Using Healthy Gut Bacteria to Boost Immune Treatment for Advanced Bowel Cancer

March 17, 2026 updated by: Qingqi Hong, The First Affiliated Hospital of Xiamen University

An Exploratory Study of Fecal Microbiota Transplantation (FMT) Combined With Immunotherapy and Chemotherapy in Microsatellite Stable Metastatic Colorectal Cancer (MSS mCRC)

This research protocol outlines an exploratory study on the combination of early-life fecal microbiota transplantation (yFMT) with immunotherapy and chemotherapy in patients with microsatellite stable metastatic colorectal cancer (MSS mCRC). The single-center, single-arm study aims to assess the safety of yFMT in conjunction with immunotherapy and chemotherapy, with a secondary focus on exploring its efficacy and impact on the patients' immune microenvironment. The study will enroll 10 patients aged 18-75 who have progressed after first-line chemotherapy and targeted therapy. The intervention involves six sessions of yFMT every two weeks, alongside PD-1 inhibitor immunotherapy and FOLFIRI chemotherapy. The primary endpoints are the incidence of serious adverse events (SAEs), treatment-related adverse events (TRAEs), and intervention adjustments due to adverse events, while secondary endpoints include progression-free survival (PFS), objective response rate (ORR), and overall survival (OS). The study is expected to last two years from initiation to data analysis completion, and it will be conducted at the Gastrointestinal Tumor Surgery Department of the First Affiliated Hospital of Xiamen University.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The research protocol for the study titled "Exploratory Study of Early Life Fecal Microbiota Transplantation (yFMT) Combined with Immunotherapy and Chemotherapy in Microsatellite Stable Metastatic Colorectal Cancer (MSS mCRC)" is designed to investigate a novel treatment approach for patients with MSS mCRC, a group that typically does not respond well to immunotherapy. The study is being conducted at the Gastrointestinal Tumor Surgery Department of the First Affiliated Hospital of Xiamen University.

Objectives:

Primary Objective: To evaluate the safety of combining yFMT with immunotherapy (PD-1 inhibitor) and chemotherapy (FOLFIRI) in patients with MSS mCRC.

Secondary Objectives: To explore the efficacy of the combined treatment in terms of progression-free survival (PFS), objective response rate (ORR), and overall survival (OS), as well as to assess the impact of yFMT on the patients' immune microenvironment and its potential synergistic effects with immunotherapy and chemotherapy.

Study Design:

The study is a single-center, single-arm trial with a total of 10 participants. The study timeline includes a screening period of 2 weeks, a treatment period of 3 months, and a follow-up period of 9 months.

Participants:

The study will enroll 10 patients aged between 18 and 75 years, regardless of gender.

Inclusion Criteria: Patients must have a confirmed diagnosis of MSS mCRC, must have experienced disease progression after first-line chemotherapy and targeted therapy, and must have an ECOG performance status of 0-1.

Exclusion Criteria: Patients with a history of FMT, severe organ dysfunction (heart, lung, liver, kidney), other malignancies, psychiatric disorders, pregnancy or lactation, and those unable to provide informed consent will be excluded.

Interventions:

Participants will receive yFMT every two weeks for a total of six sessions, along with PD-1 inhibitor immunotherapy and FOLFIRI chemotherapy.

Endpoints:

Primary Endpoints: The incidence of serious adverse events (SAEs), treatment-related adverse events (TRAEs), and the rate of intervention adjustments due to adverse events.

Secondary Endpoints: PFS, ORR, and OS.

Statistical Analysis:

Descriptive statistics will be used to calculate the incidence rates and 95% confidence intervals for primary endpoints.

Kaplan-Meier methods will be used for secondary endpoints to estimate survival functions and calculate median survival times with 95% confidence intervals.

Duration:

The study is expected to last for approximately two years from the initiation of the study to the completion of data analysis.

Research Team:

The project is led by Principal Investigator Dr. Hong Qingqi, who is a Chief Physician. The team includes a multidisciplinary group of professionals, including other physicians, nurses, and researchers, all of whom have received Good Clinical Practice (GCP) training.

Ethical Considerations:

The study will adhere to the principles of the Declaration of Helsinki and will be approved by the hospital's ethics committee before initiation.

Informed consent will be obtained from all participants or their legal representatives.

Data Management:

All data will be collected, managed, and stored in accordance with GCP guidelines and relevant regulations to ensure confidentiality and integrity.

This study aims to provide a comprehensive evaluation of the safety and potential benefits of yFMT in combination with immunotherapy and chemotherapy for MSS mCRC, potentially offering a new treatment paradigm for this challenging disease.

