Opsumit: endothelin receptor antagonist for pulmonary hypertension

Opsumit (macitentan) is a new once-daily, dual endothelin receptor antagonist for pulmonary arterial hypertension (WHO class II or III).

Women should not become pregnant for 1 month after discontinuation of macitentan
Women should not become pregnant for 1 month after discontinuation of macitentan

PHARMACOLOGY

Macitentan is an endothelin receptor antagonist with a high affinity for both endothelin A and B receptors in pulmonary arterial smooth muscle. It inhibits endothelin-mediated activation of second messenger systems that cause vasoconstriction and cell proliferation.1

CLINICAL STUDIES

The efficacy and safety of macitentan in patients with symptomatic pulmonary arterial hypertension (PAH) were assessed in a double-blind phase III study (n=742).2

Patients were randomised to receive either placebo or macitentan at 3mg (unlicensed dose) or 10mg once daily, in addition to their existing therapy with phosphodiesterase-5 inhibitors or oral/inhaled prostanoids.1,2

PAH symptoms

The primary endpoint, time to first occurrence of a morbidity or mortality event (death, atrial septostomy, lung transplantation, other worsening of PAH or initiation of iv or sc prostanoids) occurred in 46.4% of patients in the placebo group, 38% of those who received macitentan 3mg and 31.4% of those given macitentan 10mg. Overall, 37.2% of patients taking placebo experienced worsening of their PAH symptoms (most frequent primary endpoint) compared with 24.4% of those treated with macitentan 10mg (p<0.001).1,2 

Reduced risk of death

Macitentan 10mg daily reduced the risk of death due to PAH or hospitalisation for PAH (secondary endpoint) by 20.7% (p<0.001) compared with placebo. In addition, patients who received macitentan 10mg daily also experienced functional improvement at month 6, as observed by a mean increase from baseline in 6-minute walking distance of 12.5m (p=0.008) compared with placebo.2

Safety profile

The most common adverse effects of macitentan were nasopharyngitis, headache and anaemia.1,2

References:

  1. Opsumit Summary of Product Characteristics, December 2013.
  2. Pulido T et al. N Engl J Med 2013; 369: 809–18.

View Opsumit drug record

Further information: Actelion

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