Conference Coverage
Macitentan Promising for Long-Term Outcomes in PAH
Major Finding: Macitentan treatment reduced the risk of morbidity and mortality by 30% in patients who received 3 mg once daily and by 45% in...
Another endothelin receptor blocker, macitentan, has been approved for treating pulmonary arterial hypertension, the Food and Drug Administration announced on Oct. 18.
In a study of 742 patients with pulmonary arterial hypertension (PAH), macitentan over an average of 2 years was "effective in delaying disease progression, a finding that included a decline in exercise ability, worsening symptoms of PAH or need for additional PAH medication," according to the FDA statement issued on Oct. 18. Anemia, nasopharyngitis, sore throat, bronchitis, headache, and urinary tract infection were among the common side effects associated with treatment, the statement said.
It will be marketed as Opsumit by Actelion Pharmaceuticals US. The approved indication is for the treatment of PAH, WHO Group I, to delay disease progression, which includes death, initiation of intravenous or subcutaneous prostanoids, or clinical worsening of PAH (decreased 6-minute walk distance, worsened PAH symptoms and need for additional PAH treatment, according to Actelion). The approved dose is 10 mg daily; it is an oral medication.
Like the other endothelin receptor blockers, macitentan’s label includes a boxed warning that it is a teratogen and should not be used in pregnant women, and that women can receive the drug only through a REMS (Risk Evaluation and Mitigation Strategy) program that will restrict the drug’s distribution. Under the Opsumit REMS, distribution of the drug will be restricted and prescribers will have to enroll in the REMS and become certified to prescribe the drug. Female patients will also need to be enrolled and must comply with pregnancy testing and contraception requirements before starting treatment. Pharmacies that dispense the drug will need to be certified and will dispense the drug only to authorized patients, the FDA said.
The study of 742 patients was SERAPHIN (Study With an Endothelin Receptor Antagonist in Pulmonary Arterial Hypertension to Improve Clinical Outcome), which compared treatment with 3 mg or 10 mg of macitentan once a day, or placebo, and were allowed to be treated with phosphodiesterase-5 inhibitors or oral or inhaled prostanoids, according to Actelion.
The primary end point, a composite of a PAH event or death from any cause, was reached by 38% of patients receiving 3-mg macitentan and 31% of those receiving 10-mg macitentan, compared with 46% of patients receiving placebo. The hazard ratios of 0.7 for the 3-mg dose and 0.55 for the 10-mg dose were statistically significant.
Macitentan is under review in Europe, Canada, Switzerland, Australia, Taiwan, Korea and Mexico, according to Actelion.
Actelion also markets bosentan (Tracleer), another endothelin receptor antagonist, which was approved for treating PAH in 2001. Ambrisentan (Letairis; Gilead), also an endothelin receptor antagonist, was approved in 2007.