Feasibility Study of MET-4: Evaluating Fecal Microbiome Effects in Immunotherapy Patients (MET4-IO)

Feasibility Study of Microbial Ecosystem Therapeutics (MET-4) to Evaluate Effects of Fecal Microbiome in Patients on ImmunOtherapy (MET4-IO)

This study is designed to assess the safety, tolerability and engraftment (cumulative relative abundance) of MET-4 strains when given in combination with immune checkpoint inhibitors (ICIs). There will be a safety cohort (group A) of 5 subjects which will receive MET-4 in addition to standard of care (SOC) ICI. After the safety cohort, 40 patients will be enrolled in group B which will be randomized to MET4 with SOC ICI vs. control group with SOC ICI only. Group C will enroll 20 patients who have already started on SOC ICI and have had first unconfirmed progression of disease and expected to continue with standard ICI treatment. These patients will be randomized to continue receiving standard ICI alone, or SOC ICI with MET4.

Study Overview

• Status: Active, not recruiting
• Conditions: All Solid Tumors
• Intervention / Treatment: Biological: MET-4

Detailed Description

Human associated microorganisms (the microbiota) inhabit virtually all surfaces of the human body. The gut is densely colonized by the microbiota which aids in the digestion. Animal and human observational and experimental evidence show a link between gut microbiota and the activation, regulation and function of the immune system. Pre-clinical studies in mouse models have linked the gut microbiota to efficacy of anticancer therapies. Microbial Ecosystem Therapeutics (MET) is a new treatment approach developed as an alternative to fecal transplantation. MET consists of a defined mixture of pure live cultures of intestinal bacteria isolated from a stool sample of a healthy donor.

This study is designed to assess the safety, tolerability and engraftment (cumulative relative abundance) of MET-4 strains when given in combination with immune checkpoint inhibitors (ICIs).

• Study Type: Interventional
• Enrollment (Estimated): 65
• Phase: Phase 2; Phase 3

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5G 2M9
      • Princess Margaret Cancer Centre

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Signed written and voluntary informed consent
• Age >=18 years, male or female
• Histologically or cytological documented locally-advanced or metastatic solid malignancy which is incurable.
• Group A: Is already on treatment with monotherapy anti-PD-1 or PD-L1 immune checkpoint inhibitor, not in the context of a therapeutic clinical trial.

Group B: Is intended to start on treatment with monotherapy anti-PD-1 or PD-L1 immune checkpoint inhibitors as considered appropriate by treatment physician, and not in the context of a therapeutic clinical trial.

Group C: Is already on treatment with monotherapy anti-PD-1 or PD-L1 immune checkpoint inhibitor, not in the context of a therapeutic clinical trial with first unconfirmed PD on evaluation scan per investigator's assessment.

• Be willing to provide 10-15 unstained slides of archival tissue sample. Subjects who decline or have not sufficient archived tissue samples may still enroll if all other criteria are eligible.
• Be willing and able to provide stool and blood specimen for analyses at protocol specified time points.
• Have measurable disease based on RECIST 1.1
• Performance status of 0-2 on the Eastern Cooperative Oncology Group (ECOG) performance scale.
• Prior therapy with any immunotherapy allowed.
• Not pregnant for females of child bearing potential as indicated by negative serum or urine pregnancy test within 72 hours of study start.

Exclusion Criteria:

• Subjects unable to swallow orally administered medications or any subjects with gastrointestinal disorders likely to interfere with absorption (e.g. bowel obstruction, short gut syndrome, blind loop syndrome, ileostomy etc). Subjects with colostomies may be enrolled.
• Any condition that, in the opinion of the Investigator, would interfere with subject safety, or evaluation of the collected specimen and interpretation of study result.
• Pregnant or planning to get pregnant in the next 6 months.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group A: Safety Cohort; Subjects with advanced solid tumors already on ICI will receive treatment with MET-4 in addition to SOC ICI. MET-4 is administered orally as an initial daily loading dose (5g) of MET-4 over 2 days followed by a daily maintenance dose (1.5g) of MET-4 and will be continued until unacceptable toxicity, progression of disease	Biological: MET-4; Microbial Ecosystem Therapeutics (MET) is a new treatment approach developed as an alternative to fecal transplantation. Unlike donor stool used in fecal transplants, which are incompletely characterised complex communities of microbes and associated metabolites and fecal material, MET consists of a defined mixture of pure live cultures of intestinal bacteria isolated from a stool sample of a healthy donor.
Experimental: Group B; Eligible subjects with advanced solid tumors starting ICI will be randomised in a 3:1 ratio stratifying for prior IO exposure, to receive MET-4 together with any approved PD-1/PD-L1 inhibitor as per SOC or control group. There will be a run-in period for subjects in the MET-4 treatment group. Following the run-in period of ICI therapy, subjects will be administered the same MET-4 dose as subjects in group A.	Biological: MET-4; Microbial Ecosystem Therapeutics (MET) is a new treatment approach developed as an alternative to fecal transplantation. Unlike donor stool used in fecal transplants, which are incompletely characterised complex communities of microbes and associated metabolites and fecal material, MET consists of a defined mixture of pure live cultures of intestinal bacteria isolated from a stool sample of a healthy donor.
Experimental: Group C; In group C, eligible subjects with advanced solid tumors whom are already on ICI with first unconfirmed PD on evaluation scans per investigator's assessment, will be randomised in a 1:1 ratio to receive MET-4 in addition to the PD-1/PD-L1 inhibitor as per SOC or control group. These subjects must be clinically stable and are to be continued on ICI at the discretion of the investigator. There will be no run-in period for this cohort. Subjects will be administered the same MET-4 dose as subjects in groups A and B.	Biological: MET-4; Microbial Ecosystem Therapeutics (MET) is a new treatment approach developed as an alternative to fecal transplantation. Unlike donor stool used in fecal transplants, which are incompletely characterised complex communities of microbes and associated metabolites and fecal material, MET consists of a defined mixture of pure live cultures of intestinal bacteria isolated from a stool sample of a healthy donor.
Experimental: Group D; In group D, eligible subjects with stage III or resected stage IV melanoma who are to start adjuvant ICI, will be randomized in a 1:1 ratio to receive MET-4 in addition to anti-PD1 antibody +/- anti-CTLA4 antibody as per SOC or control group. Patients will be stratified per BRAF mutation status. Subjects will be administered the same MET-4 dose as subjects in groups A, B and C. MET-4 will be initiated as run-in for a minimum of 1 week, and maximum of 2 weeks before ICI administration. MET-4 will be continued until unacceptable toxicity, confirmed PD by RECIST v1.1 or completion of 1 year of ICI, whichever occurs earlier. Subjects in the control arms of groups B, C and D will be treated with ICI therapy as per institution standard of care without MET-4.	Biological: MET-4; Microbial Ecosystem Therapeutics (MET) is a new treatment approach developed as an alternative to fecal transplantation. Unlike donor stool used in fecal transplants, which are incompletely characterised complex communities of microbes and associated metabolites and fecal material, MET consists of a defined mixture of pure live cultures of intestinal bacteria isolated from a stool sample of a healthy donor.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cumulative relative abundance of immunotherapy-responsiveness associated species at day 12 of MET-4	Fecal microbial abundance measured via qPCR and Nanostring analysis of stool at approximately day 12	Approximately 12 days
Changes in relative abundance of immunotherapy-responsiveness associated MET-4 strains between baseline and approximately day 12	Microbiome gene sequencing of stool at baseline and approximately day 12 post first dose	Approximately 12 days
Number of participants with treatment-related adverse events assessed by CTCAE v.5.0	Related toxicities and severity collected as per CTCAE version 5.0	2 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cumulative relative abundance of immunotherapy-responsiveness associated species at later MET-4 or control time points (approximately 24 weeks and/or 1-2 weeks following the end of treatment).	Fecal microbial abundance measured via qPCR and Nanostring analysis of stool at baseline and week 24 after first dose and EOT.	2 years
Changes in relative abundance of immunotherapy-responsiveness associated MET-4 strains between baseline and later MET-4 or control timepoints (approximately 24 weeks and/or 1-2 weeks following the end of treatment)	Microbiome gene sequencing of stool at baseline and week 24 after first dose and EOT.	2 years
Bacterial taxonomic diversity between baseline and follow-up samples	Microbiome gene sequencing of stool at baseline, day 10-16 post first dose, week 3-4 post first dose, and week 24 after first dose and EOT.	2 years

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Response	Objective response rates of ICI when given in combination with MET-4 as measured per RECIST v1.1 and iRECIST	2 years
Progression free survival	Time from randomization until disease progression or death as measured per RECIST v.1.1 and iRECIST	2 years
Changes in immune cell subsets in the systemic circulation in response to MET-4 through serial blood sampling.	Flow cytometry/CyTOF of blood at baseline, 6-8 weeks post first dose of MET, 24 weeks post first dose	24 weeks
Characterization of tumor microenvironment of archived tumor samples	Standard immunohistochemistry (IHC) of baseline archival tumor	2 years
Dynamic measures of microbiome as correlates of blood immune profiling	Flow cytometry/CyTOF of blood at baseline, week 3-4 post first dose of MET, and week 24 post first dose, and stool microbiome gene profiling at baseline, 10-16 days first dose of MET, week 3-4 post first dose, week 24 post first dose and end of treatment.	2 years

Collaborators and Investigators

• Sponsor: University Health Network, Toronto
• Collaborators: NuBiyota
• Investigators: Principal Investigator: Anna Spreafico, MD, Princess Margaret Cancer Centre; Principal Investigator: Lillian Siu, MD, Princess Margaret Cancer Centre

Study record dates

Study Major Dates

• Study Start (Actual): November 30, 2018
• Primary Completion (Actual): December 1, 2024
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: September 24, 2018
• First Submitted That Met QC Criteria: September 25, 2018
• First Posted (Actual): September 26, 2018

Study Record Updates

• Last Update Posted (Actual): February 9, 2026
• Last Update Submitted That Met QC Criteria: February 5, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: MET4-IO-001

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: No
• Studies a U.S. FDA-regulated device product: No