ALKS Stock Falls Despite Positive Narcolepsy Study Results

Alkermes ALKS announced positive top-line data from the phase II Vibrance-1 study for its oral orexin 2 receptor agonist, alixorexton, in treating narcolepsy type 1. The study showed statistically significant, clinically meaningful improvements in wakefulness and excessive daytime sleepiness across all doses. However, the 6 mg dose was the only one to achieve statistical significance in reducing weekly cataplexy rates. Despite this, treatment with alixorexton was generally safe and well-tolerated. The company plans to initiate a global phase III program for alixorexton in patients with NT1.

Alkermes plc (NASDAQ: ALKS) announced today that its phase II Vibrance-1 study of alixorexton, an oral orexin 2 receptor agonist, has shown statistically significant and clinically meaningful improvements in wakefulness and excessive daytime sleepiness across all doses tested in patients with narcolepsy type 1 (NT1). The study met its primary goal, demonstrating a significant improvement in wakefulness compared to placebo.

Alixorexton, formerly known as ALKS 2680, showed robust and clinically meaningful improvements in patient-reported outcomes related to excessive daytime sleepiness, fatigue, and cognition. The drug candidate was generally well-tolerated across all doses tested. Notably, the 6 mg dose was the only one to achieve statistical significance in reducing weekly cataplexy rates.

The study, a global, randomized, double-blind, placebo-controlled, multiple-dose phase 2 trial, enrolled 92 patients with NT1. Participants were randomized to receive one of three doses of alixorexton (4 mg, 6 mg, or 8 mg) or placebo for six weeks. The primary endpoint, measured by the Maintenance of Wakefulness Test (MWT), showed statistically significant improvements in mean sleep latency compared to placebo at week six (p0.0001 at all doses).

Key secondary endpoints, including the Epworth Sleepiness Scale (ESS) and weekly cataplexy rates (WCR), also demonstrated statistically significant improvements at all doses tested. Patient-reported outcome measures, such as the Narcolepsy Severity Scale (NSS), British Columbia Cognitive Complaints Inventory (BC-CCI), and PROMIS-Fatigue, showed clinically meaningful improvements from baseline compared to placebo.

Alkermes plans to present detailed safety and efficacy results from the Vibrance-1 study at the upcoming World Sleep Congress in September. The company is moving forward with a global phase III program for alixorexton in patients with NT1, based on the positive topline data from the Vibrance-1 study.

References:
[1] https://www.nasdaq.com/articles/alkermes-vibrance-1-phase-2-study-alixorexton-narcolepsy-type-1-meets-primary-goal
[2] https://www.biospace.com/press-releases/alkermes-announces-positive-topline-results-from-vibrance-1-phase-2-study-of-once-daily-alixorexton-in-patients-with-narcolepsy-type-1