Impact of Multiple Doses of BAY63-2521 on Safety, Tolerability, Pharmacokinetics and Pharmacodynamics in Patients With Interstitial Lung Disease (ILD) Associated Pulmonary Hypertension (PH)

Inclusion Criteria: * Diagnosis of an interstitial lung disease (usual interstitial pneumonia \[UIP\], nonspecific interstitial pneumonia \[NSIP\] or sarcoidosis) with high resolution CT and a total lung capacity (TLC) ≤ 90% or scleroderma associated pulmonary arterial hypertension (PAH) with total lung capacity (TLC) ≤ 80%. * Interstitial lung disease (ILD) must have been stable for at least 3 months (decrease in forced vital capacity (FVC)\< 10% and diffusing capacity of lung for carbon monoxide (DLco) \< 15 % in 3 months), i.e. no significant changes in pulmonary function testing and stable medication in terms of ILD (e.g., corticosteroids, immunosuppressants) * Mean pulmonary vascular resistance (PVR) \> 400 dyne sec cm-5 or mean pulmonary arterial pressure (PAP mean) \> 30 mmHg * Pulmonary capillary wedge pressure (PCWP) \< 15 mmHg * Hemodynamic parameters at baseline (PAP, PCWP, cardiac output \[CO\], systemic mean arterial pressure \[SAP\]) * High resolution computer tomography (HRCT) (should not be older than 12 months prior start of the study) * Heart rate \> 55 beats per minute (BPM) and \< 105 BPM at rest * Systolic blood pressure (SBP) \> 90 mmHg * World Health Organisation (WHO) functional class II, III and IV * 6 Minute Walking Test (6MWT) \> 100m and \< 450 m * Stable controlled arterial hypertension according to current guidelines * Women of childbearing potential will be included in the study if the pregnancy test is negative and combination of condoms with a safe and highly effective contraception method (hormonal contraception with implants or combined oral contraceptives, certain intra-uterine devices \[IUDs\]) is granted. Exclusion Criteria: * Co-medication: * Patients pretreated with specific medication for pulmonary arterial hypertension (PAH) like endothelin receptor antagonists, prostaglandins or phosphodiesterase type 5 (PDE 5) blockers are excluded from the trial. * Requirement for concomitant use of nitrates are contraindicated. * Pre-existing clinically relevant lung disease other than ILD including. * Bronchial asthma and Chronic Obstructive Pulmonary Disease (COPD) with a forced expiratory volume in one second (FEV1)/FVC \<60% pred., active tuberculosis * Pulmonary hypertension of another WHO group (I, II, IV and V) * Severe congenital abnormalities of the lungs, thorax and diaphragm * Clinical or radiological evidence of a pulmovenoocclusive disease (PVOD) * Systemic hemodynamics * Acute or severe chronic left heart failure (ejection fraction (EF) \< 50%) * Severe coronary artery disease (CAD; EF \< 50%); CAD patients must be asymptomatic and stable * Congenital or acquired valvular or myocardial disease if clinically significant apart from tricuspid valvular insufficiency due to pulmonary hypertension * Pulmonary function * TLC predicted \< 30% * FEV1 (related to FVC) \< 60% predicted * Blood gases at room air * Arterial partial carbon dioxide pressure (Pa CO2) \> 45 mmHg * Arterial partial oxygen pressure (Pa O2) \< 50 mmHg at O2 supply \>/= 4 L/min * Peripheral organ function * Moderate or severe hepatic insufficiency (Child-Pugh Class Band C and/or total bilirubin \> 2.5 mg/dl (0.043 mmol/L); and/or hepatic transaminases \>3 upper limit normal \[ULN\]) * Moderate or severe renal insufficiency (creatinine \> 2 mg/dl) or creatinine clearance according to Cockroft-Gault formula \< 35 mL/ min