A Phase 1 interventional study of Commensal Bacteria Strains in Liver Diseases, Liver Failure and Cirrhosis, Liver, sponsored by University of Chicago. Recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-11-04.
Sponsored by University of Chicago · Phase 1, Interventional, and Treatment
The Microbiota Augmentation to Reestablish Commensal Organisms (MARCO) trial is a single center prospective adaptive phase 1b clinical trial in patients who are hospitalized with complications of liver disease and have low fecal metabolite levels (butyrate and deoxycholic acid). The study intervention is 1 of 9 novel live Commensal Consortia each containing eight commensal bacterial strains derived from healthy donors. The primary objective of the study is to determine safety and tolerability of Commensal Consortia administration.
The global burden of chronic liver disease (CLD) continues to rise. CLD is often clinically silent until an initial decompensation event, after which care is largely supportive without the ability to significantly modify the underlying disease with current therapies. Due to the high rates of infection in patients with liver disease, empiric, broad spectrum antibiotics are commonly prescribed. This practice is associated with altered gut microbiome compositions, reduced levels of health-promoting bacterial metabolites and high levels of antibiotic resistant organisms, findings that correlate with poor clinical outcomes including infection, repeat hepatic decompensation, re-hospitalization and death.
The primary objective of this clinical trial is to test the safety of commensal bacterial strain combinations designed to reconstitute microbiota compositions and metabolite production in patients with liver disease and profound dysbiosis as measured by low fecal metabolite (butyrate and deoxycholic acid) concentrations. The exploratory outcomes include strain engraftment and bacterial metabolite production.
The trial will occur in two phases. During the first phase, 8 patients will be recruited and administered the same combination of bacterial strains for 7 doses. Patients will be monitored for safety and tolerability. Additionally, fecal samples will be collected to assess for the presence of administered strains and fecal metabolite production.
After the first phase, additional combinations of bacteria will be chosen based upon the safety, engraftment and metabolite production in the first phase. In this adaptive phase, an additional 16 subjects will be enrolled and randomized to one of two additional consortia. In the two phases, a total of 24 patients will be enrolled, and each will be followed for 12 months to assess both primary (safety and tolerability) and exploratory (engraftment and metabolite production) outcomes. The investigators anticipate completing enrollment within 12 months of trial initiation.
824 studies on the registry are indexed under Liver Diseases; 152 are open to participants now.
This study's planned enrollment of 24 is below the median of 52 across 521 interventional studies indexed under Liver Diseases.
Browse Liver Diseases studies →University of Chicago is the lead sponsor of 924 studies on the registry; 185 are open to participants now.
Of its 103 completed or terminated interventional studies of FDA-regulated products, 72 (70%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
They will be identified as having liver disease, liver failure, and/or cirrhosis based on a combination of at least one of the following:
Exclusion Criteria:
Chronic or prophylactic antibiotic administration other than rifaximin, ciprofloxacin, or trimethoprim-sulfamethoxazole.
-Rifaximin will be either temporarily held or switched to another non-antibiotic therapy (e.g. lactulose or sodium benzoate) during the treatment phase of the trial. Potential subjects in whom the treating hepatologist deem it unsafe to pause or switch from Rifaximin therapy during the 7-10 day treatment phase will be excluded from the study.
Patients with known intestinal barrier dysfunction, including active GI bleeding, enteropathy (including celiac disease), clinically active inflammatory bowel disease (Crohn's or Ulcerative Colitis), ischemic colitis, microscopic colitis, (GVHD), or gastrointestinal .
o Active inflammatory bowel disease (IBD) will be defined based on a combination of:
Patients who are allergic to both ampicillin/sulbactam and meropenem.
Special populations:
Women of childbearing age will have a:
Another investigational drug or LBP:
Patients who are prescribed metformin will require either:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
After a transplant from a donor, the donor’s immune cells attack the recipient’s body, often the skin, gut or liver.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
INR, PT and aPTT (clotting tests)
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GVHD (graft-versus-host disease)
After a transplant from a donor, the donor’s immune cells attack the recipient’s body, often the skin, gut or liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Allogeneic and autologous transplant
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Stage 1: 1st 8 patients enrolled will receive Consortium A. This consortium contains 7 different organisms.
Biological: Commensal Bacteria Strains
Stage 2: Based on fecal metagenomic and metabolomic data from Stage 1, subjects may be assigned to this Commensal Consortium. This consortium contains 7 different organisms.
Biological: Commensal Bacteria Strains
Stage 2: Based on fecal metagenomic and metabolomic data from Stage 1, subjects may be assigned to this Commensal Consortium. This consortium contains 7 different organisms.
Biological: Commensal Bacteria Strains
Stage 2: Based on fecal metagenomic and metabolomic data from Stage 1, subjects may be assigned to this Commensal Consortium. This consortium contains 7 different organisms.
Biological: Commensal Bacteria Strains
Stage 2: Based on fecal metagenomic and metabolomic data from Stage 1, subjects may be assigned to this Commensal Consortium. This consortium contains 7 different organisms.
Biological: Commensal Bacteria Strains
Stage 2: Based on fecal metagenomic and metabolomic data from Stage 1, subjects may be assigned to this Commensal Consortium. This consortium contains 7 different organisms.
Biological: Commensal Bacteria Strains
Stage 2: Based on fecal metagenomic and metabolomic data from Stage 1, subjects may be assigned to this Commensal Consortium. This consortium contains 8 different organisms.
Biological: Commensal Bacteria Strains
Stage 2: Based on fecal metagenomic and metabolomic data from Stage 1, subjects may be assigned to this Commensal Consortium. This consortium contains 7 different organisms.
Biological: Commensal Bacteria Strains
Stage 2: Based on fecal metagenomic and metabolomic data from Stage 1, subjects may be assigned to this Commensal Consortium. This consortium contains 7 different organisms.
Biological: Commensal Bacteria Strains
7 doses containing 7 capsules will be administered over 7-10 days
Also known as: Lyophilized live commensal bacterial strains (Live Biotherapeutic Product), Commensal Consortium
The incidence of adverse events (AEs and SAEs) attributable to the Commensal Consortia
Adverse events will be monitored for 1 year after Commensal Consortium administration using in-person contact, telephone calls and/or Patient-Reported Outcomes
Time frame: Day 1- Month 12
Patient-Reported Outcomes Measurement Information System (PROMIS) scores after Commensal Consortia administration
Tolerability will be assessed for 1 year after Commensal Consortium administration through completion of PROMIS surveys. Surveys will be obtained by the investigators using in-person contact, telephone calls and/or Patient-Reported Outcomes.
Time frame: Day 1- Month 12
The presence of administered bacterial strains in fecal samples
Stool samples will be collected at regular intervals and subjected to shotgun metagenomic sequencing. Strain engraftment will be defined as detection of the administered strains.
Time frame: Day 1- Month 12
Metabolite concentrations in fecal samples
Concentrations of targeted metabolites will be measured in fecal samples collected at regular intervals after Commensal Consortium administration.
Time frame: Day 1- Month 12
Plan to share: No
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