A Phase 2/3 interventional study of Epidiolex and Placebo in Sanfilippo Syndrome and Mucopolysaccharidosis III, sponsored by Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center. Recruiting at 1 site in United States. Open to participants aged 4 Years and older. Per ClinicalTrials.gov, last updated 2026-09-15.
Sponsored by Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center · Phase 2/3, Interventional, and Treatment
The goal of this clinical trial is to test cannabidiol in Sanfilippo syndrome. The main questions it aims to answer are: 1) determine the safety of cannabidiol in Sanfilippo syndrome, and 2) explore the efficacy of cannabidiol in treating the neurobehavioral symptoms and functional outcomes of Sanfilippo syndrome.
Each participant's caregiver will be asked to complete surveys related to the participant's behavior, mood, sleep, stooling, pain, and caregiver stress intermittently throughout the study. All participants will be enrolled into one of two cohorts based on enrollment order:
Sanfilippo syndrome, or Mucopolysaccharidosis type III (MPS III), is a rare genetic lysosomal storage disease characterized by the accumulation of heparan sulfate due to insufficient production of lysosomal enzymes. Consequently, a buildup of heparan sulfate causes progressive neurodegeneration, leading to significant neurobehavioral problems. These neurobehavioral symptoms are highly disruptive and distressing to families, have a significant impact on the quality of life of the patients and their families, and likely interfere with adjunctive therapeutic attempts at supporting the child. To date, there are no approved therapies for the treatment of the neurobehavioral symptoms of Sanfilippo syndrome. Cannabidiol (CBD), a compound derived from the cannabis plant but without the psychoactive effects, has been shown to be safe and effective in the treatment of children with severe epilepsy disorders. Studies have shown that CBD improves behavior in children with autism. This study will use Epidiolex, a pharmaceutical-grade purified oral solution of cannabidiol that was approved by the FDA for the treatment of severe pediatric epilepsy disorders. Study subjects will include approximately 35 participants with Sanfilippo syndrome. Participants will undergo baseline clinical evaluations, and neurobehavioral, and functional outcomes will be collected from parent-reported questionnaires. Participants will then receive either Epidiolex or placebo for 16 weeks. Following this period and an 8-week washout, participants will cross over and receive the opposite treatment for 16 weeks. Safety labs and questionnaires will be collected throughout these periods to assess safety and efficacy. Participants and study personnel will be blinded to the treatment status of each participant. When this blinded portion of the trial is completed, all participants will receive Epidiolex open-label for 52 weeks to measure long-term safety. The type and severity of adverse events will be collected to measure safety, and different behavioral and functional outcomes will be collected to measure efficacy.
58 studies on the registry are indexed under Mucopolysaccharidosis III; 16 are open to participants now.
This study's planned enrollment of 35 is above the median of 12 across 33 interventional studies indexed under Mucopolysaccharidosis III.
Browse Mucopolysaccharidosis III studies →Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center is the lead sponsor of 67 studies on the registry; 1 is open to participants now.
Of its 11 completed or terminated interventional studies of FDA-regulated products, 5 (45%) have results posted.
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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.
If taking any of the following, no dose changes for the last 8 weeks:
One of the following criteria are met:
Exclusion Criteria:
Equitable selection will be used when choosing participants. An individual who meets any of the following criteria will be excluded from participation in this study:
Concomitant use of any of the following therapies:
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.
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.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
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.
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.
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.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
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.
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.
Oral Epidiolex (cannabidiol) administered twice daily (BID) Week 1: 5 mg/kg/day BID Weeks 2-8: 10 mg/kg/day BID Weeks 9-16: 20 mg/kg/day BID 8-week washout; cross-over to placebo comparator starting on Week 24.
Drug: Epidiolex
Week 1: Dose escalate to maximum tolerated placebo dose Weeks 2-16: Maximum tolerated placebo dose 8-week washout; cross-over to Experimental group starting at week 24, following the same dose-escalation as the Experimental arm.
Drug: Placebo
Epidiolex (cannabidiol) oral solution is a clear, colorless to yellow liquid containing cannabidiol at a concentration of 100 mg/mL. Inactive ingredients include dehydrated alcohol (7.9% w/v), sesame seed oil, strawberry flavor, and sucralose.
Also known as: Cannabidiol; CBD
Placebo oral solution is a yellow oily solution containing the excipients sesame oil and anhydrous ethanol with added sweetener (sucralose) and strawberry flavoring
Sanfilippo Behavior Rating Scale (SBRS)- mood/anger/aggression score
The Sanfilippo Behavior Rating Scale is a 68-item questionnaire, developed by Shapiro et al to assess the behavioral phenotype of children with Sanfilippo syndrome and its progression over time. The Sanfilippo Behavior Rating Scale mood/anger/aggression cluster is one of four clusters and two domains that make up the Sanfilippo Behavior Rating Scale. A higher score indicates more severe mood/anger/aggression symptoms. Each question within the mood/anger/aggression cluster is scored on a scale of 0-6 and a total mean score is calculated. The mean mood/anger/aggression score is standardized using the mean and standard deviation from a cohort of Sanfilippo patients, categorized as "slow progressors," ages 81-220 months. This reference cohort was chosen to best match the age distribution of our participants.
Time frame: Changes over 16 weeks of treatment versus 16 weeks of placebo
Plan to share: No
No publications or documents are linked to this record.
Started Apr 2026 (actual). Primary completion is estimated for Apr 2027, 12 months after the start.
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Studies of the drug tested here: Cannabidiol
Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center