Around 3,000 patients with pulmonary arterial hypertension (PAH) in England could now benefit from treatment with Actelion's Opsumit (macitentan), which is now available on prescription in the country.

PAH is a severe, life-threatening illness characterised by abnormally high blood pressure in the arteries between the heart and lungs, and, despite recent advances in treatment, it remains a progressive disease with high death rates.

Opsumit is a novel endothelin receptor antagonist used as a monotherapy or in combination with other medicines for the long-term treatment of the condition, in adults whose disease has reached a certain level of severity (WHO Functional Class (FC) II to III).

The drug's approval in Europe was based on data from the SERAPHIN study showing that it resulted in a 45% relative risk reduction of the composite morbidity-mortality endpoint when compared to placebo, a treatment effect long sought after by healthcare professionals.

Also, the reduction in risk was found to be 38% for patients already on background therapy for PAH, while the drug also cut the risk of PAH related death or hospitalisation up to end of treatment by 50%, the firm noted.

Opsumit also hit safety targets, with side effects found to be mild-to-moderate in nature, with the most common being nasopharyngitis (14.0%), headache (13.6%) and anaemia (13.2%).

Other drugs currently available to treat the condition in England include calcium channel blockers such nifedipine as for idiopathic forms or targeted therapy with Actelion's own Tracleer (bosentan) or Gilead's Letairis (ambrisentan).