A Phase 4 interventional study of Cannabidiol Oral Solution in Lennox-Gastaut Syndrome, sponsored by Jazz Pharmaceuticals. Not yet recruiting at 3 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-22.
Sponsored by Jazz Pharmaceuticals · Phase 4, Interventional, and Treatment
This is a Phase 3b/Phase 4 study. The purpose of this study is to learn more about the efficacy of using CBD-OS as an add-on therapy for the treatment of LGS in adults.
68 studies on the registry are indexed under Lennox Gastaut Syndrome; 14 are open to participants now.
This study's planned enrollment of 40 is close to the median of 40 across 49 interventional studies indexed under Lennox Gastaut Syndrome.
Browse Lennox Gastaut Syndrome studies →Jazz Pharmaceuticals is the lead sponsor of 173 studies on the registry; 18 are open to participants now.
Of its 42 completed or terminated interventional studies of FDA-regulated products, 32 (76%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
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.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
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.
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
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.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
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.
CYP3A (CYP3A4) inhibitors and inducers
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
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.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants who will receive the Cannabidiol Oral Solution (CBD-OS) titrated up to a dose of 20 mg/kg per day or the maximum tolerated dose for 24 consecutive weeks.
Drug: Cannabidiol Oral Solution
100 mg/ml Cannabidiol Oral solution (CBD-OS)
Also known as: JZP926, CBD-OS, Epidiolex, Epidyolex
Percentage of participants reporting 50% or more reduction in their 28-day average countable major motor seizure frequency
Time frame: End of Treatment Period, Week 24
Retention Rate
Retention Rate is defined as percentage of participants completing or continuing CBD-OS treatment at different timepoints in the study
Time frame: At Weeks 8, 12, 16 and 24
Percentage of participants experiencing worsening, change, no change or improvement in in their 28-day average countable major motor and total seizure frequency
As reported in participants' electronic diaries
Time frame: Baseline to Week 4, Baseline to Week 8, Baseline to Week 12, Baseline to Week 16, Baseline to Week 24
Percentage of participants considered treatment responders
Treatment responders will be categorized as those experiencing a 50% or more reduction, a 75% or more reduction or 100% reduction in their 28-day average seizure frequency as reported in participants' electronic diaries
Time frame: Baseline to Week 4, Baseline to Week 8, Baseline to Week 12, Baseline to Week 16, Baseline to Week 24
Change in 28-day average frequency of countable major motor and total seizures
Assessed per 28 days from electronic diary entries
Time frame: Baseline to Week 4, Baseline to Week 8, Baseline to Week 12, Baseline to Week 16, Baseline to Week 24
Change in number of seizure-free days
Assessed per 28 days from electronic diary entries
Time frame: Baseline to Week 4, Baseline to Week 8, Baseline to Week 12, Baseline to Week 16, Baseline to Week 24
Change in CaGI-S severity of seizure scores
Caregiver Global Impression of Severity (CaGI-S) is a single-item, 5-point Likert-type rating scale (ranging from 0 "not severe at all" to 5 "very severe"). Using this scale, caregivers will be asked to rate their impression of the participant's severity of seizures, and the severity of the impact caused by the seizure.
Time frame: Baseline to Week 16, Baseline to Week 24
Change in CaGI-S severity of impact of seizures scores
Caregiver Global Impression of Severity (CaGI-S) is a single-item, 5-point Likert-type rating scale (ranging from 0 "not severe at all" to 5 "very severe"). Using this scale, caregivers will be asked to rate their impression of the participant's severity of the impact caused by the seizure.
Time frame: Baseline to Week 16, Baseline to Week 24
Change in VAS scores
Visual Analog Scale (VAS) is a caregiver-reported tool used to quantify the severity of impact of subjective non-seizure symptoms and assesses sleep, communication, and disruptive behavior. The VAS enables sensitive detection of changes in non-seizure domains (disruptive behavior, Sleep, and Communication) important to patients with LGS and their caregivers. The VAS has a total score ranging from 0 to 100 with the higher score indicating worse conditions.
