Trial Outcomes & Findings for 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 (NCT NCT04168385)

NCT ID: NCT04168385

Last Updated: 2025-12-08

Results Overview

TEAE = Treatment-emergent Adverse Event; AESI = Adverse Event of Special Interest..

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

52 participants

Primary outcome timeframe

From informed consent through approximately 4.5 years, including 30 days after last dose.

Results posted on

2025-12-08

Participant Flow

A total of 52 participants were enrolled at 17 sites across 8 countries (Australia, Belgium, Canada, France, Poland, Spain, United Kingdom and United States). Participants were previously on maralixibat for an average of 4 years before entering this study.

The screening period starts when informed consent (by the legally authorized representative) is signed.The duration of the screening period is up to 4 weeks, during which all procedures listed for the screening visit in the schedule of assessment must be completed. A total of 43 subjects completed the study and a total of 9 discontinued early.

Participant milestones

Participant milestones
Measure	Maralixibat: ALGS Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with ALGS received maralixibat doses in the range of 0.15 mg/kg QD to 0.45 mg/kg BID.	Maralixibat: PFIC Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with PFIC received maralixibat doses in the range of 0.3 mg/kg QD to 0.6 mg/kg BID.
Overall Study STARTED	40	12
Overall Study COMPLETED	33	10
Overall Study NOT COMPLETED	7	2

Reasons for withdrawal

Reasons for withdrawal
Measure	Maralixibat: ALGS Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with ALGS received maralixibat doses in the range of 0.15 mg/kg QD to 0.45 mg/kg BID.	Maralixibat: PFIC Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with PFIC received maralixibat doses in the range of 0.3 mg/kg QD to 0.6 mg/kg BID.
Overall Study Withdrawal by Subject	1	0
Overall Study Adverse Event	2	1
Overall Study Liver transplant	3	1
Overall Study Listed for liver transplant	1	0

Baseline Characteristics

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

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Maralixibat: ALGS n=40 Participants Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with ALGS received maralixibat doses in the range of 0.15 mg/kg QD to 0.45 mg/kg BID.	Maralixibat: PFIC n=12 Participants Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with PFIC received maralixibat doses in the range of 0.3 mg/kg QD to 0.6 mg/kg BID.	Total n=52 Participants Total of all reporting groups
Age, Customized Age Categorical · 5 to 8 years	8 Participants n=9 Participants	4 Participants n=6 Participants	12 Participants n=9 Participants
Age, Customized Age Categorical · 9 to 12 years	18 Participants n=9 Participants	7 Participants n=6 Participants	25 Participants n=9 Participants
Age, Customized Age Categorical · 13 to 18 years	9 Participants n=9 Participants	1 Participants n=6 Participants	10 Participants n=9 Participants
Age, Customized Age Categorical · > 18 years	5 Participants n=9 Participants	0 Participants n=6 Participants	5 Participants n=9 Participants
Sex: Female, Male Female	19 Participants n=9 Participants	7 Participants n=6 Participants	26 Participants n=9 Participants
Sex: Female, Male Male	21 Participants n=9 Participants	5 Participants n=6 Participants	26 Participants n=9 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	5 Participants n=9 Participants	1 Participants n=6 Participants	6 Participants n=9 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	21 Participants n=9 Participants	11 Participants n=6 Participants	32 Participants n=9 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	14 Participants n=9 Participants	0 Participants n=6 Participants	14 Participants n=9 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=9 Participants	0 Participants n=6 Participants	0 Participants n=9 Participants
Race (NIH/OMB) Asian	0 Participants n=9 Participants	1 Participants n=6 Participants	1 Participants n=9 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=9 Participants	0 Participants n=6 Participants	0 Participants n=9 Participants
Race (NIH/OMB) Black or African American	3 Participants n=9 Participants	0 Participants n=6 Participants	3 Participants n=9 Participants
Race (NIH/OMB) White	22 Participants n=9 Participants	10 Participants n=6 Participants	32 Participants n=9 Participants
Race (NIH/OMB) More than one race	0 Participants n=9 Participants	1 Participants n=6 Participants	1 Participants n=9 Participants
Race (NIH/OMB) Unknown or Not Reported	15 Participants n=9 Participants	0 Participants n=6 Participants	15 Participants n=9 Participants
Region of Enrollment Canada	2 participants n=9 Participants	0 participants n=6 Participants	2 participants n=9 Participants
Region of Enrollment Belgium	2 participants n=9 Participants	0 participants n=6 Participants	2 participants n=9 Participants
Region of Enrollment United States	18 participants n=9 Participants	8 participants n=6 Participants	26 participants n=9 Participants
Region of Enrollment Poland	1 participants n=9 Participants	1 participants n=6 Participants	2 participants n=9 Participants
Region of Enrollment United Kingdom	8 participants n=9 Participants	3 participants n=6 Participants	11 participants n=9 Participants
Region of Enrollment Australia	4 participants n=9 Participants	0 participants n=6 Participants	4 participants n=9 Participants
Region of Enrollment France	4 participants n=9 Participants	0 participants n=6 Participants	4 participants n=9 Participants
Region of Enrollment Spain	1 participants n=9 Participants	0 participants n=6 Participants	1 participants n=9 Participants

