ICON-2: FMT and Bezlotoxumab Compared to FMT and Placebo for Patients With IBD and CDI (ICON-2)

November 18, 2025 updated by: Jessica Ravikoff Allegretti, Brigham and Women's Hospital

A Randomized Controlled Trial to Compare the Effectiveness of Fecal Microbiota Transplantation (FMT) in Combination With Bezlotoxumab Compared to FMT and Placebo for the Prevention of CDI Recurrence in Patients With Inflammatory Bowel Disease and Recurrent Clostridium Difficile Infection

This is a randomized controlled trial to assess the clinical and microbiological impacts of FMT in combination with Bezlotoxumab (bezlo) compared to FMT in combination with placebo in patients with both inflammatory bowel disease (IBD) a and clostridium difficile infection (CDI). The investigators will prospectively enroll up to 150 IBD-CDI patients from 4 tertiary care FMT referral centers. Patients will be randomized 1:1 to either receive FMT in combination with Bezlo of FMT and a placebo infusion. Donor stool from healthy donors will be obtained from OpenBiome. OpenBiome is a nonprofit 501(c)(3) organization that provides hospitals with screened, filtered, and frozen material ready for clinical use. Patients will be enrolled and followed prospectively for 3 months post therapy. Stool and blood samples as well as clinical data will be collected at baseline, week 1, 8 and 12.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
61

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

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

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Massachusetts
      • Boston, Massachusetts, United States, 02115
        • Brigham and Women's Hospital

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adults age 18 or greater
  • History of ≥ 2 episodes of recurrent CDI. CDI is defined as the presence of diarrhea ( Bristol 6 or 7 for 48 hours and a confirmatory test for CDI). Preferred testing will be a two-step method using GDH/EIA toxin, though PCR will be accepted based on hospital availability with confirmation of the most recent episode occurring within the prior 3 months
  • Confirmed diagnosis of IBD (ulcerative colitis, Crohn's disease or indeterminate colitis)
  • Undergoing FMT via colonoscopy for CDI as part of standard medical care

Exclusion Criteria:

  • Unable or unwilling to undergo a colonoscopy
  • Inpatient status, though patients can be screened while inpatients, the must be outpatient for the planned colonoscopy.
  • Anticipated immediate or upcoming surgery within 30 days
  • Need for continued non-anti-CDI antibiotic therapy
  • History of total proctocolectomy
  • Female patients who are pregnant or breastfeeding or plan to become pregnant in the next 6 months.
  • Patients who are unable to give informed consent
  • Participation in a clinical trial in the preceding 30 days or simultaneously during this trial
  • Severe food allergy (anaphylaxis or anaphylactoid-like reaction)
  • Life expectancy < 6 months
  • Unable to adhere to protocol requirements
  • Patient who have received an FMT in the past year
  • Any condition that the physician investigators deems unsafe, including other conditions or medications that the investigator determines that it will put the subject at greater risk from FMT
  • Patient who is diagnosed with NYHA class 3 or 4 Heart Failure
  • Lab value of WBC <3.0 x 103/mm3 , Platelets <100 x 103/mm3 , ALT or AST > 1.5 x institutional ULN
  • EBV or CMV negative if a patient is severely immunosuppressed ( defined as 3 or more immunosuppressing agents)

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: FMT + Bezlo
Patients in this arm will received an FMT via colonoscopy ( 250ml) as well as a single IV infusion of bezlotoxumab (10mg/kg) that will take place over 60 mins.
Drug: Bezlotoxumab
This is a a fully human monoclonal antibody that binds to C. difficile toxin B, and is indicated to prevent recurrence of CDI in adults at risk for recurrent CDI (rCDI).
Other Names:
  • Zinplava
Drug: Fecal Microbiota Transplantation
FMT is an infusion of prescreened donor stool that will be administered via colonoscopy
Other Names:
  • FMT
Placebo Comparator: FMT + Placebo
Patients in this arm will receive a single FMT via colonoscopy (250ml) and a placebo (saline) infusion (250cc) over
Drug: Fecal Microbiota Transplantation
FMT is an infusion of prescreened donor stool that will be administered via colonoscopy
Other Names:
  • FMT
Drug: Placebo
placebo is an infusion of normal saline.
Other Names:
  • Saline

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Number of Participants With Clostridium Difficile Recurrence
Time Frame: 8 weeks
positive test for CDI by EIA toxin
8 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Diarrheal symptoms
Time Frame: 12 weeks
Number of Bowel movements daily
12 weeks
Rectal bleeding
Time Frame: 12 weeks
presence or absence of rectal bleeding
12 weeks
Abdominal Pain
Time Frame: 12 weeks
presence of absence of abominal pain
12 weeks

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Brigham and Women's Hospital

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 1, 2020

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
August 3, 2023

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 1, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 26, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 1, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 4, 2019

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 9, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 18, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2018 (U.S. NIH Grant/Contract)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

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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