Clinical Trials and Observational Studies
Participate in Research
Clinical Studies in STXBP1 Disorders
Research is not just the responsibility of scientists and doctors. It is important that patients participate to whatever extent they are able, including: 1) sharing their information so researchers can understand how STXBP1 disorders affect individuals; and 2) volunteering for clinical studies or trials to help doctors understand how treatments affect patients. In rare diseases such as STXBP1 disorders, it can be difficult for potential treatments to reach the required number of participants to be granted FDA approval. In the absence of large numbers, we must leverage the resources we do have, which include our strong patient community.
Clinical studies seek to answer questions such as:
What symptoms do patients experience, and how do the symptoms change over time?
Does this investigational drug work?
Does it work better than another medicine already available?
Does it cause any side effects?
Are there any other benefits that could improve patient quality of life?
Clinical Studies include both Clinical Trials, where treatments are being tested, and Observational Studies, where the goal is to better understand patient symptoms with current Standard of Care.
Clinical Trials
Thanks to community engagement and study participation, the first clinical trials in STXBP1 disorders have started, and there are many more therapies under development in the pipeline.
Clinical trials are research studies performed in people and test new ways to detect, diagnose, treat or prevent diseases. Below is a list of current or planned clinical trials involving STXBP1 disorders.
For a general overview of clinical trials click here.
And, to see how you can help the STXBP1 community get ready for clinical trials go here.
-
Bexicaserin (LP352) is a selective serotonin receptor agonist drug that is under development for the treatment of seizures in individuals with developmental epileptic encephalopathies (DEEs) including STXBP1-RD.
The DEEpOCEAN Study is a Phase 3 trial investigating the efficacy, safety, and tolerability of Bexicaserin in the treatment of seizures in children and adults with DEEs. Lundbeck/Longboard Pharmaceuticals is sponsoring the trial.
Site: 80 sites in 17 countries, including over two dozen in the US
Enrollment: 320 participants
More information:
Lundbeck video from Jan 2026 presentation to STXBP1 community: https://www.stxbp1disorders.org/blog/deep-ocean-study-for-bexicaserin-from-lundbeck
Please visit these websites more information and to see if your loved one qualifies to take part in the study
Rest of World: https://deepdeestudy.global/
Additional information can be fournd here: https://clinicaltrials.gov/study/NCT06719141
Status: *This study IS currently enrolling participants*
-
Relutrigine is a first-in-class small molecule with a mechanism of precision sodium channel modulation that is under development for the treatment of seizures in individuals with developmental epileptic encephalopathies (DEEs).
The EMERALD Study is a Phase 3, randomized, placebo-controlled trial investigating the efficacy, safety, tolerability, and pharmacokinetics of Relutrigine in the treatment of seizures in children and adults with DEEs. Praxis Medicines is sponsoring the trial.
Site: Families can choose to participate from home, in-clinic, or combined participation.
Enrollment: 160 participants
More information:
Please visit https://resiliencestudies.com/ for more information and to see if your loved one qualifies to take part in the study
Additional information can be found here: https://clinicaltrials.gov/study/NCT07010471
Status: *This study has fully enrolled*
Though the study has now closed, any family interested in Praxis' Expanded Access Program can have their primary neurologist submit a request to EAP@praxismedicines.com. Information on the Expanded Access Program is available here: https://praxismedicines.com/eap. Praxis will review on a case by case basis.
-
UCB Biosciences, in partnership with Citizen Health, is conducting a Phase 3 clinical trial called STARS that is investigating the drug Staccato Alprazolam for prolonged seizures.
The study is for patients aged 12 years and older with focal or generalized epilepsy (or both) and who experience seizures lasting longer than 3 minutes.
Sites: Multiple clinic sites in 14 countries
Enrollment: 250 participants
More information:
Citizen Health, a secure, patient-focused, digital platform is supporting this study. To learn more or speak with someone from the Citizen Health team, please call (855) 244-4550 or email stars@citizenhealth.com
Additional Information:
Prolonged Epileptic Seizures Research | The Stars Study
ClinicalTrials.cov: NCT05077904
Status: This study IS currently prescreening and enrolling participants
-
This is a pilot non-controlled clinical trial with adjunctive fenfluramine for the treatment of five different types of developmental and epileptic encephalopathies (DEEs), including STXBP1, focused on epileptic and "non-epileptic outcomes for patients of 2 to 35 years of age.
