hemodynamically unstable, or have acute renal, cardiac or pulmonary failure * Concurrent malignancy except non-melanoma skin cancers * Patients who have required systemic antibiotics for infected digital ulcers within 2 weeks of screening * Patients receiving phosphodiesterase-5 inhibitors, endothelin receptor antagonists, or prostanoids within 4 weeks of screening * Patients receiving cyclosporine within 6 weeks of screening * Patients who have participated in any investigational study within 30 days of screening * Pregnant or nursing women * Patients with a history of drug or alcohol abuse within 6 months of screening * Histor…