Alkermes announced that its investigational orexin‑2 receptor agonist, alixorexton, met both primary endpoints in the Vibrance‑2 Phase 2 study for narcolepsy type 2. The study demonstrated statistically significant and clinically meaningful improvements in wakefulness, measured by the Maintenance of Wakefulness Test, and in excessive daytime sleepiness, measured by the Epworth Sleepiness Scale, at week 8. The 14 mg and 18 mg doses achieved statistical significance on the wakefulness endpoint, while the 18 mg dose reached significance on the sleepiness endpoint, after adjustment for multiplicity across the three active doses.
The randomized, double‑blind trial enrolled 93 patients and assigned them in a 1:1:1:1 ratio to once‑daily alixorexton at 10 mg, 14 mg, 18 mg, or placebo. All three active doses were well tolerated, with no new safety signals identified and no serious treatment‑emergent adverse events reported. The safety profile supports the feasibility of advancing the drug into a global Phase 3 program slated for the first quarter of 2026.
Alkermes’ results mark the first time an oral orexin‑2 receptor agonist has shown efficacy in a large Phase 2 study for narcolepsy type 2, a rare neurological sleep disorder. The data reinforce the strategic importance of Alkermes’ orexin pipeline and position alixorexton as a potential first‑in‑class treatment option for patients with narcolepsy and related disorders, potentially creating a new revenue stream for the company.
Chief Medical Officer Dr. Craig Hopkinson said the Vibrance‑2 topline results “are the first demonstration in a large, randomized phase 2 study that an orexin 2 receptor agonist can drive clinically meaningful improvements in wakefulness and excessive daytime sleepiness in patients without known orexin deficiency, with a generally well‑tolerated profile.” He added that the findings “provide critical insights that will inform our registrational program.”
Despite the positive clinical data, Alkermes’ stock fell 14 % in pre‑market trading and opened 17 % lower on November 12. Investors cited the fact that the dual primary endpoints were achieved only in the higher dose cohorts (14 mg and 18 mg) and that the data were adjusted for multiplicity, which tempered enthusiasm and raised concerns about the robustness of the efficacy signal and its implications for the upcoming Phase 3 trial.
Alkermes will host an investor webcast on November 12 at 8:30 a.m. Eastern Time to discuss the Vibrance‑2 findings in more detail and outline the next steps for the Phase 3 program. The company’s continued focus on the orexin pipeline signals confidence in the therapeutic potential of alixorexton, while the market reaction underscores the importance of dose‑dependent efficacy and statistical rigor in advancing a novel treatment to regulatory approval.
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