Study of MRM-3379 in Male Participants with Fragile X Syndrome

2025-523738-21-00 Protocol ​​ENV-202​ Therapeutic exploratory (Phase II) Authorised, recruitment pending

Status Authorised, recruitment pending · 1 EU/EEA countries · 3 sites · Protocol ​​ENV-202​

Overview

Sponsor-declared trial summary

Phase Therapeutic exploratory (Phase II)
Status Authorised, recruitment pending
Participants planned 69
Countries 1
Sites 3

​​Fragile X Syndrome​

​​To evaluate the safety and tolerability of MRM-3379 in male participants with FXS on the basis of the following endpoints: ​- Incidence and severity of TEAEs ​- Withdrawal due to AEs​

Key facts

Sponsor
Mirum Pharmaceuticals Inc.
Participant type
Pediatric, Patients
Age range
0-17 years, 18-64 years
Gender
Male
Therapeutic area
Diseases [C] - Congenital, Hereditary, and Neonatal Diseases and Abnormalities [C16]
Decision date (initial)
2026-04-27
Transition trial
No
Low-intervention
No
Rare-disease indication
Yes
Vulnerable population
Yes
Funding sources
Mirum Pharmaceutical, Inc.

External identifiers

EU CT number
2025-523738-21-00
ClinicalTrials.gov
NCT07209462

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Safety, Efficacy, Therapy, Pharmacokinetic

​​To evaluate the safety and tolerability of MRM-3379 in male participants with FXS on the basis of the following endpoints:

​- Incidence and severity of TEAEs

​- Withdrawal due to AEs​

Secondary objectives 2

  1. To evaluate the preliminary efficacy of MRM-3379 in male participants with FXS on the basis of the following endpoints: - Key secondary endpoint: Change from baseline on the NIH-TCB Crystallized Cognition: Composite (CCC): Composed from the Picture Vocabulary Test (PVT) and Oral Reading Recognition Test (ORRT) change sensitive scores - Other secondary endpoint: Clinician Global Impression-Change (CGI-C) score
  2. To describe the PK properties of MRM-3379 on the basis of the following endpoint: - Steady-state MRM-3379 and metabolite plasma concentrations

Conditions and MedDRA coding

​​Fragile X Syndrome​

VersionLevelCodeTermSystem organ class
28.0 PT 10017324 Fragile X syndrome 100000004850

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 6

  1. 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.
  2. Male, 13–45 years of age (inclusive).
  3. Weight ≥30 kg and BMI ≥18 and <36 kg/m2 (inclusive)
  4. Diagnosis of FXS with a molecular genetic ≥200 CGG repetitions.
  5. Have a consistent caregiver(s) who is willing and able to be present regularly and reliably with the participant.
  6. Able to swallow tablets or capsules

Exclusion criteria 1

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

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 1

  1. To evaluate the safety and tolerability of MRM-3379 in male participants with FXS on the bases of the following endpoints: -Incidence and severity of TEAEs; - Withdrawal due to AEs.

Secondary endpoints 2

  1. To evaluate the preliminary efficacy of MRM-3379 in male participants with FXS on the basis of the following endpoints: - Key secondary endpoint: Change from baseline on the NIH-TCB Crystallized Cognition Composite (CCC): Composed from the Picture Vocabulary Test (PVT) and Oral Reading Recognition Test (ORRT) change sensitive scores; - Other secondary endpoint: Clinician Global Impression-Change (CGI-C) score
  2. To describe the PK properties of MRM-3379 on the basis of the following endpoint: Steady-state MRM-3379 and metabolite plasma concentrations

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 2

MRM-3379

PRD12800407 · Product

Active substance
MRM-3379
Pharmaceutical form
CAPSULE, HARD
Route of administration
ORAL USE
Max daily dose
00 mg milligram(s)
Max total dose
00 mg milligram(s)
Max treatment duration
12 Week(s)
Authorisation status
Not Authorised
MA holder
MIRUM PHARMACEUTICALS, INC.
Paediatric formulation
No
Orphan designation
No

MRM-3379

PRD12800406 · Product

Active substance
MRM-3379
Pharmaceutical form
CAPSULE, HARD
Route of administration
ORAL USE
Max daily dose
00 mg milligram(s)
Max total dose
00 mg milligram(s)
Max treatment duration
12 Week(s)
Authorisation status
Not Authorised
MA holder
MIRUM PHARMACEUTICALS, INC.
Paediatric formulation
No
Orphan designation
No

Placebo 1

Placebo for MRM-3379

N/A · Product

Other product name
N/A
Pharmaceutical form
N/A
ATC code
N/A — N/A
Marketing authorisation
N/A
MA holder
N/A
MA country
Iceland
Paediatric formulation
No

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Mirum Pharmaceuticals Inc.

