Alkermes plc presents new data from the Vibrance-1 phase 2 study evaluating alixorexton in patients with narcolepsy type 1 (NT1) at the American Academy of Neurology (AAN) 2026 Annual Meeting, taking place April 18-22, 2026 in Chicago. Alixorexton is a novel, investigational, oral, selective orexin 2 receptor (OX2R) agonist in development for the treatment of NT1, narcolepsy type 2 (NT2) and idiopathic hypersomnia (IH).
Vibrance-1, a randomized, placebo-controlled, double-blind phase 2 study conducted in 92 patients with NT1, demonstrated clinically meaningful and statistically significant improvements from baseline compared to placebo in wakefulness, cognition, and fatigue. New data to be presented at AAN augment the detailed positive results from the six-week, randomized double-blind treatment (RDBT) period previously presented at the 2025 World Sleep Congress. The new data demonstrate clinically meaningful improvements from pre-treatment baseline on established measures evaluating excessive daytime sleepiness and cataplexy, as well as participant-reported outcomes, including narcolepsy symptom severity, cognitive functioning and fatigue in patients with NT1 through the seven-week open-label extension. More than 95% (n=88) of participants who entered Vibrance-1 completed treatment in both the six-week double-blind portion of the trial and the seven-week open-label extension for a total of 13 weeks.
“Results from the Vibrance-1 phase 2 study of alixorexton provide a rich and comprehensive dataset that allows us to better understand its treatment effects on core symptoms of narcolepsy type 1. Improvements observed at week 6 across patient-reported measures of disease severity, cognitive functioning and fatigue were sustained through the seven-week open-label extension, supporting the durability of alixorexton’s effects,” said Giuseppe Plazzi, M.D., Ph.D., Neurologist, Director of the Narcolepsy Center at the IRCCS of the Neurological Sciences of Bologna and Professor of Childhood Neuropsychiatry at the University of Modena and Reggio Emilia. “These patient-reported outcomes highlight clinically relevant dimensions of narcolepsy that are often underrecognized, yet central to patients’ daily functioning, and demonstrate alixorexton’s potential to make a meaningful impact for people living with narcolepsy type 1.”
Exploratory patient-reported outcomes (PROs) in Vibrance-1 included the Narcolepsy Severity Scale-Clinical Trials (NSS-CT)1, British Columbia Cognitive Complaints Inventory (BC-CCI)2, Patient Global Impression of Severity (PGI-S) for Cognition3, PROMIS-Fatigue Short-form 6a (PROMIS-Fatigue)4, and PGI-S for Fatigue. 3 Clinically meaningful improvements were seen across all PRO measures at week 6 with alixorexton, with improvements sustained through weeks 12-13.5
Alixorexton was generally well tolerated across all doses tested throughout the six-week, RDBT period and the seven-week open-label extension period. No serious treatment-emergent adverse events (TEAEs) were reported. Most TEAEs were mild to moderate in severity.
“The breadth and depth of the data generated in the Vibrance-1 study provide strong evidence of alixorexton’s potential to meaningfully impact the lives of patients by addressing multiple elements across the spectrum of disease burden of narcolepsy type 1. Importantly, the differentiated profile observed across patient-reported symptom severity, cognition and fatigue highlights alixorexton’s potential to offer a distinct and clinically relevant approach for patients with narcolepsy,” said Craig Hopkinson, M.D. (MBChB), Chief Medical Officer and Executive Vice President, Research & Development at Alkermes. “These data provide a strong foundation for our phase 3 program and reinforce our confidence as we enroll the recently initiated Brilliance Studies in narcolepsy type 1 and type 2. We look forward to further characterizing alixorexton’s efficacy and safety profile in these pivotal trials.”
Details of the poster presentation are as follows:
Poster Number: 14-002
Title: Improvement in Patient-Reported Disease Severity, Cognitive Functioning, and Fatigue in Patients With Narcolepsy Type 1 Treated With Alixorexton, an Orexin 2 Receptor Agonist, in the Vibrance-1 Phase 2 Study
Presenter: Giuseppe Plazzi, M.D., Ph.D., Neurologist, Director of the Narcolepsy Center at the IRCCS of the Neurological Sciences of Bologna and Professor of Childhood Neuropsychiatry at the University of Modena and Reggio Emilia
Presentation Date: Monday, April 20, 2026 from 5:00 – 6:00 p.m. CT during Poster Session 6
Source Alkermes
