Xyrem (sodium oxybate) is currently marketed as the first and only approved treatment for cataplexy, a sudden loss of muscle tone that is a debilitating symptom of narcolepsy.
The supplemental new drug application (sNDA) is expected to expand the Xyrem label to encompass improvement in the other primary symptoms of narcolepsy, specifically the reduction of excessive daytime sleepiness (EDS) and the improvement in fragmented nighttime sleep.
Currently there is no medication approved to treat all of the primary symptoms of narcolepsy. Prior to approval of Xyrem, antidepressants were used off-label to treat cataplexy. EDS has been treated with stimulant medications and disrupted night-time sleep by sedative-hypnotic medications.
The sNDA includes two phase IIIb trials with EDS as the primary efficacy measure, as well as positive data relating to the treatment of other components of narcolepsy. The FDA user fee (PDUFA) deadline is ten months from the date the FDA receives the sNDA submission.
John Bullion, CEO of Orphan Medical, stated, “Approval of this sNDA will allow us to market to all narcolepsy patients, effectively increasing the available market for Xyrem from approximately $50 million to an estimated $275 million.”
The sNDA submission completes the company’s narcolepsy development program, and focus will now be directed to completing a proof-of-principle trial in fibromyalgia, a chronic pain syndrome. Orphan Medical is also exploring other indications for Xyrem based on early clinical experience.