Ironwood Pharmaceuticals, Inc. approved the marketing application for LINZESS® (linaclotide) for adults with irritable bowel syndrome with constipation (IBS-C) in China. Ironwood anticipates that it will launch the drug with its partner in China, AstraZeneca, in the second half of 2019. Linaclotide is a guanylate cyclase-C (GC-C) receptor agonist currently approved and available for the treatment of adults with IBS-C or chronic idiopathic constipation (CIC) in the United States and more than 30 other countries. Data from the Phase III trial in China indicated that patients treated with linaclotide showed a statistically significant improvement compared to placebo-treated patients for both co-primary endpoints. Regarding the first primary endpoint, 60.0% of linaclotide-treated patients were Abdominal Pain/Discomfort Responders, compared to 48.8% of placebo-treated patients (p=0.001). Regarding the second primary endpoint, 31.7% of linaclotide-treated patients were IBS Degree of Relief Responders, compared to 15.4% of placebo-treated patients (p < 0.0001). Statistically significant improvements were achieved in all pre-specified secondary endpoints in this trial, including abdominal pain, abdominal discomfort, bloating, straining, frequency of complete spontaneous bowel movements, frequency of spontaneous bowel movements and stool consistency. The most common adverse event reported in linaclotide-treated patients was diarrhea (9.4% for linaclotide vs. 1.2% for placebo). Discontinuation due to diarrhea was 0.7% for linaclotide vs. 0.2% for placebo. Overall rates of discontinuation due to adverse events were 1.7% for linaclotide vs. 1.4% for placebo. The randomized, double-blind, placebo-controlled Phase III clinical trial randomized 839 adults with IBS-C in China, Australia, Canada, New Zealand and the United States. Patients were randomized 1:1 to receive either 290mcg of linaclotide, or placebo, for 12 weeks. The co-primary endpoints of the trial were (i) 12-Week Abdominal Pain/Discomfort Responder, which is defined as a patient who has at least a 30% improvement in his/her abdominal pain or abdominal discomfort level for at least half of the weeks in the 12-week treatment period, and (ii) 12-Week IBS Degree of Relief Responder, which is defined as a patient who rates their IBS symptoms as being considerably relieved or completely relieved for at least half of the weeks in the 12-week treatment period.