NEW ORLEANS -- An investigational drug to relieve chronic constipation was effective and caused no unexpected safety issues in two phase III trials, researchers said here. Linaclotide, a chloride channel activator that boosts intestinal fluid secretion, significantly increased the number and quality of spontaneous bowel movements in patients who had been almost completely reliant on laxatives, according to Anthony Lembo, MD, of Beth Israel Deaconess Medical Center in Boston. Both trials "met their primary efficacy endpoint," he told attendees here at Digestive Disease Week, with significant improvement in every prespecified secondary endpoint compared with baseline and with placebo.
The drug appeared to be almost immediately effective. At baseline, the mean weekly CSBM count was about 0.3, with 70% of patients having a count of zero. By week two, the mean in the active-treatment groups had risen to 2.5, whereas in the placebo group it was about 0.8. Spencer Dorn, MD, a gastroenterologist at the University of North Carolina in Chapel Hill, N.C., called the linaclotide data "very impressive." He said the drug would be "a welcome addition" to the sparse existing options for chronic constipation. Particularly appealing, Dorn said, was that linaclotide appeared to have faster onset than polyethylene glycol-based remedies and fewer side effects than more potent therapies.