Site: Madrid, Spain
More information: https://clinicaltrials.gov/ct2/show/NCT05232630
Status: *This study IS currently enrolling participants*
-
Glycerol phenylbutyrate is a FDA approved drug, sold under the brand name Ravicti, for the treatment of urea cycle disorders. Experimental evidence in animals suggests that this drug could enhance the functioning of the STXBP1 protein. A small clinical trial is being conducted to determine if this drug could be beneficial for STXBP1 encephalopathy, specifically in regards to reducing seizure freequency.
Site: USA (NY and CO)
More Information: For latest update from the study, click here
ClinicalTrials.gov: https://clinicaltrials.gov/ct2/show/NCT04937062
*This trial is no longer recruiting STXBP1 patients.*
If anyone outside of this study has or currently is taking Phenylbutyrate for STXBP1-related disorders, please see the Phenylbutyrate studies under Observational Studies on this page, or naturalhistory@stxbp1disorders.org at the STXBP1 Foundation. There is interest in learning from everyone's experiences.
-
Dr. Kristin Barbour from University of California, San Diego is conducting a study on those taking Ravicti (phenylbutyrate) outside of a clinical trial. The goal is to understand the potential benefits and/or side effects of phenylbutyrate for STXBP1, SLC6A1, and SYNGAP. Interviews with parents and physicians will be conducted, and summarized in a case series publication.
Inclusion criteria:
Age: Children 0-17 years old Genetic diagnoses: STXBP1, SLC6A1, or SYNGAP
Medication: Current or prior use of phenylbutyrateTo participate: Contact Dr. Kristen Barbour, at kkbarbour@health.ucsd.edu
-
The Danish Epilepsy Centre is conducting an observational study to understanding the potential benefits and/or side effects of phenylbutyrate for STXBP1 and SLC6A1, for patients with current or prior use of phenylbutyrate. Families can complete a data request, or be interviewed.
To participate: Contact Cathrine Elisabeth Gjerulfsen, MD at caet@filadelfia.dk
-
This is a prospective observational study to evaluate the phenotype of 10 patients under 10 years of age with developmental epileptic encephalopathy due to mutation of the STXBP1 gene. The study will consist of a clinical and neurodevelopmental evaluation, magnetic resonance imaging, prolonged electroencephalogram, cardiological study, and analysis of biomarkers in cerebrospinal fluid. These patients will be followed up for 3 years. The aim of the study is, knowing the baseline phenotype, to analyse the response to commonly used drugs and to anticipate the response to different drugs available on the market in this group of patients based on clinical and biomarker assessment (EEG, MRI and study of specific proteins and neurotransmitters in plasma, urine and CSF).
Site: Spain (Madrid)
More information: https://clinicaltrials.gov/study/NCT06356233
-
CAP-002 is a first-in-class, intravenously (IV) administered gene therapy engineered to supplement STXBP1 haploinsuficiency. CAP-002 is engineered to cross the blood brain barrier, following IV adminstration, to achieve high levels of neuronal targeting while also reducing unwanted targeting of the liver and other tissues.
The SYNRGY Study is a Phase 1/2a, first-in-human, open-label, multi-center, dose-escalation trial to assess the safety, tolerability, and efficacy of a single intravenous (IV) dose of CAP-002 administered to participants with STXBP1-RD ages ≥18 months to <8 years of age.
Sites: 4 sites: Children’s Hospital of Philadelphia; Children’s Hospital of Colorado; Weill Cornell Medicine; Texas Children’s Hospital.
Enrollment: Phase 1 is a dose escalation phase that will dose approximately 6 participants divided into 2 cohorts (Cohort 1 and Cohort 2) while Phase 2a will have 1 dose cohort and dose approximately 6 participants.
More Information:
Trial details can be found at ClinicalTrials.gov here: NCT06983158
For additional information please vist the Capsida site.
Status: **THIS STUDY IS CURRENTLY ON HOLD AND NOT ENROLLING PARTICIPANTS**
Observational Studies
An observational study is a type of study that observes an individual or group without any intervention or treatment. This section includes natural history and registry studies, as well as other observational studies.
Natural History Studies and Registries
A natural history study looks at how a disease changes over time in a patient population. A patient registry is an organized system for collecting, storing, and disseminating information about people who have a disease. Some patient registries function or can be used for natural history studies and are often used to recruit patients for clinical trials.
