Fragile X Syndrome (FXS)Phase 2/3NCT07439510
A Study to Investigate the Effects and Safety of Codabakalner for the Treatment of FXS in Male Participants and Adult Participants With ADS
A Phase 2/3 study testing Codabakalner in people with Fragile X Syndrome (FXS) and Autism Spectrum Disorder (ASD), run by Spinogenix.
Trial summary
This is a Study to Investigate the Effects and Safety of Codabakalner for the Treatment of Fragile X Syndrome in Male Participants and Adult Participants with Autism Spectrum Disorders Read more about this study
- Who is it for?
- Ages 18 to 45 years, men only
- Conditions the study is for
- Fragile X Syndrome (FXS), Autism Spectrum Disorder (ASD)
- What is being tested?
- Codabakalner
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 120 participants
- Where
- No sites listed yet
- Study dates
- 1 Dec 2026to 30 Jun 2030
- Phase
- Phase 2/3
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 18 to 45 years
- Men only
- No healthy volunteers
- Adult
Who may be able to join
- Phase 2b: Adult males aged 18 to 45 years, inclusive Phase 3: Males aged 13-45 years, inclusive Mental age >/= 36mon
- Diagnosis of Fragile X as confirmed with genetic testing and Stanford Binet testing or
- Confirmed diagnosis ASD per DSM5-TR and EEG criteria
- Patient must have caregiver
- Must be in good health with no significant medical history
Who cannot join
- Any physical or psychological condition that prohibits study completion
- Uncontrolled seizures or history of epilepsy with a seizure in the past 6 months.
- Auditory or visual impairments that cannot be corrected
- History of suicidal behaviour or suicidal ideation
- Screening vital signs that are abnormal per protocol specification
- ECG that are abnormal and clinically significant
Show all 9Show fewer
- History of substance abuse or dependence within 6 months
- Other investigational products within 30 days
- Unable to swallow capsules
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: A Phase 2b/3, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Efficacy, Safety, and Pharmacokinetics of Codabakalner in Male Participants With Full Mutation Fragile X Syndrome and Adult Participants With Autism Spectrum Disorders
This is a Study to Investigate the Effects and Safety of Codabakalner for the Treatment of Fragile X Syndrome in Male Participants and Adult Participants with Autism Spectrum Disorders
Read the detailed description
This Phase 2b/3, randomized, double-blind, placebo-controlled, 2-part study will evaluate the efficacy, safety and tolerability of different dose regimens of codabakalner in adult male participants with Fragile X syndrome. The results from Phase 2b will be hypothesis generating and will inform the Phase 3 design.
Phase 2b, dose-regimen finding, 4-arm parallel design: Eligible participants will be randomized 1:1:1:1 to receive codabakalner at different doses or matched placebo. Participants will receive study intervention over 4 weeks and will be followed up for 4 weeks after last dose of study intervention.
Phase 3, 2-arm parallel design: Eligible participants will be randomized 1:1 to receive codabakalner or matched placebo. The dose of codabakalner administered in the Phase 3 will be defined based on analysis of Phase 2b. Participants will receive study intervention over 12 weeks and will be followed up for 4 weeks after last dose of study intervention.
