The purpose of this study was to assess the efficacy of Hibero (Mirabegron) versus active control (Ditropan: Oxybutynin Chloride) in the treatment of pediatric subjects (5 to < 18 years of age) with overactive bladder. This study will further evaluate the safety of mirabegron in pediatric subjects with OAB after multiple dose adminstration.

The trial consists of four periods (Screening/ Washout (2 weeks); Baseline; 4 weeks from baseline; 8 weeks from baseline) excluding the safety monitoring period. It is a randomized, open label, parallel group, and active control comparator trial. The subject will be assigned either to Hibero (Mirabegron) 50 mg or Ditropan (Oxybutynin Chloride) 10 mg at baseline (randomization). The subject will be asked to take the IP or active comparator by mouth without crushing the pill for 8 weeks, and the frequency of oral administration depends on the prescribed method.

Inclusion Criteria:

• Subject has been diagnosed with overactive bladder (incontinence, frequent urination, enuresis) according to the International Children's Continence Society (ICCS)
• Ages between 5 and 18
• Subject has baseline body weight of 11 kg
• Subject has symptoms of overactive bladder even after two weeks of wash-out period
• Subject is able to follow and record information on 48 hours voiding diary during the trial period
• Subject is able to swallow oral pill form of Hibero (Mirabegron) or Ditropan (Oxybutynin Chloride)
• Subject has agreed to be followed up for 10 weeks, including the safety monitoring period
• Subject, who is sexually active, has agreed to use at least one effective contraceptive method throughout the trial period, including the safety monitoring period.
• The baseline hCG urine test should be negative for female subject to be enrolled in the trial.
• Subject has normal ECG and vital signs (blood pressure, pulse) at the time of screening

Exclusion Criteria:

• Subject has been diagnosed with congenital lower urinary tract dysfunction, neurogenic detrusor overactivity, or secondary detrusor overactivity.
• Subject is currently in treatment for psychiatric disorder (i.e. depression, attention-deficit/ hyperactivity disorder, bipolar disorder, schizophrenia)
• Subject uses clean intermittent catheterization (CIC) for neurogenic detrusor overactivity or due to urologic dysfunction.
• At the time of baseline (randomization), the urine test returns positive for urinary tract infection (UTI).
• Subject has a history of operation on the lower urinary tract or due to vesicoureteral reflux.
• Subject is unable to swallow the pill form of Hibero (Mirabegron) or Ditropan (Oxybutynin Chloride).
• Subject is unwilling or unable to follow the directions from the clinical trial team.
• Subject has been exposed to either mirabegron or any form of antimuscarinic before the study enrollment (as for antimuscarinic, a subject may be enrolled after two weeks of washout period).
• Subject has anaphylactic reactions either to mirabegron or ditropan
• Subject has moderate to severe hepatic or renal impairment subjects.
• Subject has been prescribed with strong CYP3A4 inhibitors and have moderate-severe hepatic or renal impairment
• Subject with the following conditions: lower urinary tract obstruction, urinary retention, glaucoma, narrow tunnel vision, paralytic intestinal obstruction, moderate-severe cardiovascular impaired, ulcerative colitis
• As both investigational products contain lactose, the administration of the products is prohibited for those with galactose intolerance, Lapp lactase deficiency, glucose-galactose malabsorption
• Subject with uncontrolled hypertension, which is defined as systolic blood pressure greater than or equal to 180 mmHg and/or diastolic blood pressure greater than or equal to 110 mmHg.
• Subject has previous history or currently in treatment for any type of cardiovascular disorders.