Alkermes Announces Positive Topline Results for Alixorexton in Narcolepsy Type 1 Study.

Alkermes has announced positive topline results from the Vibrance-1 Phase 2 study of once-daily Alixorexton in patients with narcolepsy Type 1. Alixorexton demonstrated clinically meaningful and statistically significant improvements in wakefulness compared to placebo at all doses tested. It also showed robust and consistent improvements in patient-reported outcomes related to disease severity, fatigue, and cognition. Alixorexton was generally well tolerated at all doses tested. The detailed results will be presented at the upcoming World Sleep Congress, supporting advancement to Phase 3 development.

DUBLIN, July 2, 2025 — Alkermes plc (Nasdaq: ALKS) has announced positive topline results from the Vibrance-1 Phase 2 study evaluating its investigational oral orexin 2 receptor (OX2R) agonist, alixorexton, in patients with narcolepsy type 1 (NT1). The study demonstrated statistically significant, clinically meaningful improvements in wakefulness at all doses tested compared to placebo, with alixorexton also showing robust improvements in patient-reported outcomes related to disease severity, fatigue, and cognition.

Alixorexton, previously known as ALKS 2680, is being developed as a once-daily treatment for NT1, narcolepsy type 2 (NT2), and idiopathic hypersomnia (IH). The Vibrance-1 study, a global, randomized, double-blind, placebo-controlled, multiple dose phase 2 study, enrolled 92 patients with NT1. Patients were randomized to receive one of three doses of alixorexton (4 mg, 6 mg, or 8 mg) or placebo once-daily for six weeks.

The primary endpoint, the Maintenance of Wakefulness Test (MWT), showed statistically significant and clinically meaningful improvements from baseline in mean sleep latency compared to placebo at week six (p0.0001 at all doses). Additionally, alixorexton demonstrated statistically significant improvements in excessive daytime sleepiness on the Epworth Sleepiness Scale (ESS) at week six (p0.0001 at all doses) and numerically improved weekly cataplexy rates across all doses compared to placebo, achieving statistical significance at the 6 mg dose (p=0.005).

Alixorexton also showed consistent and clinically meaningful improvements in patient-reported outcomes, including the Narcolepsy Severity Scale (NSS), British Columbia Cognitive Complaints Inventory (BC-CCI), and PROMIS-Fatigue. No treatment-emergent serious adverse events were reported, and most treatment-emergent adverse events were mild to moderate in severity.

Craig Hopkinson, M.D., Chief Medical Officer and Executive Vice President, Research & Development at Alkermes, stated, "These positive topline data represent an important stride forward for the alixorexton development program and Alkermes' broader portfolio of orexin 2 receptor agonists. We are moving forward expeditiously to initiate a global phase 3 program based on these compelling results."

Detailed results from the Vibrance-1 study will be presented at the upcoming World Sleep Congress, taking place from September 5-10, 2025, in Singapore. The company plans to initiate a global phase 3 program for alixorexton in patients with NT1 following the presentation of these data.

References:
[1] https://investor.alkermes.com/news-releases/news-release-details/alkermes-announces-positive-topline-results-vibrance-1-phase-2