Fragile X SyndromePhase 2NCT07209462
Study of MRM-3379 in Male Participants With Fragile X Syndrome (BLOOM)
A Phase 2 study testing Low dose of MRM-3379, Middle Dose of MRM-3379 and High dose of MRM-3379 in people with Fragile X Syndrome, run by Mirum Pharmaceuticals, Inc. at 18 sites in 2 countries.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 13 to 45 years, men only
- Conditions the study is for
- Fragile X Syndrome
- What is being tested?
- Low dose of MRM-3379, Middle Dose of MRM-3379 and High dose of MRM-3379
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 60 participants
- Where
- 18 sitesin 2 countries
- Study dates
- 22 Nov 2025to Oct 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
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 13 to 45 years
- Men only
- No healthy volunteers
- Child, Adult
Who may be able to join
- 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
Who cannot join
- History of or current medical condition other than FXS and related issues that would place the participant at higher risk from study participation
Trial locations and contacts
18 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
18 sites in 2 countries
United States15 sites, 15 recruiting
- Recruiting
Emory University - The Emory Clinic - Clifton Road
Atlanta, Georgia, 30322
Robin Vinson, 404-778-8533, robin.vinson@emory.edu
Nadia Ali, 404-778-8613, nadia.ali@emory.edu
- Recruiting
Children's Hospital Colorado
Aurora, Colorado, 80045
Nicole Tartaglia, 720-777-6895, Nicole.Tartaglia@childrenscolorado.org
Nicole Tartaglia
- Recruiting
Kennedy Krieger Institute, John Hopkins School of Medicine
Baltimore, Maryland, 21205
Kennedy Krieger, 443-923-3850, ResearchTrials@KennedyKrieger.org
Stephanie Morris
- Recruiting
Boston Children's Hospital
Boston, Massachusetts, 02115
Michelle Coughlin, 857-218-3842, michelle.Coughlin@childrens.harvard.edu
Katherine Pawlowski, 857-218-5472, Katherine.pawlowski@childrens.harvard.edu
- Recruiting
Rush University Medical Center-Clinical Operation
Chicago, Illinois, 60612
Lorelai Konen, 312-942-2815, Lorelai_Konen@rush.edu
Molly Flanagan, 312-942-1876, Molly_L_Flanagan@rush.edu
- Recruiting
Cincinnati Children's Hospital Medical Center
Cincinnati, Ohio, 42229
Hannah Sachs, 513-803-1150, Hannah.Sachs@cchmc.org
Priya Ramesh, 513-636-4433, Priya.Ramesh@cchmc.org
- Recruiting
Amnova Clinical Research, LLC
Irvine, California, 92604
Maggie Wang, 949-358-7447, maggie@amnovaresearch.com
Jannet Guerrero, 949-861-7479, jannet.guerrero@amnovaresearch.com
- Recruiting
Suburban Research Associates
Media, Pennsylvania, 19063
Naya Square, 610-891-9024 ext. 1128, Nsquare@suburbanresearch.com
Kristen Dopf
- Recruiting
Neurology
Miami, Florida, 33136
Dr. Barbara Coffey, 305-243-2759, bjc134@miami.edu
Barbara Coffey
- Recruiting
University of Minnesota Department of Medicine
Minneapolis, Minnesota, 55414
Rachel Floersch, 612-626-8424, Floer013@umn.edu
Brittany Faanes, 612-625-5929, Grego318@umn.edu
- Recruiting
Children's Hospital of Orange County - Pediatric Subspecialty
Orange, California, 92868
Adrienne Moore, 714-288-7456, Adrienne.Moore@choc.org
Stanley Friers, (714) 288-7683, Stanley.Friers@choc.org
- Recruiting
Southwest Autism Research & Resource Center
Phoenix, Arizona, 85006
Riley Stark, 480-351-0567, rstark@autismcenter.org
Padmaja Lakamsani, PLakamsani@autismcenter.org
- Recruiting
Uc Davis Mind Institute
Sacramento, California, 95817
Melissa Heys, 916-703-0301, meheys@health.ucdavis.edu
Abigail Borbe, 916-703-0281, amoradelhigareda@health.ucdavis.edu
- Not yet recruiting
Intermountain Healthcare - Park City Specialty Clinic
Salt Lake City, Utah, 84108
Peter Farr, 801-587-2103, peter.farrell@hsc.utah.edu
Karina Mattson, 801-587- 7573, karina.mattson@hsc.utah.edu
- Recruiting
UMass Memorial Health
Worcester, Massachusetts, 01655
Taylor Merk, 774-455-4119, Taylor.merk@umassmed.edu
Lauren Venuti, 774-455-4113, Lauren.venuti@umassmed.edu
Spain3 sites, 3 recruiting
- Recruiting
Parc Tauli Hospital Universitari
Barcelona, 08208
Aida Gonzalez, +34 93 723 10 10 ext. 80817, agonzalezru01@tauli.cat
Ana Roche-Martinez
- Recruiting
Sant Joan De Deu Barcelona Hospital
Barcelona, 08950
Ana Gutierrez, 607-797-244 ext. 80947, ana.gutierrezg@sjd.es
Genís Oña Esteve, 607-799-616 ext. 80948, genis.ona@sjd.es
- Recruiting
Hospital Regional Universitario de Málaga (H. Civil)
Málaga, 29009
Jonathan Dawood, +34 620 25 35 35, jonathanjosepd@gmail.com
Jesús Herrera- Imbroda
About this study
Official title: Randomized, Double-Blind, Placebo-Controlled, Phase 2 Study of MRM-3379 in Male Participants With Fragile X Syndrome
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
- Conditions
- Fragile X Syndrome
- Being tested
- Low dose of MRM-3379, Middle Dose of MRM-3379, High dose of MRM-3379, Placebo, Low dose of MRM-3379 Open-Label
- Keywords
- Fragile X Syndrome, FXS, FMR, Phosphodiesterase 4, PDE4
- Medical subject headings
- Fragile X Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low dose of MRM-3379Drug
Oral capsule
Middle Dose of MRM-3379Drug
Oral capsule
High dose of MRM-3379Drug
Oral capsule
PlaceboDrug
Capsules matched to study drug without the active pharmaceutical ingredient
Low dose of MRM-3379 Open-LabelDrug
Oral capsule
