Ironwood Pharmaceuticals, Inc. (NASDAQ: IRWD) and Forest Laboratories, Inc. (NYSE: FRX) today announced they will be presenting linaclotide results from Phase 3 clinical trials in patients with irritable bowel syndrome with constipation (IBS-C) during the 2011 Digestive Disease Week (DDW) annual meeting that will be held in Chicago from May 7 through May 10, 2011. Linaclotide is an investigational guanylate cyclase type-C (GC-C) agonist for the treatment of IBS-C and chronic constipation (CC). Ironwood and Forest released top-line results from the two Phase 3 IBS-C trials late last year.

Linaclotide IBS-C data will be reported in three oral presentations. The scheduled times and titles of the presentations are:

- Efficacy and Safety of Once Daily Linaclotide in Patients with Irritable Bowel Syndrome with Constipation: A 12-Week, Randomized, Double-Blind, Placebo-Controlled Phase 3 Trial Followed by a 4-Week Randomized Withdrawal Period, an oral presentation by Satish Rao, M.D. on Monday, May 9 at 4:25 p.m. (CDT)

- Efficacy and Safety of Once-daily Linaclotide Administered Orally for 26 Weeks in Patients with IBS-C: Results From a Randomized, Double-blind, Placebo-controlled Phase 3 Trial, an oral presentation by William Chey, M.D. on Monday, May 9 at 4:30 p.m. (CDT)

- Effect of Linaclotide on Quality of Life in Adults with Irritable Bowel Syndrome with Constipation: Pooled Results from Two Randomized, Double-Blind, Placebo-Controlled Phase 3 Trials, an oral presentation by Robyn Carson, M.P.H. on Saturday, May 7 at 3:09 p.m. (CDT)

Ironwood and Forest will also present additional analyses of linaclotide Phase 3 CC data and preclinical data (full Phase 3 CC data were presented at DDW last year). The scheduled times and titles of those presentations are:

- The Effect of Linaclotide on Measures of Abdominal and Bowel Symptoms in Patients With Chronic Constipation and Abdominal Pain: Pooled Results from Two Phase 3 Trials, an oral presentation by Anthony Lembo, M.D. on Saturday, May 7 at 2:15 p.m. (CDT)

- Effect of Linaclotide on Quality of Life among Patients with Chronic Constipation (CC) with Abdominal Symptoms, a poster of distinction presented by Robyn Carson, M.P.H. on Saturday, May 7 from noon - 2:00 p.m. (CDT)

- A Novel Role of Cyclic GMP in Colonic Sensory Neurotransmission in Healthy and TNBS-treated Mice, a poster of distinction presented by Stuart Brierley, Ph.D. on Sunday, May 8 from noon - 2:00 p.m. (CDT)

About Linaclotide

Linaclotide, an investigational drug, is an agonist of the guanylate cyclase type-C (GC-C) receptor located on the luminal surface of the intestine. In preclinical models, linaclotide reduced visceral hypersensitivity, increased fluid secretion, and accelerated intestinal transit. The effects on secretion and transit are mediated through cyclic guanosine monophosphate (cGMP), which is also believed to modulate the activity of local nerves to reduce pain. Linaclotide is an orally delivered peptide that acts locally in the gut with no measurable systemic exposure at therapeutic doses and is intended for once-daily administration. Linaclotide is in Phase 3 clinical development for the treatment of irritable bowel syndrome with constipation (IBS-C) and chronic constipation (CC). The efficacy portion of linaclotide's development program has been completed and will support the NDA submission for both indications, as well as the MAA submission for the IBS-C indication. Long-term safety studies are underway. In Phase 3 efficacy studies, the most commonly reported side effect was diarrhea. Most events of diarrhea were reported as mild to moderate. An issued composition of matter patent for linaclotide provides protection to 2025. Ironwood and Forest are co-developing and, if it is approved, will co-promote linaclotide in the United States. Ironwood has out-licensed linaclotide to Almirall for European development and commercialization, and to Astellas Pharma Inc. for development and commercialization in Japan, Indonesia, Korea, the Philippines, Taiwan, and Thailand.

About Irritable Bowel Syndrome with Constipation (IBS-C)

IBS-C is a chronic functional gastrointestinal disorder characterized by abdominal pain, discomfort, and bloating associated with altered bowel habits, and as many as 11 million people in the U.S. suffer from it. There are currently few available therapies to treat this disorder and there is a high rate of dissatisfaction with available therapies. Patients suffering from IBS-C can be affected physically, psychologically, socially, and economically.

About Chronic Constipation (CC)

As many as 34 million Americans suffer from symptoms associated with CC and 8.5 million patients have sought treatment. Patients with CC often experience hard and lumpy stools, straining during defecation, a sensation of incomplete evacuation, and fewer than three bowel movements per week, as well as discomfort and bloating. This condition significantly affects patients' quality of life by impairing their ability to work and participate in typical daily activities. There is a high rate of dissatisfaction with currently available treatments.

About Digestive Disease Week (DDW)

DDW is the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy, and gastrointestinal surgery. Jointly sponsored by the American Association for the Study of Liver Diseases, the American Gastroenterological Association (AGA) Institute, the American Society for Gastrointestinal Endoscopy, and the Society for Surgery of the Alimentary Tract, DDW takes place May 7-10, 2011, at the McCormick Place Convention Center, Chicago. The meeting showcases approximately 5,000 abstracts and hundreds of lectures on the latest advances in GI research, medicine and technology.

Ironwood Pharmaceuticals
Forest Laboratories, Inc.