MRX-800: A Long-Term Safety Study of Maralixibat in the Treatment of Cholestatic Liver Disease in Subjects Who Previously Participated in a Maralixibat Study (MERGE)

December 4, 2025 updated by: Mirum Pharmaceuticals, Inc.

MRX-800: A Long-Term Safety Study of Maralixibat, an Apical Sodium Dependent Bile Acid Transporter Inhibitor (ASBTi), in the Treatment of Cholestatic Liver Disease in Subjects Who Previously Participated in a Maralixibat Study

Evaluate the long-term safety of maralixibat (MRX) in subjects with cholestatic liver disease including, but not limited to, Alagille Syndrome (ALGS), Progressive Familial Intrahepatic Cholestasis (PFIC) and Biliary Atresia.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This is a multicenter, open-label study of maralixibat in subjects diagnosed with cholestatic liver disease (including, but not limited to ALGS, PFIC or Biliary Atresia) who have previously participated in a maralixibat clinical study. All subjects received maralixibat in the previous studies and will continues to receive maralixibat in this study.

Study Type

Interventional

Enrollment (Actual)

52

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Australia
    • New South Wales
      • Westmead, New South Wales, Australia, 2145
        • Children's Hospital Westmead
    • Victoria
      • Parkville, Victoria, Australia, 3052
        • The Royal Children's Hospital Melbourne
  • Belgium
      • Brussels, Belgium
        • Cliniques universitaires Saint-Luc
  • Canada
      • Toronto, Canada
        • Hospital for Sick Children
  • France
      • Paris, France, 75015
        • Hôpital Necker-Enfants Malades
      • Paris, France, 94275
        • Hôpital Kremlin Bicêtre
  • Poland
      • Warsaw, Poland, 04-730
        • The Children's Memorial Health Institute
  • Spain
      • Madrid, Spain, 261
        • Hospital Universitario La Paz- Hospital Materno Infantil
  • United Kingdom
      • Birmingham, United Kingdom
        • Birmingham Children's Hospital
      • Leeds, United Kingdom, LS1 3EX
        • Leeds Teaching Hospital NHS Trust
      • London, United Kingdom, SE5 9RS
        • Paediatric Liver Center, Kings College Hospital
  • United States
    • California
      • Los Angeles, California, United States, 90027
        • Children's Hospital Los Angeles
    • Indiana
      • Indianapolis, Indiana, United States, 46202
        • Riley Hospital for Children
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Children's Hospital of Philadelphia
      • Pittsburgh, Pennsylvania, United States, 15224
        • Children Hospital of Pittsburgh
    • Texas
      • Houston, Texas, United States, 77030
        • Baylor College of Medicine/Texas Children's Hospital
    • Washington
      • Seattle, Washington, United States, 98105
        • Seattle Children's Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

1 year and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria Subjects will need to meet all criteria below to be considered eligible for the study.

  1. Provide informed consent and assent (as applicable) per the Institutional Review Board/Ethics Committee (IRB/EC).

  2. Previously participated in a maralixibat study and with approval of the Medical Monitor. Previous participation is defined as:

    • Having completed the EOT Visit, for subjects coming from the maralixibat Phase 2 studies.
    • Having completed the entire duration of the study (i.e., core and extension, if applicable), for subjects coming from the maralixibat Phase 3 studies.
  3. At least 1 year of age
  4. Males, and females of non-childbearing potential. Males and non-pregnant, non-lactating females of childbearing potential who are sexually active must agree to use acceptable contraception during the study and 30 days following the last dose of the study medication. Females of childbearing potential must have a negative pregnancy test.
  5. Caregivers (and/or age appropriate subjects) must have access to email or phone for scheduled remote visits if applicable.
  6. Subject and caregiver willingness to comply with all study visits and requirements.

Exclusion Criteria

A subject will be excluded from the study if any of the following exclusion criteria are met:

  1. Experienced an AE or SAE related to maralixibat during the lead-in protocol that led to permanent discontinuation of the subject from maralixibat.
  2. Any conditions or abnormalities (including laboratory abnormalities) which, in the opinion of the Investigator or Medical Monitor may compromise the safety of the subject or interfere with the subject participating in or completing the study.
  3. History of non-adherence to medical regimens, unreliability, medical condition, mental instability or cognitive impairment that, in the opinion of the Investigator or Sponsor medical monitor, could compromise the validity of informed consent, compromise the safety of the subject, or lead to non-adherence with the study protocol or inability to conduct the study procedures.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Maralixibat
Participants will all receive Maralixibat oral solution
Drug: Maralixibat

Maralixibat chloride oral solution orally twice daily (up to 1200* mcg/kg/day), and according to indication.

*equivalent to 1140 mcg/kg/day maralixibat

Other Names:
  • Formerly LUM001 and SHP625

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of Treatment-Emergent Adverse Events
Time Frame: From informed consent through approximately 4.5 years, including 30 days after last dose.
TEAE = Treatment-emergent Adverse Event; AESI = Adverse Event of Special Interest..
From informed consent through approximately 4.5 years, including 30 days after last dose.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Long-Term Effect on Pruritus
Time Frame: From Baseline through Week 160, including Change from Baseline values.
Change from Baseline in Pruritus Severity assessed using the Clinician Scratch Score (CSS), a 5-point scale where 0 indicates no evidence of scratching and 4 indicates cutaneous mutilation with bleeding, hemorrhage, and scarring.
From Baseline through Week 160, including Change from Baseline values.
Long-Term Effect on Serum Bile Acid Levels
Time Frame: From Baseline through Week 160, including Change from Baseline values.
From Baseline through Week 160, including Change from Baseline values.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Mirum Pharmaceuticals, Inc.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 16, 2020

Primary Completion (Actual)

September 4, 2024

Study Completion (Actual)

September 4, 2024

Study Registration Dates

First Submitted

October 1, 2019

First Submitted That Met QC Criteria

November 17, 2019

First Posted (Actual)

November 19, 2019

Study Record Updates

Last Update Posted (Actual)

December 8, 2025

Last Update Submitted That Met QC Criteria

December 4, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • MRX-800

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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