This is a Phase 2b, multicenter, randomized, double-blind, placebo-controlled, parallel-group study designed to evaluate the efficacy, safety, and tolerability of solabegron modified release low dose or high dose tablets, compared to matched placebo, administered once daily for 12 weeks to adult female subjects with overactive bladder symptoms (frequency, urgency, and predominantly urgency incontinence) for at least 6 months.

Inclusion Criteria:

• Adult female subjects 18 to 80 years of age, with a ≥ 6-month history of symptoms of overactive bladder including: frequency, urgency, urgency urinary incontinence, and mixed incontinence. Subjects must provide written informed consent and either be of non-childbearing potential or of childbearing potential meeting specific criteria (e.g., negative pregnancy test, sexual inactivity, acceptable methods of birth control, and use of hormonal contraceptives).

Exclusion Criteria:

• Subjects must have no history of pelvic or bladder disease, e.g., uterine prolapse, malignancy, prior surgery, or treatment with botulinum toxin.
• Diabetes insipidus or poorly controlled Type 1 or Type 2 diabetes mellitus
• Cardiac conditions:
• prior cardiovascular events or procedures within 6 months of screening
• congestive heart failure
• abnormal ECG findings, including ECG QT correction interval (QTc) > 470 msec at the Screening Visit
• systolic blood pressure ≥ 180 mmHg or diastolic blood pressure ≥ 100 mmHg, or heart rate > 100 beats per minute
• Abnormal tests of liver function
• History of prior infection due to HIV or hepatitis B or hepatitis C virus
• Allergy or hypersensitivity to solabegron or mirabegron
• Women of childbearing potential: breastfeeding, pregnant, or actively trying to become pregnant
• Participation in a trial of an investigational or marketed drug ≤ 30 days prior to the Screening Visit or in any clinical trial of an investigational drug that may affect urinary function within 3 months prior to Screening Visit.
• Inability to read, understand, or complete study-related materials

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