Progressive Familial Intrahepatic Cholestasis (PFIC)Phase 3NCT04185363
An Extension Study of Maralixibat in Patients With Progressive Familial Intrahepatic Cholestasis (PFIC)
A Phase 3 study testing Maralixibat in people with Progressive Familial Intrahepatic Cholestasis (PFIC), run by Mirum Pharmaceuticals, Inc. at 28 sites in 16 countries.
Trial summary
The primary objective of this open label extension study is to evaluate the long-term safety and tolerability of maralixibat. Read more about this study
- Who is it for?
- Ages 1 year to 18 years
- Conditions the study is for
- Progressive Familial Intrahepatic Cholestasis (PFIC)
- What is being tested?
- Maralixibat
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 84 participants
- Where
- 28 sitesin 16 countries
- Study dates
- 8 Jan 2020to 23 Apr 2025
- Phase
- Phase 3
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 1 year to 18 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- Provide informed consent and assent (as applicable) per Institutional Review Board/Ethics Committee (IRB/EC)
- Completion of study MRX-502
Who cannot join
- Any female who is pregnant or lactating or who is planning to become pregnant
- Administration of prohibited medication between the MRX-502 EOT visit and the MRX 503 Baseline Visit (Day 0)
- History of non-compliance in study MRX-502, non-adherence to medical regimens, unreliability, mental instability or incompetence that could compromise the validity of informed consent or lead to non-adherence with the study protocol based on Investigator judgment
- Experienced an adverse event (AE) or serious adverse event (SAE) related to maralixibat during the MRX-502 study that led to permanent discontinuation of the subject from maralixibat
- Any other conditions or laboratory abnormalities that, in the opinion of the Investigator or Sponsor Medical Monitor, may compromise the safety of the subject, or interfere with the subject participating in or completing the study
- Cognitive impairment of the subject or caregiver that would, in the opinion of the investigator, preclude appropriate understanding of study information and compliance with study procedures
Trial locations and contacts
28 sites in 16 countries.
28 sites in 16 countries
United States10 sites
Medical University of South Carolina
Charleston, South Carolina, 29425
Cincinnati Children's Hospital
Cincinnati, Ohio, 45229
University of Texas Southwestern Medical Center
Dallas, Texas, 75390
Children's Hospital Los Angeles
Los Angeles, California, 90027
Advent Health
Orlando, Florida, 32803
Children Hospital of Pittsburgh
Pittsburgh, Pennsylvania, 15224
University of Texas, Health Science Center San Antonio
San Antonio, Texas, 78229
Seattle Children's Hospital
Seattle, Washington, 98105
Children's Hospital at Montefiore
The Bronx, New York, 10461
Medstar Georgetown University Hospital
Washington D.C., District of Columbia, 20007
France2 sites
Groupement Hospitalier Est Hopital, Femme Mère Enfant de Lyon
Lyon
CHU de Toulouse - Hôpital des Enfants
Toulouse, 31059
Italy2 sites
Azienda Ospedaliera Papa Giovanni XXIII - Unita di Pediatria
Bergamo, 24127
Ospedale Pediatrico bambino Gesu'
Roma
United Kingdom2 sites
Birmingham Children's Hospital
Birmingham
King's College Hospital NHS Foundation Trust
London
Austria1 site
Medizinische Universität Wien, Universitätsklinik für Kinder- und Jugendheilkunde
Vienna
Brazil1 site
Sociedade Beneficente de Senhoras Hospital Sírio-Libanês
São Paulo
Canada1 site
University of Alberta - Women and Children's Health Research Institute
Edmonton, Alberta
About this study
Official title: An Open-label Extension Study to Evaluate the Long-term Safety and Efficacy of Maralixibat in the Treatment of Subjects With Progressive Familial Intrahepatic Cholestasis (PFIC)
The primary objective of this open label extension study is to evaluate the long-term safety and tolerability of maralixibat.
Read the detailed description
The study will be conducted at multiple sites in North America, Europe, Asia, and South America.
