Disciplined development.
Enduring commitment.
We focus on rare diseases where scientific insight, patient urgency, and clinical clarity align. Our pipeline reflects a deliberate strategy—advancing programs with strong biological rationale, defined regulatory pathways, and the potential to deliver impact. We work closely with patients and advocacy leaders to ensure lived experience informs how we design trials, define meaningful endpoints, and prepare for potential access and commercialization.
With three approved medicines and additional late-stage programs progressing toward potential registration, we are building a diversified rare disease portfolio designed for long-term growth.
Rare liver diseases
Mode of Action
LIVMARLI works by blocking an important bile acid transport protein on the surface of the small intestine. This results in more bile acids being excreted in the feces, which then leads to lower levels of bile acids systemically.1
About LIVMARLI
LIVMARLI (maralixibat) is an orally administered, ileal bile acid transporter (IBAT) inhibitor available in both liquid and tablet formulations.1
LIVMARLI is approved by the FDA for the treatment of cholestatic pruritus in patients with ALGS three months of age and older, and for the treatment of cholestatic pruritus in patients with PFIC 12 months of age and older.
LIVMARLI is not for use in patients with PFIC type 2 who have a severe defect in the bile salt export pump (BSEP) protein.
LIVMARLI has been authorized by the European Commission for the treatment of cholestatic pruritus in patients with ALGS two months of age and older, and for the treatment of PFIC in patients three months of age and older.
LIVMARLI is also available in more than 30 countries globally for the treatment of patients with ALGS and PFIC.
A liquid formulation of LIVMARLI is currently being evaluated for pruritus in rare cholestatic settings in the Phase 3 EXPAND study.
Cholestasis (PFIC)
Cholestatic Settings
Mode of Action
Volixibat is designed to block an important bile acid transport protein on the surface of the small intestine. That may result in more bile acids being excreted in the feces, which then leads to lower levels of bile acids systemically.2
About Volixibat
Volixibat is a minimally absorbed, orally administered investigational therapy designed to selectively inhibit IBAT, a protein that is primarily responsible for recycling bile acids from the intestine to the liver. We believe that volixibat may offer a novel approach in the treatment of rare cholestatic liver diseases by blocking the recycling of bile acids, thereby reducing bile acids systemically.2 Volixibat is currently being studied as a treatment option for pruritus associated with primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC), with secondary endpoints evaluating safety and tolerability, markers of disease progression, fatigue, and quality of life.3,4
What We’ve Seen in Clinical Trials
An extended analysis of the Phase 2b VANTAGE study evaluating volixibat in patients with PBC highlighted statistically significant improvements in pruritus and numeric improvements in fatigue, the two most burdensome symptoms of PBC. Additionally, 70% of patients experienced a ≥50% reduction in serum bile acids. Reductions in inflammatory biomarker IL-31 were also observed. No new safety signals were observed, and adverse events were similar between the 20 mg and 80 mg treatment groups. The most common adverse event was diarrhea (77%) with all cases mild to moderate; one case resulted in discontinuation. Given the similar results with both efficacy and safety between the 20 mg BID and 80 mg BID doses, the 20 mg BID dose was selected for the confirmatory portion of the VANTAGE study.5
Volixibat Clinical Trials
The blinded interim analysis for the VISTAS study in PSC was announced on June 17, 2024. The VISTAS PSC study exceeded the prespecified [interim analysis] efficacy threshold and the 20 mg BID dose was selected for the confirmatory portion.
Cholangitis (PSC)
Cholangitis (PBC)
Mode of Action
Brelovitug is designed to bind a key protein on the surface of hepatitis D and hepatitis B viruses, known as the hepatitis B surface antigen (HBsAg). By binding to this protein, brelovitug may help neutralize virus particles and support their removal from the bloodstream. This approach may help lower virus levels and reduce ongoing liver inflammation.6
About Brelovitug
Brelovitug is an investigational, fully human monoclonal antibody being studied for the treatment of chronic hepatitis delta virus (HDV), the most severe form of viral hepatitis.7 It is designed to recognize and bind to a specific protein found on the surface of both hepatitis D and hepatitis B viruses.6 By targeting this shared protein, brelovitug aims to help reduce the amount of virus in the body. Brelovitug has FDA Breakthrough Therapy designation for the treatment of HDV and PRIME and Orphan designations from the European Medicines Agency.
What We’ve Seen in Clinical Trials
In a Phase 2 study evaluating brelovitug in patients with HDV, 100% of participants had a virological response, defined as ≥2 log reduction of HDV RNA from baseline or reaching TND, at Week 48. Additionally, combined virologic response and ALT normalization rates were 65-82% across doses every 1 to 4 weeks. The most common adverse event was injection-site erythema (11-45%), and there were no treatment-related serious adverse events or discontinuations.6
Brelovitug Clinical Trials
Brelovitug is being evaluated in the AZURE program, a global, registrational Phase 3 clinical development program for the treatment of chronic HDV. The program includes multiple open-label studies designed to assess the primary endpoint of combined virologic and biochemical response.
