Ironwood Pharmaceuticals, Inc. (NASDAQ: IRWD) and Forest Laboratories, Inc. (NYSE: FRX) announced today that LINZESS™ (linaclotide) was approved by the U.S. Food and Drug Administration (FDA) as a once-daily treatment for adult men and women suffering from irritable bowel syndrome with constipation (IBS-C) or chronic idiopathic constipation (CIC). IBS-C and CIC are chronic functional gastrointestinal disorders that affect as many as 13 million 1 and 35 million 2 adult Americans, respectively. Symptoms associated with IBS-C include abdominal pain and constipation; symptoms associated with CIC include constipation (infrequent stools, hard stools and incomplete evacuation). There are few treatment options for these conditions, particularly options that relieve abdominal pain associated with IBS-C. “The symptoms experienced by patients with IBS-C and chronic idiopathic constipation can have a significant impact on affected individuals,” said William D. Chey, M.D., professor of gastroenterology at the University of Michigan Health System. “The approval of LINZESS provides physicians with a new, evidence-based, effective treatment option for their adult patients with IBS-C and chronic idiopathic constipation.” Linaclotide, the active ingredient in LINZESS, is a first-in-class guanylate cyclase-C (GC-C) agonist and acts locally in the intestine with minimal systemic exposure. In nonclinical studies, linaclotide has been shown to reduce intestinal pain and accelerate gastrointestinal transit. Linaclotide-induced intestinal pain reduction is thought to result from an increase in cyclic guanosine monophosphate (cGMP), which has been shown to decrease the activity of pain-sensing nerves. In placebo-controlled Phase III clinical trials of more than 2,800 adults, LINZESS was shown to significantly reduce abdominal pain in IBS-C patients and significantly increase bowel movement frequency in both IBS-C patients and CIC patients. Improvements were reported in the first week of treatment and maintained throughout the treatment period. When a subset of LINZESS-treated patients in the trials were switched to placebo, they reported their symptoms returned toward pretreatment levels within one week, while placebo-treated patients switched to LINZESS reported symptom improvements. LINZESS has not been studied in pediatric patients. LINZESS is contraindicated in pediatric patients up to 6 years of age. The use of LINZESS in pediatric patients 6 through 17 years of age should be avoided.