This table provides information on several natural history studies and registries, as well as how they complement each other, and work together. And, you can help speed research efforts right away by building a readily-available pool of data on STXBP1.
If you experience any issues with registering or have a comment to share, please email naturalhistory@stxbp1disorders.org.
| Study | Focus | What's Involved | Who Can Participate | |
|---|---|---|---|---|
| STARR | Prospective medical and cross-symptom | Clinical visit and set of surveys every 6 months (in clinic) | US, Canada, and Mexico | |
| RARE-X | Cross-symptom including neurological, GI, motor and vision | Series of surveys (online) | Global, participant must speak English fluently | |
| Simons Searchlight | Neurodevelopmental, medical and autism | Medical history interviews, set of surveys, and bio-samples (online) | Global, participant must speak English, Spanish, French, or Dutch fluently | |
| Citizen Health | Health records | One-time form to complete, plus updates to medical providers | US - Citizen Health will request records. Global, medical records can be uploaded; must be in English | |
| ESCO Natural History Study | Prospective medical and cross-symptom | Clinical visit and set of surveys every 6 months (in clinic) | Europe | |
| ESCO Patient Registry | Medical history | Medical history interview and caregiver surveys | Europe |
-
The STARR study is a prospective, multi-site natural history study for STXBP1-Related Disorders (STXBP1-RD). The purpose of this study is to gain a better understanding of how STXBP1-RD progresses over time and develop a standardized set of clinic assessments and biomarkers for STXBP1-RD patients. This study is an important step in preparing our community for upcoming clinical trials for new drugs and therapeutics.
Sites: USA (CO, NY, PA, TX)
To learn more about the STARR study, please click here.
You can also find information on the STARR Study on clinicaltrials.gov (NCT06555965).
-
The European STXBP1 Consortium (ESCO) has established a European patient registry and natural history study to support better understanding the underlying biology of STXBP1-RD and to identify disease markers of severity and to eventually follow-up treatment effects.
More information
Clinicaltrials.gov: https://clinicaltrials.gov/study/NCT06625112
ESCO Website on Patient Registry: https://stxbp1eu.org/esco-patient-registry/
ESCO Website on Natural History Study: https://stxbp1eu.org/esco-natural-history-study/ -
RARE-X is a data collection program which asks general questions on all body systems in a “head to toe” survey. Follow up surveys ask more detailed questions on identified symptoms from the initial survey. Surveys are done online and at one’s own pace. At this time, they are accepting anyone from around the world, but must be able to read English fluently.
RARE-X is also being used for the caregiver surveys in the STARR natural history study.
Sites: Remote, International
More information: https://rare-x.org/
How to participate: https://www.stxbp1disorders.org/rare-x
-
Simons Searchlight is a study, funded by the Simons Foundation, that aims to collect natural history information for families with specific genetic changes that have a known association to neurodevelopmental disorders, like seizures, developmental delay, and/or features of autism.
Sites: Remote, International
More Information:
STXBP1 website: https://www.stxbp1disorders.org/simonssearchlight
Simons website: http://simonssearchlight.orgHow to Participate: Click here to learn more and join.
-
Citizen Health is a natural history study that utilizes information collected in electronic medical records. It requires no in-person visits or phone calls. In the US, Citizen Health will collect records for participants. In other countries, medical records must be obtained by the participant and uploaded; records must be in English.
Sites: Remote, International
Registering is easy here:
https://www.stxbp1disorders.org/citizen-healthMore Information:
https://www.citizen.health/How to participate:
https://www.citizen.health/partners/stxbp1-foundation -
The STXBP1 Foundation has partnered with COMBINEDBrain for our biorepository program. Families can provide biosamples, which are important tools for researchers to advance STXBP1 research.
More information: https://stxbp1disorders.org/biorepository -
Dr. Cyrus Boelman, working closely with collaborators, Drs. Jennifer Engle, Danielle Andrade and Cecil Hahn has launched a Canadian national registry for STXBP1. The project is surveying people living with STXBP1 disorders across Canada. The goal is to better understand this rare disorder, by way of characterizing the spectrum of symptoms, understand how they may be best managed, and from this understanding educate others, including physicians, researchers and therapists, to improve the quality of life of those affected by the disorder.
