FDA Approves Toviaz for Overactive Bladder

Laurie Barclay, MD

November 03, 2008

November 3, 2008 — The US Food and Drug Administration (FDA) has approved fesoterodine fumarate (Toviaz, Pfizer) for the treatment of overactive bladder (OAB) in adults. Fesoterodine, which is already available in Europe, will be available in the United States in the first half of 2009.

By relaxing the bladder muscle and regulating involuntary bladder contractions, fesoterodine fumarate reduces urinary frequency, the urge to urinate, and sudden urinary incontinence associated with OAB.

Although OAB affects approximately 1 in 6 Americans, it still remains highly undertreated, according to a news release by the drug's manufacturer.

"Patients who suffer from [OAB] face quality of life issues that can hamper their ability to enjoy life to its fullest," George Benson, MD, deputy director of the Division of Reproductive and Urologic Products at the FDA's Center for Drug Evaluation and Research, said in an FDA news release. "This new drug will provide an additional treatment option to help them manage problems with [OAB]."

The once-daily, extended-release tablet is available in 4-mg (recommended starting dose) or 8-mg dose strengths. Depending on individual patient response and tolerability, the dose may be increased from 4 to 8 mg if needed. Fesoterodine is not approved for pediatric use.

The structure of fesoterodine fumarate is chemically similar to that of tolterodine tartrate (Detrol LA, Pfizer). The latter drug, in extended-release capsule formulation, is currently the most prescribed drug for OAB medication.

Approval of fesoterodine was based on two 12-week, phase 3 randomized controlled trials to determine the safety and efficacy of the 4- and 8-mg doses. In the combined trials, a total of 554 patients were assigned to receive placebo, 554 patients to receive fesoterodine 4 mg daily, and 566 patients to receive fesoterodine8 mg daily. Mean age of the participants was 58 years, and most were women.

Both studies showed a statistically significant, clinically meaningful improvement in reducing the number of voiding episodes per day (19% reduction with fesoterodine 8 mg vs 11% with placebo) and the number of urinary incontinence episodes per day (88% median reduction in urge urinary incontinence with fesoterodine 8 mg vs 50% with placebo). Reductions in urge incontinence occurred as early as week 2 of treatment and were maintained for 12 weeks.

"The FDA approval of Toviaz is good news for patients and treating physicians," said Victor Nitti, professor and vice chairman of urology at the New York University Langone Medical Center and a principal investigator for the drug. "Clinical trials with Toviaz showed strong efficacy and favorable tolerability, and the ability to titrate the dose of Toviaz allows physicians flexibility in treating each patient based on individual history and need."

The most frequently reported side effect of fesoterodine is dry mouth (incidence, 7% for placebo, 19% for fesoterodine 4 mg, 35% for fesoterodine8 mg). Most cases of dry mouth were mild to moderate, causing discontinuation in less than 1% of patients. Incidence of constipation was 2% with placebo, 4% with fesoterodine 4 mg, and 6% with fesoterodine 8 mg. Dry eyes and difficulty voiding occurred less often.

The dose of fesoterodine should not be increased above 4 mg in patients with severe renal impairment or in patients taking ketoconazole or other medications that inhibit the metabolism of fesoterodine.

Contraindications to use of fesoterodine include urinary or gastric retention; uncontrolled, narrow-angle glaucoma; and severe hepatic impairment. In patients with severe constipation or other types of decreased gastrointestinal motility, fesoterodine should be used only with caution.


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