Fragile X SyndromePhase 2NCT03862950
A Trial of Metformin in Individuals With Fragile X Syndrome (Met)
A Phase 2 study testing Metformin in people with Fragile X Syndrome and Fragile X Mental Retardation Syndrome, run by University of Alberta at 2 sites in Canada.
Trial summary
This study is a controlled trial of metformin in individuals with fragile X syndrome between the ages of 6 and 35 years. Participants will be randomized in a double-blind design to either drug or placebo and will attend three visits to the study site in a 4-month period for a series of tests. Read more about this study
- Who is it for?
- Ages 6 to 35 years
- Conditions the study is for
- Fragile X Syndrome, Fragile X Mental Retardation Syndrome, Mental Retardation, X-Linked
- What is being tested?
- Metformin
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 125 participants
- Where
- 2 sitesCanada
- Study dates
- 24 May 2019to 16 Dec 2025
- Phase
- Phase 2
- Are there results?
- None posted in the registry
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 6 to 35 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- Subject has Fragile X syndrome with a molecular genetic confirmation of the full FMR1 mutation (>200 CGG repeats) or the other loss of function mutations of the FMR1 gene (SNVs and deletions of the gene).
- Subject is a male or non-pregnant, non-lactating female age 6 through 35 years, inclusive.
- Subjects who are capable of becoming pregnant must use an acceptable method of birth control for the duration of the study. Acceptable forms of birth control include abstinence (only for subjects who are not sexually active), intrauterine devices in place for at least 3 months, oral contraceptives, surgical sterilization, or adequate barrier methods.
- Subject must have a caregiver (parent, guardian, or other legally authorized representative) who is willing to participate in the whole study.
- Subject and caregiver are able to attend the clinic regularly and reliably.
- Subject and/or subject's caregiver is able to understand, read, write and speak English or French fluently to complete study-related materials.
Show all 10Show fewer
- For subjects who are not their own legal guardian, subject's caregiver is able to understand and sign an informed consent to participate in the study.
- The use of concomitant medication must be stable, in terms of dose and dosing regimen, for at least 4 weeks prior to Screening and must remain stable during the period between first visit (Screening) and the commencement of the study; every effort should be made to maintain stable regimens of allowed concomitant medications from the time of commencement of double-blind study medication until the last study assessment.
- Behavioral/educational treatments must be stable for 4 weeks prior to first visit (Screening) and must remain stable during the period between Screening and the commencement of randomized double-blind study medication.
- 10. Overall age equivalent is not higher than 13 and IQ is not higher than 85, as assessed at Screening on the Leiter-III, and subject must speak at least occasional 3-word phrases.
Who cannot join
- Families that are not cooperative and will not follow through with the demands of this study.
- Subject has a life-threatening medical problem or other major systemic illness that compromises health or safety and/or would interfere with this study.
- Age younger than 6 or older than 35 years.
- History of intolerable adverse events with metformin.
- Current or recent metformin treatment (within the past 4-months).
- BMI inferior to 2 standard deviations below the mean for age using the World Health Organization scale.
Show all 11Show fewer
- Serum creatinine > 1.4 mg/dl (female) or > 1.5 mg/dl (male).
- History of metabolic acidosis or a condition with lactic acidosis.
- Severe Vitamin B12 deficiency.
- Pregnancy at screening or unwillingness to use acceptable method of birth control, if applicable.
- Age equivalent higher than 13 or IQ higher than 85 on the Leiter-III at Screening.
Trial locations and contacts
2 sites in 1 country.
Canada2 sites
University of Alberta
Edmonton, Alberta, T6G 2E1
CHU Sainte-Justine
Montreal, Quebec, H3T 1C5
About this study
Official title: A Double-Blind, Placebo-Controlled Trial of Metformin in Individuals With Fragile X Syndrome (FXS)
This study is a controlled trial of metformin in individuals with fragile X syndrome between the ages of 6 and 35 years. Participants will be randomized in a double-blind design to either drug or placebo and will attend three visits to the study site in a 4-month period for a series of tests. The primary objectives are to assess safety, tolerability, and efficacy of metformin in the treatment of language deficits, behavior problems, and obesity/excessive appetite in individuals with fragile X syndrome.
