Critical Therapeutics, Inc. has submitted a New Drug Application (NDA) to the US Food and Drug Administration (FDA) for the twice daily, controlled-release formulation of zileuton (zileuton CR).

Zileuton CR is an investigational drug for the prevention and chronic treatment of asthma in adults and children 12 years of age and older. Critical Therapeutics currently markets its asthma drug, Zyflo (zileuton tablets), the immediate-release formulation of zileuton, in the US, Zyflo is the only 5-lipoxygenase inhibitor approved for marketing by the FDA.

"Our NDA submission is a major milestone that moves us one-step closer to bringing zileuton CR to market," stated Frank Thomas, President of Critical Therapeutics. "We believe the twice daily dosing regimen of zileuton CR will provide a more convenient option for patients than the current four-times-a-day dosing regimen of Zyflo and consequently should improve patient compliance and expand product use, if approved by the FDA."

The NDA includes results from two previously completed phase III clinical trials that evaluated the safety and efficacy of zileuton CR in 818 asthma patients. The NDA also includes results from three pharmacokinetic studies, previously completed by Critical Therapeutics. Pending FDA approval of the NDA, the company expects to launch zileuton CR in the second half of 2007.

"As part of our commercialization strategy for zileuton CR, we also are preparing our first phase IIIb clinical trial, which is designed to help identify specific patient types or subgroups that could benefit most from treatment with zileuton CR beyond current standard of care," added Thomas. "To complement zileuton CR, we are developing an intravenous formulation of zileuton for potential use in emergency room and urgent care settings for patients experiencing acute exacerbations of asthma."

The controlled-release formulation of zileuton utilizes SkyePharma PLC's Geomatrix technology. Critical Therapeutics entered in to an agreement in December 2003 with SkyePharma, through its subsidiary Jagotec, under which SkyePharma would manufacture zileuton CR for clinical trials, regulatory review and commercial sale.

According to the American Lung Association, approximately 20 million Americans have asthma, a chronic inflammatory disorder that occurs when the walls of the bronchial tubes become inflamed, causing the muscles to constrict and extra mucus to be produced. The Mayo Clinic notes that asthma can lead to a broad range of symptoms such as difficulty breathing, wheezing, chest tightness, and coughing, and in some cases, breathing may become so difficult that a flare-up may become life-threatening if not properly managed.