Hyderabad-based Suven Life Sciences today announced positive topline results from a Phase 2 clinical trial evaluating its investigational drug samelisant for the treatment of excessive daytime sleepiness (EDS) in adult patients with narcolepsy.
The randomized, placebo-controlled study met its primary endpoint, demonstrating that samelisant treatment resulted in a statistically significant and clinically meaningful reduction in EDS at day 14 compared to placebo, as measured by the Epworth Sleepiness Scale (ESS) total score.
Samelisant also showed statistically significant improvements compared to placebo on secondary efficacy measures including the Clinical Global Impression-Severity (CGI-S) scale for EDS, the Patient Global Impression of Change (PGI-C), and the Clinical Global Impression of Change (CGI-C).
The company said samelisant was generally safe and well-tolerated, with no serious adverse events or deaths reported in the trial.
Narcolepsy is a chronic neurological disorder characterized by EDS, which refers to persistent sleepiness and the inability to stay awake and alert during the day resulting in unintended lapses into drowsiness or sleep. EDS is one of the main symptoms that can significantly impair daily functioning in narcolepsy patients.
Current standard of care medications such as stimulants and wake-promoting agents have limited efficacy and undesirable side effects in many patients. Samelisant is an investigational selective histamine 3 receptor antagonist that promotes wakefulness by increasing the levels of histamine, norepinephrine and dopamine in the brain.
According to Suven Life Sciences, the significant reduction in EDS seen with samelisant in this Phase 2 study underscores its potential as an emerging therapeutic option that can meaningfully improve EDS symptoms in people living with narcolepsy.
Study Details
The Phase 2 trial enrolled 190 narcolepsy patients between ages 18-65 years. Participants were randomized equally into three arms – placebo, samelisant 2 mg, and samelisant 4 mg administered once daily.
The study was conducted across approximately 60 sites in the US and Canada. The 14-day treatment period was selected based on the rapid onset of action observed with samelisant from earlier Phase 1 results.
The primary outcome measure was change in ESS total score from baseline to day 14. The ESS is a validated 8-item questionnaire that subjectively measures a person’s general level of daytime sleepiness.
Key Efficacy Results
Patients treated with the 2 mg dose of samelisant showed a statistically significant improvement in ESS total score compared to placebo at day 14, the primary endpoint. The higher 4 mg dose also numerically reduced ESS but did not achieve statistical significance.
For the key secondary endpoint, both the 2 mg and 4 mg doses produced statistically significant decreases in CGI-S scores for EDS versus placebo.
Similarly, samelisant treatment led to significant improvements in the secondary PGI-C and CGI-C endpoints that assessed global impressions of change in EDS severity relative to baseline.
Safety Outcomes
Suven reported samelisant was well tolerated, with mostly mild-to-moderate side effects. The most common adverse events were headaches, nausea, and dizziness. The rate of discontinuations due to adverse events was low across treatment arms. There were no deaths or serious adverse events observed during the study.
Based on the positive Phase 2 results, Suven Life Sciences plans to request an End-of-Phase 2 meeting with the US FDA in Q1 2024 to discuss the study data and design of a Phase 3 clinical program needed to support registration of samelisant for narcolepsy.
The company will present the full trial data at upcoming medical conferences, including at the Neuroscience 2023 conference to be held in Washington DC in November this year.
Samelisant has the potential to be the first approved H3 receptor antagonist for narcolepsy if the late-stage studies meet their objectives.
Narcolepsy is a chronic neurological disorder that impairs the brain’s ability to regulate normal sleep-wake cycles. People with narcolepsy experience daytime sleep episodes, sleep paralysis, hallucinations, and in some cases episodes of cataplexy triggered by emotions.
It is estimated to affect over 200,000 Americans. There is currently no cure for narcolepsy. Treatments focus on managing symptoms through medications, lifestyle changes, and behavioral therapies.
Suven Life Sciences is a clinical stage biopharmaceutical company focused on developing novel therapies for central nervous system (CNS) disorders.
Headquartered in Hyderabad, Suven has a pipeline of 7 clinical-stage assets targeting cognitive impairment, neuropsychiatric conditions, sleep disorders, and other CNS indications with high unmet need.
