Shares of Alkermes Plc (NASDAQ:ALKS) moved higher on Wednesday following the release of favorable phase 2 trial results for alixorexton, the companys experimental treatment for narcolepsy type 2. The Vibrance-2 study reached its dual primary endpoints, showing statistically significant and clinically meaningful improvements versus placebo in both wakefulness and excessive daytime sleepiness at the eight-week assessment.
The trial enrolled 93 adults diagnosed with narcolepsy type 2. Once-daily alixorexton produced measurable gains on the Maintenance of Wakefulness Test (MWT) and on the Epworth Sleepiness Scale (ESS). At the start of the study, participants recorded a mean sleep latency of approximately six minutes. By week eight, observed mean sleep latencies rose to roughly 16 minutes for the 10 mg dose and to about 14 minutes for both the 14 mg and 18 mg doses.
On the MWT, the 14 mg and 18 mg dose levels reached statistical significance compared with placebo. For the ESS, which captures patient-reported excessive daytime sleepiness, the 18 mg dose achieved statistical significance. At baseline, the study cohort had an average ESS score near 17, a level consistent with severe excessive daytime sleepiness. By the week eight evaluation, a majority of participants receiving alixorexton across all dose groups reported either normal or only mild excessive daytime sleepiness.
Patient-reported improvements in wakefulness were maintained through a subsequent five-week open-label extension period. The investigational agent also produced clinically meaningful benefits on exploratory patient-reported outcomes that assessed fatigue and cognition.
Alixorexton was generally well tolerated at the doses tested. The trial reported no serious treatment-emergent adverse events. The most frequently observed adverse events among treated participants included pollakiuria, insomnia, micturition urgency, dizziness and headache. Completion rates were high: more than 95% of participants finished the eight-week blinded treatment period, and nearly 90% completed the 13-week open-label extension.
Alixorexton is described as a novel, oral, selective orexin 2 receptor agonist. In addition to narcolepsy type 2, the compound is being developed for narcolepsy type 1 and idiopathic hypersomnia.
Key points
- Vibrance-2 met both primary endpoints at week eight for wakefulness and daytime sleepiness in 93 adults with narcolepsy type 2.
- Objective and patient-reported measures improved across dose groups, with the 14 mg and 18 mg doses significant on MWT and the 18 mg dose significant on ESS.
- The results and tolerability profile are driving market interest in Alkermes, affecting healthcare and biotech equities.
Risks and uncertainties
- The data come from a phase 2 study with 93 participants; further studies are required to confirm findings in larger populations and later phases.
- Adverse events such as pollakiuria, insomnia, micturition urgency, dizziness and headache were observed and may affect tolerability.
- Outcomes reported through an open-label extension reflect non-blinded data collection; longer-term safety and efficacy remain to be established.