Virus (HDV)
Rare genetic diseases
About CHOLBAM
CHOLBAM is a prescription medicine. It is a bile acid used for8:
- Treatment of bile acid synthesis disorders (malfunction in the production of bile acid in the liver) due to a lack of a single enzyme responsible for bile acid production.
- Treatment (in addition to other treatments) of peroxisomal disorders (a loss of function in important parts of the cell), including Zellweger spectrum disorders, in patients who show signs or symptoms of liver disease, pale stools due to too much fat, or problems resulting from not absorbing certain vitamins (A, D, E, K).
The safety and effectiveness of CHOLBAM on symptoms outside of the liver have not been studied.
and PBD-ZSD
Mode of Action
In individuals with CTX, a mutation in the CYP27A1 gene prevents an important enzyme (sterol 27-hydroxylase) from working properly. This prevents the body from making chenodeoxycholic acid (CDCA). CDCA plays an important role in regulating the bile acid production process. When there is not enough CDCA, it can cause the buildup of CTX toxins.9,10
CTEXLI is designed to help stop the buildup of CTX toxins and may act to replace the CDCA missing in adults with CTX.11
About CTEXLI
CTEXLI is a bile acid approved by the FDA for the treatment of adults with CTX. It is the first and only treatment designed to reduce the overproduction of toxic bile acid precursors.11
Xanthomatosis (CTX)
Mode of Action
MRM-3379 is an allosteric inhibitor of phosphodiesterase-4D (PDE4D), designed to selectively modulate cAMP signaling. Inhibition of PDE4D may restore cAMP levels and promote expression of genes involved in normal synaptic function and formation.
About MRM-3379
MRM-3379 is an allosteric inhibitor of PDE4D that we believe may offer a novel approach in the treatment of FXS by restoring transcription of genes involved in synaptic plasticity to improve cognition, language, and daily function. MRM-3379 is being studied in FXS.
a Approved in the below regions:
- U.S. – In cholestatic pruritus in patients with ALGS three months of age and older; available in both oral solution and tablet formulations
- E.U. – In cholestatic pruritus in patients with ALGS two months of age and older
- Canada – In cholestatic pruritus in patients with ALGS; available in both oral solution and tablet formulations
- Pediatrics (12 months to 18 years): Based on the data submitted and reviewed by Health Canada, the safety and efficacy of LIVMARLI in these pediatric patients have been established. Therefore, Health Canada has authorized an indication for pediatric use
- Pediatrics (<12 months): The safety and efficacy of LIVMARLI in these pediatric patients have not been established
b Approved in the below regions:
- U.S. – In cholestatic pruritus in patients with PFIC 12 months of age and older; available in both oral solution and tablet formulations
- E.U. – For the treatment of PFIC in patients three months of age and older
- Canada – In cholestatic pruritus in patients with PFIC; available in both oral solution and tablet formulations
- Pediatrics (12 months to 18 years): Based on the data submitted and reviewed by Health Canada, the safety and efficacy of LIVMARLI in these pediatric patients have been established. Therefore, Health Canada has authorized an indication for pediatric use
- Pediatrics (<12 months): The safety and efficacy of LIVMARLI in these pediatric patients have not been established
c Phase 3 topline data expected Q4 2026
d Blinded interim analysis for VISTAS study in PSC announced on June 17, 2024; study continues as planned
e Interim data from the Phase 2b VANTAGE clinical trial examining the safety and efficacy of volixibat for the treatment of PBC was announced on June 17, 2024; study continues as planned
f Phase 3 topline data expected 2H 2026 (U.S. registrational program)
g Phase 3 topline data expected 1H 2028 (E.U. registrational program)
h PBD-ZSD = Peroxisome biogenesis disorder-Zellweger Spectrum Disorder
i CTEXLI (chenodiol) tablets has been approved by the FDA for the treatment of adults with CTX
j Phase 2 topline data expected 1H 2027
Novel treatments for
rare diseases
Learn more about our FDA-approved medicines developed to
address rare and challenging conditions.
Our clinical trials
At Mirum, working closely with the rare disease community is paramount. Patients and their families play an integral role in helping us evaluate investigational therapies through clinical trials and generate the evidence needed for regulatory approval in the U.S. and beyond.
For more information about Mirum’s clinical trials, please contact:
- Healthcare providers: clinicaltrials@mirumpharma.com
- Patients and families: medinfo@mirumpharma.com (U.S. & International [non-Europe]); medinfoEU@mirumpharma.com (Europe)
Pruritus in Rare Cholestatic Settings
Phase 3 EXPAND Study
Evaluating the safety and efficacy of LIVMARLI (maralixibat) in pediatric and adult patients with pruritus associated with general cholestatic liver disease.
