Clinical trial Recruiting at 1 site Phase 3 Interventional Ages 18 and up

Samelisant for Narcolepsy: A Phase 3 Test for EDS and Cataplexy

Official title: A Phase 3, Double-blind, Placebo-controlled, Parallel-group, Multicenter Study to Evaluate the Efficacy and Safety of Samelisant Compared to Placebo in Patients With Narcolepsy With or Without Cataplexy

Run by Suven Life Sciences Limited · NCT07540364 · Data updated 2026-11-12

This phase 3 study tests whether Samelisant can reduce daytime sleepiness and cataplexy in adults with narcolepsy.

More Narcolepsy trials

Quick facts

PhasePhase 3
Study typeInterventional
Ages18 Years and up
SexAll
Enrollment240 (estimated)
SponsorSuven Life Sciences Limited
Industry-sponsored
Locations1 site (Columbia, South Carolina)
StatusRecruiting
StartedSeptember 2026
Main results expectedNovember 19, 2027
Study endsDecember 19, 2027
Registry record updatedSeptember 3, 2026
Trial IDNCT07540364 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Adults (≥18 years) with narcolepsy (NT1 or NT2), including those with ongoing cataplexy, who meet specific sleepiness and sleep-wake criteria and consent to the protocol.

Probably not a fit

Patients with narcolepsy who do not respond to Samelisant or who experience adverse effects that necessitate discontinuation may not benefit.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a randomized, double-blind, placebo-controlled study conducted at multiple centers to evaluate the efficacy and safety of Samelisant over 12 weeks in adults with narcolepsy (with or without cataplexy). Participants are assigned to Samelisant or placebo in parallel groups, and neither participants nor investigators know the assignment during the trial. Outcomes include daytime sleepiness, weekly cataplexy events, attention, alertness, quality of life, and overall narcolepsy symptoms, with safety monitoring throughout. Eligibility requires adults with narcolepsy, specific cataplexy history for NT1, sleep study parameters, and consent to adhere to the protocol.

Why it matters

Potential benefit: If successful, participants may experience reduced daytime sleepiness and fewer cataplexy episodes.

How similar studies have gone: This development program builds on prior research in narcolepsy therapies, with mixed success in similar CNS agents depending on endpoints.

Who can join: the full rules

Show full inclusion / exclusion criteria
Key Inclusion Criteria:

1. Body mass index ranging from 18 to 45 kg/m2 (both inclusive).
2. Narcolepsy with or without cataplexy (Narcolepsy Type 1 \[NT1\] or Narcolepsy Type 2 \[NT2\]) based on the International Classification of Sleep Disorders 3-TR/ Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) criteria for the diagnosis of narcolepsy.
3. For NT1 only, current continuing presence of cataplexy as defined by participant report for the last 3 months and have average of ≥4 weekly cataplexy events during the last 2 weeks of the washout period.
4. At the screening Visit and the Baseline Visit, participants who are not on treatment for EDS must have ESS scores ≥12 (as assessed with a look-back period of 1 week).
5. A mean MWT time of \<12 minutes across the first 4 sessions at Baseline.
6. Willingness to complete the study protocol with full compliance with procedures and sign an informed consent form.
7. Able to show compliance with sleep diary entries for at least 5 times/week in the final 2 weeks of the screening Period (non-compliant participants will not be included).

Key Exclusion Criteria:

1. Median habitual wake-up time after 9 am as assessed by sleep diary, habitual sleep time of \<6 h and median habitual bedtime past 1 am, as determined by sleep diary entries.
2. Use of any investigational therapy within the 30-day period (or 5 half-lives, whichever is longer) prior to enrollment.
3. History of (within past 3 months) or current substance use disorder involving illicit drugs, alcohol, or marijuana, as per DSM-5-TR criteria. Alcohol and/or recreational drugs use within 24 hours of study visits is strictly prohibited.
4. Excessive caffeine (defined as \>600 mg/day) use at least 1 week prior to Baseline assessments and during the study.
5. Nicotine dependence that affects sleep (eg, a participant who routinely awakens at night to smoke).
6. If receiving stimulants, modafinil, oxybates, pitolisant, solriamfetol, bupropion or other treatments for narcolepsy, and unwilling or unable to complete weaning 2 weeks prior to Baseline visit (Day 1)
7. Clinically significant ECG abnormalities. Participants are excluded with a screening ECG Fridericia's correction of QT (QTcF) interval ≥450 msec for men and ≥470 msec for women obtained after 5-minute rest in a supine position using a digital ECG.
8. Concurrent use of hypnotics, tranquilizers, centrally acting H1 receptor antagonists, benzodiazepines, anticonvulsants, or clonidine, tricyclic antidepressants that have H1-antihistamine properties (clomipramine, protriptyline).
9. Adjunctive pharmacotherapy directed against cataplexy (including but not limited to venlafaxine, fluoxetine, and gamma hydroxybutyrate) is prohibited.
10. An occupation requiring variable shift work, variable wake times, night shifts, frequent overnight travel or expected overnight travel across \> 3 time zones during the study which disrupts sleep patterns and working remotely leading to inconsistent sleep duration.

Where it's running

  • Bogan Sleep Consultants
    Columbia, South Carolina, United States
    Recruiting

Study contacts

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How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
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Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.