Phase 3 Brilliance Studies Begin for Alixorexton in Narcolepsy

Alkermes has initiated the Brilliance phase 3 program to evaluate oral alixorexton versus placebo in adults with narcolepsy type 1 (NT1) and type 2 (NT2).

The phase 3 program includes three randomized, double-blind, placebo-controlled studies conducted over 12 weeks: two NT1 trials (Brilliance NT1 Study 302 and Study 304) and one NT2 trial (Brilliance NT2 Study 303). In NT1, each study will compare two alixorexton dosing regimens with placebo; in NT2, the study will compare three dosing regimens with placebo. Alkermes reports expected enrollment of approximately 150 participants in each NT1 study and approximately 180 participants in the NT2 study, with sites across North America, Asia Pacific, and Europe.

Across all three trials, the primary endpoint is change in mean sleep latency on the Maintenance of Wakefulness Test (MWT), described as an objective assessment of wakefulness versus placebo. Key secondary outcomes include change in Epworth Sleepiness Scale (ESS) score and, for NT1, change in mean weekly cataplexy rate. Additional secondary assessments include patient-reported measures spanning fatigue, cognition, and disease-severity domains.

Dosing comparisons in the Brilliance studies include once-daily and split-dose regimens of alixorexton, with options varying by narcolepsy population and study. Each NT1 trial will randomize participants to one of two alixorexton dosing regimens or placebo, while the NT2 trial will randomize participants to one of three alixorexton dosing regimens or placebo.

Participants who complete the 12-week double-blind portion of a Brilliance study are eligible to enter a long-term, open-label safety study. Alkermes characterizes alixorexton as an investigational, oral selective orexin 2 receptor agonist, and notes prior evaluation in a phase 1 study as well as in the phase 2 Vibrance-1 (NT1) and Vibrance-2 (NT2) studies. Alixorexton has received U.S. Food and Drug Administration Breakthrough Therapy designation for the treatment of NT1.