Axsome Therapeutics has announced that its investigational narcolepsy therapy has met the primary endpoint in a Phase III trial.

AXS-12 (reboxetine), the norepinephrine reuptake inhibitor and cortical dopamine modulator achieved the primary endpoint in the ENCORE trial (NCT05059223), reducing the frequency of cataplexy attacks by 72% at the one-month mark, and 82% at six months.

The multi-centre, two-period Phase III trial sought to evaluate the long-term efficacy and safety of AXS-12 in patients with both narcolepsy and cataplexy. The trial comprised a six-month open-label period consisting of 68 patients, followed by a three-week double-blind, placebo-controlled, randomised withdrawal period.

The company is now looking to submit a new drug application (NDA) before the US Food and Drug Administration (FDA) off the back of its Phase III findings.

Axsome Therapeutics CEO Herriot Tabuteau said: “We are pleased by the improvements not only in cataplexy but also in excessive daytime sleepiness and cognition reported by a majority of patients in the trial with long-term AXS-12 treatment. Importantly, these improvements were accompanied by a favourable long-term safety and tolerability profile. We plan to move expeditiously towards an NDA filing for AXS-12 and intend to request a pre-NDA meeting with the FDA.”

In the second part of the study, investigators used the Narcolepsy Symptom Assessment Questionnaire (NSAQ) to show that patients who were taken off AXS-12 experienced a worsening of their symptoms compared to those continuing on AXS-12 at three weeks.

Michael Thorpy, director of the Sleep-Wake Disorders Center at the Montefiore Medical Center, said: “Clinical evidence continues to support AXS-12 as a novel treatment option for narcolepsy that has the potential to rapidly and durably ameliorate one of the most debilitating symptoms for patients, cataplexy, while also reducing the severity of excessive daytime sleepiness, and improving cognition and overall function.”

Elsewhere in the narcolepsy field, Alkermes has commenced the Phase II Vibrance-2 clinical trial of ALKS 2680 in adults with narcolepsy type 2. Meanwhile, Avadel Pharmaceuticals has dosed the first subject in the Phase III REVITALYZ clinical trial of LUMRYZ for the treatment of idiopathic hypersomnia.