View full study details at www.clinicaltrials.gov
Primary Sclerosing Cholangitis (PSC)
Phase 2b VISTAS Study
Evaluating the efficacy and safety of volixibat in patients with pruritus caused by PSC.
View full study details at www.clinicaltrials.gov
Primary Biliary Cholangitis (PBC)
Phase 2b VANTAGE Study — Enrolling
Evaluating the efficacy and safety of volixibat in patients with itching caused by PBC.
View full study details at www.clinicaltrials.gov
Chronic Hepatitis Delta Virus (HDV)
Phase 3 AZURE Studies
Evaluating the efficacy and safety of brelovitug for the treatment of chronic HDV.
View full study details for AZURE-1 and AZURE-4 at www.clinicaltrials.gov
Fragile X Syndrome (FXS)
Phase 2 BLOOM Study – Enrolling
Evaluating the safety and tolerability of MRM-3379 in male patients with FXS.
View full study details at www.clinicaltrials.gov
Clinical development is a critical part of evaluating experimental therapies as potential impactful medicines for people with rare diseases. We are committed to rigorous testing of experimental treatments in order to secure regulatory approval and expand access to safe, effective therapies.
LIVMARLI Expanded Access Program for ALGS and PFIC
Mirum has a limited Early/Expanded Access Program (EAP) open in some countries outside of the U.S., offering access to LIVMARLI (maralixibat) for eligible patients with ALGS and PFIC who do not have access to LIVMARLI and do not qualify for ongoing clinical trials, until LIVMARLI is commercially available in those countries.
- To learn about the EAP, licensed physicians outside of the U.S. can contact medicineaccess@clinigengroup.com
- To learn more about Mirum’s open clinical trials, please visit www.clinicaltrials.gov
Compassionate Use
Currently, we are prioritizing access to LIVMARLI and our investigational products through our clinical trials. We are unable to offer compassionate use access to LIVMARLI or our investigational products at this time.
Mirum reserves the right to revise this policy at any time.
References
- Gonzales E, Sturm E, Stormon E, et al. Durability of treatment effect with long-term maralixibat in children with Alagille syndrome. Oral presentation at: American Association for the Study of Liver Diseases Annual Meeting (The Liver Meeting); November 8-12, 2019; Boston, MA.
- Key CC, McKibben A, Chien E, et al. A phase 1 dose-ranging study assessing fecal bile acid excretion by volixibat, an apical sodium dependent bile acid transporter inhibitor, and coadministration with loperamide. Virtual presentation at: American Association for the Study of Liver Diseases Annual Meeting (The Liver Meeting Digital Experience); November 13-16, 2020.
- A study to evaluate efficacy and safety of an investigational drug named volixibat in patients with itching caused by primary sclerosing cholangitis (PSC) (VISTAS). Clinical trial registration No. NCT04663308. Accessed August 8, 2025. https://clinicaltrials.gov/study/NCT04663308
- A study to evaluate efficacy and safety of an investigational drug named volixibat in patients with itching caused by primary biliary cholangitis (VANTAGE). Clinical trial registration No. NCT05050136. Accessed August 8, 2025. https://clinicaltrials.gov/study/NCT05050136
- Heneghan MA, Shiffman ML, Weinstein D, et al. Volixibat for the treatment of cholestatic pruritus in primary biliary cholangitis: an adaptive, randomized, placebo-controlled phase 2b trial (VANTAGE): 28-week interim results. Presented at: EASL 2025; May 9, 2025; Amsterdam, the Netherlands.
- Agarwal K, Jucov A, Dobryanska M, et al. Brelovitug (BJT-778) monotherapy achieved 100% virologic response in patients with chronic hepatitis D: on treatment week 48 phase 2 study results. Presented at: AASLD 2025; November 7-11, 2025; Washington, D.C.
- What is hepatitis delta? Hepatitis B Foundation. Accessed January 14, 2026. https://www.hepb.org/research-and-programs/hepdeltaconnect/what-is-hepatitis-delta/
- CHOLBAM® (cholic acid) capsules. Prescribing Information. Mirum Pharmaceuticals, Inc.
- Freedman SF, Brennand C, Chiang J, et al. Prevalence of cerebrotendinous xanthomatosis among patients diagnosed with acquired juvenile-onset idiopathic bilateral cataracts. JAMA Ophthalmol. 2019;137(11):1312-1316. doi:10.1001/jamaophthalmol.2019.3639
- Köroğlu M, Karakaplan M, Gündüz E, et al. Cerebrotendinous xanthomatosis patients with late diagnosed in single orthopedic clinic: two novel variants in the CYP27A1 gene. Orphanet J Rare Dis. 2024;19(1):53-65. doi:10.1186/s13023-024-03082-4
- CTEXLI® (chenodiol) tablets. Prescribing Information. Mirum Pharmaceuticals, Inc.