Read the detailed description
This is a multi-center study at the University of Alberta and CHU Sainte-Justine for fragile X syndrome (FXS) patients aged 6 to 35 years inclusive. It is a randomized, double-blind, placebo-controlled trial of metformin (also known as Glumetza, Glucophage, Fortamet), a type 2 diabetes medication that can also improve obesity and excessive appetite.
Metformin has emerged as a candidate drug for the targeted treatment of FXS based on animal studies showing rescue of multiple phenotypes in the FXS model. Metformin may contribute to normalizing signaling pathways in FXS in the central nervous system, which may include activities of mTOR and PI3K, both of which have shown to be pathogenically overactive in FXS. In addition, metformin inhibits phosphodiesterase, which would lead to correction of cAMP levels, and MMP9 production, which is also elevated in FXS. Looking at the potential signaling pathways, metformin appears to be a good candidate for targeting several of the intracellular functions in neurons disrupted in FXS and, therefore, has potential to rescue several types of symptoms in individuals with FXS. Researchers have utilized metformin in the clinical treatment of over 20 individuals with FXS between the ages of 4 and 58 years and have found the medication to be well tolerated and to provide benefits not only in lowering weight gain and normalizing appetite but also in language and behavior. In this controlled trial, the researchers hope to further assess metformin's safety and benefits in the areas of language and cognition, eating and weight loss, and overall behavior.
Each participant will be involved in this trial for a period of 4 months. This will include 3 visits to one of the sites and 5 phone calls. At each visit, the researchers will assess behavioral, cognitive, and language development. The researchers will also assess the side effects of the study medication throughout the trial.
- Conditions
- Fragile X Syndrome, Fragile X Mental Retardation Syndrome, Mental Retardation, X-Linked, Genetic Diseases, X-Linked, Trinucleotide Repeat Expansion, Fra(X) Syndrome
- Being tested
- Placebo Medication, Metformin
- Keywords
- Congenital Abnormalities, Metformin, Nervous System Diseases, Chromosome Disorders
- Medical subject headings
- Fragile X Syndrome, X-Linked Intellectual Disability, Genetic Diseases, X-Linked, Intellectual Disability, Neurobehavioral Manifestations, Sex Chromosome Disorders, Congenital Abnormalities, Nervous System Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Placebo MedicationDrug
Also called Placebo
Placebo liquid or capsules given in parallel to active medication.
MetforminDrug
Also called Glumetza, Glucophage, Fortamet
Active medication
| Study group | Role | What they receive |
|---|---|---|
| Placebo Medication | Placebo comparator | The placebo will be dosed in a weight-dependent manner. For participants under 50kg at baseline, the initial dose will be 250mg once per day, and if this dose is well tolerated, they will increase each week by 250mg until a maximum dose of 1000mg daily is reached. For participants at and above 50kg at baseline, the initial dose will be 500mg once per day, and if this dose is well tolerated, they will increase each week by 500mg until a maximum dose of 2000mg daily is reached. After the 4-week titration period, each participant will continue dosing at his or her maximum tolerated dose daily for the remaining 12 weeks of the study. Receives: Drug: Placebo Medication |
| Active Metformin Medication | Active comparator | The active metformin medication will be dosed in a weight-dependent manner. For participants under 50kg at baseline, the initial dose will be 250mg once per day, and if this dose is well tolerated, they will increase each week by 250mg until a maximum dose of 1000mg daily is reached. For participants at and above 50kg at baseline, the initial dose will be 500mg once per day, and if this dose is well tolerated, they will increase each week by 500mg until a maximum dose of 2000mg daily is reached. After the 4-week titration period, each participant will continue dosing at his or her maximum tolerated dose daily for the remaining 12 weeks of the study. Receives: Drug: Metformin |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from baseline in the Expressive Language Sampling (ELS) mean Number of Different Words (NDW) score
The ELS is collected from shared interactions around a wordless picture book involving the participant and the examiner. The primary outcome measure will be Number of Different Words (NDW) derived from transcripts of audiorecorded samples of spoken language taken from two sampling contexts (conversation and narration), according to procedures described by Abbeduto and colleagues (Abbeduto et al., 1995; Kover et al., 2012). Samples are collected pre- and post- treatment using different books on each occasion. The mean of NDW in conversation and NDW in narration will be computed, and statistically adjusted through analysis of covariance for differences in talkativeness as outlined in Conners et al., 2018. The mean NDW score ranges from 1 to infinite/unspecified. An increase (positive change) in score from baseline to follow-up indicates improvement. The greater the increase, the greater the improvement.
