Alkermes plc (NASDAQ: ALKS) announced that its investigational drug alixorexton received orphan drug designations from regulatory authorities in the United States and Europe for treating rare sleep disorders.

The U.S. Food and Drug Administration granted orphan drug designation to alixorexton for treating idiopathic hypersomnia, while the European Commission provided the designation for narcolepsy treatment. Alixorexton is an oral, selective orexin 2 receptor agonist being developed to treat narcolepsy type 1, narcolepsy type 2, and idiopathic hypersomnia.

Orphan drug designation provides development incentives for treatments targeting rare diseases. In the U.S., benefits include tax credits for clinical testing, exemptions from certain FDA fees, and seven years of market exclusivity if approved. European designation offers protocol assistance, reduced regulatory fees, and up to 10 years of market exclusivity upon approval.

The drug previously received Breakthrough Therapy designation from the FDA for narcolepsy type 1 treatment. Alkermes is currently conducting phase 3 Brilliance Studies in adults with narcolepsy type 1 and type 2, and a phase 2 Vibrance-3 study in adults with idiopathic hypersomnia.

"These orphan drug designations represent important milestones for the alixorexton program," said Craig Hopkinson, Chief Medical Officer at Alkermes, according to the company's press release.

Narcolepsy affects the brain's ability to regulate sleep-wake cycles, with excessive daytime sleepiness as the primary symptom. Idiopathic hypersomnia is characterized by excessive daytime sleepiness despite normal sleep durations and affects an estimated 40,000 people in the U.S.