- Being tested
- Codabakalner, Placebo
- Keywords
- Fragile X Syndrome, Fragile X Chromosome, cognitive outcomes, Autism, Autism Spectrum Disorder
- Medical subject headings
- Fragile X Syndrome, Autism Spectrum Disorder, Autistic Disorder
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CodabakalnerDrug
Also called SPG601
synthetic small molecule
PlaceboDrug
Placebo
| Study group | Role | What they receive |
|---|---|---|
| Phase 2b: Active | Active comparator | Phase 2b: Participants with FXS or ASD will be randomized to receive a daily dose of codabakalner daily for 4 weeks Receives: Drug: Codabakalner |
| Phase 2b: Placebo | Placebo comparator | Participants with FXS or ASD will be randomized to receive a daily dose of placebo over 4 weeks. Receives: Drug: Placebo |
| Phase 3: Active | Active comparator | Participants with FXS will be randomized to receive a daily dose of codabakalner determined from Phase 2b over 12 weeks Receives: Drug: Codabakalner |
| Phase 3: Placebo | Placebo comparator | Participants with FXS will be randomized to receive a daily dose of placebo for 12 weeks Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Phase 2b: FXS- Change from baseline in Total Cognition Composite Change Sensitive Score from the NIH-TCB
The NIH Toolbox (NIH-TCB) Total Cognition Composite Change-Sensitive Score (CSS) is used to measure cognitive change over time. Higher scores indicate higher level of functioning. The scores typically span across the developmental range, often extending well above and below the 500-point mark depending on the age and cognitive ability of the individual.
Measured: 28 days
Phase 2b: ASD - Change from Baseline at Day 28 on the Vineland Adaptive Behavior Scales in ASD(Vineland-III) Adaptive Behavior Composite Score
Vineland Adaptive Behavior Composite (ABC) have a mean of 100 and a standard deviation of 15, where scores from 85 to 115 reflect expected or average adaptive functioning
Measured: 28 days
Phase 3: FXS - Change from baseline in Total Cognition Composite score from the NIH-TCB
The NIH Toolbox (NIH-TCB) Total Cognition Composite Change-Sensitive Score (CSS) is used to measure cognitive change over time. It is calculated by combining the Crystallized Composite (reading/vocabulary) and Fluid Composite (memory/executive function/speed) scores. Higher scores indicate higher level of functioning.
Measured: 12 weeks
Secondary outcomes (25)
Phase 2b: FXS- Change from baseline in Fluid Reasoning Composite Change Sensitive Scores from the NIH-TCB
The Fluid Cognition Composite (FCC) from the NIH Toolbox Cognition Battery (NIHTB-CB) is designed to measure changes to neurological functioning. It combines scores from five tests (Dimensional Change Card Sort, Flanker, List Sorting, Pattern Comparison, and Picture Sequence Memory) to provide a measure of executive function, memory, and processing speed. Higher scores indicate higher level of functioning. Superior ability is 130, average is approx. 100 and less than 70 is impairment.
Measured: 28 days
Phase 2b: FXS- Change from baseline in Flanker Scores from the NIH-TCB
The Flanker test measures executive attention, inhibitory control, and attention by having participants identify the direction of a central arrow (or fish for young children) while ignoring surrounding flanking stimuli. Yields a standardized score scaled with a mean of 100 and a standard deviation of 15 (up to a maximum score of 130)
Measured: 28 days
Phase 2b- FXS Change from Baseline at Day 28 on the Vineland Adaptive Behavior Scales (Vineland-III) Adaptive Behavior Composite Score
Vineland Adaptive Behavior Composite (ABC) have a mean of 100 and a standard deviation of 15, where scores from 85 to 115 reflect expected or average adaptive functioning
Measured: 28 days
Phase 2b: FXS and ASD: Change from baseline at Day 28 in Clinical global impression of severity (CGI-S) as assessed by the investigator
This is a 7-point clinician-rated tool used to measure how ill a patient is at the time of assessment
Measured: 28 days
Phase 2b: FXS and ASD: Change from baseline at Day 28 in Clinical global impression of improvement as assessed by the investigator
The Clinical Global Impression-Improvement (CGI-I) scale is a clinician rated scale used to assess treatment response. The score ranges from 1 to 7 (with 1 being "very much improved", 4 being "no change" to 7 being "very much worse")
Measured: 28 days
Phase 2b: FXS and ASD: Change from baseline at Day 28 in Caregiver global impression of change (CGI-C) as assessed by the caregiver
The Caregiver Global Impression of Improvement (CGI-C) is a global measure to provide a caregiver's perspective of a subject's overall condition. The caregiver will use a 7-point scale to assess how the condition has changed from baseline. A higher number indicates worsening condition.
