US firm, Adolor Corporation, received a boost this week after partner, GlaxoSmithKline, announced positive top-line results from a Phase II clinical trial of the gastrointestinal drug, Entereg (alvimopan), in the treatment of opioid-induced bowel dysfunction - a common and serious clinical problem for millions of patients taking opioids chronically to manage painful conditions, such as severe back pain and osteoarthritis.

A Phase 2b study included some 522 non-cancer patients with OBD, and showed that all three oral doses of Entereg achieved statistically significant effects on the primary endpoint of weekly frequency of spontaneous bowel movements versus placebo. Side effects affecting the GI tract were the most common, occurring in 30% to 43% of Entereg receivers, compared to 36% on placebo. Most frequently reported were abdominal pain, nausea and diarrhoea and GI adverse events were also the most common reason for study withdrawal. A review of safety data is ongoing.

“We are very pleased with the results of this study,” said Yvonne Greenstreet, senior vice president, medicine developments centre at GSK. “These initial results… are consistent with previous observations from other studies and we believe that the changes seen are clinically important and provide the platform for the development of an important new therapy for patients with OBD.”

Entereg has already been filed with the US Food and Drug Administration as a treatment for a GI condition known as post-operative ileus, which is characterised by abdominal distension and pain, as well as nausea and vomiting [[09/09/04f]]. However, approval could be delayed after the agency asked for more information about a Phase III clinical trial [[12/01/05e]].