A Phase 2 interventional study of S247240 Low dose and S247240 Middle dose in Fragile X Syndrome (FXS), sponsored by Institut de Recherches Internationales Servier (I.R.I.S.). Not yet recruiting. Open to male participants aged 18 Years to 45 Years. Per ClinicalTrials.gov, last updated 2026-11-12.
Sponsored by Institut de Recherches Internationales Servier (I.R.I.S.) · Phase 2, Interventional, and Treatment
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This study is a multicenter, double-blind, randomized, placebo-controlled study to assess the safety and tolerability of 3 doses of S247240 in male participants with Fragile X Syndrome aged 18 to 45 years old. Participants will participate for 14 weeks of treatment. The study is also intended to characterize the PK profile of S247240 and to obtain preliminary assessments of the efficacy of S247240 in mental status examination scales and tests over the 14 weeks of treatment period.
115 studies on the registry are indexed under Fragile X Syndrome; 25 are open to participants now.
This study's planned enrollment of 100 is above the median of 54 across 92 interventional studies indexed under Fragile X Syndrome.
Browse Fragile X Syndrome studies →Institut de Recherches Internationales Servier (I.R.I.S.) is the lead sponsor of 6 studies on the registry; 3 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: S247240 Low dose
Drug: S247240 Middle dose
Drug: S247240 High dose
Other: Placebo
Participants will receive a liquid solution of S247240 low dose, to be taken orally twice daily.
Participants will receive a liquid solution of S247240 middle dose, to be taken orally twice daily.
Participants will receive a liquid solution of S247240 high dose, to be taken orally twice daily.
Participants will receive a liquid solution containing no active drug, to be taken orally twice daily.
Number of Adverse Events (AEs)
Time frame: Through Week 16
Severity of AEs
Time frame: Through Week 16
Change from baseline at Week 14 in NRS-FXS score
The Numerical Rating Scale - Fragile X Syndrome (NRS-FXS) is based on patient-specific behaviors within the domains of Daily Function, Language/Communication, and Emotions and behaviors. The score in each domain ranges from 0 to 10, with higher numbers indicating better functioning. This will be completed by the participant's caregiver.
Time frame: Through Week 14
Change from baseline at Week 14 in CGI-S score
The Clinical Global Impression-Severity (CGI-S) score ranges from 1 to 7, with higher numbers indicating worse functioning. This will be completed by the clinician.
Time frame: Through Week 14
Change from baseline to Week 14 in CGI-I score
The Clinical Global Impression-Improvement (CGI-I) score ranges from 1 to 7, with higher numbers indicating a worsening in functioning. This will be completed by the clinician.
Time frame: Through Week 14
Change from baseline at Week 14 in ABC-C FXS score
The Aberrant Behavior Checklist - Community, Fragile X Syndrome (ABC-C FXS) is a 58-item questionnaire that assesses the severity of behaviors. Each item is rated on a 4-point scale from 0 to 3 with higher numbers indicating worse functioning. This will be completed by the participant's caregiver.
Time frame: Through Week 14
Change from baseline at Week 14 in NIH-TCB score
For the National Institutes of Health - Toolbox Cognition Battery (NIH-TCB) 6 Fluid Battery tests, higher scores indicate better cognitive functioning. Superior ability is 130; average is approx. 100 and less than 70 is impairment. This will be completed by the participant.
Time frame: Through Week 14
Change from baseline to Week 14 in PARS score
The Pediatric Anxiety Rating Scale (PARS) ranges from 0 to 25, with higher numbers indicating worse functioning. This will be completed by a central clinician through a remote interview of the participant's caregiver.
Time frame: Through Week 14
Change from baseline to Week 14 in ADAMS score
The Anxiety Depression and Mood Scale (ADAMS) contains 29 subscales, each of which has a score ranging from 0 to 3 with higher numbers indicating worse functioning. This will be completed by the participant's caregiver.
Time frame: Through Week 14
Change from baseline to Week 14 in VABS-3 score
Each item of the Vineland Adaptive Behavior Scale Third Edition (VABS-3) ranges from 0 to 2. This yields an ABC score which ranges from 20 to 140, and sub-domain V-scale scores which range from 1 to 24. This will be completed by a central clinician through a remote interview of the participant's caregiver.
Time frame: Through Week 14
Sleep quality as assessed by PSQI score
The Pittsburgh Sleep Quality Index (PSQI) ranges from 0 to 21, with higher numbers indicating worse sleep quality. This will be completed by the participant's caregiver.
Time frame: Through Week 16
Quality of life as assessed by EQ-5D-5L score
The EuroQol-5Dimension-5Level (EQ-5D-5L) is a questionnaire assessing health status. It consists of 2 parts, one descriptive part assessing health in 5 dimensions, and one visual analogue scale which scores from 0 to 100, with higher scores indicating better health status. This will be completed by the participant's caregiver.
Time frame: Through Week 14
Measured concentration at the end of a dosing interval at steady state (Ctrough) of S247240 in plasma
Time frame: Through Week 16
Observed maximum plasma concentration after administration (Cmax) of S247240 in plasma
Time frame: Through Week 16
Area Under the concentration time curve from time zero up to the next administration (AUCtau) of S247240 in plasma
Time frame: Through Week 16
No study locations are listed for this record.
Plan to share: Yes — Qualified scientific and medical researchers can request access to anonymized patient-level and study-level clinical trial data. Access can be requested for all interventional clinical studies: used for Marketing Authorization (MA) of medicines and new indications approved after 1 January 2014 in the European Economic Area (EEA) or the United States (US). where Servier is the Marketing Authorization Holder (MAH). The date of the first MA of the new medicine (or the new indication) in one of the EEA Member States will be considered for this scope. In addition, access can be requested for all interventional clinical studies in patients: sponsored by Servier with a first patient enrolled as of 1 January 2004 onwards for New Chemical Entity or New Biological Entity (new pharmaceutical form excluded) for which development has been terminated before any Marketing authorization (MA) approval.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report
Time frame: After Marketing Authorization in EEA or US if the study is used for the approval.
Access criteria: Researchers should register on Servier Data Portal and fill in the research proposal form. This form in four parts should be fully documented. The Research Proposal Form will not be reviewed until all mandatory fields are completed.
No publications or documents are linked to this record.
Start is estimated for Jan 2027; primary completion for Dec 2028, 23 months later.
Of 15 phase 2 interventional studies under Fragile X Syndrome, half reached primary completion within 24 months of starting (the median), counting those still running; a quarter within 15 and three quarters within 37. This study's planned 23 months is close to that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.
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Institut de Recherches Internationales Servier (I.R.I.S.)