Ironwood Pharmaceuticals, Inc. (NASDAQ:IRWD) announced today that the United States Patent and Trademark Office (USPTO) has issued a Notice of Allowance for a patent application covering methods of using LINZESS® (linaclotide) to treat patients with irritable bowel syndrome with constipation (IBS-C) or chronic idiopathic constipation (CIC). The patent application, co-owned by Ironwood and Forest Laboratories, Inc., is expected to issue in mid-2014 and extend LINZESS patent protection into 2031. The patent application specifically applies to LINZESS, which is the current U.S. commercial formulation of linaclotide. This formulation combines the active ingredient linaclotide with certain excipients, resulting in a product that is stable at room temperature for long periods and suitable for oral dosing, in a capsule that dissolves in the stomach and allows linaclotide to reach its target site of action along the surface of the intestinal epithelium. Creating a room temperature stable oral formulation for linaclotide, a fourteen amino acid peptide, was one of the most significant challenges Ironwood and Forest overcame in developing the molecule into a commercially-viable product. This patent would be a significant addition to the LINZESS patent portfolio, providing patent protection for LINZESS for several additional years. LINZESS is approved and marketed in the United States for the treatment of adult patients suffering from IBS-C or CIC. It is the first and only guanylate cyclase-C (GC-C) agonist approved by the FDA. Composition of matter patents currently cover LINZESS to 2024, and a pending patent term extension would extend the composition of matter patent coverage to 2026. Ironwood and Forest also own pending patent applications covering the LINZESS commercial formulation, which are expected to provide further patent protection. A notice of allowance is a written notification issued after the USPTO makes a determination that a patent can be granted from an application. The vast majority of patent applications that receive a notice of allowance will proceed to issue as a U.S. patent; however, a notice of allowance is not a guarantee of patent issuance.