Bayer Announces Start of Riociguat Phase 3B Study In PAH Patients

Bayer HealthCare announced the enrollment of the first patient in the open label, multi-center, multinational Phase III B pilot study evaluating riociguat in patients with pulmonary arterial hypertension (PAH) who have insufficient response to treatment with PDE-5i inhibitors.

The drug has previously shown robust efficacy compared against phosphodiesterase-5 inhibitors (PDE-5i) in the pivotal Phase III clinical trial. In the current Phase IIIB study labeled RESPITE (Riociguat clinical Effects Studied in Patients with Insufficient Treatment response to PDE-5 inhibitors) riociguat will be specifically assessed in patients either as a monotherapy or combined with an endothelin receptor antagonist (ERA).

Dr. Joerg Moeller, Member of the Bayer HealthCare Executive Committee and Head of Global Development, said that the drug has potential advantages over traditional PDE-5 inhibitors. Riociguat, approved under the brand name Adempas in the U.S., offers a new mode of action for pulmonary hypertension (PH) that is unique from PDE5-inhibitors which may have an additive effect on systemic blood pressure. The drug is a soluble guanylate cyclase (sGC) stimulator discovered and developed by Bayer as an oral treatment to home in on a key molecular mechanism underlying pulmonary hypertension.

Pulmonary hypertension is a severe, progressive, and potentially lethal disorder of the heart and lungs in which the pulmonary artery blood pressure is above normal. Patients with PH suffer decreased exercise capacity and reduced quality of life. Pulmonary arterial hypertension is a type of PH in which the blood pressure in the pulmonary arteries is markedly increased due to vasoconstriction. Similar to PH, this can lead to heart failure and death. The disease is rare and afflicts an estimated 15 to 52 people per one million worldwide.

The European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) has given a positive opinion for riociguat in two forms of pulmonary hypertension: pulmonary arterial hypertension and chronic thromboembolism pulmonary hypertension. The company has already secured approval for the drug in the two indications from the FDA in October 2013.