Axsome Therapeutics announced today that its drug Sunosi (solriamfetol) successfully met the primary endpoint in a pivotal Phase 3 clinical trial for adults with Attention-Deficit/Hyperactivity Disorder (ADHD), demonstrating statistically significant improvement in ADHD symptoms compared to placebo.
The multicenter, randomized, double-blind, placebo-controlled trial evaluated the efficacy and safety of Sunosi in adult patients with ADHD. Participants receiving Sunosi showed meaningful reductions in ADHD symptoms as measured by the ADHD Rating Scale (ADHD-RS), the study's primary outcome measure.
"These positive Phase 3 results represent an important milestone in addressing the significant unmet needs of adults living with ADHD," said Herriot Tabuteau, MD, CEO of Axsome Therapeutics. "With limited treatment options currently available for adult ADHD patients, Sunosi could potentially offer a valuable new therapeutic approach for this condition."
Dose-Dependent Efficacy and Safety Profile
The trial evaluated multiple dosing regimens of Sunosi, revealing a dose-dependent response in efficacy. Higher doses demonstrated greater symptom improvement, though researchers noted some safety considerations at the highest dose levels tested.
The most commonly reported adverse events included insomnia, decreased appetite, anxiety, and headache, consistent with the known safety profile of Sunosi in its currently approved indications. The company reported that the drug was generally well-tolerated across most dosing groups.
Dr. David Goodman, Assistant Professor at Johns Hopkins School of Medicine and a principal investigator in the trial, commented, "The robust efficacy demonstrated in this trial is particularly encouraging. The dose-dependent response provides important insights for optimizing treatment approaches if Sunosi receives approval for ADHD."
Current Treatment Landscape and Market Potential
ADHD affects approximately 4-5% of adults worldwide, with many patients experiencing significant functional impairment in daily activities, work performance, and social relationships. Current pharmacological treatments for adult ADHD primarily include stimulants and non-stimulant medications, each with limitations regarding efficacy, tolerability, or convenience.
Sunosi, a dopamine and norepinephrine reuptake inhibitor (DNRI), is already FDA-approved for excessive daytime sleepiness associated with narcolepsy and obstructive sleep apnea. This successful trial in ADHD could potentially expand its therapeutic applications.
Industry analysts suggest that approval for adult ADHD would significantly expand Sunosi's market potential. Axsome acquired Sunosi from Jazz Pharmaceuticals in 2022 for approximately $53 million, and the drug generated $57.9 million in revenue in 2022.
Regulatory Pathway and Next Steps
Based on these positive results, Axsome plans to meet with regulatory authorities to discuss the path toward a supplemental New Drug Application (sNDA) for Sunosi in adult ADHD.
"We intend to work closely with the FDA to bring this potential new treatment option to adults with ADHD as efficiently as possible," said Tabuteau. "The robust data from this Phase 3 trial will form the cornerstone of our regulatory submission."
The company indicated that full trial results, including detailed efficacy and safety data, will be presented at upcoming scientific conferences and submitted for publication in peer-reviewed journals.
Clinical Trial Design and Patient Population
The Phase 3 trial enrolled approximately 300 adults diagnosed with ADHD according to DSM-5 criteria. Participants were randomized to receive either Sunosi at various doses or placebo for 6 weeks. The primary endpoint was the change from baseline in the ADHD-RS total score, a validated scale measuring the core symptoms of ADHD.
Secondary endpoints included Clinical Global Impression scales, functional outcome measures, and quality of life assessments. The trial also collected comprehensive safety data, including vital signs, laboratory parameters, and adverse events.
The study design incorporated rigorous inclusion and exclusion criteria to ensure a representative adult ADHD population while maintaining patient safety throughout the trial.
