8-K: Alkermes Reports Positive Phase 2 Results for Narcolepsy Drug Alixorexton, Advancing to Phase 3

Alkermes plc announced positive topline results from its Vibrance-1 Phase 2 study of alixorexton, demonstrating significant improvements in wakefulness and patient-reported outcomes for narcolepsy type 1 patients, supporting advancement to Phase 3.

Summary

• Positive topline results were announced from Vibrance-1, a global, randomized, double-blind, placebo-controlled, multiple-dose Phase 2 study evaluating alixorexton (formerly ALKS 2680) in 92 patients with narcolepsy type 1 (NT1).
• Alixorexton is a novel, investigational, oral orexin 2 receptor (OX2R) agonist in development as a once-daily treatment for NT1, narcolepsy type 2 (NT2), and idiopathic hypersomnia (IH).
• Alixorexton met the primary endpoint across all doses tested (4 mg, 6 mg, or 8 mg), demonstrating statistically significant, clinically meaningful, and dose-dependent improvements from baseline compared to placebo in wakefulness on the Maintenance of Wakefulness Test (MWT) at week six (p<0.0001 at all doses).
• The study achieved normative wakefulness (mean sleep latency >20 minutes) across all dose groups on the MWT.
• Alixorexton demonstrated robust and clinically meaningful improvements compared to placebo on patient-reported outcomes related to excessive daytime sleepiness (Epworth Sleepiness Scale, ESS, p<0.0001 at all doses), narcolepsy symptom severity (Narcolepsy Severity Scale, NSS, p<0.001 at all doses), cognitive complaints (British Columbia Cognitive Complaints Inventory, BC-CCI, p<0.0001 at all doses), and fatigue (PROMIS-Fatigue, p<0.01 at all doses).
• Weekly cataplexy rates numerically improved across all doses compared to placebo, achieving statistical significance at the 6 mg dose (p=0.005).
• Alixorexton was generally well tolerated at all doses tested in the randomized double-blind period; no treatment-emergent serious adverse events were reported, and most treatment-emergent adverse events (TEAEs) were mild to moderate in severity.
• No treatment-related safety signals were observed in hepatic and renal parameters, vital signs, or ophthalmic exams.
• More than 95% of patients who participated in the six-week double-blind portion of the trial entered into the seven-week open-label extension, which is ongoing.

Sentiment

Score: 9

Explanation: The results are overwhelmingly positive, meeting primary and key secondary endpoints with strong statistical significance and clinical meaningfulness across multiple symptoms. The drug was well-tolerated, and the company plans to rapidly advance to Phase 3, indicating high confidence. This represents a significant step forward for the drug and the company's pipeline.

Positives

• Alixorexton met its primary endpoint, demonstrating statistically significant (p<0.0001 at all doses) and clinically meaningful improvements in wakefulness on the MWT across all doses tested in NT1 patients.
• Achieved normative wakefulness (mean sleep latency >20 minutes) across all dose groups on the MWT.
• Showed robust and clinically meaningful improvements in patient-reported outcomes for excessive daytime sleepiness (p<0.0001 at all doses), narcolepsy symptom severity (p<0.001 at all doses), cognitive complaints (p<0.0001 at all doses), and fatigue (p<0.01 at all doses).
• Demonstrated statistically significant improvement in weekly cataplexy rates at the 6 mg dose (p=0.005).
• Was generally well tolerated across all doses, with no treatment-emergent serious adverse events reported and most TEAEs being mild to moderate.
• No treatment-related safety signals were observed in key physiological parameters.
• Over 95% patient retention into the open-label extension, indicating strong tolerability and perceived benefit.
• The positive data support rapid initiation of a global Phase 3 program for alixorexton in NT1.

Risks

• Initial clinical results for alixorexton may not be predictive of results of future stages of ongoing clinical studies, future clinical studies, or real-world results.
• Ongoing or future clinical studies for alixorexton may not be initiated or completed on expected timelines or at all.
• Alixorexton could be shown to be ineffective or unsafe in future studies.
• Potential changes in the cost, scope, and duration of the alixorexton development program.
• General risks and uncertainties described in the company's Annual Report on Form 10-K for the year ended December 31, 2024, and in subsequent SEC filings.

Future Outlook

The positive topline data from Vibrance-1 support the rapid initiation of a global Phase 3 program for alixorexton in patients with narcolepsy type 1. Alkermes believes the therapeutic potential of orexin 2 receptor agonists extends beyond improvements in wakefulness to other symptoms like fatigue and cognition. Ongoing Phase 2 studies (Vibrance-2 for NT2 and Vibrance-3 for IH) are continuing.