Measured: Baseline, End of Treatment/Week 16
Secondary outcomes (22)
Change from baseline in the FXS-normed Aberrant Behavior Checklist - Community Edition (ABC-C)
The ABC-C is a 58-item caregiver-rated behavior scale used to examine treatment effects on challenging behaviors for individuals with FXS in the following domains: (1) irritability, agitation, crying; (2) lethargy, social withdrawal; (3) stereotypic behavior; (4) hyperactivity, noncompliance; and (5) inappropriate speech. Analysis will be performed utilizing the Sansone et al. (2012) FXS-normed ABC scoring measures.
Measured: Baseline, Week 8, End of Treatment/Week 16
Improvement of symptoms in FXS using the Clinical Impression - Improvement (CGI-I) scale
The CGI is a clinician-rated scale utilizing history from the caregiver and incorporating it into a clinical rating, first for severity, and then for clinical follow-up. The CGI-S will be used at the baseline assessment to judge symptom severity as 1 = Normal, not at all ill; 2 = Borderline ill; 3 = Mildly ill; 4 = Moderately ill; 5 = Markedly ill; 6 = Severely ill; and 7 = Among the most extremely ill. The CGI-I will be used at the Week 8 and End of Treatment/Week 16 visits to judge the change in clinical impression as 1 = Very Much Improved; 2 = Much Improved; 3 = Minimally Improved; 4 = No Change; 5 = Minimally Worse; 6 = Much Worse; and 7 = Very Much Worse.
Measured: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the Visual Analog Scale (VAS)
The VAS will be used to measure the severity of three specific behavioral symptoms targeted in this study: behavior problems, language abilities, and eating behavior. For each behavior the caregiver is instructed to mark their impression of the behavior at the baseline visit and again at the Week 8 and End of Treatment/Week 16 visits. The calculated distance in cm between the visit marks thereby demonstrates whether each behavior stayed the same, improved, or worsened during the study and by how much. The scale is from 0 cm (defined as "worst behavior") to 10 cm ("behavior not a problem").
Measured: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the Vineland Adaptive Behavior Scales-Third Edition (VABS-III) Adaptive Behavior Composite Score
The VABS-III is a caregiver survey interview that measures the personal and social skills of individuals from birth through adulthood. It was designed to assess handicapped and non-handicapped persons in their personal and social functioning and is appropriate for individuals of all ages. The Adaptive Behavior Composite (ABC) score is calculated from the caregiver responses using age-adjusted scoring tables. ABC scores range from 20 to 160 and indicate low (20-70), moderately low (70-85), adequate (85-115), moderately high (115-130), or high (130-160) overall adaptive functioning.
Measured: Baseline, End of Treatment/Week 16
Change from baseline in the Anxiety Depression and Mood Screen (ADAMS) overall score
The CSHQ consists of a series of questions relating to the sleep habits of children. It will be completed by caregivers of all participants, regardless of participant age, at the baseline, Week 8, and End of Treatment/Week 16 visits.
Measured: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the Swanson, Nolan and Pelham Questionnaire (SNAP-IV) overall score
The SNAP-IV, based on DSM-V criteria for ADHD, is a caregiver-rated questionnaire that effectively identifies those with and without ADHD and accurately predicts presentation specifier (inattention, hyperactivity/impulsivity, and combined). Its psychometric properties and clinical utility have been demonstrated in multiple studies since its introduction in 2001, and it has been found to be reliable and well validated with normative data from both parents and teachers. It will be completed by caregivers of all participants at baseline, Week 8, and End of Treatment/Week 16.
Measured: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the Pediatric Quality of Life Questionnaire (PedsQL) Parent Proxy overall score
The PedsQL Parent Proxy consists of a series of questions relating to a child's quality of life and is administered to the caregiver of the participant. The parent proxy module designed for children 8-12 years of age will be administered to the caregivers of all participants, regardless of participant age, because the questions therein are most appropriate for the overall study population's cognitive age and ability. It will be completed at the baseline, Week 8, and End of Treatment/Week 16 visits. For any participants not in school, questions pertaining to "school" will be replaced with references to "work" or other activities in their life.
