Valiloxybate

Following screening visit and verification of inclusion/exclusion criteria and informed consent, participants will undergo a multiple sleep latency test (MSLT) and polysomnogram (PSG) assessments to confirm eligibility for randomization. Participants will be randomized to two groups: placebo or XW10172 MR. The drug will be taken orally at bedtime for 6 weeks of treatment that will consist of a 2-week dose escalation/titration period and a 4-week stable-dose maintenance period. There will be a 2-week safety period following dosing.