October 22 ,2013 | By Márcio Barra
Last Friday, the FDA approved Opsumit (macitentan) 10 mg once daily, from Actelion, for the treatment adults with pulmonary arterial hypertension (PAH). This is the second drug for the treatment of PAH on Actelion’s portfolio, following Tracleer (bosentan), which loses exclusivity from 2015, and the second drug approved for PAH this month by the FDA, after Adempas (riociguat), from Bayer.
PAH is high blood pressure condition that occurs in the arteries connecting the heart to the lungs. It causes the right side of the heart to work harder than normal, which can lead to limitations on exercise ability and shortness of breath. Opsumit is an endothelin receptor antagonist, which blocks endothelin receptors, thus relaxing the pulmonary arteries. This helps decrease the blood pressure within the lung vasculature that supply deoxygenated blood to the lungs.
The drug is being touted by Actelion as the only medicine approved by the FDA to delay disease progression and reduce the need for PAH hospitalization.
The approval of Opsumit was partly based on data from the SERAPHIN ((Study with an Endothelin Receptor Antagonist in Pulmonary Arterial Hypertension to Improve Clinical Outcome) phase III trial. The study, published in the New England Journal of Medicine, recruited 742 patients and showed that the risk of a morbidity/mortality event was cut by 45% in patients who had been prescribed a two year treatment plan of Opsumit compared to those on placebo. The drug showed best results in the 10mg OD dosage whilst less tangible benefits were evident in the 3mg OD dosage. The study also showed a reduction in the risk of PAH related hospitalization and death by 50% as compared to placebo.
Opsumit will be lauched in the U.S. in November 2013, and it is currently under review in Europe. Opsumit is also being evaluated in a pivotal phase III program in patients suffering from digital ulcers associated with systemic sclerosis, with results expected in the first half of 2014. A phase I study is also currently ongoing for the treatment of glioblastoma.
Opsumit carries a Boxed Warning alerting patients and health care professionals that the drug should not be used in pregnant women because it can harm the developing fetus. Female patients can receive the drug only through the Opsumit Risk Evaluation and Mitigation Strategy (REMS) Program
Common side effects of the drug observed in clinical trials include low red blood cell count (anemia), common cold-like symptoms (nasopharyngitis), sore throat, bronchitis, headache, flu and urinary tract infection.