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Developmental and Epileptic Encephalopathy (DEE)Phase 3NCT07723976

A Study to Evaluate the Safety and Efficacy of CBD-OS in Participants With DEE

A Phase 3 study testing CBD-OS in people with Developmental and Epileptic Encephalopathy (DEE), run by Jazz Pharmaceuticals.

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Sites and contacts
Official record
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Trial summary

The efficacy, safety, and tolerability of CBD-OS have been evaluated for the treatment of seizures associated with Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and Tuberous sclerosis complex (TSC). Read more about this study

Who is it for?
Ages 1 year and older
What is being tested?
CBD-OS
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
120 participants
Where
No sites listed yet
Study dates
30 Oct 2026to 4 Sep 2029
Phase
Phase 3
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 1 year and older
  • All sexes
  • No healthy volunteers
  • Child, Adult, Older adult

Participants are eligible to be included in the study only if all the following criteria apply:

  1. Is at least 1 year of age at the time of signing the informed consent/assent.
  2. Meets the clinical phenotype for DEE as specified in the protocol.
  3. Per the investigator, the underlying etiology contributes to developmental impairment and seizures.
  4. Has had, or is willing to complete, confirmatory imaging and/or genetic testing to determine etiology of DEE.
  5. Is currently receiving antiseizure intervention, such as treatment with a stable regimen of at least 1 ASM or an established intervention for epilepsy (eg, ketogenic diet or neurostimulation).
  6. All medications or interventions for epilepsy have been stable for ≥ 28 days prior to starting the baseline period (Visit 2) with no planned changes to the regimen for the duration of the Double-blind Treatment Period.

Participants are excluded from the study if any of the following criteria apply:

  1. Has a concurrent, confirmed diagnosis of non-epileptic seizures or events that can confound the assessment of the efficacy measures, in the opinion of the investigator.
  2. The etiology of the participant's seizures is a progressive neurologic disease.
  3. Has known or suspected hypersensitivity to cannabinoids or any of the excipients of the study intervention, such as sesame oil.
  4. Has an active central nervous system (CNS) infection, demyelinating disease, degenerative neurologic disease, or any CNS disease deemed to be progressive during the study that may confound the interpretation of the study results (including autoimmune encephalitis).
  5. Is currently being treated with Epidiolex or recently received treatment with Epidiolex within 28 days prior to screening.
  6. Has experienced a lack of efficacy and/or poor tolerability to an adequate treatment regimen of Epidiolex based on medical history and the clinical judgement of the investigator. Participants who discontinued treatment for reasons other than safety, tolerability, or lack of efficacy and previously received Epidiolex ≥ 28 days prior to starting the Baseline Period (Visit 2) may be eligible for the study after consultation with the medical monitor and/or sponsor representative.
  7. Has been taking felbamate for less than 12 months prior to screening. Participants who are stable on felbamate for ≥ 12 months are eligible for inclusion.

Trial locations and contacts

No sites are listed yet. Contact the study team or a site near you to ask about taking part.

Clinical Trial Disclosure & Transparency contact

215-832-3750

ClinicalTrialDisclosure@JazzPharma.com

About this study

Official title: A Phase 3, Multicenter, Randomized, Double-blind, Placebo-Controlled Study to Evaluate the Safety and Efficacy of Cannabidiol Oral Solution (CBD-OS, JZP926-OS) in Participants Aged 1 Year and Older With Developmental and Epileptic Encephalopathy (DEE)

The efficacy, safety, and tolerability of CBD-OS have been evaluated for the treatment of seizures associated with Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and Tuberous sclerosis complex (TSC). The current JZP926-303 study is being conducted to evaluate the safety and efficacy of CBD-OS in participants with Developmental and Epileptic Encephalopathy (DEE).