Measured: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the EuroQol-5D (EQ-5D) overall score
This is a standardized instrument developed by the EuroQol Group as a measure of health-related quality of life that can be used in a wide range of health conditions and treatments. The EQ-5D consists of a descriptive system and the EQ VAS. We will use the EQ-5D-Y, EQ-5D-Y parent proxy, EQ-5D-3L, and EQ-5D-3L parent proxy depending on the participants age and ability. The descriptive system comprises five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. The EQ VAS records the patient's self-rated health on a vertical visual analogue scale. This can be used as a quantitative measure of health outcome that reflects the patient's own judgement. The scores on these five dimensions can be presented as a health profile or can be converted to a single summary index number (utility) reflecting preferability compared to other health profiles.
Measured: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the Care Related Quality of Life (CarerQoL) overall score
The CarerQol was designed to measure and value the impact of providing informal care on carers. It combines a subjective burden measure that provides a comprehensive description of the caregiving situation (CarerQol-7D) with a valuation of informal care in terms of well-being (CarerQol-VAS).
Measured: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in The Memory Game
This is an online test developed in the Bolduc Laboratory done on a tablet at home. Participants are asked to remember association between sets of pictures. The test has been done in typical development and developmental delay for participants 4 years and up. The test has an online consent form followed by a short demonstration video. The participants are then shown pairs of pictures they must remember. Testing is performed right after the presentation and again 24 hours later. For the 24 hours testing, the participants/caregivers will receive an email reminder and will be invited to login to the Memory Game site to perform the association test this time without being shown the demonstration video. The testing takes about 20 minutes the first day and 7 minutes the second day. It will be completed before treatment starts and after treatment ends.
Measured: Baseline, End of Treatment/Week 16
Change from baseline in the Child Sleep Habits Questionnaire (CSHQ) overall score
The CSHQ consists of a series of questions relating to the sleep habits of children. It will be completed by caregivers of all participants, regardless of participant age, at the baseline, Week 8, and End of Treatment/Week 16 visits.
Measured: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Picture Sequence Memory Test
This test involves recalling increasingly lengthy series of illustrated objects and activities around different themes (e.g., "playing at the park," "working on the farm") that are presented in a particular order on the screen. Encoding, storage, and retrieval of episodic memories depend on a neural network including the temporal lobe (especially the hippocampus), the prefrontal cortex, and limbic/temporal association areas. Patients with FXS perform approximately two standard deviations below normal on PSM, which demonstrates good feasibility, test-retest reliability in both healthy children and those with ID; and moderate correlation with FSIQ.
Measured: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Flanker Inhibitory Control and Attention Test
Flanker is a measure of inhibition and visual attention. On each trial, a central directional target is flanked by similar stimuli on the left and right. The participant chooses the direction of the central stimulus. On congruent trials, the flankers face the same direction as the target. On incongruent trials, they face the opposite direction. Patients with FXS demonstrate profound deficits on Flanker, performing about 7 standard deviations below normal, and significantly worse than IQ-matched controls with Down syndrome. This test demonstrates excellent test-retest reliability and correlates significantly with FSIQ and dialing functioning in children and adolescents with ID.
Measured: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Dimensional Change Card Sort Test
This is a measure of cognitive flexibility. Two target pictures are presented that vary along two dimensions (i.e., shape and color). Participants are asked to match a series of bivalent test pictures (e.g., yellow balls and blue trucks) to the target pictures, first according to one dimension (e.g., color) and then, after a number of trials, according to the other dimension (e.g., shape). "Switch" trials are also employed, in which the participant must change the dimension being matched. It demonstrates good test-retest reliability and correlates well with FSIQ in children and adolescents with ID, including FXS .
Measured: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox List Sorting Working Memory Test
This test requires immediate recall and sequencing of different visually and orally presented stimuli. Pictures of different foods and animals are displayed with accompanying audio recording and written text (e.g., "elephant"), and the participant is asked to state the items in size order from smallest to largest, first within a single dimension (either animals or foods, called 1-List) and then on 2 dimensions (foods, then animals, called 2-List). The raw score is the number of items recalled and sequenced correctly.
Measured: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Pattern Comparison Processing Speed Test
This test measures speed of processing by asking participants to discern whether two side-by-side pictures are the same or not the same by touching "yes" or "no" (or a happy or frowning face for lower mental age). Participants' raw score is the number of items correct in a 90-second period. The items are designed to be simple to distinguish.
