Six hundred and thirty-six women diagnosed with urge urinary incontinence (UUI) by a three-item self-administered questionnaire (3IQ) will be randomized to 12 weeks of fesoterodine or matching placebo. The study will take place at up to 14 clinical sites in the US. All participants who complete the 12-week randomized trial will be offered open-label fesoterodine for an additional 9 months.

The hypothesis of the randomized controlled trial is that among women diagnosed with urge incontinence using the 3IQ, fesoterodine is more effective than placebo in reducing the mean number of urge incontinence episodes per day.

Inclusion Criteria:

• Ambulatory females ≥ 18 years old
• Urge Urinary Incontinence (subject-reported) for ≥ 3 months prior to Screening (Visit 1)
• On the 3IQ: Response b to Question 3: During the last 3 months, did you leak urine most often: b. When you had the urge or the feeling that you needed to empty your bladder, but could not get to the toilet fast enough?
• On a 3-day bladder diary, documentation of an average of 1 UUI episode per 24 hours (3 UUI episodes in 3 days)
• Capability of understanding and having signed the informed consent form after full discussion of the research nature of the treatment and its risk and benefits
• Ability to perform all procedures and tests required by the protocol
• Willingness to remain on stable medication regime for duration of the randomized controlled trial. Participants will be asked to not add new medications during the randomized controlled trial, such as diuretics and other medications which may affect their voiding pattern.

Exclusion Criteria:

• Any condition that would contraindicate their usage of fesoterodine including: hypersensitivity to the active drug (fesoterodine fumarate) and its ingredients or any of the excipients, history of urinary retention, gastric retention, uncontrolled narrow angle glaucoma, myasthenia gravis, severe hepatic impairment (Child Pugh C), severe ulcerative colitis, toxic megacolon, fistula or a hole in your bladder or rectum, birth defect leading to urine leakage, and urine leakage starting in childhood.
• Clinically significant hepatic or renal disease.
• Neurologic conditions such as stroke, multiple sclerosis, spinal cord injury, or Parkinson's disease.
• Symptomatic pelvic organ prolapse defined as participant report of feeling or seeing a bulge outside the vagina within the past 3 months.
• History of lower urinary tract/pelvic surgery (e.g. surgery for incontinence in the past 5 years, surgery in the past 6 months for prolapse or hysterectomy), intra-vesical therapy (botox), and/or bulk injections within the past 6 months.
• A known history of interstitial cystitis or a significant pain component associated with OAB symptoms, uninvestigated hematuria, urogenital cancer, interstitial or external radiation to the pelvis or external genitalia.
• Urinary tract infection (UTI) as shown by the results of the urinalysis at screening or recurrent urinary tract infection (RUTIs) defined as treatment for UTI >3 times in the last year.
• Use of any electrostimulation, bladder training, or pelvic floor exercises (with certified incontinence practitioners) within 4 weeks of Screening.
• Received study medication in any previous fesoterodine clinical trial.
• Prior failure for either efficacy or tolerability of ≥ 2 OAB medications in the last year. (failure: inadequate symptom control after two medications for a minimum of one month each)
• Has been treated within 2 weeks prior to Screening and/or is currently being treated with: - Any drug treatment for overactive bladder, including antimuscarinic OAB medications.
• Any drugs with significant anticholinergic and antispasmodic effects (see exception for tricyclic antidepressants below)
• Has started treatment with tricyclic antidepressants or estrogens within 4 weeks prior to Screening and/or is not on a stable dose.
• Intermittent or unstable use of diuretics. Treatment with diuretics initiated within 2 weeks prior to baseline is not permitted.
• Treatment with potent CYP3A4 inhibitors, such as clarithromycin, ketoconazole, and itraconazole within 2 weeks prior to Screening.
• Administration of medications capable of inducing hepatic enzyme metabolism or transport (e.g., barbiturates, rifampicin, carbamazepine, phenytoin, primidone, or St. John's Wort) in the past 30 days.
• Previously received any investigational drug within 30 days prior to trial entry.
• Alcohol and/or any other drug abuse in the opinion of the investigator.
• Participants who are pregnant, nursing, or with a positive urine pregnancy test or who are intending to become pregnant within 3 months after the completion of the trial.
• Participants that have been pregnant (> 20 weeks gestation) in the previous 6 months.
• Participants of childbearing potential who are heterosexually active but unwilling or unable to use an adequate form of contraception to prevent pregnancy during the study. Reliable contraceptive methods may include intrauterine devices (IUD), contraceptive pills of combination type, hormonal implants, injectable contraceptives or latex condoms with a spermicide.
• Participants who have any medical (including known history of major hematological, renal, cardiovascular, or hepatic abnormalities) or psychological condition or social circumstances that would impair their ability to participate reliably in the trial, or those who may increase the risk to themselves or others by participating.
• Participants who, in the opinion of the investigator, are not likely to complete the trial for whatever reason.