ALKS 2680 - (Vibrance-1)

July 13, 2026: Alkermes plc (NASDAQ: ALKS) reported results from a planned interim analysis of an ongoing open-label long-term extension (LTE) study of alixorexton (oral selective orexin 2 receptor agonist) in adults with narcolepsy type 1 (NT1) and type 2 (NT2), with a May 12, 2026 data cutoff and efficacy assessed at LTE week 24 (~9 months after first dose for rollover participants from the Phase 2 Vibrance-1/2 trials).

NT1 (Vibrance-1 rollover; 78/92 enrolled; ~90% still on treatment): At week 24, all dose groups achieved normative wakefulness on MWT (MSL ≥20 min), with mean observed MSL ~29 minutes overall; mean ESS was 7.5 (normal range). Median weekly cataplexy rate was 2 at week 24 (across LTE participants). Exploratory patient-reported cognition (BC-CCI) and fatigue (PROMIS-Fatigue) improvements were generally maintained.

NT2 (Vibrance-2 rollover; 63/93 enrolled; ~80% still on treatment): Mean observed MSL was ~18 minutes at week 24; ESS improvements were sustained in the normal range for 14 mg and 18 mg groups (mean ESS 8.9 overall).

Safety: No serious TEAEs reported in NT1 or NT2; most TEAEs were mild/moderate (common events included headache and urinary symptoms; insomnia noted in NT2).

Alkermes said it plans to present the results at an upcoming medical meeting and is enrolling Phase 3 Brilliance studies in NT1/NT2 and continuing the Phase 2 Vibrance-3 study in idiopathic hypersomnia, with completion of Vibrance-3 planned later in 2026.