DUBLIN, August 24, 2026
Alkermes plc announced the publication of positive Vibrance-1 Phase 2 results for alixorexton in The Lancet Neurology, strengthening the clinical evidence for the investigational oral orexin 2 receptor (OX2R) agonist in adults with narcolepsy type 1 (NT1). The publication highlights statistically significant improvements in wakefulness and cataplexy, alongside clinically meaningful patient-reported improvements involving disease severity, fatigue, cognition and health-related quality of life. The findings are particularly relevant to the ongoing development of alixorexton as Alkermes advances the program into its global Brilliance Phase 3 studies.
Vibrance-1 Shows Broad Clinical Benefits in NT1
The Vibrance-1 Phase 2 study enrolled 92 adults with narcolepsy type 1 and evaluated once-daily alixorexton at 4 mg, 6 mg and 8 mg doses against placebo during a six-week randomized, double-blind treatment period. According to the published findings, alixorexton produced significant improvements in both objective and subjective measures of excessive daytime sleepiness, assessed using the Maintenance of Wakefulness Test (MWT) and Epworth Sleepiness Scale (ESS). Importantly, all three dose groups achieved mean MWT sleep-latency values within the normative range of at least 20 minutes, while ESS scores reached the clinically relevant threshold of 10 or below at Week 6. These results provide key clinical support for alixorexton’s potential to improve daytime wakefulness, one of the major symptoms affecting people living with narcolepsy.
Alixorexton Also Targets Cataplexy and Patient Burden
Beyond wakefulness, the Vibrance-1 results provide evidence across several dimensions of narcolepsy disease burden. The 6 mg alixorexton group demonstrated a statistically significant reduction in weekly cataplexy rate compared with placebo. The study also reported clinically meaningful improvements in exploratory patient-reported outcomes covering overall disease severity, fatigue, cognition and health-related quality of life. This broader effect profile is important because narcolepsy can substantially affect daily functioning beyond excessive daytime sleepiness alone. From a development perspective, the combination of improvements in objective testing, patient-reported outcomes and cataplexy provides Alkermes with a wider clinical evidence base as the company moves toward potentially demonstrating the value of alixorexton across multiple symptoms of NT1.
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Positive Phase 2 Data Support Brilliance Phase 3 Program
Alixorexton was generally well tolerated across the tested doses, with most treatment-emergent adverse events reported as mild to moderate and no serious treatment-emergent adverse events during the study. Alkermes is now advancing alixorexton through the global Brilliance Phase 3 program in adults with both narcolepsy type 1 and narcolepsy type 2, following positive results from its Phase 2 Vibrance program. The company is also evaluating alixorexton in Vibrance-3 Phase 2 for idiopathic hypersomnia. The investigational therapy is designed to selectively activate OX2R, a receptor involved in the brain’s wake-promoting pathways. Alixorexton has received FDA Breakthrough Therapy designation for NT1, while regulatory authorities have also granted orphan designations in relevant indications. The Lancet Neurology publication therefore represents an important scientific milestone for Alkermes as the company seeks to establish whether selective orexin pathway activation can provide a broader treatment approach for patients whose symptoms remain inadequately controlled.
Source:Alkermes press relese