Measured: 28 days
Phase 2b: FXS and ASD: Change from baseline at Day 28 in the Numerical Rating Scale as completed by the caregiver
Numerical rating scale (NRS) scores based on patient-specific behaviors within the domains of Daily Function, Language, and Academic Skill. Caregiver will rate individual from 0 to 10, where 0 indicates 'worst problem' and 10 indicates' no problem at all.'
Measured: 28 days
Phase 2b: FXS and ASD - Incidence, nature, and severity of adverse events (AEs) and serious adverse events (SAEs)
Incidence, nature, and severity of treatment emergent adverse events (TEAEs) and serious adverse events (SAEs)
Measured: 28 days
Phase 2b: FXS and ASD - Change from baseline in Columbia-Suicide Severity Rating Scale (C-SSRS) throughout the study
Prospective suicidality assessment is performed using the Columbia-Suicide Severity Rating Scale (C-SSRS), a questionnaire to evaluate suicidal ideation and behavior. Answer "yes" on item 4 or 5 of the Suicidal Ideation section or "yes" on any item of the Suicidal Behavior section is considered positive. Range is 2-25
Measured: 28 days
Phase 2b: FXS and ASD - The PK parameters of codabakalner concentrations in plasma-Cmax
Maximum concentration of drug in plasma following dose
Measured: 28 days
Phase 2b: FXS and ASD: Change from baseline to Day 28 in EEG resting state relative power in the alpha, theta, and gamma bands during rest
EEG power bands categorize brain electrical activity into five primary frequency ranges that reflect different states of arousal, sleep, and cognition
Measured: 28 days
Phase 3: Change from baseline to week 12 in Total Cognition Composite score from the NIH-TCB
The NIH Toolbox (NIH-TCB) Total Cognition Composite Change-Sensitive Score (CSS) is used to measure cognitive change over time. It is calculated by combining the Crystallized Composite (reading/vocabulary) and Fluid Composite (memory/executive function/speed) scores. Higher scores indicate higher level of functioning. The scores typically span across the developmental range, often extending well above and below the 500-point mark depending on the age and cognitive ability of the individual.
Measured: 12 weeks
Phase 3: Incidence, nature, and severity of adverse events (AEs) and serious adverse events (SAEs)
Incidence, nature, and severity of treatment emergent adverse events (TEAEs) and serious adverse events (SAEs)
Measured: 12 weeks
Phase 3: Change from baseline in Columbia-Suicide Severity Rating Scale (C-SSRS) throughout the study
Prospective suicidality assessment is performed using the Columbia-Suicide Severity Rating Scale (C-SSRS), a questionnaire to evaluate suicidal ideation and behavior. Answer "yes" on item 4 or 5 of the Suicidal Ideation section or "yes" on any item of the Suicidal Behavior section is considered positive. Range is 2-25
Measured: 12 weeks
Phase 3: Change from baseline to Week 4, Week 8, and Week 12 in Flanker from the NIH-TCB
Flanker Inhibitory control will assess inhibitory control and attention through asking participant to focus on one stimuli will not focusing on any stimuli surrounding it.
Measured: 12 weeks
Phase 3: Change from baseline to Week 4, Week 8, and Week 12 in Fluid Reasoning Composite Change Sensitive Scores from the NIH-TCB
The Fluid Cognition Composite (FCC) from the NIH Toolbox Cognition Battery (NIHTB-CB) is designed to measure changes to neurological functioning. It combines scores from five tests (Dimensional Change Card Sort, Flanker, List Sorting, Pattern Comparison, and Picture Sequence Memory) to provide a measure of executive function, memory, and processing speed. Higher scores indicate higher level of functioning. Superior ability is 130, average is approx. 100 and less than 70 is impairment.