5 Total trials 2 Recruiting 2 Ended
Commercial
Sponsor organisation
Mirum Pharmaceuticals Inc.
Address
989 East Hillsdale Boulevard
City
Foster City
Postcode
94404-2113
Country
United States

Scientific contact point

Organisation
Mirum Pharmaceuticals Inc.
Contact name
Mirum Pharmaceuticals, Inc.

Public contact point

Organisation
Mirum Pharmaceuticals Inc.
Contact name
Arturo Galano

Third parties 15

OrganisationCity, countryDuties
Medidata Solutions Inc.
ORG-100016256
 New York, United States Other, E-data capture
Cogstate Inc.
ORG-100045256
 New Haven, United States Other
Icon Laboratory Services Inc.
ORG-100037135
 Farmingdale, United States Laboratory analysis
Primevigilance USA Inc.
ORG-100047266
 Raleigh, United States Code 8
Lumanity Patient Centered Outcomes LLC
ORG-100044473
 Boston, United States Other
Meeting Protocol Worldwide LP
ORG-100049471
 Dallas, United States Other
Qualworld
ORG-100053844
 Sorbiers, France Other
Icon Clinical Research Limited
ORG-100008322
 Dublin 18, Ireland Laboratory analysis
Subject Well Inc.
ORG-100049892
 Austin, United States Other
Centogene GmbH
ORG-100043695
 Rostock, Germany Laboratory analysis
Parexel International (IRL) Limited
ORG-100022780
 Dublin 2, Ireland On site monitoring, Code 10, Code 11, Code 12, Code 2, Code 5, Data management
Edetek Inc.
ORG-100045957
 Princeton, United States Code 10
Suvoda LLC
ORG-100043523
 Conshohocken, United States Interactive response technologies (IRT)
Biotrial
ORG-100006463
 Rennes, France Other
Alturas Analytics Inc.
ORG-100045347
 Moscow, United States Other

Locations

1 EU/EEA country · 3 investigational sites

By country

CountryMS statusPlanned subjectsSites
Spain Authorised, recruitment pending 15 3
Rest of world
United States
 — 54 —

Investigational sites

Spain

3 sites · Authorised, recruitment pending
Hospital Universitario Regional De Malaga
202: Unidad de Gestion Clínica Salud Mental, Avenida De Carlos De Haya S/N, 29010, Malaga
Hospital Sant Joan De Deu Barcelona
200: Pediatric Neurology, Passeig De Sant Joan De Deu 2, 08950, Esplugues De Llobregat
Parc Tauli Hospital Universitari
201: Pediatric Unit, Parc Del Tauli 1, 08208, Sabadell

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 12 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

TypeTitleVersion
Protocol (for publication) D1_Protocol Main English ENV-202 Public 2.0
Protocol (for publication) D4_Patient facing document Regulatory Filenote English ENV-202 Public NA
Protocol (for publication) D4_Patient facing document_Rating Scale 1_English ENV-202 Public 1.0
Protocol (for publication) D4_Patient facing document_Rating Scale 1_Spanish_ENV-202 Public 2.0
Protocol (for publication) D4_Patient facing document_Rating Scale 2_English ENV-202 Public 1.0
Protocol (for publication) D4_Patient facing document_Rating Scale 2_Spanish_ENV-202 Public 2.0
Recruitment arrangements (for publication) K1_ESP Recruitment Procedure Description English ENV-202 Public 1.0
Subject information and informed consent form (for publication) L1_ESP Country ICF Assent Spanish ENV-202 Public 1.1
Subject information and informed consent form (for publication) L1_ESP Country ICF Caregiver Parent-Legal Spanish ENV-202 Public 1.2
Subject information and informed consent form (for publication) L1_ESP Country ICF Pregnant Form Spanish ENV-202 Public 1.1
Synopsis of the protocol (for publication) D1_Lay Protocol Synopsis Main English ENV-202 Public 1.0
Synopsis of the protocol (for publication) D1_Lay Protocol Synopsis Main Spanish ENV-202_Public 1.0

Application history

1 submissions — initial application plus substantial / non-substantial modifications

#TypeCodeSubmittedReference MSConclusionDecision date
1 INITIAL IN 2025-12-12 Spain Acceptable with conditions
2026-04-20
 2026-04-27

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