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

NCT07209462 | Recruiting Phase 2 FDA Drug

• 1 other identifier: ENV-202
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 15

Brief 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. 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

Keywords

Fragile X Syndrome; FXS; FMR; Phosphodiesterase 4; PDE4

Outcome Measures

Primary Outcomes (1)

• Incidence and severity of treatment-emergent adverse events and Withdrawal due to adverse events and withdrawal due to adverse events

  Baseline to Week 12

Study Arms (5)

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

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

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

Drug: High dose of MRM-3379

Arm 4 :Placebo

PLACEBO COMPARATOR

Participants 16-45 years of age randomized to this arm will receive Placebo

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

Drug: Low dose of MRM-3379 Open-Label

Interventions

Low dose of MRM-3379 DRUG

Oral capsule

Arm 1: Low Dose of MRM-3379

Middle Dose of MRM-3379 DRUG

Oral capsule

Arm 2: Middle dose of MRM-3379

Placebo DRUG

Capsules matched to study drug without the active pharmaceutical ingredient

Arm 4 :Placebo

Low dose of MRM-3379 Open-Label DRUG

Oral capsule

Arm 5: Low dose of MRM-3379 Open-Label

High dose of MRM-3379 DRUG

Oral capsule

Arm 3: High dose of MRM-3379

Eligibility Criteria

• Age: 13 Years - 45 Years
• Gender Eligibility Details: Male
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• History of or current medical condition other than FXS and related issues that would place the participant at higher risk from study participation

Sponsors & Collaborators

• Mirum Pharmaceuticals, Inc.: lead

Study Sites (15)

Southwest Autism Research & Resource Center

Phoenix, Arizona, 85006, United States

RECRUITING

Amnova Clinical Research, LLC

Irvine, California, 92604, United States

RECRUITING

Children's Hospital of Orange County - Pediatric Subspecialty

Orange, California, 92868, United States

NOT YET RECRUITING

Uc Davis Mind Institute

Sacramento, California, 95817, United States

NOT YET RECRUITING

Children's Hospital Colorado

Aurora, Colorado, 80045, United States

NOT YET RECRUITING

Neurology

Miami, Florida, 33136, United States

NOT YET RECRUITING

Emory University - The Emory Clinic - Clifton Road

Atlanta, Georgia, 30322, United States

NOT YET RECRUITING

Rush University Medical Center-Clinical Operation

Chicago, Illinois, 60612, United States

RECRUITING

Kennedy Krieger Institute, John Hopkins School of Medicine

Baltimore, Maryland, 21205, United States

NOT YET RECRUITING

Boston Children's Hospital

Boston, Massachusetts, 02115, United States

NOT YET RECRUITING

UMass Memorial Health

Worcester, Massachusetts, 01655, United States

RECRUITING

University of Minnesota Department of Medicine

Minneapolis, Minnesota, 55414, United States

NOT YET RECRUITING

Cincinnati Children's Hospital Medical Center

Cincinnati, Ohio, 42229, United States

NOT YET RECRUITING

Suburban Research Associates

Media, Pennsylvania, 19063, United States

RECRUITING

Intermountain Healthcare - Park City Specialty Clinic

Salt Lake City, Utah, 84108, United States

NOT YET RECRUITING

MeSH Terms

Conditions

Fragile X Syndrome

Condition Hierarchy (Ancestors)

X-Linked Intellectual Disability; Intellectual Disability; Neurobehavioral Manifestations; Neurologic Manifestations; Nervous System Diseases; Sex Chromosome Disorders; Chromosome Disorders; Congenital Abnormalities; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Genetic Diseases, Inborn; Genetic Diseases, X-Linked; Heredodegenerative Disorders, Nervous System

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 2, 2025
• First Posted: October 7, 2025
• Study Start: November 22, 2025
• Primary Completion (Estimated): October 1, 2027
• Study Completion (Estimated): October 1, 2027
• Last Updated: April 21, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

US (15)