PRIMARY outcome

Timeframe: From informed consent through approximately 4.5 years, including 30 days after last dose.

Population: Includes all participants with Alagille Syndrome (ALGS) or Progressive Familial Intrahepatic Cholestasis (PFIC) who received at least one dose of maralixibat.

TEAE = Treatment-emergent Adverse Event; AESI = Adverse Event of Special Interest..

Outcome measures

Outcome measures
Measure	Maralixibat: ALGS n=40 Participants Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with ALGS received maralixibat doses in the range of 0.15 mg/kg QD to 0.45 mg/kg BID.	Maralixibat: PFIC n=12 Participants Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with PFIC received maralixibat doses in the range of 0.3 mg/kg QD to 0.6 mg/kg BID.	Maralixibat: Overall Combined results of ALGS and PFIC Groups
Incidence of Treatment-Emergent Adverse Events Treatment-emergent AESI	0 Participants	1 Participants	—
Incidence of Treatment-Emergent Adverse Events Serious Treatment-Related Adverse Event	0 Participants	0 Participants	—
Incidence of Treatment-Emergent Adverse Events Serious Treatment-Related TEAE	0 Participants	0 Participants	—
Incidence of Treatment-Emergent Adverse Events TEAE Leading to Discontinuation of Study Drug	3 Participants	1 Participants	—
Incidence of Treatment-Emergent Adverse Events TEAE Leading to Death	1 Participants	0 Participants	—
Incidence of Treatment-Emergent Adverse Events TEAE ≥ 3	9 Participants	4 Participants	—
Incidence of Treatment-Emergent Adverse Events Serious TEAE	10 Participants	3 Participants	—
Incidence of Treatment-Emergent Adverse Events At least one TEAE	36 Participants	12 Participants	—

SECONDARY outcome

Timeframe: From Baseline through Week 160, including Change from Baseline values.

Population: Includes all participants with Alagille Syndrome (ALGS) or Progressive Familial Intrahepatic Cholestasis (PFIC) who received at least one dose of maralixibat.

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.

Outcome measures

Outcome measures
Measure	Maralixibat: ALGS n=40 Participants Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with ALGS received maralixibat doses in the range of 0.15 mg/kg QD to 0.45 mg/kg BID.	Maralixibat: PFIC n=12 Participants Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with PFIC received maralixibat doses in the range of 0.3 mg/kg QD to 0.6 mg/kg BID.	Maralixibat: Overall Combined results of ALGS and PFIC Groups
Long-Term Effect on Pruritus	-0.4 score on a scale Standard Deviation 0.89	-0.3 score on a scale Standard Deviation 1.12	—

SECONDARY outcome

Timeframe: From Baseline through Week 160, including Change from Baseline values.