Read the detailed description

This Phase 3, multicenter, randomized, placebo-controlled, double-blind study will evaluate the efficacy and safety of CBD-OS in participants aged ≥ 1 year with DEE. The primary objective of the 6-week Double-blind Treatment Period of the study is to assess the efficacy of CBD-OS in reducing the frequency of countable motor seizures compared with placebo in participants with DEE. In addition, the Double-Blind Treatment Period will also assess the safety and tolerability of CBD-OS. The optional 6-month open-label extension (OLE) will provide additional data on the long-term efficacy, safety, and tolerability of CBD-OS.

Being tested
CBD-OS, Placebo
Keywords
Developmental and Epileptic Encephalopathy, JZP926-OS, CBD-OS

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • CBD-OSDrug

    Also called JZP926-OS

    Oral solution, twice daily

  • PlaceboDrug

    Oral solution, twice daily

Study groups in NCT07723976
Study groupRoleWhat they receive
CBD-OSExperimentalParticipants with DEE will be randomized to CBD-OS up to 10 mg/kg twice daily for a 6-week treatment period.
Receives: Drug: CBD-OS
PlaceboPlacebo comparatorParticipants with DEE will be randomized to matching placebo for a 6-week treatment period.
Receives: Drug: Placebo
Open-Label Extension: CBD-OSExperimentalParticipants with DEE who completed the double-blind phase of the study and enter the optional OLE will begin a 22-week open-label treatment period with CBD-OS up to 10 mg/kg twice daily following a 2-week Blinded Transition Period.
Receives: Drug: CBD-OS

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in Countable Motor Seizure Frequency Per 28 Days

    Measured: Baseline up to 6 weeks of double-blind treatment period

Secondary outcomes (11)

  1. Change in Total Seizure Frequency Per 28 Days

    Measured: Baseline up to 6 weeks of double-blind treatment period

  2. Proportion of Participants Who Achieve ≥ 50% Reduction From Baseline in Countable Motor Seizure Frequency

    Measured: Baseline up to 6 weeks of double-blind treatment period

  3. Caregiver Global Impression of Change (CaGI-C) Score

    Measured: Week 6 of double-blind treatment period

  4. Change from Baseline in Caregiver Global Impression of Severity (CaGI-S) Score

    Measured: Week 6 of double-blind treatment period

  5. Change From Baseline in Number of Countable Motor Seizure-free Days per 28 Days

    Measured: Baseline up to 6 weeks of double-blind treatment period

  6. Clinical Global Impression of Change (CGI-C) Score

    Measured: Week 6 of double-blind treatment period

  7. Change from Baseline in Clinical Global Impression of Severity (CGI-S) Score

    Measured: Week 6 of double-blind treatment period

  8. Number of Participants Reporting Treatment-emergent Adverse Events

    Measured: Baseline up to 6 weeks of double-blind treatment period

  9. Mean Plasma Concentration of CBD

    Measured: Baseline up to 6 weeks of double-blind treatment period

  10. Mean Plasma Concentration of Metabolite 7-OH-CBD

    Measured: Baseline up to 6 weeks of double-blind treatment period

  11. Mean Plasma Concentration of Metabolite 7-COOH-CBD

    Measured: Baseline up to 6 weeks of double-blind treatment period

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted23 Jul 2026
  2. Study start30 Oct 2026 (estimated)
  3. Primary completion4 Sep 2029 (estimated)
  4. Study completion4 Sep 2029 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Double blind
Who is masked
Participant, Investigator
Enrolment
120 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07723976
Sponsor's protocol ID
JZP926-303
Status last verified
Jul 2026
First submitted
20 Jul 2026
Last updated
24 Jul 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
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.

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing CBD-OS in people with Developmental and Epileptic Encephalopathy (DEE), run by Jazz Pharmaceuticals.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: opening soon, as of the sponsor's last update on 24 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Clinical Trial Disclosure & Transparency (215-832-3750, ClinicalTrialDisclosure@JazzPharma.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in Countable Motor Seizure Frequency Per 28 Days (time frame: Baseline up to 6 weeks of double-blind treatment period). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07723976.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Jul 2026.

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