Low Sodium Oxybate in Patients With Idiopathic Hypersomnia

Inclusion criteria

• Primary diagnosis of IH, according to ICSD-3 criteria (does not require MSLT)
• Subjects aged 18 - 65 years
• BMI between 18 and 35 kg/m2
• Self-reported sleep duration ≥ 9 hours most days including daytime naps/sleep based upon at least 10/14 days of completed sleep diary entries
• Epworth Sleepiness Scale (ESS) ≥ 10 (required at pre-screening visit only)
• Recommended LSO by a clinical sleep specialist as part of routine medical care. The clinical sleep specialist will be responsible for titrating LSO according to standard of care.
• Subject must be willing to postpone LSO therapy until all baseline assessments completed
• If treated with wake promoting agents, traditional stimulants and/or antidepressant(s), a stable dose and regimen will be required for at least 2 months before study entry and throughout the main study
• Have used a medically acceptable method of contraception for at least 2 full menstrual cycles before participating in this study and consent to use a medically acceptable method of contraception from the first dose of study drug, throughout the entire study period, and for 30 days after the last dose of study drug.

Exclusion criteria

• Succinic semialdehyde dehydrogenase deficiency, porphyria
• Other central nervous system diseases: neurodegenerative diseases, , seizure disorders or history of head trauma associated with loss of consciousness
• Lifetime history of suicide attempt or suicidal ideation in the past six months, including answer to question #9 on PHQ-9 ≥1; PHQ-9 total score > 10; prior history of psychotic episodes; active major depressive disorder
• Change to psychiatric medication(s)/stimulant(s) within last 3 months
• History of chronic alcohol or drug abuse within the prior 12 months
• Malignant neoplastic disease requiring therapy within the prior 12 months
• Heart failure, severe hypertension or other cardiovascular disease compromising the patient's well-being or ability to participate in this study
• Renal or hepatic impairment
• Compromised respiratory function (e.g., history of COPD, pulmonary hypertension, and/or poorly controlled asthma)
• Diagnosis of sleep-related breathing disorders (AHI ≥ 15 events/h using 4 % AHI) or high suspicion for sleep disordered breathing
• Any sleep apnea treatment (e.g., Positive Airway Pressure (PAP) therapy, oral appliance therapy, etc.)
• No regular sleep at night: shift work or other continuous, non-disease-related life conditions
• Participation in another study of an investigational drug within the 28 days prior to Screening visit or currently
• Pregnant and/or breast-feeding
• Ear jewelry and/or piercings that subject not willing to/unable to remove
• Use of device/implant that may interfere with the study devices/procedures (e.g., vagal nerve stimulator)
• Smoke and/or use of smokeless tobacco products
• Subjects who, in the opinion of the investigator(s), may not be suitable for the study