Phase II study results of riociguat for CTEPH and PAH published online

Bayer HealthCare Pharmaceuticals, Inc. today announced that the study "Riociguat for chronic thromboembolic pulmonary hypertension and pulmonary arterial hypertension: a phase II study" was published online this week by the European Respiratory Journal.  Results of this study to assess the safety, tolerability and the feasibility of individual dose titration of riociguat were previously presented at the 2009 International Conference of the American Thoracic Society.

Chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH) are two debilitating forms of pulmonary hypertension (PH) with low survival rates.  Riociguat (BAY 63-2521) is an investigational oral agent being studied for the potential treatment of PH that targets soluble guanylate cyclase (sGC), a receptor for nitric oxide (NO).  

According to the published results, 96 percent of the patients enrolled completed the study, and the majority of patients (72 percent) were able to be titrated from the starting dose of 1 mg t.i.d. by 0.5 mg increments every two weeks to a maximum target dose of 2.5 mg t.i.d.  Sixty-five patients (87 percent) who received at least one dose of riociguat reported an adverse event (AE), including 11 serious adverse events (SAE).  Adverse events were judged to be drug-related in 42 patients (56 percent), and most (96 percent) were considered mild or moderate in severity.  The incidence of AEs was not considered related to the dose of riociguat.  Dyspepsia, headache and hypotension were the most-frequently reported adverse events (AEs), and three participants (4 percent) discontinued the study because of AEs (two due to SAEs; one with pulmonary edema related to pulmonary venous occlusive disease and one with progressive right heart failure).  The publication also describes the effects of riociguat on secondary pharmacodynamic endpoints.

"Pulmonary hypertension is a severe and life-threatening disease that progresses rapidly and, despite advances in patient care over the last few years, there is a real need for additional therapies," said lead investigator Prof. Hossein Ardeschir Ghofrani, Head of the Pulmonary Hypertension Division, Department of Internal Medicine, University of Giessen, Germany. "These preliminary findings support further research and randomized clinical trials to determine the efficacy and safety of riociguat as a potential treatment for these forms of pulmonary hypertension are underway."