Time frame: Baseline to Week 16, Baseline to Week 24
Change in CaGI-S severity of level of alertness scores
CaGI-S Alertness is a caregiver single item assessment on a 5-point Likert-type rating scale (ranging from 0 "not severe at all" to 5 "very severe") assessing their impression of participant's severity of level of awareness
Time frame: Baseline to Week 16, Baseline to Week 24
Change in CaGI-S severity of overall condition scores
CaGI-S Overall Condition is a caregiver single item assessment on a 5-point Likert-type rating scale (ranging from 0 "not severe at all" to 5 "very severe") assessing their impression of participant's severity of overall condition
Time frame: Baseline to Week 16, Baseline to Week 24
CaGI-C level of alertness scores
Caregiver Global Impression of Change (CaGI-C) Alertness is a caregiver single item assessment on a 7-point Likert-type rating scale (ranging from 1 "very much improved" to 7 "very severe") assessing their impression of participant's severity of level of awareness
Time frame: At Week 16, at week 24
CaGI-C overall condition scores
Caregiver Global Impression of Change (CaGI-C) overall condition is a caregiver single item assessment on a 7-point Likert-type rating scale (ranging from 1 "very much improved" to 7 "very severe") assessing their impression of participant's severity of overall condition
Time frame: At Week 16, at week 24
Change in CGI-S overall condition scores
Clinician Global Impression of severity (CGI-S) Overall Condition is a clinician single item assessment on a 5-point Likert-type rating scale (ranging from 1 "not severe at all" to 5 "very severe") assessing their impression of participant's severity of level of overall condition
Time frame: Baseline to Week 16, Baseline to Week 24
CGI-C overall condition scores
Clinician Global Impression of Change (CGI-C) Overall Condition is a clinician single item assessment on a 7-point Likert-type rating scale (ranging from 1 "very much improved" to 5 "very much worse") assessing their impression of participant's change of overall condition
Time frame: At Week 16, At Week 24
Change in ELDQOL Behavior subscale scores
Epilepsy and Learning Disabilities Quality of Life (ELDQOL) is designed for the caregiver to rate the quality of life (QOL) in children with severe epilepsy and learning disabilities over the last month. The questionnaire has a total of 28 main questions, grouped into 4 subscales: behavior, seizure severity, mood, and side effects. The ELDQOL behavior subscale includes 9 of the 28 total main questions with a total score ranging from 9 to 36 with the higher score indicating greater behavioral problems
Time frame: Baseline to Week 16, Baseline to Week 24
Change in ELDQOL seizure severity subscale scores
Epilepsy and Learning Disabilities Quality of Life (ELDQOL) is designed for the caregiver to rate the quality of life (QOL) in children with severe epilepsy and learning disabilities over the last month. The questionnaire has a total of 28 main questions, grouped into 4 subscales: behavior, seizure severity, mood, and side effects. The ELDQOL seizure severity subscale includes 14 of the 28 total main questions with a total score ranging from 10 to 56 with the higher score indicating greater seizure severity
Time frame: Baseline to Week 16, Baseline to Week 24
Change in ELDQOL mood scale subscale scores
Epilepsy and Learning Disabilities Quality of Life (ELDQOL) is designed for the caregiver to rate the quality of life (QOL) in children with severe epilepsy and learning disabilities over the last month. The questionnaire has a total of 28 main questions, grouped into 4 subscales: behavior, seizure severity, mood, and side effects. The ELDQOL mood scale subscale includes 1 of the 28 total questions with a total score ranging from 16 to 64 with the higher score indicating greater mood problems
Time frame: Baseline to Week 16, Baseline to Week 24
Change in ELDQOL side-effects profile subscale scores
Epilepsy and Learning Disabilities Quality of Life (ELDQOL) is designed for the caregiver to rate the quality of life (QOL) in children with severe epilepsy and learning disabilities over the last month. The questionnaire has a total of 28 main questions, grouped into 4 subscales: behavior, seizure severity, mood, and side effects. The ELDQOL side-effects profile subscale includes 2 of the 28 total main questions with a score ranging from 19 to 76 with the higher score indicating greater side effects
Time frame: Baseline to Week 16, Baseline to Week 24
Number of participants reporting adverse events leading to discontinuation
Time frame: Up to week 24
Time the adverse events started from baseline
Time frame: Up to week 24
Number of Participants with Abnormal Laboratory Values
Time frame: Up to week 24
Change in suicidal ideation scores
As evaluated by the Columbia-Suicide Severity Rating Scale (C-SSRS). The questionnaire has a total score ranging from 0 to 5 with a score of 0 indicating no suicidal ideation is present.
Time frame: Baseline, up to week 24
Change in number of suicide attempts
As per the response in the C-SSRS
Time frame: Baseline, up to week 24
Percentage of participants requiring inpatient hospitalization due to epilepsy
Time frame: Up to week 24
Change in number of usage of rescue medication
Time frame: Baseline, Up to week 24
Plan to share: Yes — In accordance with ICMJE requirements, Jazz Pharmaceuticals may provide qualified external researchers access to individual participant data (IPD) and clinical trial data that underlie the results of this trial upon request. Qualified researchers can submit a request on https://www.jazzpharma.com/science/clinical-trial-data-sharing/ as outlined. Jazz Pharmaceuticals reserves the right not to consider a request. For inquiries about Jazz's data sharing policy contact clinicaldatasharing@jazzpharma.com.
Data sharing details ↗ · www.jazzpharma.com
No publications or documents are linked to this record.
Start is estimated for Nov 2026; primary completion for Dec 2028, 25 months later.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
Get 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: Cannabidiol