Riociguat Clinical Effects Studied in Patients With Insufficient Treatment Response to Phosphodiesterase-5 Inhibitor

Inclusion Criteria: * Male or female patients (18 -75 years of age) with idiopathic, familial, drug/toxin induced and associated PAH due to congenital heart disease (Group I / Dana Point Classification of PH) demonstrating insufficient response to treatment with PDE-5i for at least 3 months * Patients with and without endothelin receptor antagonist (ERA) therapy * World Health Organization Functional Class (WHO FC) III at screening * 6-minute walking distance (6MWD) of 165-440 m * Cardiac index \<3.0 L/min/m\*2. Exclusion Criteria: * All types of PH except subtypes of Dana Point Group I specified in the inclusion criteria * Evidence of clinically significant restrictive or obstructive parenchymal lung diseases * Diffusing capacity of the lung for carbon monoxide (DLCO) \<30% predicted * History or active state of serious hemoptysis / pulmonary hemorrhage including those managed by bronchial artery embolization * Patients unable to perform a valid 6MWD test * Pregnant women (i.e. positive pregnancy test or other signs of pregnancy), or breast feeding women, or women with childbearing potential not using a combination of 2 effective methods of birth control, for example a combination of condoms with a safe and highly effective contraception method (prescription oral contraceptives, contraceptive injections, contraceptive patch, intrauterine device) or a double barrier method is used throughout the study.