Measured: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Oral Reading Recognition Test
The participant is asked to read and pronounce letters and words as accurately as possible. The test administrator scores them as right or wrong. The items are administered by computer adaptive testing (CAT; continuously adapted depending on performance), and participant responses are scored by the examiner. For the youngest children, the initial items require identification of letters (as opposed to symbols) and identification of a specific letter in an array of 4 symbols. A theta score is calculated for this test.
Measured: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Picture Vocabulary Test
This measure of receptive vocabulary is administered in a CAT format. The respondent is presented with an audio recording of a word and four photographs on the screen and is asked to select the picture that most closely matches the meaning of the word. A theta score is calculated for this test.
Measured: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Speeded Matching Test
This test measures speed of processing by asking participants to discern whether four side-by-side pictures match the target image at the top of the screen. The items are presented one group at a time on the iPad screen, and the participant is given 119.999 seconds of actual presentation time (excluding transitions between items) to respond to as many items as possible (up to a maximum of 130). The items are designed to be simple so as to most purely measure processing speed. Speeded Matching gives a raw score, which is the number of items the participant correctly responds to (up to 130) in 119.999 seconds.
Measured: Baseline, End of Treatment/Week 16
Change from baseline in Eye Tracking
For individuals with FXS, we have demonstrated that the social gaze measure shows decreased visual fixations on the eye region while viewing human faces (with greater fixation to the nose region), and these individuals show abnormal pupillary dilation, an indication of sympathetic nervous system reactivity, compared with controls. While these measures do not appear to map directly onto caregiver-reported anxiety of the individuals level of anxiety, the results are consistent with high rates of social anxiety and sympathetic reactivity in FXS. Stimuli are presented on a Tobii T120 eye-tracker. The system has several benefits that make it conducive to testing individuals with developmental disorders. Stimuli consist of sixty colored photographs of adult human faces each showing a calm, happy, or fearful expression, and sixty scrambled versions of the face images.
Measured: Baseline, End of Treatment/Week 16
Change from baseline in Event Related Potentials during the Auditory Oddball Paradigm and Pseudoword Paradigm
Recently, researchers were able to obtain EEG recordings and ERP responses during an auditory oddball paradigm from patients with FXS enrolled in a controlled trial of minocycline. The study demonstrated the potential feasibility and sensitivity of ERPs as an indicator of cortical processing changes in a targeted treatment trial. It appears to provide a biomarker and measure for the human equivalent of cortical hyperexcitability. Additionally, we will administer a recently developed task looking at EEG habituation to pseudowords to assess word learning with EEG. Data is acquired using a Brainproducts Quickamp system. Raw data is imported into Brainvision Analyzer software for analysis. The continuous data is segmented according to the event type and filtered. We also analyze the EEG data at resting state for the oddball paradigm according to frequency distribution and the occurrence of spontaneous oscillations, and pseudoword habituation with ERP, energy and time-frequency analyses.
Measured: Baseline, End of Treatment/Week 16
Change from baseline in the Sensory Profile-2 or Sensory Profile Adolescents/Adults
The Sensory Profile 2 family of assessments evaluates a child's sensory processing patterns in the context of everyday life. The forms are completed by caregivers, who are in the strongest position to observe the child's response to sensory interactions that occur throughout the day. The Adolescent/Adult Sensory Profile was developed to assess sensory processing abilities in individuals beyond childhood. The Sensory Profile Adolescents/Adult is a self report, however, if the participant is unable to complete it themself, we will ask their caregiver to complete it and we will make note of who completed it. The French versions are the Profil sensoriel 2 and the Profil sensoriel-adolescent/adulte.
Measured: Baseline, Week 8, End of Treatment/Week 16
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Mar 2019
- Study start24 May 2019
- Primary completion16 Dec 2025
- Study completion16 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Fragile X SyndromeStudies of the same condition, open and under way.
