At long last, GlaxoSmithKline and partner Adolor Corp have received the thumbs-up from US regulators for their new bowel drug Entereg.

After a number of delays, the US Food and Drug Administration has approved Entereg (alvimopan) to help patients regain gastrointestinal function (post-operative ileus) earlier following bowel resection surgery. The treatment will initially only be available for short-term use in hospitals registered under a risk management programme established by GSK and Adolor.

The road to approval has been a rocky one ever since Entereg, was first submitted for FDA approval in June 2004. The agency delayed its progress several times, asking for more data and questioning its side-effects profile especially in long-term use.

However an advisory panel recommended use of the drug in January, on a 9-6 vote, but warned that GSK and Adolor’s risk management programme would need strengthening because of long-term concerns of heart attack. Nevertheless, since then, the FDA twice delayed issuing an approvable letter.

Adolor was delighted and chief executive Michael Dougherty noted that Entereg “is the first and only product that has demonstrated the ability to address this serious condition which has negative consequences for patients, and imposes considerable expense on the health-care system”. The approval for Entereg, which is a peripherally acting mu-opioid receptor antagonist, was based on five clinical studies involving more than 2,500 bowel resection patients.

GSK and Adolor noted that they plan to commence a study in patients undergoing radical cystectomy, another population in which POI is a significant burden, as part of its postmarketing commitment. Analysts are predicting peak sales of over $150 million.