0743 Vibrance-2: A Randomized Phase 2 Study Evaluating Efficacy and Safety of the Orexin 2 Receptor Agonist Alixorexton in Patients with Narcolepsy Type 2
Abstract Introduction Narcolepsy type 2 (NT2) is characterized by excessive daytime sleepiness, heterogeneous symptom severity, and typically normal endogenous orexin levels. The Vibrance-2 phase 2 study evaluated alixorexton, a selective orexin 2 receptor agonist, in patients with NT2. Methods Vibrance-2 was a placebo-controlled, dose-ranging phase 2 study. After a 2-week washout from current narcolepsy medications, adults with NT2 meeting ICSD-3-TR diagnostic criteria were randomized 1:1:1:1 to receive placebo or alixorexton once daily at doses of 10, 14, or 18mg for 8 weeks, followed by an optional 5-week open-label extension. Dual primary endpoints were the change from baseline to week 8 in mean sleep latency (MSL) on the Maintenance of Wakefulness Test (MWT) and on the Epworth Sleepiness Scale (ESS). Safety evaluation included treatment-emergent adverse events (TEAEs). P-values were adjusted for multiplicity. Results Ninety-three patients were randomized to placebo (n=24) or alixorexton (10mg, n=23; 14mg, n=22; 18mg, n=24); 90 completed double-blind treatment. At baseline, patients had severe symptoms (MWT: 5.6 minutes; ESS: 17.4). The study met its dual primary endpoints. At week 8, MSL on MWT increased 9.3, 6.7, and 6.7 minutes at 10, 14, and 18mg, respectively, from baseline versus placebo, with statistically significant differences observed for the 14 and 18mg doses (adjusted p< 0.05). ESS improved by -2.1, -3.2, and -3.6 points from baseline versus placebo at week 8 for the 10, 14, and 18mg groups, respectively, with statistical significance observed for the 18mg dose (adjusted p< 0.05), where more than 70% of patients achieved normalization. TEAEs in 10% of all alixorexton-treated patients through week 8 were pollakiuria, insomnia, micturition urgency, dizziness, and headache. Most TEAEs were mild-to-moderate with no serious TEAEs. Conclusion Vibrance-2 was the first large clinical trial in patients with NT2 to demonstrate positive results with an orexin 2 receptor agonist. Alixorexton resulted in statistically significant and clinically meaningful improvements in wakefulness and daytime sleepiness at Week 8 and was generally well tolerated. These results support phase 3 clinical development of alixorexton as a treatment for NT2. Support (if any) Alkermes, Inc.
1246 Examining Unaddressed Needs in Narcolepsy Type 1 Care to Inform Clinical Practice Improvements
Abstract Introduction As targeted treatments for narcolepsy type 1 (NT1) emerge, timely diagnosis and care planning are essential to optimize outcomes. This ongoing initiative aims to identify and address barriers to NT1 recognition and treatment to support practice improvements and patient-centered care. Methods Patient surveys (N=38) were collected in August 2025 through collaboration with the Hypersomnia Foundation to inform an ongoing initiative at five US sleep centers. Results from patient surveys are reviewed at expert-led clinic-based sessions to identify patient needs in care, and case-based discussions challenge participants to apply the latest evidence into practice scenarios. Pre- and post-session surveys are designed to measure the impact on knowledge, confidence, and self-reported performance. Additionally, clinicians will develop strategies for care improvement. Results The top patient-reported barriers to NT1 diagnosis were finding a provider familiar with sleep disorders (42%) and limited appointments/referrals (26%). Ninety-five percent waited over 1 year for formal diagnosis (1-5 years, 71%; 5-10 years, 19%; >10 years, 5%). Narcolepsy symptoms had a significant impact on daily living (82%; 4 or 5 on a 5-point Likert scale), with many patients reporting fatigue (63%), excessive daytime sleepiness (58%), disrupted nighttime sleep (53%), sleep paralysis (50%), and cataplexy (37%) despite treatment. Patients’ top treatment goals were finding a treatment that is effective for their symptoms/type of narcolepsy (61%) and that improves daily functioning/quality of life (55%). However, 19% (1, 2, or 3 on a 5-point Likert scale) reported their care team had not discussed treatment options and 37% (1, 2, or 3 on a 5-point Likert scale) were not routinely asked about treatment goals. Patients were interested in discussing the cause of narcolepsy (63%) and their preferences for treatment (61%). Preliminary findings from the clinic-based sessions have generated practical strategies to address identified gaps in NT1 care. Conclusion Patient surveys uncovered persistent challenges in NT1 diagnosis, communication, and treatment planning. Incorporating these perspectives and case-based scenarios into clinic-based sessions have the potential to improve focused approaches to care and can provide a foundation for integrating evidence into practice as the NT1 landscape evolves. Support (if any) This program was supported by an educational grant from Takeda Pharmaceuticals U.S.A., Inc.
0731 Cognitive and Functional Outcomes from the Phase 3 Open-Label Extension and Randomized-Withdrawal ENCORE Trial of AXS-12 in Narcolepsy with Cataplexy
Abstract Introduction AXS-12 (reboxetine) is a highly selective norepinephrine reuptake inhibitor and cortical dopamine modulator under development for the treatment of narcolepsy. Long-term efficacy and safety of AXS-12 in participants with narcolepsy with cataplexy (NT1) were previously reported from the Phase 3 ENCORE trial. To better understand the impact of AXS-12 on overall functional burden in NT1, we evaluated changes in cognition and functional outcomes during the ENCORE trial. Methods ENCORE included a 24-week open-label extension (OLE) period, followed by a 3-week double-blind randomized-withdrawal (DBRW) period. During the OLE, participants received AXS-12 (5 mg once-daily for 1 week, twice-daily for 23 weeks). Following this, participants were randomized 1:1 to continue twice-daily AXS-12 for 3 weeks or switch to once-daily AXS-12 plus placebo for 1 week, then placebo twice-daily for 2 weeks. P-values reported are nominal. Results ENCORE enrolled 68 participants; 42 completed the OLE and entered the DBRW (AXS-12, n=22; placebo, n=20). In the OLE, participants treated with AXS-12 reported improvement in the NSAQ Ability to Concentrate item at 1 (54.8%) and 6 (58.5%) months. Participants reported improvement in concentration, assessed by PGI-C, at 1 (66.7%) and 6 (70.0%) months. Narcolepsy overall, assessed by the CGI-C, improved at 1 (90.3%) and 6 (90.2%) months; and improved at 1 (77.8%) and 6 (80.0%) months, assessed by the PGI-C. Functional impairment, assessed by the WPAI, was reduced from 53.0% at baseline to 34.0% at 1 month and 24.3% at 6 months. In the DBRW, a greater proportion of participants switched to placebo experienced worsening on the NSAQ Ability to Concentrate item (52.6% vs 14.3%; P=0.011), and PGI-C for ability to concentrate (57.9% vs 22.2%; P=0.029) at 3 weeks compared with those continuing AXS-12. A greater proportion switched to placebo also reported worsening of their narcolepsy overall (PGI-C) at 3 weeks compared with those continuing AXS-12 (52.6% vs 16.7%; P=0.024). Treatment with AXS-12 was generally well tolerated. Conclusion Long-term, open-label treatment with AXS-12 was associated with improvements in cognitive/functional domains and productivity. Randomized withdrawal to placebo led to worsening cognition and narcolepsy overall. These results further support the long-term therapeutic benefit of AXS-12 for narcolepsy. Support (if any) Axsome Therapeutics Inc.