Study to Evaluate the Efficacy and Safety of Vibegron Administered Orally for 12 Weeks to Women With Irritable Bowel Syndrome

Inclusion Criteria:

- Diagnosis of irritable bowel syndrome (IBS) with predominantly diarrhea (IBS-D) or IBS
with mixed episodes of diarrhea and constipation (IBS-M) according to the Rome IV
criteria

- Has completed a colonoscopy according to the American Gastroenterological Association
criteria, with no clinically significant findings in the last 5 years

- Has no clinically significant findings on a physical examination or clinical
laboratory tests that could interfere with study participation or confound study
assessments, in the opinion of the Investigator. Fecal calprotectin and serum tissue
transglutaminase antibody (IgA) must be negative. (Normal complete blood cell count
and C-reactive protein is required by Rome IV.)

Exclusion Criteria:

- Diagnosis of IBS-C or IBS-U per Rome IV criteria

- History of chronic idiopathic constipation or functional constipation

- Structural abnormality of the gastrointestinal tract or a disease (e.g., known small
intestine bacterial overgrowth) or condition that can affect gastrointestinal motility

- History of a gastrointestinal motility disorder other than IBS (e.g., gastroparesis,
intestinal pseudo-obstruction, achalasia, Parkinsons disease, multiple sclerosis,
spinal cord injury)

- Prior history of a gastrointestinal malignancy, inflammatory bowel disease, celiac
disease

- Planned gastrointestinal or abdominal surgery within the next 6 months

- Co-existing gastroesophageal reflux disease or functional dyspepsia with symptoms
predominant to IBS symptoms

- Symptoms or diagnosis of a medical condition other than IBS that may contribute to
abdominal pain (e.g., interstitial cystitis; fibromyalgia currently being treated with
pregabalin or gabapentin; and endometriosis with uncontrolled abdominal pain)