Riociguat launched for pulmonary hypertension
Bayer has launched riociguat in the UK, a new medicine indicated for both chronic thromboembolic pulmonary hypertension and pulmonary arterial hypertension. Both conditions are characterised by increased blood pressure in the arteries of the lungs which can cause symptoms such as breathlessness and fatigue and can be life-threatening.
Riociguat is a soluble guanylate cyclase stimulator, a new class of medicines. It stimulates the same cell-signalling pathway as the vasodilator nitric oxide. Riociguat will be marketed as Adempas.
Current routine treatment for chronic thromboembolic pulmonary hypertension is pulmonary endarcterectomy — surgical removal of blood clots in the arteries of the lungs. However, riociguat can now be prescribed for patients in whom surgery is not appropriate or who have not responded to pulmonary endarcterectomy. It can also be prescribed for pulmonary arterial hypertension, including heritable or idiopathic forms or when associated with connective tissue disease. The medicine is used to improve exercise capacity — both sets of patients need to be within WHO functional class II or III (see Panel below).
World Health Organization functional classification
Class I: Patients with pulmonary hypertension (PH) but without resulting limitation of physical activity. Ordinary physical activity does not cause undue dyspnoea or fatigue, chest pain or near syncope.
Class II: Patients with PH resulting in slight limitation of physical activity. They are comfortable at rest. Ordinary physical activity causes undue dyspnoea or fatigue, chest pain or near syncope.
Class III: Patients with PH resulting in marked limitation of physical activity. They are comfortable at rest. Less than ordinary activity causes undue dyspnoea or fatigue, chest pain or near syncope.
Class IV: Patients with PH with inability to carry out any physical activity without symptoms. These patients manifest signs of right-heart failure. Dyspnoea or fatigue, or both, may be present at rest. Discomfort is increased by any physical activity.
In two phase III studies, riociguat significantly improved exercise capacity compared with placebo. In addition, it improved pulmonary vascular resistance and WHO functional class.
The European Medicines Agency found there to be a favourable benefit-to-risk ratio when it assessed the medicine. However, it pointed out a number of adverse events that were “of concern”, including haemoptysis, pulmonary haemorrhage and renal impairment. The most common side effects were headache, hypotension, gastrointestinal adverse events, dizziness and peripheral oedema.
It is noted in the summary of product characteristics that patients who smoke have lower absorption of riociguat and so dose adjustment may be necessary for patients who start or stop smoking during treatment.
Action: Activates nitric oxide cell signalling pathway that causes vasodilation — it directly stimulates soluble guanylate cyclase and increases its sensitivity to nitric oxide.
Dose: Recommended starting dose is 1mg three times daily for two weeks. Dose should be increased by 0.5mg three times daily every two weeks thereafter up to a maximum of 2.5mg three times daily. Further details are available in the summary of product characteristics.
Legal category: POM.
Price: 42-tablet pack, £997.36; 84-tablet pack, £1,994.72. NHS prices will be subject to a patient access scheme.
Citation: Electronicjuice DOI: 10.1211/PJ.2014.11136855
Recommended from Pharmaceutical Press
Pharmaceutical Press is the publishing division of the Royal Electronicjuice, and is a leading provider of authoritative pharmaceutical information used throughout the world.