Dimethyl Fumarate (DMF) in Systemic Sclerosis-Associated Pulmonary Arterial Hypertension

Inclusion Criteria: 1. Signed inform consent prior to any study-mandated procedures 2. Adult patients 18-80 years of age 3. World Health Organization Group 1 PAH associated with scleroderma (SSc-PAH) 4. WHO functional Class II-III 5. 6MWD 150 to 450 meters 6. Right heart catheterization demonstrating mPAP≥ 25 mmHg and PCWP or left ventricular end diastolic pressure ≤15mm Hg and pulmonary vascular resistance ≥240 dynes/cm-5 (3 Wood units) within 12 weeks prior to study entry. 7. ACR defined systemic sclerosis Exclusion Criteria: 1. Pulmonary hypertension associated with * PAH of any etiology other than scleroderma * PH of any etiology other than WHO Group I PAH * Pulmonary venous hypertension defined as PCWP or LVEDP \>15 mHg * Untreated sleep apnea with AHI \>20 or SaO2 Nadir \<87% * Chronic thromboembolic disease * Sarcoidosis 2. Participation in a clinical investigational study within the previous 30 days 3. Moderate to severe hepatic impairment (e.g., Child-Pugh Class B or C) 4. Renal failure defined as: * estimated creatinine clearance \<30 m/min * serum creatinine\>2.5 mg/dl 5. Serum aspartate aminotransferase (AST) and or alanine aminotransferase (ALT) \> 1.5 times the upper limit of normal 6. Systolic blood pressure \< 90mmHg 7. Recently started (\< 8 weeks prior to randomization) or planned cardiopulmonary rehabilitation program based on exercise 8. Pregnant or lactating women 9. Need for HAART therapy 10. Planned treatment or treatment with another investigational drug within 1 month prior to start 11. Moderate to severe interstitial lung disease, defined by FVC \< 80% or evidence on HRCT of fibrosis or ground glass changes involving more than 30% of lung parenchyma