Alkermes plc announced detailed positive results from the Vibrance-2 phase 2 dose-ranging study evaluating alixorexton in adults with narcolepsy type 2 (NT2). Once-daily alixorexton met the study's dual primary endpoints, demonstrating statistically significant and clinically meaningful improvements from baseline compared to placebo on the Maintenance of Wakefulness Test (MWT) and Epworth Sleepiness Scale (ESS) at week eight. These results mark the first large phase 2 study of an orexin 2 receptor agonist to demonstrate such benefits in NT2 patients. Patient-reported improvements in wakefulness were sustained through the five-week open-label extension period.

The randomized double-blind treatment period included 93 participants randomized to receive 10 mg, 14 mg, or 18 mg doses of alixorexton or placebo. On the MWT, the 14 mg (p=0.049) and 18 mg (p=0.047) doses achieved statistical significance, with observed mean sleep latencies of approximately 14 to 16 minutes at week eight compared to a baseline of approximately 6 minutes. On the ESS, the 18 mg dose achieved statistical significance (p=0.046), with participants reporting normal or mild excessive daytime sleepiness by week eight and mean scores within the normal range by week 13.

Alixorexton also demonstrated clinically meaningful improvements across exploratory patient-reported outcomes evaluating fatigue and cognition. Improvements in PROMIS-Fatigue and British Columbia Cognitive Complaints Inventory (BC-CCI) scores were observed as early as week two and continued through week 13. The drug was generally well tolerated at all doses tested, with no serious treatment-emergent adverse events reported. The most common adverse events were pollakiuria, insomnia, micturition urgency, dizziness, and headache.

Based on the positive results from the Vibrance Studies, Alkermes has initiated a global phase 3 program evaluating once-daily and split dose regimens of alixorexton in patients with narcolepsy type 1 (NT1) and NT2. The company is currently enrolling patients in the phase 3 Brilliance Studies for NT1 and NT2 and completing the phase 2 Vibrance-3 study for idiopathic hypersomnia (IH).

Clinical Trial Status

Alixorexton is being evaluated in the following studies:

Regulatory Designations

The U.S. Food and Drug Administration (FDA) has granted alixorexton Breakthrough Therapy designation for NT1 and Orphan Drug Designation (ODD) for the treatment of IH. The European Commission has granted ODD for the treatment of narcolepsy. These designations provide incentives such as tax credits, fee exemptions, and market exclusivity—seven years in the U.S. and up to 10 years in the EU—if approved.

RBC Capital analyst Leonid Timashev has maintained an Outperform rating on Alkermes (NASDAQ: ALKS) while raising the stock's price target to $56 from the previous $45.

Rating and Price Target Update

The adjustment reflects a revised outlook on the company's performance. The new price target of $56 represents an increase over the prior target of $45.