- More trials run by University of AlbertaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 125 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Alberta
- Sponsor type
- University, hospital or other
- Collaborators
- St. Justine's Hospital
- Responsible party
- Sponsor
- Investigators
- Francois Bolduc, MD, Principal investigator, University of Alberta
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03862950
- Sponsor's protocol ID
- FXSMET-2018 Version 16
- Status last verified
- Jan 2026
- First submitted
- 26 Feb 2019
- Last updated
- 8 Jan 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Dy ABC, Tassone F, Eldeeb M, Salcedo-Arellano MJ, Tartaglia N, Hagerman R. Metformin as targeted treatment in fragile X syndrome. Clin Genet. 2018 Feb;93(2):216-222. doi: 10.1111/cge.13039. Epub 2017 Sep 25.
PubMed 28436599Monyak RE, Emerson D, Schoenfeld BP, Zheng X, Chambers DB, Rosenfelt C, Langer S, Hinchey P, Choi CH, McDonald TV, Bolduc FV, Sehgal A, McBride SMJ, Jongens TA. Insulin signaling misregulation underlies circadian and cognitive deficits in a Drosophila fragile X model. Mol Psychiatry. 2017 Aug;22(8):1140-1148. doi: 10.1038/mp.2016.51. Epub 2016 Apr 19.
PubMed 27090306Gantois I, Khoutorsky A, Popic J, Aguilar-Valles A, Freemantle E, Cao R, Sharma V, Pooters T, Nagpal A, Skalecka A, Truong VT, Wiebe S, Groves IA, Jafarnejad SM, Chapat C, McCullagh EA, Gamache K, Nader K, Lacaille JC, Gkogkas CG, Sonenberg N. Metformin ameliorates core deficits in a mouse model of fragile X syndrome. Nat Med. 2017 Jun;23(6):674-677. doi: 10.1038/nm.4335. Epub 2017 May 15.
PubMed 28504725
Study at a glance
From the registry record, last updated by the sponsor on 8 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Double-Blind, Placebo-Controlled Trial of Metformin in Individuals With Fragile X Syndrome (FXS)
- ClinicalTrials.gov ID
- NCT03862950
- Acronym / sponsor ID
- FXSMET-2018 Version 16
- Conditions
- Fragile X Syndrome, Fragile X Mental Retardation Syndrome, Mental Retardation, X-Linked, Genetic Diseases, X-Linked, Trinucleotide Repeat Expansion, Fra(X) Syndrome
- Keywords
- Congenital Abnormalities, Metformin, Nervous System Diseases, Chromosome Disorders
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 125 participants (actual)
- Lead sponsor
- University of AlbertaUniversity, hospital or other
- Collaborators
- St. Justine's Hospital
- Study start
- 24 May 2019 (actual)
- Primary completion
- 16 Dec 2025 (actual)
- Study completion
- 16 Dec 2025 (actual)
- First posted
- 5 Mar 2019 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study is a controlled trial of metformin in individuals with fragile X syndrome between the ages of 6 and 35 years. Participants will be randomized in a double-blind design to either drug or placebo and will attend three visits to the study site in a 4-month period for a series of tests. The primary objectives are to assess safety, tolerability, and efficacy of metformin in the treatment of language deficits, behavior problems, and obesity/excessive appetite in individuals with fragile X syndrome.
Detailed description
This is a multi-center study at the University of Alberta and CHU Sainte-Justine for fragile X syndrome (FXS) patients aged 6 to 35 years inclusive. It is a randomized, double-blind, placebo-controlled trial of metformin (also known as Glumetza, Glucophage, Fortamet), a type 2 diabetes medication that can also improve obesity and excessive appetite.
Metformin has emerged as a candidate drug for the targeted treatment of FXS based on animal studies showing rescue of multiple phenotypes in the FXS model. Metformin may contribute to normalizing signaling pathways in FXS in the central nervous system, which may include activities of mTOR and PI3K, both of which have shown to be pathogenically overactive in FXS. In addition, metformin inhibits phosphodiesterase, which would lead to correction of cAMP levels, and MMP9 production, which is also elevated in FXS. Looking at the potential signaling pathways, metformin appears to be a good candidate for targeting several of the intracellular functions in neurons disrupted in FXS and, therefore, has potential to rescue several types of symptoms in individuals with FXS. Researchers have utilized metformin in the clinical treatment of over 20 individuals with FXS between the ages of 4 and 58 years and have found the medication to be well tolerated and to provide benefits not only in lowering weight gain and normalizing appetite but also in language and behavior. In this controlled trial, the researchers hope to further assess metformin's safety and benefits in the areas of language and cognition, eating and weight loss, and overall behavior.
