Little future seen for Glaxo, Adolor bowel drug

By Ben Hirschler

LONDON, April 10 (Reuters) - An experimental bowel drug from GlaxoSmithKline Plc (GSK.L) and its partner Adolor Corp. (ADLR.O) has little commercial future following safety problems that caused trials to be put on hold, analysts said on Tuesday.

The setback is bad news for Adolor, whose shares fell 57 percent in after-hours trading on Monday, but will barely move the dial at Glaxo, Europe's biggest pharmaceuticals group, where future sales are expected to be impacted by less than 1 percent.

Glaxo and Adolor suspended clinical tests of Entereg as a treatment for constipation due to opioid painkillers after it was linked to a higher risk of heart attacks and other serious heart problems, fractures and skin cancers. The problems with Entereg, also known as alvimopan, mark the second safety issue for a bowel medicine in just over a week, after Novartis AG's (NOVN.VX) Zelnorm was pulled from the U.S. market on March 30 for a different constipation condition.

Glaxo and Adolor said they would continue to push ahead with development of Entereg as a short-term treatment for post-operative ileus (POI), or bowel dysfunction after surgery, but analysts said this was a much smaller potential market.

Entereg has had a chequered history, with the U.S. Food and Drug Administration seeking more information on the product twice already, so the latest setback is not a complete surprise.

Both companies still plan to resubmit an application for POI use this quarter but analysts at UBS said the new safety signals could delay this process and raise questions as to whether Entereg would ever get to market.

Analysts had been expecting a U.S. marketing green light and launch either late this year or early in 2008.

The opioid-induced bowel dysfunction (OBD) indication was seen as higher-risk, since the drug would be used on a long-term basis, potentially exposing patients to greater side effect dangers. But that also made it commercially more attractive.