Testing gaboxadol in adult males with Fragile X Syndrome

Placebo-Controlled, Single-Dose Challenge Study of Gaboxadol in Adult Males With Fragile X Syndrome (FXS)

PHASE2 · Children's Hospital Medical Center, Cincinnati · NCT06334419

This study is testing if a single dose of gaboxadol can help adult males with Fragile X Syndrome feel better.

Quick facts

PhasePHASE2
Study typeInterventional
Enrollment10 (estimated)
Ages18 Years to 40 Years
SexMale
SponsorChildren's Hospital Medical Center, Cincinnati (other)
Locations1 site (Cincinnati, Ohio)
Trial IDNCT06334419 on ClinicalTrials.gov

What this trial studies

This clinical trial evaluates the effects of a single dose of gaboxadol in adult males aged 18 to 40 with Fragile X Syndrome (FXS). Participants will undergo four visits, two at home and two at a clinic, spaced 14 days apart, where they will receive either gaboxadol or a placebo in a blinded manner. The study aims to assess the safety and efficacy of gaboxadol in this population, with careful monitoring of compliance and health status throughout the trial.

Who should consider this trial

Good fit: Ideal candidates are adult males aged 18 to 40 with a confirmed diagnosis of Fragile X Syndrome.

Not a fit: Patients outside the age range or those without a confirmed diagnosis of Fragile X Syndrome will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a new treatment option for managing symptoms associated with Fragile X Syndrome.

How similar studies have performed: While there have been studies on treatments for Fragile X Syndrome, the specific use of gaboxadol in this context is novel and has not been extensively tested.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Subject consents to participate, or if they are not their own legal guardian, offers assent supported by legally authorized representative consent
2. Subject is willing and able to comply with the study procedures as specified in the protocol and to comply with the study drug administration. Caregiver also commits to the study requirements prior to any study-related procedures
3. Subject and caregiver are both able to understand the spoken national language clearly and caregiver can read and write to complete study assessments
4. Males age 18 to 40 years (inclusive)
5. Has FXS with molecular genetic confirmation of the full FMR1 mutation (\>200 cysteine-guanine-guanine \[CGG\] repeats). May have been confirmed historically or at Screening
6. Is in general good health as deemed by the Investigator, determined by physical examination, medical history, and laboratory tests
7. If receiving serotonin-selective reuptake inhibitor (SSRI), serotonin-norepinephrine reuptake inhibitor (SNRI), or serotonin antagonist and reuptake inhibitor (SARI), is on a stable, well-tolerated dose for the previous 3 months with no further changes anticipated
8. Is not sexually active or can confirm at least one form of contraceptive

Exclusion Criteria:

1. Any chronic major medical comorbid condition deemed by the Investigator as presenting added risk to the subject, including but not limited to, refractory hypertension, kidney disease, or liver disease
2. Diagnosed with diabetes (Type 1 or II) or receiving any anti-diabetic medication
3. Unstable seizure disorder, defined by any seizure within 6 months prior to baseline visit and/or a change in any anti-convulsant drug dosing in the 60 days prior to study consent
4. Changes in psychotropic or anti-convulsant (where taken for reasons other than seizure control) drug treatment within 30 days prior to Screening
5. Significant changes in any educational, behavioral, and/or dietary interventions the month prior to Screening
6. Planned initiation of new, or modification of ongoing, interventions during the study
7. Unable or unwilling to take oral medication (whole capsule, despite assistance with a spoonful of applesauce, yoghurt, or equivalent liquid food)
8. Consumption of liver enzyme inducers or inhibitors including and not limited to foods, medicines, herbal remedies and supplements three days prior to any Visit. Foods or beverages containing CYP3A4/5 inhibitors (e.g., grapefruit, pomegranate, pomelo, and star fruit) should be avoided before taking study medication and for up to 1 hour post dose throughout the study
9. Has abnormal baseline laboratory assessments including, but not limited to, alanine aminotransferase (ALT) or aspartate aminotransferase (AST) or total bilirubin \>1.5 × the upper limit of normal (ULN), serum creatinine \>1.5 x ULN or other clinically relevant laboratory abnormality
10. Has a clinically significant heart rate or blood pressure (BP) at Screening as judged by the Investigator
11. Has received an investigational drug in any prior clinical study within 30 days or 5 half-lives (whichever is longer) prior to Screening

Where this trial is running

Cincinnati, Ohio

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Fragile X Syndrome, Fragile X, FXS

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.