Study Type

Interventional

Enrollment (Estimated)

10

Phase

  • Early Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Histologically or cytologically confirmed diagnosis of MSS mCRC
  • Experienced disease progression after first-line chemotherapy and targeted therapy
  • ECOG performance status of 0-1

Exclusion Criteria:

  • History of FMT
  • Severe organ dysfunction (heart, lung, liver, kidney)
  • Other malignancies, psychiatric disorders, pregnancy or lactation
  • Unable to provide informed consent

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: yFMT + PD-1 Inhibitor + FOLFIRI Group
This study evaluates a combined intervention of young-donor fecal microbiota transplantation (yFMT), PD-1 inhibitor immunotherapy, and FOLFIRI chemotherapy for microsatellite stable metastatic colorectal cancer (MSS mCRC) patients. yFMT (6 sessions every 2 weeks via nasogastric tube or oral capsules) aims to modulate the gut microbiome and enhance immune response, administered concurrently with weight-based PD-1 inhibitor and FOLFIRI regimen (fluorouracil, leucovorin, irinotecan) synchronized every 2 weeks. This 3-month treatment period, followed by 9-month follow-up, tests the hypothesis that yFMT synergistically improves immunotherapy efficacy through microbiome alteration. Patients are closely monitored for adverse events with prompt management and regimen adjustments to ensure safety.
Drug: yFMT
This study evaluates a triple-combination therapy for MSS mCRC comprising: (1) yFMT (6 biweekly sessions via nasogastric tube or oral capsules using young-donor fecal microbiota to modulate gut microbiome); (2) weight-based PD-1 inhibitor immunotherapy; and (3) FOLFIRI chemotherapy (fluorouracil, leucovorin, irinotecan) synchronized biweekly with yFMT. The 3-month treatment period tests the hypothesis that yFMT enhances immunotherapy efficacy through microbiome-mediated immune modulation, followed by 9-month follow-up. Safety monitoring includes prompt adverse event management and regimen adjustments as needed.
Other Names:
  • PD-1 Inhibitor
  • FOLFIRI Regimen

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The incidence of serious adverse events (SAEs)
Time Frame: From the initiation of yFMT treatment to the completion of follow-up
The proportion of patients experiencing serious adverse events (Grade ≥3 per CTCAE v5.0) during the treatment and follow-up period, including events related to yFMT, immunotherapy, or chemotherapy that result in death, life-threatening conditions, hospitalization, or persistent disability.
From the initiation of yFMT treatment to the completion of follow-up
treatment-related adverse events (TRAEs)
Time Frame: From the initiation of yFMT treatment to the completion of follow-up
The incidence of adverse events assessed as related to the study intervention (yFMT, PD-1 inhibitor, or FOLFIRI regimen) by the investigator, graded according to CTCAE v5.0, occurring from treatment initiation through the follow-up period.
From the initiation of yFMT treatment to the completion of follow-up
the rate of intervention adjustments due to adverse events
Time Frame: From the initiation of yFMT treatment to the completion of follow-up
The proportion of patients requiring dose reduction, treatment interruption, or discontinuation of yFMT, immunotherapy, or chemotherapy due to treatment-related adverse events, documented with reasons and duration of adjustments.
From the initiation of yFMT treatment to the completion of follow-up

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
PFS
Time Frame: From treatment initiation to radiographic disease progression (per RECIST v1.1) or death from any cause, whichever occurs first.
Progression-free survival, defined as the time from treatment initiation to radiographic disease progression (per RECIST v1.1) or death from any cause, whichever occurs first.
From treatment initiation to radiographic disease progression (per RECIST v1.1) or death from any cause, whichever occurs first.
ORR
Time Frame: Objective response will be assessed every 6-8 weeks from the initiation of yFMT treatment until disease progression, death, or completion of 12-month study period (3-month treatment + 9-month follow-up), whichever occurs first.
Objective response rate, defined as the proportion of patients achieving complete response (CR) or partial response (PR) as assessed by investigators according to RECIST v1.1 criteria.
Objective response will be assessed every 6-8 weeks from the initiation of yFMT treatment until disease progression, death, or completion of 12-month study period (3-month treatment + 9-month follow-up), whichever occurs first.
OS
Time Frame: From treatment initiation until death (any cause) or last known alive date, up to 12 months.
Overall survival, defined as the time from treatment initiation to death from any cause.
From treatment initiation until death (any cause) or last known alive date, up to 12 months.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

The First Affiliated Hospital of Xiamen University

Investigators

  • Principal Investigator: Qingqi Hong, MD, The First Affiliated Hospital of Xiamen University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

March 31, 2026

Primary Completion (Estimated)

January 31, 2028

Study Completion (Estimated)

January 31, 2028

Study Registration Dates

First Submitted

March 14, 2026

First Submitted That Met QC Criteria

March 17, 2026

First Posted (Actual)

March 20, 2026

Study Record Updates

Last Update Posted (Actual)

March 20, 2026

Last Update Submitted That Met QC Criteria

March 17, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • XMYY-2026KY036

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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