Sepracor Inc announced the US FDA has accepted for formal review Sepracor's New Drug Application (NDA) for Xopenex HFA (levalbuterol tartrate HFA) Inhalation Aerosol, a hydrofluoroalkane (HFA) metered-dose inhaler (MDI). The FDA also notified Sepracor that the Prescription Drug User Fee Act (PDUFA) date - the date by which the FDA is expected to review and act on an NDA submission -for Xopenex HFA MDI is March 12, 2005, a company release said.

Sepracor's MDI development programme included approximately 1,870 paediatric and adult subjects and 54 studies (preclinical and clinical). In 2003, Sepracor completed its phase III studies of Xopenex HFA. In each of the three, large-scale, pivotal phase III trials that Sepracor conducted, the Xopenex HFA MDI was well tolerated and met the targeted efficacy endpoints in both adults and children with asthma. In the primary airway function measure, FEV1 (a test of lung function that measures the amount of air forcefully exhaled in one second), the Xopenex HFA MDI produced statistically and clinically significant improvements relative to placebo (p<0.001).

Approximately 95 per cent of the short-acting beta-agonist inhalers sold in 2003 contained chlorofluorocarbon (CFC) propellants, according to IMS Health information. In June 2004, the FDA issued a proposed rule for the removal of the essential use exemption, which currently permits the use of CFC-containing albuterol inhalers despite environmental concerns. Removal of the essential use exemption would prevent albuterol products containing CFC propellants, including MDIs, from being marketed in the US. The Xopenex MDI uses HFA technology and does not contain a CFC propellant.

Asthma is a chronic lung disorder characterized by reversible airway obstruction and the pathologic finding of airway inflammation. According to the American Lung Association, approximately 26 million Americans have been diagnosed with asthma in their lifetime. It is the most common childhood illness and affects approximately 8.6 million children in the U.S. under the age of 18. Short-acting beta-agonists are the most-prescribed asthma therapy among primary care physicians and paediatricians in the US, according to IMS Health information.

The US short-acting bronchodilator MDI market potential at branded prices, assuming parity pricing to branded Proventil HFA, is approximately $1.6 billion.

Sepracor currently markets Xopenex brand levalbuterol HCl inhalation solution for use with a nebulizer through its primary care and hospital sales force. Xopenex inhalation solution is FDA approved for use in a nebulizer at 0.31 mg and 0.63 mg dosage strengths for treatment of children 6 to 11 years old, and in 0.63 mg and 1.25 mg dosage strengths for patients 12 years of age and older.

Sepracor expects that the Xopenex HFA MDI, if approved by the FDA, will be sold through the company's primary care sales force. Its Estorra brand eszopiclone for the treatment of insomnia received an approvable letter from the FDA on February 27, 2004.

It was on May 12, 2004, Sepracor submitted an NDA for Xopenex HFA MDI for the treatment or prevention of bronchospasm in adults, adolescents and children 4 years of age and older with reversible obstructive airway disease, such as asthma and chronic obstructive pulmonary disease (COPD).