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MRM-3379

Phase 2

Fragile X Syndrome | Small molecule | Rare Disease |Mirum Pharmaceuticals, Inc.|Trials Updated: Sep 29, 2026

MRM-3379 development status

Highest phase Phase 2
Registered trials 1 across 1 sponsor since Jul 2026

MRM-3379 target and mechanism

Molecular targetPDE4D
Target classEnzyme
ModalitySmall molecule

Also known as [14C]-MRM-3379, Low dose of MRM-3379, Middle Dose of MRM-3379

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLED
Total Trials1
Total Enrollment60

FDA Designations

No designations recorded

MRM-3379 clinical trials

MRM-3379 · 1 trial · 1 indication

Phase 2 1
NCT07209462Study of MRM-3379 in Male Participants With Fragile X Syndrome (BLOOM)Fragile X Syndrome
RECRUITING60 Analytics
PHASE2RECRUITING
Study of MRM-3379 in Male Participants With Fragile X Syndrome (BLOOM)
Fragile X SyndromeUnlock trial analytics

Study Endpoints

Primary Endpoints

Incidence and severity of treatment-emergent adverse events and Withdrawal due to adverse events and withdrawal due to adverse events
Baseline to Week 12
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Study Design & Arms

AllocationRANDOMIZED
MaskingDOUBLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Arm 1: Low Dose of MRM-3379EXPERIMENTALParticipants 16-45 years of age randomized to this arm will receive the low dose of MRM-3379
Arm 2: Middle dose of MRM-3379EXPERIMENTALParticipants 16-45 years of age randomized to this arm will receive the middle dose of MRM-3379
Arm 3: High dose of MRM-3379EXPERIMENTALParticipants 16-45 years of age randomized to this arm will receive the high dose of MRM-3379
Arm 4 :PlaceboPLACEBO_COMPARATORParticipants 16-45 years of age randomized to this arm will receive Placebo
Arm 5: Low dose of MRM-3379 Open-LabelEXPERIMENTALParticipants 13 to \< 16 years of age will receive the low dose of MRM-3370 Open-Label

Interventions

NameTypeDescription
Low dose of MRM-3379DRUGOral capsule
Middle Dose of MRM-3379DRUGOral capsule
High dose of MRM-3379DRUGOral capsule
PlaceboDRUGCapsules matched to study drug without the active pharmaceutical ingredient
Low dose of MRM-3379 Open-LabelDRUGOral capsule
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Eligibility Criteria

Age Range13 Years to 45 Years
SexMALE
Healthy VolunteersNo
Study Sites18

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 mu...

Countries:United StatesSpain
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Recent Changes (Last 90 Days)

LOWSep 29, 2026NCT07209462lastUpdatePostDate: changed
LOWSep 29, 2026NCT07209462lastUpdatePostDate: changed
LOWSep 21, 2026NCT07209462lastUpdatePostDate: changed
LOWSep 21, 2026NCT07209462lastUpdatePostDate: changed
LOWAug 24, 2026NCT07209462lastUpdatePostDate: changed
LOWAug 24, 2026NCT07209462lastUpdatePostDate: changed
LOWAug 7, 2026NCT07209462lastUpdatePostDate: changed
LOWAug 7, 2026NCT07209462lastUpdatePostDate: changed
LOWJul 28, 2026NCT07209462lastUpdatePostDate: changed
LOWJul 28, 2026NCT07209462lastUpdatePostDate: changed

Frequently asked questions about MRM-3379

What is MRM-3379?

MRM-3379 is an investigational small molecule being developed by Mirum Pharmaceuticals for Fragile X Syndrome, a rare genetic condition. It is currently in Phase 2 clinical development and has not been approved by any regulatory agency. The program is being studied in male participants aged 13 years and older.

What is MRM-3379 used for in Fragile X Syndrome?

MRM-3379 is being studied as a potential treatment for Fragile X Syndrome, a rare neurodevelopmental disorder. It is an investigational therapy in Phase 2 testing and is not approved for any use. The ongoing trial enrolls male participants aged 13 years and older in the United States and Spain.

What does MRM-3379 target?

MRM-3379 targets PDE4D, an enzyme. By acting on this phosphodiesterase target, the small molecule is designed to modulate signaling pathways relevant to Fragile X Syndrome. PDE4D inhibition is the mechanism under investigation in the Phase 2 BLOOM study of male participants with the condition.

Who is developing MRM-3379?

MRM-3379 is being developed by Mirum Pharmaceuticals, Inc., which trades on the Nasdaq under the ticker MIRM. Mirum is a rare disease focused biopharmaceutical company. The company is running the Phase 2 BLOOM trial of MRM-3379 in Fragile X Syndrome.

What phase is MRM-3379 in?

MRM-3379 is in Phase 2 clinical development. It is an investigational drug and has not been approved by the FDA or any other regulatory authority. The single ongoing trial is currently recruiting participants, with no completed trials reported for the program to date.

What clinical trials is MRM-3379 in?

MRM-3379 is being evaluated in one clinical trial, NCT07209462, titled Study of MRM-3379 in Male Participants With Fragile X Syndrome (BLOOM). The Phase 2 study is recruiting 60 male participants aged 13 years and older across the United States and Spain. It is randomized, double blind, and placebo controlled.

Is MRM-3379 the same as [14C]-MRM-3379?

Yes, [14C]-MRM-3379 is an alternative name for MRM-3379, referring to the carbon-14 labeled form of the compound. Other labels used for study arms include Low dose of MRM-3379 and Middle Dose of MRM-3379. All refer to the same investigational PDE4D-targeting small molecule from Mirum Pharmaceuticals.