A Phase 2 interventional study of Low dose of MRM-3379 and Middle Dose of MRM-3379 in Fragile X Syndrome, sponsored by Mirum Pharmaceuticals, Inc.. Recruiting at 18 sites in 2 countries. Open to male participants aged 13 Years to 45 Years. Per ClinicalTrials.gov, last updated 2026-09-29.
Sponsored by Mirum Pharmaceuticals, Inc. · Phase 2, Interventional, and Treatment
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Among 82 studies in Fragile X Syndrome with a site in United States — 11 open to participants now, 16 under way, 2 of them phase 3. Fragile X Syndrome · United States.
Among the 82 studies in Fragile X Syndrome with a site in United States, this one is the 32nd largest by planned enrollment of the 68 interventional ones that give a count, is one of 2 that started in 2025, is one of 28 in phase 2, reaches primary completion later than 11 of the 15 other live ones, and was the 79th registered.
115 studies on the registry are indexed under Fragile X Syndrome; 25 are open to participants now.
Browse Fragile X Syndrome studies →11 of the 82 studies in Fragile X Syndrome with a site in United States are open now. Recruiting first, the newest first:
Healing Hope International · Sites in United States
Ages 4–12
University of North Carolina, Chapel Hill · Sites in United States
Ages 18+ · Healthy volunteers
Children's Hospital Medical Center, Cincinnati · Sites in United States
Ages 5–10 · Healthy volunteers
Children's Hospital Medical Center, Cincinnati · Sites in United States
Ages 6 mo–26 mo · Healthy volunteers
Children's Hospital Medical Center, Cincinnati · Sites in United States
Ages 24 mo–4 yrs · Healthy volunteers
A study can be open while its sites in United States have not opened yet or have stopped. Only those recruiting at a site in United States →
Of the 18 Fragile X Syndrome studies recruiting now, 5 (28%) set no upper age limit and 13 (72%) stop at 75 or younger; 15 take children under 18; 7 take healthy volunteers.
This study: 13 Years to 45 Years · male · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
82 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 14 · Phase 2 36 · Phase 3 11 · Phase 4 2
First in 2002; this study’s year is marked. 2 started in 2025.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 60 is above the median of 54 across 92 interventional studies indexed under Fragile X Syndrome.
Median enrollment 60 across the 68 interventional studies, 100 across the 12 observational. Of the 58 that completed or were terminated, 22 (38%) have results posted.
This tab as a report to print or save as PDF → With an account.
38 of 82 have an industry lead sponsor. The 10 most frequent:
Mirum Pharmaceuticals, Inc. is the lead sponsor of 40 studies on the registry; 7 are open to participants now.
Of its 12 completed or terminated interventional studies of FDA-regulated products, 11 (92%) have results posted.
Mirum Pharmaceuticals, Inc. has 1 study filed under Fragile X Syndrome — fewer than ten, so there is no comparison to draw.
7 of the studies in Fragile X Syndrome with a site in United States that are under way reach primary completion within a year, 1 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT05367960Phase 3Tetra Discovery PartnersAn Open-Label Extension Study of BPN14770 in Subjects With Fragile X Syndrome | 2027-09-30 |
| NCT03655223RTI InternationalEarly Check: Expanded Screening in Newborns | 2026-11-30 |
| NCT06139172Rush University Medical CenterWeb Intervention for Parents of Youth With Genetic Syndromes (WINGS) | 2026-12 |
| NCT06560242Children's Hospital Medical Center, CincinnatiTracking Early Emergence of Sound Perception Impairments in FXS With Multimodal fNIRS/EEG- Infant | 2027-03-01 |
| NCT05957549Children's Hospital Medical Center, CincinnatiTracking Early Emergence of Sound Perception Impairments in FXS With Multimodal fNIRS/EEG-Preschool Age | 2027-03-01 |
Add all 7 to your calendar (.ics) → With an account.
Among the 82 studies in Fragile X Syndrome with a site in United States, from their registry updates:
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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 MRM-3379 in male participants with Fragile X Syndrome ages 16 to 45 (inclusive). In addition, a parallel cohort of participants ages 13 to \<16 will receive open-label MRM-3379. All participants will participate for 12 weeks of treatment. The study is also intended as a proof-of-concept investigation to evaluate whether MRM-3379 can improve FXS symptoms
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:
History of or current medical condition other than FXS and related issues that would place the participant at higher risk from study participation
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.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorized to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
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.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorized to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Participants 16-45 years of age randomized to this arm will receive the low dose of MRM-3379
Drug: Low dose of MRM-3379
Participants 16-45 years of age randomized to this arm will receive the middle dose of MRM-3379
Drug: Middle Dose of MRM-3379
Participants 16-45 years of age randomized to this arm will receive the high dose of MRM-3379
Drug: High dose of MRM-3379
Participants 16-45 years of age randomized to this arm will receive Placebo
Drug: Placebo
Participants 13 to \< 16 years of age will receive the low dose of MRM-3370 Open-Label
Drug: Low dose of MRM-3379 Open-Label
Oral capsule
Oral capsule
Oral capsule
Capsules matched to study drug without the active pharmaceutical ingredient
Oral capsule
Incidence and severity of treatment-emergent adverse events and Withdrawal due to adverse events and withdrawal due to adverse events
Time frame: Baseline to Week 12
Plan to share: No
No publications or documents are linked to this record.
Started Nov 2025 (actual). Primary completion is estimated for Oct 2027, 23 months after the start.
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 ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
No contact was published for this record. The registry link below has the sponsor’s details.
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