Adolor shelves Entereg studies; shares plunge

Underscoring yet again that drug development is always a high-stakes gamble, shares of Adolor collapsed this morning under the weight of the news that it was being forced to suspend a study of Entereg for opioid-induced bowel dysfunction. The move to shutter the trial came after researchers noted a higher risk of heart attacks and other cardiovascular events during a comparison study of Entereg with patients suffering from chronic, non-cancer pain. About 1.3 percent of the patients taking Entereg had heart attacks compared to none in the placebo group. Adolor is developing the therapy with GlaxoSmithKline. Serious cardiovascular events occurred in high-risk patients.

In early trading, shares of Adolor plunged 57 percent. Glaxo announced that it is withdrawing plans for a study of Entereg in patients with opioid-induced bowel dysfunction as well as another study involving patients with cancer pain. Progenics Pharmaceuticals, which is developing a competing therapy with Wyeth, saw its shares buoyed by the news.

- check out the release on the decision to halt the trial
- here's the AP report for more information