Alkermes hits narcolepsy trial goals but investors remain unimpressed

Alkermes’ OX2R agonist alixorexton met dual primary endpoints in a Phase II trial for narcolepsy type 2 (NT2), but only at higher doses and with adjusted data, triggering a sharp stock drop despite clinical progress.

Why it matters: This result supports alixorexton’s advancement to Phase III, expected to begin in Q1 2026, expanding treatment options for NT1 and NT2. However, investor skepticism underscores concerns about data interpretation and market competition.

Backstory: The Vibrance-2 study showed significant improvements on two key measures (Maintenance of Wakefulness Test and Epworth Sleepiness Scale) for 14mg and 18mg doses, but the data was adjusted for multiplicity, a statistical method to control for false positives, raising concerns about robustness. Alixorexton was well tolerated, with no serious adverse events across 93 patients.

Big picture: The race to develop next-gen narcolepsy treatments is intensifying. Alkermes faces strong competition from Centessa and Takeda, both with promising OX2R agonist candidates and projected launches by 2028.

Zoom in: Alkermes’ stock dropped 17% after the announcement. Adding to the competitive pressure on Alkermes, current non-OX2R treatments like Jazz’s Xywav and Biogen’s Wakix are already billion-dollar therapies and well-established on the market.