FDA approves mirabegron for overactive bladder

FDA has approved mirabegron (Myrbetriq, Astellas Pharma US, Inc.) to treat adults with overactive bladder (OAB), a condition in which the bladder muscle cannot be controlled, squeezes too often, or squeezes without warning.

Mirabegron, a once-daily oral selective B3-adrenoceptor agonist, was recommended for approval in April. Mirabegron has been studied extensively in more than 10,000 individuals over the last 10 years, according to PR Newswire.

An extended-release tablet taken once daily, mirabegron improves the storage capacity of the bladder by relaxing the bladder muscle during filling. Symptoms of OAB include the need to urinate too often (urinary frequency), the need to urinate immediately (urinary urgency), and the involuntary leakage of urine as a result of the need to urinate immediately (urge urinary incontinence).

“An estimated 33 million Americans suffer from overactive bladder, which is uncomfortable, disrupting, and potentially serious,” said Victoria Kusiak, MD, deputy director of the Office of Drug Evaluation III in FDA’s Center for Drug Evaluation and Research, in an FDA press release. “Today’s approval provides a new treatment option for patients with this debilitating condition.”

Mirabegron’s safety and efficacy were demonstrated in 3 double-blind, placebo-controlled, multicenter clinical trials. A total of 4,116 patients with OAB were randomly assigned to take mirabegron at doses of 25 mg, 50 mg, 100 mg, or a placebo once daily for 12 weeks.

Results showed that mirabegron 25 mg and 50 mg effectively reduced the number of times a patient urinated and the number of times a patient had wetting accidents during a 24-hour period. Patients taking mirabegron 50 mg also expelled a greater amount of urine, demonstrating the drug’s effectiveness in improving the storage capacity of the bladder.

The most common side effects observed in the trials were increased blood pressure, common cold-like symptoms (nasopharyngitis), urinary tract infection, constipation, fatigue, elevated heart rate (tachycardia), and abdominal pain. Mirabegron is not recommended for use in those with severe uncontrolled high blood pressure, end-stage kidney disease, or severe liver impairment.