Ironwood Pharmaceuticals and Forest Laboratories say that the US Food and Drug Administration has accepted their irritable bowel syndrome drug linaclotide for review.

Specifically, the New Drug Application for linaclotide  covers irritable bowel syndrome with constipation (IBS-C) and chronic constipation (CC). The FDA Prescription Drug User Fee Act (PDUFA) target action date is expected in June 2012.

The filing is based upon a Phase 3 programme comprising four double-blind placebo-controlled trials and two open-label long term safety studies. More than 2,800 patients received a once-daily dose of either linaclotide or placebo across the four trials (two studies for IBS-C and two for CC). Additionally, over 3,200 patients have enrolled in ongoing open-label safety trials and more than 2,000 of those patients have received linaclotide for at least 12 months.

Partner Almirall filed for approval in Europe of the drug, under the brand name Constella, last month. It is licensed to Astellas Pharma for development and commercialisation in Japan, Indonesia, Korea, the Philippines, Taiwan, and Thailand.