Investigational IBS Drug Improves Overall Response

Up to 24% of patients with irritable bowel syndrome with constipation responded to treatment.

Synergy Pharmaceuticals announced positive results from a clinical trial of plecanatide in patients with irritable bowel syndrome.

Plecanatide is an investigational oral compound taken once per day in patients with irritable bowel syndrome with constipation. The compound, which is composed of 16 amino acids, is nearly identical to uroguanylin, although plecanatide substitutes 1 amino acid. Uroguanylin is a human peptide that naturally occurs in the gastrointestinal tract, and targets guanylate cyclase 2C receptors.

Synergy released results from the first of two phase 3 clinical trials conducted in the plecanatide phase 3 irritable bowel syndrome (IBS) with constipation program. Both trials include a 2-week pre-treatment period, a 12-week treatment period, and a 2-week follow-up period, according to a press release from the company.

The clinical trial to evaluate the safety and efficacy of the drug enrolled 1135 adult patients with IBS. There were 377 patients administered plecanatide 3-mg, 379 patients administered plecanatide 6-mg, and 379 patients administered the placebo.

Initial analyses of the findings show that plecanatide 3-mg and 6-mg both met the primary endpoint, which was the percentage of patients classified as overall responders, Synergy reported. Investigators discovered a significant increase in overall responders compared with placebo during the 12-week treatment. The results showed 21.5% and 24% of patients responded to treatment in the plecanatide 3-mg and 6-mg groups, respectively, compared with 14.2% of patients taking placebo.

According to Synergy, a patient is classified as responding to treatment if they have at least 30% reduction in abdominal pain, and less than 1% increase of complete spontaneous bowel movement from baseline in the same week, for at least 50% of the treatment.

The most common adverse event experienced across all treatment groups was diarrhea. More serious adverse events occurred in 0.4% of patients. Synergy reported that withdrawal from treatment due to adverse events was low among all patients included, and few discontinued due to experiencing diarrhea.

Plecanatide is currently being reviewed by the FDA for the treatment of patients with chronic idiopathic constipation. If the drug receives approval for this indication, Synergy plans to file a new drug application for the treatment of patients with IBS with constipation.

“We are very pleased with these results,” said Gary S. Jacob, PhD, chairman and CEO of Synergy Pharmaceuticals Inc. “These data reinforce our strong belief that plecanatide may represent an important new treatment option for the millions of patients currently suffering from IBS-C. We look forward to the results of our second phase 3 IBS-C trial with plecanatide later this month.”