| Study group | Role | What they receive |
|---|---|---|
| Arm 1: Low Dose of MRM-3379 | Experimental | Participants 16-45 years of age randomized to this arm will receive the low dose of MRM-3379 Receives: Drug: Low dose of MRM-3379 |
| Arm 2: Middle dose of MRM-3379 | Experimental | Participants 16-45 years of age randomized to this arm will receive the middle dose of MRM-3379 Receives: Drug: Middle Dose of MRM-3379 |
| Arm 3: High dose of MRM-3379 | Experimental | Participants 16-45 years of age randomized to this arm will receive the high dose of MRM-3379 Receives: Drug: High dose of MRM-3379 |
| Arm 4 :Placebo | Placebo comparator | Participants 16-45 years of age randomized to this arm will receive Placebo Receives: Drug: Placebo |
| Arm 5: Low dose of MRM-3379 Open-Label | Experimental | Participants 13 to < 16 years of age will receive the low dose of MRM-3370 Open-Label Receives: Drug: Low dose of MRM-3379 Open-Label |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence and severity of treatment-emergent adverse events and Withdrawal due to adverse events and withdrawal due to adverse events
Measured: Baseline to Week 12
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Oct 2025
- Study start22 Nov 2025
- Primary completionOct 2027 (estimated)
- Study completionOct 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Fragile X SyndromeStudies 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
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Mirum Pharmaceuticals, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07209462
- Sponsor's protocol ID
- ENV-202
- Status last verified
- Sep 2026
- First submitted
- 2 Oct 2025
- Last updated
- 29 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 29 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Randomized, Double-Blind, Placebo-Controlled, Phase 2 Study of MRM-3379 in Male Participants With Fragile X Syndrome
- ClinicalTrials.gov ID
- NCT07209462
- Acronym / sponsor ID
- ENV-202
- Conditions
- Fragile X Syndrome
- Keywords
- Fragile X Syndrome, FXS, FMR, Phosphodiesterase 4, PDE4
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Mirum Pharmaceuticals, Inc.Industry (pharma, biotech, devices)
- Study start
- 22 Nov 2025 (actual)
- Primary completion
- Oct 2027 (estimated)
- Study completion
- Oct 2027 (estimated)
- First posted
- 7 Oct 2025 (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 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
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 5
| Arm | Type | Receives |
|---|---|---|
| Arm 1: Low Dose of MRM-3379 | Experimental | Drug: Low dose of MRM-3379Participants 16-45 years of age randomized to this arm will receive the low dose of MRM-3379 |
| Arm 2: Middle dose of MRM-3379 | Experimental | Drug: Middle Dose of MRM-3379Participants 16-45 years of age randomized to this arm will receive the middle dose of MRM-3379 |
| Arm 3: High dose of MRM-3379 | Experimental | Drug: High dose of MRM-3379Participants 16-45 years of age randomized to this arm will receive the high dose of MRM-3379 |
| Arm 4 :Placebo | Placebo comparator | Drug: PlaceboParticipants 16-45 years of age randomized to this arm will receive Placebo |
| Arm 5: Low dose of MRM-3379 Open-Label | Experimental | Drug: Low dose of MRM-3379 Open-LabelParticipants 13 to < 16 years of age will receive the low dose of MRM-3370 Open-Label |
Who may qualify
- Ages
- 13 to 45 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (7 listed)
- 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
Key exclusion criteria (1 listed)
- History of or current medical condition other than FXS and related issues that would place the participant at higher risk from study participation
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 |
|---|---|---|
| Low dose of MRM-3379Oral capsule | Drug | Arm 1: Low Dose of MRM-3379 |
| Middle Dose of MRM-3379Oral capsule | Drug | Arm 2: Middle dose of MRM-3379 |
| High dose of MRM-3379Oral capsule | Drug | Arm 3: High dose of MRM-3379 |
| PlaceboCapsules matched to study drug without the active pharmaceutical ingredient | Drug | Arm 4 :Placebo |
| Low dose of MRM-3379 Open-LabelOral capsule | Drug | Arm 5: Low dose of MRM-3379 Open-Label |
Primary outcome
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
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Sep 2026.
- Individual participant dataSharing planned: No
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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.
Southwest Autism Research & Resource Center
Phoenix, United States
Children's Hospital of Orange County - Pediatric Subspecialty
Orange, United States
18 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Low dose of MRM-3379, Middle Dose of MRM-3379 and High dose of MRM-3379 in people with Fragile X Syndrome, run by Mirum Pharmaceuticals, Inc. at 18 sites in 2 countries.
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 7 inclusion and 1 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: looking for participants now, as of the sponsor's last update on 29 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 18 sites in United States, Spain. 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 29 Sep 2026.