GlaxoSmithKline and partner Adolor will have been cheered yesterday after a US Food and Drug Administration advisory panel narrowly voted 9-6 that its mu-opioid receptor antagonist Entereg’s (alvimopan) benefits outweigh its risks. The news potentially clears the way for full approval next month; a full decision on market clearance is expected by 10 February.

The firms are seeking a green light for Entereg to aid recovery of the gastrointestinal system in patients undergoing partial removal of either the small or large bowel – an indication for which currently no drugs are approved. The narrow vote is a reflection of the concerns the panel had over heart attack risk following a study of Entereg over a longer period of time. It has specifically said its use should only be short-term and in hospital.

But the advisory panel warned that GSK and Adolor’s risk management programme would need strengthening because of the long-term risk of heart attack; the current design involves Entereg being sold only to hospital officials who would then be responsible for monitoring its use, but does not go far enough, says the panel. It should ensure it will not be used long-term in an outpatient setting.

The companies first filed for FDA approval of Entereg in 2004 to treat postoperative ileus, a transient impairment of bowel motility that often follows abdominal surgery. The agency has now issued two approvable letters, the second being in November 2006, and subsequently requested additional data to the firms’ complete response to this letter after a study last April showed an increased cardiovascular and fracture risk in Entereg patients.

GSK and Adolor are also studying Entereg in other indications, to treat bowel dysfunction among patients taking opioid pain medications for long-term use to relieve chronic pain from cancer and other medical conditions.