Patients will be recruited into double blind randomized trial of riociguat with 1:1 active drug to placebo. The table below summarizes the study design. Patients will have previously undergone right heart catheterization (RHC) within six months of initial dose dispensation and with no significant change in treatment for pulmonary hypertension.
Patients will initiated on 0.5 mg tid and titrated every 2 weeks to a maximum of 2.5 mg three times a day. The patient will be treated for 48 weeks or until clinical worsening of disease. An adjudication committee will review all cases of clinical worsening. This committee will be blinded to treatment. The determination by the adjudication committee will be used as the final determinant for the primary end point.