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

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
• •History of hepatitis B, hepatitis C, or HIV infection
• •Any medical condition that, in the opinion of the investigator, might interfere with the subject's participation in the study or poses an added risk for the subject
• •Inability to comply with study and follow-up procedures
• •Transaminase elevation \> 3X the upper limit of normal at screening
• •Hemoglobin less than 8.5 g/dL
• •Platelet count less than 100 X 109/L
• •White blood cell count less than 3.0 X 109/L
• •Serum creatinine less than 2.0 mg/dL