— First Large Phase 2 Study of an Orexin 2 Receptor Agonist to Demonstrate Clinically Meaningful and Statistically Significant Improvements in Wakefulness and Excessive Daytime Sleepiness Compared to Placebo in Narcolepsy Type 2 —

— Improvements in Wakefulness and Patient-Reported Cognition and Fatigue Were Sustained Through 13 Weeks —

— Alixorexton Was Generally Well Tolerated at All Doses Tested —

Alkermes plc (NASDAQ:ALKS) today announced detailed positive results from the Vibrance-2 phase 2 dose-ranging study evaluating alixorexton in patients with narcolepsy type 2 (NT2). Once-daily alixorexton met the study's dual primary endpoints, demonstrating statistically significant and clinically meaningful improvements from baseline compared to placebo on the Maintenance of Wakefulness Test (MWT) and Epworth Sleepiness Scale (ESS) at week eight in adults with NT2 (n=93). Patient-reported improvements in wakefulness were sustained through the five-week open-label extension period. Alixorexton also demonstrated clinically meaningful improvements across exploratory patient-reported outcomes (PROs) evaluating fatigue and cognition. Alixorexton was generally well tolerated at all doses tested (10 mg, 14 mg and 18 mg). Alixorexton is a novel, investigational, oral, selective orexin 2 receptor (OX2R) agonist in development for narcolepsy type 1 (NT1), NT2 and idiopathic hypersomnia (IH). Topline results from the Vibrance-2 study were previously announced in November 2025.