The Plecanatide Chronic Idiopathic Constipation (CIC) Study

This is a Phase IIb/III, randomized, double-blind, placebo-controlled, 12-Week, Repeat, Oral Dose Ranging, study to determine the safety and efficacy of plecanatide in patients with chronic idiopathic constipation (CIC). Subjects diagnosed with CIC via modified Rome III criteria will be screened against the inclusion and exclusion criteria for the study and enter a 2 Week pre treatment screening. During this phase patients will be required to call in their bowel movements (BM diary) as they occur, and call at least once daily to complete a patient diary of questions on their symptoms (Symptom Diary) associated with CC, as they will throughout the trial. Patients who complete at least 5 days of dosing per week, 6 of each 7 day period of BM diary calls, and continue to have less than 3 complete spontaneous movements per week (as well as meeting other inclusion and exclusion criteria) will be enrolled and randomized to one of three plecanatide doses 0.3 mg, 1.0 mg, and 3.0 mg or placebo. 880 patients will be randomized with the intent of having 200 patients per treatment group (each group the same size) included in efficacy analyses. All subjects receiving at least one dose of plecanatide or matching placebo will be included in the safety analyses.