- Being tested
- Maralixibat
- Keywords
- Cholestasis, Maralixibat, Mutation, PFIC, PFIC2, Bile Duct Diseases, Liver Diseases, Biliary Tract Diseases, Digestive System Diseases, Pediatric
- Medical subject headings
- Cholestasis, progressive familial intrahepatic 1, Cholestasis, Bile Duct Diseases, Liver Diseases, Biliary Tract Diseases, Digestive System Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
MaralixibatDrug
All subjects will receive Maralixibat oral solution (up to 600 microgram per kilogram [mcg/kg]) twice daily
| Study group | Role | What they receive |
|---|---|---|
| Maralixibat | Experimental | All subjects will receive Maralixibat oral solution Receives: Drug: Maralixibat |
What is being measured
The primary outcome is the main question the study is designed to answer.
Mean Change From Baseline Over Time in the Average Morning ItchRO(Obs) Severity Score
The Score on the ItchRo scale is a score on a 5-point scale from 0 (no itch) to 4 (very severe itch)
Measured: From Baseline to Weeks 75-78
Secondary outcomes (7)
Maintenance of ItchRO(Obs) Response (Weeks 15 - 26)
Maintenance of treatment effect is defined as the proportion of participants in the MRX-MRX treatment group (MRX-502 and MRX-503 data for subjects on MRX in the MRX-502 study) who obtain an ItchRO (Obs) response from Week 15 to Week 26 in Study MRX-503 in the primary cohort and PFIC cohort.
Measured: Week 15 - 26
Proportion of ItchRO(Obs) Responders Over Time
Proportion of ItchRO responders over time at each study visit using the 4-week study period prior to the visit as per ItchRO(Obs) responder definition.
Measured: Baseline to EOT
Mean Change From Baseline Over Time in the Average Morning ItchRO(Obs) Frequency Score
The Score on the ItchRo scale is a score on a 5-point scale from 0 (no itch) to 4 (very severe itch)
Measured: From Baseline to Weeks 75-78
Mean Change From Baseline Over Time in Total Serum Bile Acid (sBA) Levels
Mean change from baseline over time in total serum bile acid (sBA) levels
Measured: Baseline to week 70
Proportion of Subjects Who Experience an sBA Control Over Time From Week 18 to Week 26
Proportion of subjects who experience an sBA control over time from Week 18 to Week 26
Measured: From Week 18 to Week 26
Change From Baseline in Height Z-score
Height-for-age Z-score measures a participant's height relative to a reference population of children of the same age and sex. Z-scores were derived using World Health Organization growth charts for participants less than 24 months of age and Centers for Disease Control and Prevention growth charts for participants 24 months of age or older. A Z-score of 0 represents the population mean for age and sex. Positive Z-scores indicate height above the reference population mean, and negative Z-scores indicate height below the reference population mean. Higher Z-scores generally indicate greater linear growth relative to the reference population. Change from baseline was calculated as post-baseline height-for-age Z-score minus baseline height-for-age Z-score.
Measured: From baseline to Week 70
Change From Baseline in Weight Z-score
Weight-for-age Z-score measures a participant's weight relative to a reference population of children of the same age and sex. Z-scores were derived using World Health Organization growth charts for participants less than 24 months of age and Centers for Disease Control and Prevention growth charts for participants 24 months of age or older. A Z-score of 0 represents the population mean for age and sex. Positive Z-scores indicate weight above the reference population mean, and negative Z-scores indicate weight below the reference population mean. Higher Z-scores generally indicate greater body weight relative to the reference population. Change from baseline was calculated as post-baseline weight-for-age Z-score minus baseline weight-for-age Z-score.
Measured: From Baseline to Week 70
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Dec 2019
- Study start8 Jan 2020
- Primary completion23 Apr 2025
- Study completion23 Apr 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Progressive Familial Intrahepatic Cholestasis (PFIC)Studies of the same condition, open and under way.
- More trials run by Mirum Pharmaceuticals, Inc.The sponsor's other registered studies.
