A Phase 3 interventional study of Samelisant and Placebo in Narcolepsy, sponsored by Suven Life Sciences Limited. Recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-03.
Sponsored by Suven Life Sciences Limited · Phase 3, Interventional, and Treatment
Among 16 studies in Cataplexy with a site in United States — 4 open to participants now, 4 under way, 4 of them phase 3. Cataplexy · United States.
Among the 16 studies in Cataplexy with a site in United States, this one is the 5th largest by planned enrollment, is one of 4 that started in 2026, is one of 10 in phase 3, and was the 14th registered.
31 studies on the registry are indexed under Cataplexy; 5 are open to participants now.
This study's planned enrollment of 240 is above the median of 117 across 27 interventional studies indexed under Cataplexy.
Browse Cataplexy studies →4 of the 16 studies in Cataplexy with a site in United States are open now, in 10 countries. Each count lists the studies.
Of the 4 Cataplexy studies recruiting now, 2 (50%) set no upper age limit and 2 (50%) stop at 75 or younger; 0 take children under 18; 0 take healthy volunteers.
This study: 18 Years and older · all sexes · no healthy volunteers.
The full table on the hub →16 studies; the count open now beside each. This study's row is marked.
First in 2000; this study’s year is marked. 4 started in 2026.
Median enrollment 195 across the 16 interventional studies. Of the 12 that completed or were terminated, 4 (33%) have results posted.
16 of 16 have an industry lead sponsor. The 10 most frequent:
Suven Life Sciences Limited is the lead sponsor of 15 studies on the registry; 1 is open to participants now.
Of its 7 completed or terminated interventional studies of FDA-regulated products, 2 (29%) have results posted.
Suven Life Sciences Limited has 2 studies filed under Cataplexy — fewer than ten, so there is no comparison to draw.
4 of the studies in Cataplexy with a site in United States that are under way reach primary completion within a year, 4 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT07455383Phase 3Alkermes, Inc.A Study to Evaluate the Efficacy and Safety of ALKS 2680 in Adults With Narcolepsy Type 1 | 2027-05 |
| NCT07598708Phase 3Centessa Pharmaceuticals (UK) LimitedA Study to Investigate the Effects of Cleminorexton Compared With Placebo in the Treatment of Participants With Central Disorders of Hypersomnolence | 2027-09-30 |
| NCT07675135Phase 3Harmony Biosciences Management, Inc.A Phase 3 Efficacy and Safety Study of HBS-301 in Participants With Narcolepsy | 2027-10 |
| NCT07540364Phase 3Suven Life Sciences LimitedA Phase 3 Study to Evaluate the Efficacy and Safety of Samelisant in Patients With Narcolepsy (AWAKE) | 2027-11-19 |
Among the 16 studies in Cataplexy with a site in United States, from their registry updates:
Nothing recorded among them since 2026-09-25.
The primary objective of this study is to evaluate the effect of Samelisant on excessive daytime sleepiness (EDS) after 12 weeks of treatment. In addition, the study aims to assess its effectiveness in influencing the weekly frequency of cataplexy episodes (sudden bouts of muscle weakness) that occur while the individual remains conscious. Other objectives include examining the impact of Samelisant on attention and alertness, overall quality of life, the spectrum of narcolepsy symptoms, and daily functioning, as well as evaluating its safety profile.
This is a Phase 3, randomized, double-blind, placebo-controlled, parallel-group, multicenter study to evaluate the efficacy and safety of Samelisant compared to placebo in the treatment of excessive daytime sleepiness in male or female participants ≥18 years of age with narcolepsy with and without cataplexy.
Participants will be randomized to receive either Samelisant or matching placebo tablets for duration of 12 weeks. Treatment allocation will remain blinded to both participants and investigators throughout the study, except in cases of medical necessity.
31 studies on the registry are indexed under Cataplexy; 5 are open to participants now.
This study's planned enrollment of 240 is above the median of 117 across 27 interventional studies indexed under Cataplexy.
Browse Cataplexy studies →Suven Life Sciences Limited is the lead sponsor of 15 studies on the registry; 1 is open to participants now.
Of its 7 completed or terminated interventional studies of FDA-regulated products, 2 (29%) have results posted.
Compared within Cataplexy, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Narcolepsy. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Key Inclusion Criteria:
Key Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
DSM diagnostic criteria
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Washout period
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: Samelisant
Drug: Placebo
Tablet dosage form, once a day
Also known as: SUVN-G3031
Matching placebo tablets, once a day
Change from Baseline in total Epworth Sleepiness Scale (ESS) score at Week 12
The ESS is a subjective measure of daytime sleepiness. The participant rates on a 4-point Likert scale how likely it is that he/she would doze in 8 different situations. Scoring of the answers is 0 to 3, with 0 being "would never doze" and 3 being "high chance of dozing". The total ESS score ranges from 0 to 24, with higher scores indicating greater daytime sleepiness. A decrease from baseline in ESS score represents improvement.
Time frame: Baseline to Week 12
Change from Baseline for Maintenance of Wakefulness Test (MWT) score at Week 12
MWT is an objective test of sleepiness that evaluates a person's ability to remain awake under soporific conditions for a defined period of time. In the MWT, time from start of the test to the time point of falling asleep will be measured, the total score can range from 0 - 30 minutes. Higher values represent a better outcome.
Time frame: Baseline to Week 12
Change from Baseline in the Clinical Global Impression of Severity of Illness (CGI-S) score as related to excessive daytime sleepiness (EDS) at Week 12
The CGI-S will be used to rate the severity of each participant's illness related to depressive narcolepsy or EDS symptoms on a 7-point scale, which includes the following gradations: 1 = normal, not at all ill; 2 = borderline ill; 3 = mildly ill; 4 = moderately ill; 5 = markedly ill; 6 = severely ill; and 7 = among the most extremely ill.
Time frame: Baseline to Week 12
Change from Baseline in Weekly Cataplexy Rate (WCR) for Narcolepsy Type 1 (NT1) at Week 12
The WCR is a measure designed to evaluate the average weekly cataplexy frequency in participants who experience cataplexy. Participants who experience cataplexy will complete a daily diary to record the number of cataplexy attacks that occur each day beginning after discontinuation of narcolepsy medication and throughout the 12-week treatment phase of the study.
Time frame: Baseline to Week 12
Change from Baseline in Narcolepsy Severity Scale for Clinical Trials (NSS-CT) score for Narcolepsy Type 1 (NT1) at Week 12
NSS-CT is a 15-item self-administered scale that requires participants to evaluate themselves with respect to symptoms and quantitative aspects of cataplexy/sleep attacks; impact on social, family, and work life, hallucinations; and sleep paralysis. Each item requires participants to choose among 4 or 6 options. Scores range from 0 to 57 points with the following breakdown: 0 to 14 (mild), 15 to 28 (moderate), 29 to 42 (severe), 43 to 57 (very severe), where degree of severity describes the impact of the narcolepsy on the participant's life.
Time frame: Baseline to Week 12
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Sep 2026; primary completion for Nov 2027, 14 months later.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Studies of the drug tested here: Samelisant
Suven Life Sciences Limited