ClinicalTrials.gov record NCT07209462

Study of MRM-3379 in Male Participants With Fragile X Syndrome (BLOOM)

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Jul 27, 2026

Randomized, Double-Blind, Placebo-Controlled, Phase 2 Study of MRM-3379 in Male Participants With Fragile X Syndrome

StatusRecruitingThe study is currently enrolling participants. Only the study team can say whether a particular person can join.
Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.
PhasePhase 2A study that tests whether a treatment has the intended effect and continues to check safety, usually in a larger group than phase 1.
Age13 years old to 45 years old
SexMale
LocationSpain, United States
AI summaryWhat this study is about, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

This is a Phase 2, randomized, double-blind, placebo-controlled study testing three doses of MRM-3379 in males with Fragile X Syndrome. Participants aged 16–45 are randomized to low, middle, high dose, or placebo; a separate open-label low-dose group enrolls males aged 13 to under 16. All participants receive 12 weeks of treatment. The study’s main goals are to assess safety and tolerability and to evaluate whether MRM-3379 can affect FXS symptoms.

What it is studying. The study tests the safety and tolerability of three oral doses of MRM-3379 in males with Fragile X Syndrome over 12 weeks, and as a proof-of-concept it evaluates whether MRM-3379 can change FXS symptoms. A separate younger cohort (13 to <16 years) receives open-label low-dose treatment.

What the researchers hope to learn. To assess incidence and severity of treatment-emergent adverse events and withdrawals over 12 weeks, and to provide proof-of-concept data on whether MRM-3379 can affect Fragile X Syndrome symptoms.

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

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

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Drug
  • Low dose of MRM-3379
  • Middle Dose of MRM-3379
  • High dose of MRM-3379
  • Placebo
  • Low dose of MRM-3379 Open-Label

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Inclusion criteria

  • Willing and able to provide signed informed consent/assent. Where local regulations permit inclusion of participants deemed unable to provide informed consent, a legally authorized representative must provide informed consent on the participant's behalf, and the participant must provide assent if applicable.
  • Male, 13-45 years of age (inclusive)
  • Weight ≥30 kg and BMI between 18 and 36 kg/m2 (inclusive) at the screening visit
  • Diagnosis of FXS with a molecular genetic ≥200 CGG repetitions .
  • Able to perform the PVT and ORRT of the NIH-TCB
  • Have a consistent caregiver(s) who is willing and able to be present regularly and reliably with the participant
  • Able to swallow tablets or capsules

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

Study description and what participation involves

The registry record has no detailed description beyond the summary above.

AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

Participants will give informed consent (or assent with a legally authorized representative's consent where permitted) and complete screening assessments. Those 16–45 will be randomized, double-blind, to low, middle, high dose, or placebo; those 13 to <16 will receive an open-label low dose. All participants will take oral study capsules and participate in 12 weeks of treatment with regular clinic visits for safety monitoring, assessments (including the PVT and ORRT cognitive tasks), and reporting of any side effects. A consistent caregiver must be available to attend and support study visits and assessments.

How the study is structured. Phase 2 interventional trial. For ages 16–45: participants are randomized in parallel to one of three active oral dose arms or to placebo, with double-blind masking. A separate open-label low-dose arm enrolls males aged 13 to under 16. Treatment lasts 12 weeks; safety and symptom measures are collected during that time.

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

  • Some participants receive a placebo. How is that decided, and what happens for placebo-group participants when the study ends?
  • The listed sites are in Spain, United States. Is any of them reachable for me, and does the study help with travel?
  • Which of the eligibility criteria would need to be checked with tests before I could join?

More on fragile X syndrome

Clinical trials20 trials listed for fragile X syndromeEvery trial the registry lists for fragile X syndrome, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in fragile X syndrome researchLatest monthly update: September 2026. Includes: Multiple behavior challenges. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start
Nov 22, 2025
Primary completion
October 2027 (estimated)
Study completion
October 2027 (estimated)
Target enrollment
60 participants (estimated)
Last updated on registry
Sep 29, 2026
Data verified
Oct 10, 2026

Sponsor and research team

The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.

Lead sponsor
Mirum Pharmaceuticals, Inc.

Participating sites (18)

Terms used on this page · explanations by MedicalUpdates.ai

double-blind
Two types of people involved in the study do not know which intervention a participant is receiving. The ClinicalTrials.gov record specifies who is masked, for example participants, care providers, investigators or outcome assessors.
randomized
Participants are assigned to the study groups by chance, like a coin toss, rather than chosen by the doctor or the participant. This is done so the groups are comparable.
placebo-controlled
A study design in which one group receives a placebo so that the study treatment's effects can be compared with no active treatment.
cohort
A group of people who share a characteristic, such as a diagnosis, and are studied together. 'Prospective' means they are followed forward from enrolment; 'retrospective' means existing records are reviewed.
open-label
No masking is used, so the assigned intervention is not deliberately hidden from participants or study staff.
informed consent
The process of explaining a study, including its risks and what participation involves, so that a person can decide freely whether to take part. Consent is usually documented in writing, and a participant can choose to leave the study later.
assent
A child's or dependent adult's agreement to take part, given alongside the formal consent of a parent or legal representative.
legally authorized representative
A person who is legally allowed to make decisions, including consent to research, on behalf of someone who cannot consent for themselves.
screening visit
The checks done before enrolment to see whether a person qualifies, such as tests, scans or a review of medical history.
Inclusion Criteria
The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
Exclusion Criteria
The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.

The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.

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