Ironwood Pharmaceuticals, Inc and Forest Laboratories, Inc announced positive top-line results from a 26-week phase-3 clinical trial assessing the efficacy and safety of the investigational drug linaclotide in patients with irritable bowel syndrome with constipation (IBS-C).

Analyses of the data indicate a statistically significant improvement (p<0.0001) was achieved for linaclotide-treated patients compared to placebo-treated patients on all four primary endpoints, which included two composite responder endpoints encompassing abdominal pain and complete spontaneous bowel movements (CSBMs), as well as individual responder endpoints for abdominal pain and CSBMs. Significant improvement (p<0.001) was also achieved for linaclotide-treated patients compared to placebo-treated patients on all pre-specified secondary endpoints, which were measures of abdominal pain, abdominal discomfort, bloating, and bowel symptoms. Both primary and secondary endpoints were assessed over the first 12 weeks of the treatment period, and these results were consistent with the first phase-3 trial of linaclotide in patients with IBS-C.

Additionally, at each of the 26 weeks in the treatment period, mean changes from baseline in abdominal pain and CSBMs showed statistically significant improvements (p<0.0001) for linaclotide-treated patients compared to placebo-treated patients. The incidence of adverse events was similar to that observed in the first phase-3 trial of linaclotide in patients with IBS-C, with diarrhoea being the most common adverse event in linaclotide-treated patients.

"We are thrilled with the positive results from this trial, demonstrating a reduction in abdominal pain and an increase in CSBMs over the 26-week treatment period. Linaclotide's effect on these symptoms and tolerability profile has been remarkably consistent across the robust IBS-C and chronic constipation development program," said Peter Hecht, CEO of Ironwood. "We look forward to the opportunity to bring this promising treatment to the millions of individuals suffering from these chronic and highly bothersome gastrointestinal disorders."

"By successfully meeting all the primary and secondary endpoints in this trial, we now have two positive phase-3 IBS-C trials and two positive phase-3 chronic constipation trials," said Howard Solomon, chairman and chief executive officer of Forest Laboratories. "We look forward to filing the NDA for both indications in 2011."

This trial, MCP-103-302, is part of Ironwood and Forest's phase-3 programme investigating the effect of linaclotide treatment on patients with IBS-C or chronic constipation (CC). Previously, Ironwood and Forest reported positive results from the first of two phase-3 trials in patients with IBS-C and two phase-3 trials in patients with CC. The IBS-C trials were also designed to support regulatory submission in Europe. Today, in a separate press release, Ironwood and its European partner, Almirall, announced positive top-line results from this study for the EU endpoints.

Linaclotide, an investigational drug, is an agonist of the guanylate cyclase type-C (GC-C) receptor located on the luminal surface of the intestine.

Ironwood Pharmaceuticals is an entrepreneurial pharmaceutical company dedicated to the art and science of great drugmaking.

Forest Laboratories' longstanding global partnerships and track record developing and marketing pharmaceutical products in the United States have yielded its well-established central nervous system and cardiovascular franchises and innovations in anti-infective medicine.