Pfizer COVID-19 vaccine appointments are available to our patients. Sign up for Connect today to schedule your vaccination.

Phenylbutyrate for STXBP1 Encephalopathy Pilot

Clinical Trial Details

STXBP1 encephalopathy (STXBP1-E) is a neurodevelopmental disorder that often begins in infancy. Intellectual disability is a core feature, often severe to profound. Nearly all have epilepsy (95% in the largest series). The epilepsy is clinically heterogeneous, and may present as a well-defined epilepsy syndrome (e.g., early infantile epileptic encephalopathy, infantile spasms, epilepsy of infancy migrating focal seizure, or Dravet syndrome) or as non-syndromic epilepsy.

The purpose of this study is to find out what effect glycerol phenylbutyrate has on STXBP1 encephalopathy. This research study is being done because there is no known specific treatment for STXBP1 encephalopathy. There have been some experiments in animals that suggest that glycerol phenylbutyrate can improve function of the protein that is not working properly in STXBP1 encephalopathy. We do not know if it will be helpful in humans.

Key Eligibility: 

We will open enrollment to subjects aged 2 months to 17 years with STXBP1-E and seizures. Subjects will be considered eligible to participate in this study if each one of the following inclusion criteria is satisfied at screening (and prior to dosing). Note that the screening effectively takes place over two visits – an initial telephone / video chat intake prior to the 4-week observation period, followed by an in-person visit with exam, vital signs, and laboratory testing. This is done as a courtesy to the families of the subjects. Many families will travel to the study site in order to participate, and this is often burdensome due to the physical and neurological impairments of the subjects.

  1. Diagnosed with STXBP1-E; confirmed by laboratory report (i.e., a genetic test with a pathogenic mutation of STBP1 and a clinical picture consistent with the disorder, as determined by the Investigator)

  2. Is between 2 months and 17 years of age, inclusive.

  3. The child must have had at least one seizure in the past 30 days prior to enrollment. If there is high demand for the study and we have several subjects to choose, we will prefer to enroll children with a high number of seizures in the past month.

Detailed eligibility reviewed when you contact the study team.


Study contact by location

Upper East Side - Manhattan


Natasha Basma
(561) 665-0779

Primary Investigator(s)

Protocol ID(s)

Weill Cornell Medicine IRB #:



Open to Enrollment

Age Group