Actavis Seeks FDA Approval for Generic Letairis to Treat PAH Patients

Dublin, Ireland-based pharmaceutical company Actavis plc has submitted an Abbreviated New Drug Application (ANDA) to the U.S. Food and Drug Administration (FDA) regarding its generic version of the drug Letairis, originally marketed by Gilead Sciences, Inc. The company is now waiting for the decision from the FDA on the market approval of Ambrisentan Tablets in 5 mg and 10 mg doses to treat pulmonary arterial hypertension (PAH).

Ambrisentan is a treatment for PAH that works to prevent the thickening of blood vessels, particularly in the lungs and heart, as well as to lower the blood pressure in the lungs, which enables more efficient blood pumping. Actavis believes that it is the first company to seek FDA approval for a generic version of Gilead’s Letairis. If the agency rules favorably, the company may be granted 180 days of generic market exclusivity.

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The selective endothelin type-A receptor antagonist Letaris garnered $595 million in global sales in 2014, according to Gilead. Both Gilead and the Royalty Pharma Collection Trust filed a lawsuit at the U.S. District Court for the District of Delaware against Actavis on April 1 in order to avoid commercialization the generic version of ambrisentan before the expiration of U.S. Patent number RE42,462 for Letairis.

The suit was submitted under the regulation of the Hatch-Waxman Act, which means that the final approval of the ANDA submitted by Actavis can only be made by the FDA up to 30 months either from the date from the receiving of the notice regarding the filing of the Actavis ANDA or until the issue of a final decision prior to the court.

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The ANDA filed by the company may be key for several patient groups, as recent research demonstrated that treating patients with systemic sclerosis (SSc) who have borderline PAH is vital to patient health, a condition for which life expectancy after diagnosis is only one year. Actavis, which conducts operations in about 100 different countries, is dedicated to providing generic versions of novel pharmaceuticals to patients suffering from a range of indications.

GlaxoSmithKline (GSK) has also applied for a European Medicines Agency (EMA) variation to the Marketing Authorization for ambrisentan, in order to expand the currently approved indication to include its use as a first-line combination therapy with tadalafil for PAH. Ambrisentan was previously approved in the European Union (EU) as a treatment for PAH classified as WHO functional class II and III to enhance tolerance of physical activity.