Population: Includes all participants with Alagille Syndrome (ALGS) or Progressive Familial Intrahepatic Cholestasis (PFIC) who received at least one dose of maralixibat.

Outcome measures

Outcome measures
Measure	Maralixibat: ALGS n=40 Participants Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with ALGS received maralixibat doses in the range of 0.15 mg/kg QD to 0.45 mg/kg BID.	Maralixibat: PFIC n=12 Participants Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with PFIC received maralixibat doses in the range of 0.3 mg/kg QD to 0.6 mg/kg BID.	Maralixibat: Overall n=52 Participants Combined results of ALGS and PFIC Groups
Long-Term Effect on Serum Bile Acid Levels	-15.948 µmol/L Standard Deviation 31.4239	-82.647 µmol/L Standard Deviation 136.4354	-59.994 µmol/L Standard Deviation 111.0334

Adverse Events

Maralixibat: ALGS

Serious events: 10 serious events

Other events: 36 other events

Deaths: 1 deaths

Maralixibat: PFIC

Serious events: 3 serious events

Other events: 12 other events

Deaths: 0 deaths

Serious adverse events

Other adverse events

Additional Information

Mirum Clinical Trials

Mirum Pharmaceuticals, Inc.

Phone: 16506674085

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place

Restriction type: LTE60

Measure	Maralixibat: ALGS n=40 participants at risk Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with ALGS received maralixibat doses in the range of 0.15 mg/kg QD to 0.45 mg/kg BID.	Maralixibat: PFIC n=12 participants at risk Participants will all receive Maralixibat oral solution Maralixibat chloride oral solution orally twice daily Up to 1.2\* mg/kg/day), and according to indication. \*equivalent to 1.14 mg/kg/day maralixibat. Doses reported here are in maralixibat chloride. Participants with PFIC received maralixibat doses in the range of 0.3 mg/kg QD to 0.6 mg/kg BID.
Gastrointestinal disorders Abdominal mass	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Gastrointestinal disorders Anal fissure	0.00% 0/40 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	8.3% 1/12 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Gastrointestinal disorders Colitis ulcerative	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Congenital, familial and genetic disorders Coarctation of the aorta	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Congenital, familial and genetic disorders Alagille syndrome	5.0% 2/40 • Number of events 2 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Congenital, familial and genetic disorders Arteriovenous malformation	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Gastrointestinal disorders Constipation	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Gastrointestinal disorders Dyspepsia	0.00% 0/40 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	8.3% 1/12 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Gastrointestinal disorders Nausea	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
General disorders Condition aggravated	0.00% 0/40 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	8.3% 1/12 • Number of events 2 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
General disorders Oedema peripheral	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Infections and infestations Lung abscess	0.00% 0/40 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	8.3% 1/12 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Injury, poisoning and procedural complications Femur fracture	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Injury, poisoning and procedural complications Gastrointestinal procedural complication	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Injury, poisoning and procedural complications Ulna fracture	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Musculoskeletal and connective tissue disorders Arthritis	0.00% 0/40 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	8.3% 1/12 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Nodular lymphocyte predominant Hodgkin lymphoma	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Nervous system disorders Cerebral haemorrhage	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Nervous system disorders Neuralgia	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Nervous system disorders Seizure	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Nervous system disorders Syncope	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Respiratory, thoracic and mediastinal disorders Fibrinous bronchitis	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Respiratory, thoracic and mediastinal disorders Hepatopulmonary syndrome	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Skin and subcutaneous tissue disorders Pruritus	0.00% 0/40 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	8.3% 1/12 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.
Vascular disorders Hypertension	2.5% 1/40 • Number of events 1 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.	0.00% 0/12 • The timeframe for reporting adverse events was from informed consent through approximately 4.5 years, including 30 days after last dose.