Opsumit(macitentan), an orally available endothelin receptor antagonist, resulted from a tailored drug discovery process in Actelion’s laboratories.


EU Healthcare Professionals

The Opsumit FAQ Brochure and prescribing checklist are core versions approved as part of the risk management plan for Opsumit in Europe. They represent only a general guidance, while local versions are available and should be used for all EU countries. If you intend to prescribe Opsumit, please contact your local Actelion office to get access to the approved RMP materials for your country.

Current Indications

In the US, Opsumit is indicated for the treatment of PAH, WHO Group I to delay disease progression. Disease progression included: death, initiation of intravenous (IV) or subcutaneous prostanoids, or clinical worsening of PAH (decreased 6-minute walk distance, worsened PAH symptoms and need for additional PAH treatment). Opsumit also reduced hospitalization for PAH. Effectiveness was established in a long-term study in PAH patients with predominantly WHO FC II-III symptoms treated for an average of 2 years. Patients were treated with Opsumit monotherapy or in combination with phosphodiesterase-5 inhibitors or inhaled prostanoids. Patients had idiopathic and heritable PAH (57%), PAH caused by connective tissue disorders (31%), and PAH caused by congenital heart disease with repaired shunts (8%).

In Europe, Opsumit is indicated, as monotherapy or in combination, for the long-term treatment of PAH in adult patients of WHO Functional Class (FC) II to III. Efficacy has been shown in a PAH population including idiopathic and heritable PAH, PAH associated with connective tissue disorders, and PAH associated with corrected simple congenital heart disease.

Opsumit is very likely to cause major birth defects. It is contraindicated for use in pregnancy. In the US, Opsumit is distributed under a risk evaluation and mitigation strategy.


Opsumit is commercially available in over 45 markets, including the US (since November 2013), Germany (since January 2014) and Japan (since June 2015). The registration process for other countries is ongoing.

For full information please see the download.

Available Clinical Data

SERAPHIN, a global, pivotal Phase III study, was designed to evaluate the efficacy and safety of macitentan in patients with symptomatic PAH, through the primary endpoint of time to first morbidity and all-cause mortality event.

A total of 742 patients were randomized to placebo (n=250), macitentan 3 mg (n=250), or macitentan 10 mg (n=242). The primary endpoint occurred in 46.4%, 38.0%, and 31.4% of the patients in these groups, respectively. The hazard ratio for macitentan 3 mg versus placebo was 0.70 (97.5% CI, 0.52 to 0.96; p=0.0108) and the hazard ratio for macitentan 10 mg versus placebo was 0.55 (97.5% CI, 0.39 to 0.76; p<0.0001). Worsening of pulmonary arterial hypertension was the most frequent primary endpoint event. Patients were allowed to receive PAH background therapy throughout the study, either PDE-5 inhibitors or oral/inhaled prostanoids. The effect of macitentan on the endpoint was observed irrespective of background therapy for pulmonary arterial hypertension. The most commonly reported adverse drug reactions with Opsumit were nasopharyngitis (14.0%), headache (13.6%) and anemia (13.2%).


  • Pulido T et al. N Engl J Med 2013;369:809-18.
  • Gatfield J et al. PloS ONE 2012;7(10):e47662.
  • Iglarz M et al. Am J Respir Crit Care Med 2011;183:A6445.
  • Iglarz M. et al. J Pharmacol Exp Ther. 2008;327(3):736-45.
  • Sidharta PN et al. Eur J Clin Pharmacol 2011;67(10):977-84.



Please note that the information contained in this section of the website is not intended for US residents. Please visit our US webpage.

Please note that the information contained in this section of the website is not intended for US residents. Please visit our US webpage.