Trial of Linaclotide Administered to Patients With Irritable Bowel Syndrome With Constipation

Inclusion Criteria:

• Patient meets protocol criteria for IBS: reports abdominal discomfort or pain that hastwo or more of the following three features:

1. Relieved with defecation

2. Onset associated with a change in frequency of stool

3. Onset associated with a change in form (appearance) of stool

• Patient reports < 3 bowel movements (BMs) per week (in the absence of any laxative,suppository, or enema use during the preceding 24 hours) and reports straining, lumpyor hard stools, and/or sensation of incomplete evacuation during > 25% of BMs

• Patient has successfully completed protocol procedures (with no clinically significantfindings): physical exam, 12-lead ECG, or clinical laboratory tests (some patients mayrequire a colonoscopy per American Gastroenterological Association (AGA) guidelines)

• Patient is compliant with Interactive Voice Response System (IVRS) for daily diaryreporting of BM habits and IBS symptoms

Exclusion Criteria:

• Patient has history of loose or watery stools for >25% of BMs

• Patient has a structural abnormality of the gastrointestinal (GI) tract or a historyof a disease or condition that can affect GI motility

• Patient has any protocol-excluded or clinically significant medical or surgicalhistory or concomitant medication use that could confound the study assessments