Management Comments

• "These compelling results demonstrated that once-daily alixorexton normalized wakefulness and excessive daytime sleepiness scores in highly symptomatic patients with narcolepsy type 1 with a generally well tolerated profile across all doses tested. In addition, the initial data from patient-reported outcome measures related to fatigue and cognition are truly exciting and highlight the breadth of benefit that alixorexton may provide across multiple facets of narcolepsy." 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.
• "There is a clear and pressing need for new therapies for narcolepsy type 1, as patients continue to face a range of persistent symptoms that disrupt their day-to-day lives. These exciting data underscore the transformative potential of orexin 2 receptor agonists for the treatment of narcolepsy type 1 and highlight the differentiated features of alixorexton." Giuseppe Plazzi, M.D., Ph.D.
• "Based on the positive outcomes across multiple symptoms important to patients, we are moving forward expeditiously to initiate a global phase 3 program. We look forward to sharing detailed data from Vibrance-1 at the World Sleep meeting in September." Craig Hopkinson, M.D., Chief Medical Officer and Executive Vice President, Research & Development at Alkermes.
• "These positive topline data represent an important stride forward for the alixorexton development program and Alkermes broader portfolio of orexin 2 receptor agonists. Alkermes is at the forefront of development in this exciting potential therapeutic category, and these data support our hypothesis that the therapeutic potential of orexin 2 receptor agonists extends beyond improvements in wakefulness to other symptoms such as fatigue and cognition in narcolepsy." Craig Hopkinson, M.D.

Industry Context

The development of orexin 2 receptor (OX2R) agonists represents a significant advancement in the treatment of hypersomnolence disorders like narcolepsy. Orexin is a key regulator of wakefulness, and targeting this system offers a promising approach to address excessive daytime sleepiness and other symptoms. Alkermes is positioning itself at the forefront of this therapeutic category, with alixorexton showing potential to address a broader range of symptoms beyond just wakefulness, including fatigue and cognition, which are critical for patients' quality of life. This could differentiate it from existing treatments.

Comparison to Industry Standards

• Alixorexton achieved normative wakefulness (mean sleep latency >20 minutes) on the MWT, which is a key benchmark for effective narcolepsy treatments.
• The results suggest a broad benefit across multiple symptoms (wakefulness, excessive daytime sleepiness, fatigue, cognition, cataplexy) which could differentiate it from other treatments that may focus on a narrower set of symptoms.
• The high patient retention rate (over 95%) into the open-label extension suggests a favorable patient experience, which is a strong indicator for future adoption compared to therapies with less favorable tolerability profiles.
• The document highlights a "clear and pressing need for new therapies for narcolepsy type 1" and the "transformative potential of orexin 2 receptor agonists," implying that current standards are insufficient or that this class of drugs offers a significant improvement.

Stakeholder Impact

• Shareholders: Positive impact due to successful clinical trial results, de-risking of a key pipeline asset, and potential for future revenue from a new drug.
• Patients (Narcolepsy Type 1): Potential for a new, effective, and well-tolerated once-daily oral treatment that addresses a broad range of symptoms including wakefulness, excessive daytime sleepiness, fatigue, and cognition, potentially improving quality of life.
• Healthcare Providers: New therapeutic option for managing narcolepsy type 1.
• Employees: Positive impact on morale and job security due to successful research and development progress.

Next Steps

• Present detailed safety and efficacy results from the Vibrance-1 study in an oral presentation at the World Sleep Congress, taking place September 5-10, 2025, in Singapore.
• Rapidly initiate a global Phase 3 program for alixorexton in patients with narcolepsy type 1.
• Continue ongoing Phase 2 studies: Vibrance-2 (NCT06555783) evaluating alixorexton in adults with narcolepsy type 2 (NT2) and Vibrance-3 (NCT06843590) evaluating alixorexton in adults with idiopathic hypersomnia (IH).
• Continue the seven-week open-label safety extension portion of the Vibrance-1 study, followed by a long-term safety study for participants.

Key Dates

Recommendation

Keywords

Alkermes, ALKS, alixorexton, ALKS 2680, narcolepsy type 1, NT1, orexin 2 receptor agonist, OX2R, Vibrance-1, Phase 2, clinical trial, topline results, wakefulness, excessive daytime sleepiness, cataplexy, fatigue, cognition, biopharmaceutical, neuroscience