AstraZeneca has partnered with Ironwood Pharmaceuticals for the co-development and co-commercialisation in China of linaclotide, which is approved in the US for the treatment of irritable bowel syndrome with constipation and chronic idiopathic constipation. Ironwood filed a clinical trial application with the State Food and Drug Administration in China in May 2012 for a Phase III clinical trial of the drug. The deal also provides Ironwood with the opportunity to promote AstraZeneca’s Nexium® (esomeprazole magnesium) in the US for gastroesophageal reflux disease.