Efficacy and Safety of Riociguat in Patients With Systemic Sclerosis

Inclusion Criteria: * Men or women aged 18 years and older * Systemic sclerosis, as defined by ACR/EULAR (American College of Rheumatology/European League Against Rheumatism) 2013 criteria * dcSSc (diffuse cutaneous systemic sclerosis) according to the LeRoy criteria, ie, skin fibrosis proximal to the elbows and knees in addition to acral fibrosis * Disease duration of ≤ 18 months (defined as time from the first non-Raynaud's phenomenon manifestation) * ≥ 10 and ≤ 22 mRSS (modified Rodnan skin score) units at the screening visit * FVC (forced vital capacity) ≥ 45% of predicted at screening * DLCO (diffusion capacity of the lung for carbon monoxide) ≥ 40% of predicted (hemoglobin-corrected) at screening * Negative serum pregnancy test in a woman of childbearing potential at the screening visit * Women of childbearing potential must agree to use adequate contraception when sexually active. "Adequate contraception" is defined as any combination of at least 2 effective methods of birth control, of which at least 1 is a physical barrier (e.g. condom with hormonal contraception like implants or combined oral contraceptives, condom with intrauterine devices). This applies since signing of the informed consent form until 30 (+5) days after the last study drug administration. Exclusion Criteria: * Limited cutaneous SSc (systemic sclerosis) at screening * Major surgery (including joint surgery) within 8 weeks prior to screening * Hepatic insufficiency classified as Child-Pugh C * Patients with isolated AST or ALT \>3xULN or bilirubin \>2xULN can be included in the trial under the condition of additional monitoring during the trial * Estimated glomerular filtration rate (eGFR) \< 15 mL/min/1.73 m\^2 (Modification of Diet in Renal Disease formula) or on dialysis at the screening visit. Patients entering the trial with eGFR 15-29 mL/min/1.73 m\^2 will be undergo additional monitoring of renal function * Any prior history of renal crisis * Sitting SBP (systolic blood pressure) \< 95 mmHg at the screening visit * Sitting heart rate \< 50 beats per minute (BPM) at the screening visit * Left ventricular ejection fraction \< 40% prior to screening * Any form of pulmonary hypertension as determined by right heart catheterization * Pulmonary disease with FVC \< 45% of predicted or DLCO (hemoglobin-corrected) \< 40% of predicted at screening * Active state of hemoptysis or pulmonary hemorrhage, including those events managed by bronchial artery embolization * Not permitted prior and concomitant medication * Pregnant or breast feeding women * Women of childbearing potential not willing to use adequate contraception and not willing to agree to 4-weekly pregnancy testing from Visit 1 (first administration of study drug) onwards until 30 (+5) days after last study drug intake.