Open-label Phase 3 Study With Mirabegron in Children From 3 to Less Than 18 Years of Age With Neurogenic Detrusor Overactivity

Inclusion Criteria: * Subject has a body weight of greater than or equal to 11 kg. * Subject suffers from NDO confirmed by urodynamic investigation at baseline. The diagnosis of NDO must be confirmed by the presence of at least 1 involuntary detrusor contraction \> 15 cm H2O from baseline detrusor pressure, and/or a decrease in compliance leading to an increase in baseline detrusor pressure of \> 20 cm H2O. * Subject has been using CIC for at least 4 weeks prior to visit 1/screening. * Subject has a current indication for drug therapy to manage NDO. * Subject is able to take the study drug in accordance with the protocol Exclusion Criteria: * Subject has a known genitourinary condition (other than NDO) that may cause overactive contractions or incontinence or kidney/bladder stones or another persistent urinary tract pathology that may cause symptoms. * Subject has one of the following gastrointestinal problems: partial or complete obstruction, decreased motility such as paralytic ileus, subjects at risk of gastric retention. * Subject has a urinary indwelling catheter within 4 weeks prior to visit 1/screening. * Subject has a surgically treated underactive urethral sphincter * Subject has vesico-ureteral reflux grade 3 to 5. * Subject has undergone bladder augmentation surgery. * Subject receives electrostimulation therapy, if started within 30 days before visit 1/screening or is expected to start during the study period. Subjects who are on an established regimen may rema…