- 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 3
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 84 participants (actual)
Sponsor and investigators
- Lead sponsor
- Mirum Pharmaceuticals, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04185363
- Sponsor's protocol ID
- MRX-503
- Status last verified
- May 2026
- First submitted
- 2 Dec 2019
- Last updated
- 23 Jun 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- 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 23 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Open-label Extension Study to Evaluate the Long-term Safety and Efficacy of Maralixibat in the Treatment of Subjects With Progressive Familial Intrahepatic Cholestasis (PFIC)
- ClinicalTrials.gov ID
- NCT04185363
- Acronym / sponsor ID
- MRX-503
- Keywords
- Cholestasis, Maralixibat, Mutation, PFIC, PFIC2, Bile Duct Diseases, Liver Diseases, Biliary Tract Diseases
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 84 participants (actual)
- Lead sponsor
- Mirum Pharmaceuticals, Inc.Industry (pharma, biotech, devices)
- Study start
- 8 Jan 2020 (actual)
- Primary completion
- 23 Apr 2025 (actual)
- Study completion
- 23 Apr 2025 (actual)
- First posted
- 4 Dec 2019 (actual)
- Results
- Posted 23 Jun 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The primary objective of this open label extension study is to evaluate the long-term safety and tolerability of maralixibat.
Detailed description
The study will be conducted at multiple sites in North America, Europe, Asia, and South America.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Maralixibat | Experimental | Drug: MaralixibatAll subjects will receive Maralixibat oral solution |
Who may qualify
- Ages
- 1 year to 18 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (2 listed)
- Provide informed consent and assent (as applicable) per Institutional Review Board/Ethics Committee (IRB/EC)
- Completion of study MRX-502
Key exclusion criteria (6 listed)
- Any female who is pregnant or lactating or who is planning to become pregnant
- Administration of prohibited medication between the MRX-502 EOT visit and the MRX 503 Baseline Visit (Day 0)
- History of non-compliance in study MRX-502, non-adherence to medical regimens, unreliability, mental instability or incompetence that could compromise the validity of informed consent or lead to non-adherence with the study protocol based on Investigator judgment
- Experienced an adverse event (AE) or serious adverse event (SAE) related to maralixibat during the MRX-502 study that led to permanent discontinuation of the subject from maralixibat
- Any other conditions or laboratory abnormalities that, in the opinion of the Investigator or Sponsor Medical Monitor, may compromise the safety of the subject, or interfere with the subject participating in or completing the study
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 |
|---|---|---|
| MaralixibatAll subjects will receive Maralixibat oral solution (up to 600 microgram per kilogram [mcg/kg]) twice daily | Drug | Maralixibat |
Primary outcome
Mean Change From Baseline Over Time in the Average Morning ItchRO(Obs) Severity Score
Time frame: From Baseline to Weeks 75-78
The Score on the ItchRo scale is a score on a 5-point scale from 0 (no itch) to 4 (very severe itch)
7 secondary outcomes
Maintenance of ItchRO(Obs) Response (Weeks 15 - 26)
Time frame: Week 15 - 26
Proportion of ItchRO(Obs) Responders Over Time
Time frame: Baseline to EOT
Mean Change From Baseline Over Time in the Average Morning ItchRO(Obs) Frequency Score
Time frame: From Baseline to Weeks 75-78
Mean Change From Baseline Over Time in Total Serum Bile Acid (sBA) Levels
Time frame: Baseline to week 70
Proportion of Subjects Who Experience an sBA Control Over Time From Week 18 to Week 26
Time frame: From Week 18 to Week 26
Change From Baseline in Height Z-score
Time frame: From baseline to Week 70
Change From Baseline in Weight Z-score
Time frame: From Baseline to Week 70
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Jun 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Genetics Home Reference - PFICLink provided by the sponsor.
- US FDA ResourcesLink provided by the sponsor.
- Mirum Pharmaceuticals homepageLink provided by the sponsor.
- 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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
28 sites in 16 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Maralixibat in people with Progressive Familial Intrahepatic Cholestasis (PFIC), run by Mirum Pharmaceuticals, Inc. at 28 sites in 16 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 2 inclusion and 6 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: finished, as of the sponsor's last update on 23 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 28 sites in United States, France, Italy, United Kingdom, Argentina and 11 more countries. 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. 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 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 23 Jun 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Mean Change From Baseline Over Time in the Average Morning ItchRO(Obs) Severity Score (time frame: From Baseline to Weeks 75-78). 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 23 Jun 2026.