Marlborough-based Acton Pharmaceuticals announced Thursday that the Food and Drug Administration has approved its supplemental new drug application for Aerospan Inhalation Aerosol, an asthma treatment for patients 6 years of age and older.

In a press release, Acton Pharmaceuticals said it is now planning to launch Aerospan in early 2013 into the $8.3 billion US inhaled steroid market.

Annually, the disease accounts for an estimated $11.5 billion in health care costs, the release noted.