Measured: 12 weeks
Phase 3: Change from baseline to week 4 and week 8 in Total Cognition Composite score from the NIH-TCB
The NIH Toolbox (NIH-TCB) Total Cognition Composite Change-Sensitive Score (CSS) is used to measure cognitive change over time. It is calculated by combining the Crystallized Composite (reading/vocabulary) and Fluid Composite (memory/executive function/speed) scores. Higher scores indicate higher level of functioning. The scores typically span across the developmental range, often extending well above and below the 500-point mark depending on the age and cognitive ability of the individual.
Measured: 8 weeks
Phase 3: The PK parameters of codabakalner concentrations in plasma-Cmax
Maximum concentration of drug in plasma following dose
Measured: 12 weeks
Phase 3: Change in from baseline to Week 4, Week 8, and Week 12, in ABC total score and subscale scores (FXS scoring)
The Aberrant Behavior Checklist-Community edition (ABC-C) is a 58-item, caregiver-rated symptom checklist for assessing problem behaviors of children and adults with mental retardation at home, in residential facilities, and work training centers. The assessment was done by attributing to each item a score from 0 ("not at all a problem") to 3 ("problem is severe in degree") The ABC will be scored using the FXS-specific factoring system (ABC-FX) for which the total score ranks from 0 to 165.
Measured: 12 weeks
Phase 3: Change from baseline to Week 4, Week 8, and Week 12 in behaviors and other symptoms on NRS by caregiver
Numerical rating scale (NRS) scores based on patient-specific behaviors within the domains of Daily Function, Language, and Academic Skill. Caregiver will rate individual from 0 to 10, where 0 indicates 'worst problem' and 10 indicates' no problem at all.'
Measured: 12 weeks
Phase 3: Change from baseline to Week 12 in Vineland Adaptive Behavior Scale 3rd Edition
Vineland-3 Adaptive Behavior Scale (Vineland-3), using the composite score and domain scores from communication, daily living skills, and socialization.
The adaptive behavior composite standard score is computed from the sum of standard scores from the domains and converted into the adaptive behavior composite standard score. Higher scores indicate a higher adaptive level of functioning.
Measured: 12 weeks
Phase 3: Change from baseline in CGI-S as assessed by investigator
This is a 7-point clinician-rated tool used to measure how ill a patient is at the time of assessment
Measured: 12 weeks
Phase 3: Change from baseline in CGI-I as assessed by investigator
The Clinical Global Impression-Improvement (CGI-I) scale is a clinician rated scale used to assess treatment response. The score ranges from 1 to 7 (with 1 being "very much improved", 4 being "no change" to 7 being "very much worse")
Measured: 12 weeks
Phase 3: Change from baseline in Caregiver Global Impression of Improvement (CGI-C) assessments
The Caregiver Global Impression of Improvement (CGI-C) is a global measure to provide a caregiver's perspective of a subject's overall condition. The caregiver will use a 7-point scale to assess how the condition has changed from baseline. A higher number indicates worsening condition.
Measured: 12 weeks
Phase 3: Change from baseline in the Numerical Rating Scale at Week 4, Week 8, and Week 12 as completed by the caregiver
Numerical rating scale (NRS) scores based on patient-specific behaviors within the domains of Daily Function, Language, and Academic Skill. Caregiver will rate individual from 0 to 10, where 0 indicates 'worst problem' and 10 indicates' no problem at all.'
Measured: 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Feb 2026
- Study start1 Dec 2026 (estimated)
- Primary completion1 Feb 2030 (estimated)
- Study completion30 Jun 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Fragile X Syndrome (FXS)Studies of the same condition, open and under way.
- 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 2/3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 120 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Spinogenix
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07439510
- Sponsor's protocol ID
- SPG601-102 (CLARITY)
- Status last verified
- Oct 2026
- First submitted
- 18 Feb 2026
- Last updated
- 9 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No