Each participant will be involved in this trial for a period of 4 months. This will include 3 visits to one of the sites and 5 phone calls. At each visit, the researchers will assess behavioral, cognitive, and language development. The researchers will also assess the side effects of the study medication throughout the trial.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Placebo Medication | Placebo comparator | Drug: Placebo MedicationThe placebo will be dosed in a weight-dependent manner. For participants under 50kg at baseline, the initial dose will be 250mg once per day, and if this dose is well tolerated, they will increase each week by 250mg until a maximum dose of 1000mg daily is reached. For participants at and above 50kg at baseline, the initial dose will be 500mg once per day, and if this dose is well tolerated, they will increase each week by 500mg until a maximum dose of 2000mg daily is reached. After the 4-week titration period, each participant will continue dosing at his or her maximum tolerated dose daily for the remaining 12 weeks of the study. |
| Active Metformin Medication | Active comparator | Drug: MetforminThe active metformin medication will be dosed in a weight-dependent manner. For participants under 50kg at baseline, the initial dose will be 250mg once per day, and if this dose is well tolerated, they will increase each week by 250mg until a maximum dose of 1000mg daily is reached. For participants at and above 50kg at baseline, the initial dose will be 500mg once per day, and if this dose is well tolerated, they will increase each week by 500mg until a maximum dose of 2000mg daily is reached. After the 4-week titration period, each participant will continue dosing at his or her maximum tolerated dose daily for the remaining 12 weeks of the study. |
Who may qualify
- Ages
- 6 to 35 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (10 listed)
- Subject has Fragile X syndrome with a molecular genetic confirmation of the full FMR1 mutation (>200 CGG repeats) or the other loss of function mutations of the FMR1 gene (SNVs and deletions of the gene).
- Subject is a male or non-pregnant, non-lactating female age 6 through 35 years, inclusive.
- Subjects who are capable of becoming pregnant must use an acceptable method of birth control for the duration of the study. Acceptable forms of birth control include abstinence (only for subjects who are not sexually active), intrauterine devices in place for at least 3 months, oral contraceptives, surgical sterilization, or adequate barrier methods.
- Subject must have a caregiver (parent, guardian, or other legally authorized representative) who is willing to participate in the whole study.
- Subject and caregiver are able to attend the clinic regularly and reliably.
Key exclusion criteria (11 listed)
- Families that are not cooperative and will not follow through with the demands of this study.
- Subject has a life-threatening medical problem or other major systemic illness that compromises health or safety and/or would interfere with this study.
- Age younger than 6 or older than 35 years.
- History of intolerable adverse events with metformin.
- Current or recent metformin treatment (within the past 4-months).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Placebo MedicationAlso: PlaceboPlacebo liquid or capsules given in parallel to active medication. | Drug | Placebo Medication |
| MetforminAlso: Glumetza, Glucophage, FortametActive medication | Drug | Active Metformin Medication |
Primary outcome
Change from baseline in the Expressive Language Sampling (ELS) mean Number of Different Words (NDW) score
Time frame: Baseline, End of Treatment/Week 16
The ELS is collected from shared interactions around a wordless picture book involving the participant and the examiner. The primary outcome measure will be Number of Different Words (NDW) derived from transcripts of audiorecorded samples of spoken language taken from two sampling contexts (conversation and narration), according to procedures described by Abbeduto and colleagues (Abbeduto et al., 1995; Kover et al., 2012). Samples are collected pre- and post- treatment using different books on each occasion. The mean of NDW in conversation and NDW in narration will be computed, and statistically adjusted through analysis of covariance for differences in talkativeness as outlined in Conners et al., 2018. The mean NDW score ranges from 1 to infinite/unspecified. An increase (positive change) in score from baseline to follow-up indicates improvement. The greater the increase, the greater the improvement.
