FDA panel split on Xyrem

An FDA advisory panel on Wednesday voted that Xyrem from Orphan Medical (ORPH) was effective in treating one of two proposed indications, and was split on evidence of Xyrem's safety. ORPH applied for approval of Xyrem gamma hydroxy butyrate (GHB) "to reduce the incidence of cataplexy and to improve the symptom of daytime sleepiness in patients with narcolepsy." FDA's Peripheral and Central Nervous System Drugs Advisory Committee voted 5-4 that ORPH demonstrated the effectiveness of 6 to 9 g/day of Xyrem to treat cataplexy (the total and sudden loss of muscle control) in narcolepsy patients, but voted unanimously that ORPH did not provide sufficient evidence to support an indication of improvement of the symptom of daytime sleepiness in patients with narcolepsy. The panel was split 4-4 with one abstention on the evidence of safety. The committee's safety concerns centered on the small size of the safety database rather than specific safety concerns about Xyrem. The panel said the safety database potentially was not large enough to rule out serious adverse events.

Much of the advisory committee's discussion focused on widespread illegal distribution and use of GHB in date rape, bodybuilding and recreational use, and the panel heard from parents whose children died from exposure to the drug. ORPH proposed a comprehensive closed distribution system designed to reduce the risks of diversion of Xyrem to illegal uses and to ensure that patients use the product safely. The committee voted 7-1, with one abstention, to prohibit off-label use of Xyrem. ...