Based on positive phase-II trial findings, Bayer Schering Pharma will move into phase-III trials with its oral agent riociguat (BAY 63-2521). Riociguat is the first member of a new class of vasodilating agents called soluble guanylate cyclase (sGC) stimulators. It is being investigated as a new approach for the treatment of different forms of pulmonary hypertension. Riociguat demonstrated significantly improved exercise capacity in a phase-II study in patients with chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH) as compared to baseline values. The phase-III programme for these indications is planned to be initiated in late 2008.

Top-line findings from the open-label, uncontrolled phase-II study were presented today during a Bayer Schering Pharma satellite symposium at the Annual Congress of the European Respiratory Society (ERS) in Berlin, Germany. In addition to significantly increased exercise capacity, patients improved as well in terms of hemodynamic parameters such as pulmonary vascular resistance, cardiac output and pulmonary arterial pressure in comparison to baseline values. The study also showed that riociguat was well tolerated and had a favourable safety profile. Further data from the study are planned to be presented at the American Thoracic Society (ATS) International Conference in May 2009, in San Diego, California, USA.

"Riociguat has the potential to overcome limitations of current standards of care in pulmonary hypertension," said Kemal Malik, head of Global Development and member of the executive committee of Bayer HealthCare. "We are expanding into areas of high unmet medical need and riociguat is an example of the kind of novel approach to treating cardiovascular disease to which Bayer is committed."

"Pulmonary hypertension is a life threatening disease and the majority of patients are still left without a viable treatment option," said lead investigator Prof Hossein Ardeschir Ghofrani, head of the Pulmonary Hypertension Division, Department of Internal Medicine, University of Giessen, Germany. "We are very encouraged by the beneficial effects of riociguat in our study. If these findings are replicated in the upcoming Phase III trials, it will be good news indeed for patients with pulmonary hypertension and the physicians who treat them."

In addition to the completed phase-II study and the two phase-III trials in CTEPH and PAH about to begin, further phase-II studies of riociguat are underway in patients suffering from other forms of pulmonary hypertension (PH) such as PH in patients with interstitial lung disease (PH-ILD) or PH in patients with chronic obstructive pulmonary disease (PH-COPD). First results from these studies are currently expected for 2011 and 2009, respectively.

Riociguat is a member of a novel class of therapeutics called soluble guanylate cyclase (sGC) stimulators, and is being investigated as a new approach for the treatment of CTEPH and PAH, as well as other forms of PH.