FDA Approves Once-at-bedtime Sodium Oxybate with Orphan Drug Exclusivity for Narcolepsy

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This marks the first and only FDA-approved once-at-bedtime oxybate for individuals living with narcolepsy.

The US Food and Drug Administration (FDA) approves Avadel Pharmaceuticals’ extended-release formulation of sodium oxybate (LUMRYZ) for cataplexy or excessive daytime sleepiness in adults with narcolepsy. The medication was additionally granted Orphan Drug Exclusivity by the agency.1

This marks the first and only FDA-approved once-at-bedtime oxybate for individuals living with narcolepsy, according to the statement from Avadel.

“This long-awaited therapy for people living with narcolepsy fills a critical unmet need by avoiding the burden of a second middle-of-the-night dose that immediate-release oxybate products require,” stated Michael Thorpy, MD, investigator, REST-ON Phase 3 trial, Director of the Sleep-Wake Disorders Center at Montefiore Medical Center, and Professor of Neurology at the Albert Einstein College of Medicine. “The once-at-bedtime dosing regimen of LUMRYZ may help restore a more natural sleep-wake cycle.”

Positive results from the pivotal Phase 3 REST-ON clinical study completed in March 2020 supported today’s FDA decision. The therapy demonstrated highly statistically significant (p < 0.001) and clinically meaningful improvement compared to placebo across all three co-primary endpoints in the trial.

The FDA has deemed once-a-night oxybate clinically superior to currently marketed twice-nightly oxybate products and granted the drug seven years of Orphan Drug Exclusivity, which is dedicated to supporting the development of drugs that treat rare conditions, or those affecting less than 200,000 US patients.

Narcolepsy is a chronic neurological condition that impairs the brain's ability to regulate the sleep-wake cycle, affecting approximately one in 2000 people in the US.

“As we have heard from key stakeholders, previously approved narcolepsy therapies have the potential to disrupt sleep by either causing insomnia or through forced awakening during the middle of the night for their crucial second dose,” Greg Divis, Chief Executive Officer of Avadel, stated. “LUMRYZ can now offer people with narcolepsy the opportunity for an uninterrupted night sleep while receiving the full benefit of their prescribed treatment in one single bedtime dose that addresses their symptoms of narcolepsy.”


  1. Avadel Pharmaceuticals Announces Final FDA Approval of LUMRYZ™ (sodium oxybate) for Extended-Release Oral Suspension as the First and Only Once-at-Bedtime Oxybate for Cataplexy or Excessive Daytime Sleepiness in Adults with Narcolepsy. Avadel. News Release. May 1, 2023.