The purpose of this study is to assess the efficacy and safety of oral OV101 (gaboxadol) in pediatric subjects with Angelman syndrome.

Inclusion Criteria:

• Male or female and 2 to 12 years old (inclusive) at the time of informed consent

• Confirmed molecular diagnosis of AS

• Has a CGI-S-AS score of 3 or more at baseline.

• Meets the following age-appropriate body weight criterion:

  1. Subjects 2 to 3 years old must have a minimum body weight of 9 kg.
  2. Subjects 4 years and older must be between 17 kg and 64 kg (inclusive).

• Stable concomitant mediations for at least 4 weeks before study start

Exclusion Criteria:

• Any condition that would limit study participation
• Clinically significant lab or vital sign abnormalities at the time of screening
• Poorly controlled seizures (weekly seizures of any frequency with a duration more than 3 minutes, weekly seizures occurring more than 3 times per week, each with a duration of less than 3 minutes, or as defined by investigator assessment)
• Use of prescription medications for sleep, minocycline, or levodopa within the 4 weeks prior to Day 1 or during the study. Benzodiazepines chronically administered for seizure control are permitted.
• Cannot comply with protocol study assessments during screening or caregiver unable to comply with study requirements.
• Enrolled in any clinical trial or used any investigational agent within the 30 days before screening or concurrently with this study.

Double (Participant/Care Giver and Investigator/Outcomes Assessor)