Alixorexton’s Phase II performance sets it up for late-stage success, according to analysts at Truist Securities. Alkermes expects to launch a global late-stage program early next year for narcolepsy type 2.
Alkermes’ investigational orexin 2 receptor agonist alixorexton improved both wakefulness and daytime sleepiness in a mid-stage study of narcolepsy type 2, opening a path for late-stage development.
The 18-mg daily dose of alixorexton met the dual primary endpoints at the eight-week follow-up point of the Phase II Vibrance-1 study. Without providing specific data, Alkermes reported that the drug candidate led to significant improvements in mean sleep latency—how long it takes a patient to fall asleep—as well as daytime sleepiness.
Alixorexton’s 14-mg dose also met significance on mean sleep latency.
In a note to investors on Wednesday, analysts at Truist Securities said these findings are “highly competitive” in the narcolepsy type 2 (NT2) space, and are “good enough to advance & succeed in Ph3.”
Alkermes plans to begin Phase III studies of alixorexton “as quickly as possible,” Chief Medical Officer Craig Hopkinson said in a statement. The biotech expects to launch a global program in the first quarter of 2026.
Designed to be orally available, alixorexton works by selectively activating the orexin 2 receptor, in turn facilitating several wake-promoting pathways affecting the brain. Aside from NT2, Alkermes is also testing the drug in idiopathic hypersomnia and narcolepsy type 1 (NT1).
This broad activity, according to Truist, could help set alixorexton apart in the narcolepsy space. “Our base case is that there will be multiple orexin agonists that reach the market,” the analysts wrote, however pointing out that Alkermes has put in place several strategies that “position alixorexton for commercial success.”
One such strategy is to test the drug across various related sleep disorders. Indeed, at the 2025 World Sleep Congress in September, Alkermes presented data, also from Vibrance-1, demonstrating significantly prolonged sleep latency and improved cognition and fatigue in patients with NT1. Stifel analysts at the time called the cognitive outcomes “especially interesting,” given how patients with NT1 typically present with compromised cognition because of their disease.
Also crucial to alixorexton’s success, according to Truist’s Wednesday note, is Alkermes’ $2.1 billion acquisition of sleep rival Avadel last month. The deal brings into the Alkermes fold the narcolepsy drug Lumryz, which the FDA approved in 2023 to address excessive daytime sleepiness in this disease. The dug is expected to make $265 million to $275 million this year.
