Open-label, Long-term Safety, Efficacy, and Pharmacokinetics Study of Vibegron in Pediatric Subjects 2 Years to < 18 Years of Age With NDO and on CIC

Inclusion Criteria:

* Male or female participants, age 2 years to \< 18 years and weighing at least 11 kg at the Screening Visit.
* Participant has been diagnosed with NDO due to one of the following: spinal dysraphism, which includes spina bifida (eg, myelomeningocele, meningocele) and all forms of tethered cord; or acquired NDO from a spinal cord injury or spinal cord surgery, with the injury/surgery having occurred at least 6 months prior to the Screening Visit; or acquired NDO due to transverse myelitis with diagnosis at least 12 months prior to the Screening Visit.
* Participant undergoes CIC at least 3 times per 24 hours (with the last CIC performed prior to going to sleep for the night) for at least 4 weeks prior to the Screening Visit.

Exclusion Criteria:

* Participant has cerebral palsy, uncontrolled epilepsy, diabetes insipidus, or Stage 2 hypertension
* Participant has an active malignancy in the 12 months prior to the Screening Visit.
* Participant has been administered intravesical botulinum toxin within 9 months prior to the Screening Visit and should remain off this therapy during the study.
* Participant is taking digoxin or lithium within 10 days prior to Screening Visit or plans to start taking either during the study.
* Participant currently uses or plans to use a baclofen pump during the study.
* Participant has had urethral dilatation or urethral surgery in the 3 months prior to the Screening Visit.
* Participant has undergone bladder augmentation surgery.
* Participant has a known genitourinary condition (other than NDO) that may cause overactive contractions or incontinence (bladder exstrophy, urinary tract obstruction, urethral diverticulum or fistula) or bladder stones or another persistent urinary tract pathology that may cause symptoms.
* Participant has an insufficient urethral sphincter, has had implantation of an artificial sphincter, has a surgically-treated underactive urethral sphincter, or, in the 6 months prior to the Screening Visit, has undergone pelvic gender reassignment surgery.
* Participant has one of the following gastrointestinal problems: partial or complete obstruction, decreased motility such as paralytic ileus, risk of gastric retention, or malabsorption syndrome of any form.
* Participant has acute fecal impaction or, within the 3 months prior to the Screening Visit, had fecal impaction that required hospitalization or ambulatory surgical treatment.
* Participant had a urinary indwelling catheter in the 4 weeks prior to the Screening Visit.
* Participant has moderate to severe dilating vesicoureteral reflux (Grade IV to V) or severe renal failure.
* Participant started electrostimulation/neuromodulation therapy in the 4 weeks before the Screening Visit, or is expected to start this therapy during the study period.
* Participant has participated in another clinical trial and/or has taken an investigational drug within 4 weeks prior to the Screening Visit.
* Participant is unable, or parent/caregiver is not willing, to washout any medication for the management of NDO.
* Participant is a female of childbearing potential who is unwilling or unable to use a highly effective method of contraception for the duration of the study.
* Female participants who are currently breastfeeding or plan to breastfeed any time from the Screening Visit until 28 days after the final study drug administration.