Axsome's Sunosi Shows Mixed Results in Major Depressive Disorder Trial

Axsome Therapeutics has reported mixed results from a phase 3 proof-of-concept study of Sunosi (solriamfetol) in patients with major depressive disorder (MDD). While the trial did not meet its primary endpoint in the overall patient population, it showed promise in treating MDD patients with excessive daytime sleepiness (EDS).

Trial Results and Future Plans

The six-week study, which included 342 participants, failed to demonstrate significant improvements in the primary endpoint for the overall MDD patient group. However, among the 51 participants with severe EDS, daily treatment with a 300-mg dose of Sunosi resulted in "clinically meaningful and numerically greater improvements compared to placebo" on multiple efficacy measures, including the Montgomery-Åsberg Depression Rating Scale.

Based on these findings, Axsome plans to initiate a phase 3 trial specifically targeting MDD patients with EDS later this year. CEO and founder Herriot Tabuteau, M.D., stated, "The promising results with solriamfetol in MDD patients with severe EDS align with its known pharmacology and support its further evaluation in this potentially new indication."

Sunosi's Background and Market Performance

Axsome acquired Sunosi from Jazz Pharmaceuticals in 2022 for $53 million upfront. The drug, a dopamine and norepinephrine reuptake inhibitor, received FDA approval in 2019 for treating EDS associated with narcolepsy or obstructive sleep apnea.

Initially projected to reach peak sales of $500 million, Sunosi's performance under Jazz Pharmaceuticals fell short of expectations, with 2021 sales of $58 million. However, the drug has shown improved market traction under Axsome's management, with sales reaching $94 million in the previous year.

Axsome's Recent Successes and Pipeline

The mixed results for Sunosi in MDD represent a rare setback for Axsome, which has experienced a string of recent successes. The company secured FDA approval for its migraine treatment Symbravo two months ago, a drug with blockbuster potential. Additionally, Axsome's first approved product, the MDD treatment Auvelity, generated sales of $291 million last year.

Axsome continues to explore Sunosi's potential in other indications, including attention-deficit/hyperactivity disorder (ADHD), binge eating disorder, and excessive sleepiness associated with shift work disorder. The company recently reported successful phase 3 trial results for Sunosi in ADHD patients, further expanding its potential applications.