Ironwood Pharmaceuticals, Inc. (NASDAQ: IRWD) and AstraZeneca Pharmaceuticals Co., Ltd. today announced the initiation in China of a Phase III clinical trial of linaclotide for the treatment of adults with irritable bowel syndrome with constipation (IBS-C). Linaclotide is currently approved in the United States for adults with IBS-C or chronic idiopathic constipation (CIC) and in the European Union for adults with moderate to severe IBS-C. “IBS-C is estimated to affect at least 13 million adults in China, causing hallmark symptoms such as abdominal pain and constipation,” said David Snow, President of AstraZeneca China. “If approved in China, linaclotide could be the first prescription treatment specifically for IBS-C and could then help address an unmet need for millions of suffering patients.” The double-blind, randomized, placebo-controlled Phase III clinical trial is expected to enroll approximately 800 adults with IBS-C in China, Australia and New Zealand. The design of the trial is similar to the 12-week Phase III IBS-C trial that supported linaclotide regulatory approval in the United States and European Union. Patients will be randomized 1:1 to receive either 290mcg of linaclotide or placebo for 12 weeks. The co-primary endpoints of the trial are (i) Abdominal Pain/Discomfort Responder at 12 weeks, which is defined in the study protocol as a patient who has at least a 30 percent improvement in his/her abdominal pain/discomfort level for at least half of the treatment period, and (ii) IBS Degree of Relief Responder at 12 weeks, which is defined in the study protocol as a patient who is considerably or completely relieved of symptoms for at least half of the treatment period. Ironwood and AstraZeneca anticipate the availability of top-line data in the first half of 2015 and, if approved by the China Food and Drug Administration (CFDA), anticipate that linaclotide could be commercialized in China in 2017.