22 secondary outcomes
Change from baseline in the FXS-normed Aberrant Behavior Checklist - Community Edition (ABC-C)
Time frame: Baseline, Week 8, End of Treatment/Week 16
Improvement of symptoms in FXS using the Clinical Impression - Improvement (CGI-I) scale
Time frame: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the Visual Analog Scale (VAS)
Time frame: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the Vineland Adaptive Behavior Scales-Third Edition (VABS-III) Adaptive Behavior Composite Score
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in the Anxiety Depression and Mood Screen (ADAMS) overall score
Time frame: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the Swanson, Nolan and Pelham Questionnaire (SNAP-IV) overall score
Time frame: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the Pediatric Quality of Life Questionnaire (PedsQL) Parent Proxy overall score
Time frame: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the EuroQol-5D (EQ-5D) overall score
Time frame: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the Care Related Quality of Life (CarerQoL) overall score
Time frame: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in The Memory Game
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in the Child Sleep Habits Questionnaire (CSHQ) overall score
Time frame: Baseline, Week 8, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Picture Sequence Memory Test
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Flanker Inhibitory Control and Attention Test
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Dimensional Change Card Sort Test
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox List Sorting Working Memory Test
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Pattern Comparison Processing Speed Test
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Oral Reading Recognition Test
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Picture Vocabulary Test
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in the NIH Toolbox Speeded Matching Test
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in Eye Tracking
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in Event Related Potentials during the Auditory Oddball Paradigm and Pseudoword Paradigm
Time frame: Baseline, End of Treatment/Week 16
Change from baseline in the Sensory Profile-2 or Sensory Profile Adolescents/Adults
Time frame: Baseline, Week 8, End of Treatment/Week 16
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Jan 2026.
- Background: PubMed 28436599Dy ABC, Tassone F, Eldeeb M, Salcedo-Arellano MJ, Tartaglia N, Hagerman R. Metformin as targeted treatment in fragile X syndrome. Clin Genet. 2018 Feb;93(2):216-222. doi: 10.1111/cge.13039. Epub 2017 Sep 25.
- Background: PubMed 27090306Monyak RE, Emerson D, Schoenfeld BP, Zheng X, Chambers DB, Rosenfelt C, Langer S, Hinchey P, Choi CH, McDonald TV, Bolduc FV, Sehgal A, McBride SMJ, Jongens TA. Insulin signaling misregulation underlies circadian and cognitive deficits in a Drosophila fragile X model. Mol Psychiatry. 2017 Aug;22(8):1140-1148. doi: 10.1038/mp.2016.51. Epub 2016 Apr 19.
- Background: PubMed 28504725Gantois I, Khoutorsky A, Popic J, Aguilar-Valles A, Freemantle E, Cao R, Sharma V, Pooters T, Nagpal A, Skalecka A, Truong VT, Wiebe S, Groves IA, Jafarnejad SM, Chapat C, McCullagh EA, Gamache K, Nader K, Lacaille JC, Gkogkas CG, Sonenberg N. Metformin ameliorates core deficits in a mouse model of fragile X syndrome. Nat Med. 2017 Jun;23(6):674-677. doi: 10.1038/nm.4335. Epub 2017 May 15.
- Individual participant dataSharing planned: Undecided
Related trials for Fragile X Syndrome
Not yet recruitingPhase 2
Inhibition of Aggressive Behavior in Participants With Fragile X Syndrome
Aggressive Behavior in Fragile X Syndome
RecruitingObservational study
Rare Disease Patient Registry & Natural History Study - Coordination of Rare Diseases at Sanford
Rare Disorders, Undiagnosed Disorders
Not yet recruiting
Single Session Support for Parents of Children With Neurodevelopmental Disabilities Struggling With Anxious Avoidance
Neurodevelopmental Disorders, Autism Spectrum Disorder (ASD)
RecruitingObservational study
Development of Non-Invasive Prenatal Diagnosis for Single Gene Disorders
Invasive PreNatal Diagnosis in a Context of Family History of Single-gene Disorders, Including, Sickle Cell Disease
Not yet recruitingPhase 2/3
A Study to Investigate the Effects and Safety of Codabakalner for the Treatment of FXS in Male Participants and Adult Participants With ADS
Fragile X Syndrome (FXS), Autism Spectrum Disorder (ASD)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Francois Bolduc, MD principal investigator
University of Alberta
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Metformin in people with Fragile X Syndrome and Fragile X Mental Retardation Syndrome, run by University of Alberta at 2 sites in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 11 exclusion criteria. 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: finished, as of the sponsor's last update on 8 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
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 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change from baseline in the Expressive Language Sampling (ELS) mean Number of Different Words (NDW) score (time frame: Baseline, End of Treatment/Week 16). 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 NCT03862950, which also lists 3 linked publications.
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 8 Jan 2026.