Site: Canada (Remote)
More Information:https://www.stxbp1.ca/
How to Participate: Email stxbp1.registry@ubc.ca or Call 1 604 875 2121
-
The National Brain Gene Registry aims to learn more about genes that are involved in brain development and behavior. We have a large list of genes we are interested in and STXBP1 is on that list! It is a completely remote study that involves two virtual meetings: an initial consent/registration meeting and a telehealth appointment with the research coordinators. There will also be some additional surveys for the parents to complete. All of these assessments will particularly help with reclassifying variants of uncertain significance to benign or pathogenic and generally learning more about this rare disorder to influence potential management options.
Sites: USA (Remote)
More information: https:/braingeneregistry.wustl.edu/ or email ataylor4@childrensnational.org
-
This study is exploring whether the knowledge and experience gained during the T-GaiD project (Treatment of Gait Disorders in Dravet Syndrome - NCT03857451) can be transferred to other populations with similar problems, i.e. motor and gait problems as a result of a genetic disorder characterized by epilepsy and developmental delay. In this pilot study, 40 people with Tuberous Sclerosis Complex and 30 people with STXBP1 will be recruited via the Antwerp University Hospital and invited for a gait analysis in the M²OCEAN movement lab. The aim of the pilot study is to evaluate the feasibility of the 3D gait analysis protocol and to determine the sensitivity of the primary (summative measure of the severity of gait abnormalities) and the secondary (spatio-temporal and kinematic gait parameters) outcome measures.
Site: Belgium (Antwerp)
More Information:
https://clinicaltrials.gov/study/NCT05161494How to Participate: Contact Dr. Hannah Stamberger (https://weckhuysenlab.sites.vib.be/en)
-
NYU Langone researchers are recruiting from across multiple rare genetic epilepsies, including STXBP1, with the aim to help improve care and clinical trial outcomes.
If your child has had video EEGs and/or you can submit videos of seizures captured on your cell phone, you can participate. The study also includes surveys (in English).
The videos will be used to better understand and identify different types of seizures, then create educational materials.
Sites: Remote, International
More information: https://www.stxbp1disorders.org/blog/new-observational-study-on-seizure-or-seizure-like-movements-nownbsprecruiting
How to participate: ontact their Research Coordinator, Kim Nguyen, by email at Kim.Nguyen2@nyulangone.org or phone at 646-558-0842
-
Dr. Constance Smith-Hicks at Kennedy Krieger Institute is recruiting children and adults with STXBP1 who have had previous overnight/24-hour EEGs or polysomnograms to study the relationship between sleep, behavior, and cognition.
Site: Remote
To Participate: Emily Schneider
phone: 667-205-4381
email: schneiderej@kennedykrieger.org -
COMBINEDBrain has launched a Validation Study of the The Observer Reported Toileting Abilities Survey (ORTAS). They are looking for participants to help test a 30-minute online survey on toileting abilities in individuals with neurodevelopmental disorders (NDD). The survey covers questions about a person’s diagnosis, symptoms, treatments, and ability to toilet independently, or not. Survey is open to all but currently only available in English at this time.
They are looking to recruit 200 participants, including:
Caregivers of individuals with NDD
Caregivers of neurotypical children (ages 1-6) as controls
Adults with NDD
Your input will contribute to research on this important aspect of daily life.
Sites: Remote, International (English only)
More Information: Flyer
How to Participate: Email COMBINEDBrain at ORTAS@combinedbrain.org
-
Boston Children’s is conducting two studies on Epilepsy-Dyskinesia, a retrospective study and a prospective registry & natural history.
Both studies aim to advance the understanding of the clinical and molecular spectrum of epilepsy-dyskinesia syndromes, which are monogenic diseases causing both movement disorders and epilepsy.
The Epilepsy-Dyskinesia Study is a retrospective study, meaning it will include clinical data that already exists. The study is open to patients 0-18 years old.
The Registry and Natural History of Epilepsy-Dyskinesia Syndromes is collecting longitudinal clinic data and biological samples for patients. It is open to patients 0 to 30 years old.
STXBP1 is one of many disorders included in these observational studies.
Sites: Boston Children’s Hospital
More Information:
Retrospective Study:
https://clinicaltrials.gov/study/NCT06585605
Prospective Registry & Natural History: https://clinicaltrials.gov/study/NCT06967727How to Participate: Email movementdisorders@childrens.harvard.edu