WAYNE, N.J., April 8, 2013 /PRNewswire/ -- Bayer HealthCare announced today that the New Drug Application (NDA) for its oral investigational compound riociguat has been accepted for filing and granted priority review by the U.S. Food and Drug Administration (FDA) for the treatment of inoperable chronic thromboembolic pulmonary hypertension (CTEPH) or with persistent or recurrent CTEPH after pulmonary endarterectomy (PEA) and pulmonary arterial hypertension (PAH). Both CTEPH and PAH are life-threatening diseases. CTEPH is a form of pulmonary hypertension in which blood clots and thromboembolic occlusion of pulmonary vessels leads to increased pressure in the pulmonary arteries. PAH is a disease characterized by elevated pressure in the pulmonary arteries. "We are pleased that the FDA has granted priority review of the riociguat NDA for two distinct forms of pulmonary hypertension," said Pamela A. Cyrus, MD, Vice President and Head of U.S. Medical Affairs, Bayer HealthCare Pharmaceuticals. "This milestone reinforces our commitment to advancing treatment options for cardio-pulmonary diseases, and brings us one step closer to potentially providing the first pharmacological treatment for inoperable or persistent/recurrent CTEPH and a new treatment option for PAH." The FDA grants priority review to medicines that provide a treatment where little or no adequate therapy exists. Under the Prescription Drug User Fee Act (PDUFA), the FDA aims to complete its review within six months of the 60-day filing receipt of the NDA submission (eight months total), rather than the standard 12-month review cycle. The NDA submission is supported by data from two global Phase III studies of riociguat CHEST-1 and PATENT-1. Data from these two studies were presented in October 2012 at CHEST, the annual meeting of the American College of Chest Physicians (ACCP). Both Phase III studies on riociguat met their primary endpoint. About CHEST CHEST (Chronic Thromboembolic Pulmonary Hypertension sGC-Stimulator Trial) is a Phase III trial to assess the efficacy and safety of oral riociguat in the treatment of patients with either inoperable CTEPH or CTEPH which has persisted or reoccurred after pulmonary endarterectomy (PEA). CHEST is a multi-center, multi-national program with active centers in 26 countries. The program includes a randomized, double-blinded, placebo-controlled trial phase (CHEST-1) and an open label extension trial phase (CHEST-2). In the CHEST-1 study, 261 patients with inoperable CTEPH or with persistent or recurrent CTEPH after PEA were randomized and treated with either riociguat or placebo orally for 16 weeks. The primary endpoint of the trial was improvement in 6-minute walking distance. Riociguat was titrated, over a period of eight weeks in doses of 0.5 mg increments, from 1.0 mg up to 2.5 mg, three times a day. After the titration phase, patients were followed up for another eight weeks on their last dose to complete CHEST-1. Patients from both arms then had the option of participating in the open label extension study (CHEST-2) after completing an eight-week blinded sham titration. CHEST-2 is continuing to investigate riociguat in CTEPH patients.