IgA Monoclonal Gammopathy of Undetermined SignificancePhase 2NCT07209371
Rifaximin Versus No Intervention for the Treatment of IgG/IgA (Non-IgM) Monoclonal Gammopathy of Undetermined Significance
A Phase 2 study testing Rifaximin and Biospecimen Collection in people with IgA Monoclonal Gammopathy of Undetermined Significance and Non-IgM Monoclonal Gammopathy of Undetermined Significance, run by Fred Hutchinson Cancer Center at 1 site in United States.
Trial summary
This phase II trial compares the effect of rifaximin to no intervention for the treatment of IgG/IgA monoclonal gammopathy of undetermined significance (MGUS). Rifaximin is a type of antibiotic that is only used in cancer chemotherapy (antineoplastic antibiotic). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- IgA Monoclonal Gammopathy of Undetermined Significance, Non-IgM Monoclonal Gammopathy of Undetermined Significance
- What is being tested?
- Rifaximin and Biospecimen Collection
- Type of treatment
- Pill or oral medicine, Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 50 participants
- Where
- 1 siteUnited States
- Study dates
- 22 Jan 2026to 1 May 2028
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age ≥ 18 years
- Ability to understand and willingness to sign a written informed consent document. Legally authorized representatives may sign and give informed consent on behalf of potential study participants
- Clinical diagnosis of IgG/IgA (non-IgM) monoclonal gammopathy of undetermined significance (MGUS) based on International Myeloma Working Group (IMWG)-2014 criteria (Rajkumar et al, Lancet Oncology, 2014). It is recognized that not all patients with clinical diagnosis of MGUS undergo bone marrow biopsy. Bone marrow biopsy confirmation will not be required if not clinically indicated per treating provider
- Agree to use adequate contraception
- For women of child-bearing potential: prior to study entry and for the duration of study participation
- For men: prior to study entry, for the duration of study participation, and one month after completion of rifaximin administration (for men)
- No antibiotic use in the preceding 2 weeks
Who cannot join
- Participants who are receiving other investigational agents
- Pregnant women
- Known hypersensitivity to rifaximin
- Another concurrent malignancy requiring active therapy
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Fred Hutch/University of Washington Cancer Consortium
Seattle, Washington, 98109
Madhav Dhodapkar, MBBS, 206-606-4888, mdhodapk@fredhutch.org
Madhav Dhodapkar, MBBS
About this study
Official title: Rifaximin Versus No Intervention in Patients With IgG/IgA (Non-IgM) Monoclonal Gammopathy of Undetermined Significance
This phase II trial compares the effect of rifaximin to no intervention for the treatment of IgG/IgA monoclonal gammopathy of undetermined significance (MGUS). Rifaximin is a type of antibiotic that is only used in cancer chemotherapy (antineoplastic antibiotic). It works by damaging the cell's DNA and may kill cancer cells or precancerous cells like those found with MGUS. Giving rifaximin may kill more precancerous cells in patients with IgG/IgA MGUS.
Read the detailed description
OUTLINE: Patients are randomized to 1 of 2 arms.
ARM A: Patients receive rifaximin orally (PO) three times daily (TID) for 14 days in the absence of disease progression or unacceptable toxicity. Patients undergo blood sample collection throughout the study.
ARM B: Patients undergo blood sample collection throughout the study.
After completion of study intervention, patients are followed up at 90 days.
- Conditions
- IgA Monoclonal Gammopathy of Undetermined Significance, Non-IgM Monoclonal Gammopathy of Undetermined Significance
- Being tested
- Rifaximin, Biospecimen Collection
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
RifaximinDrug
Also called Xifaxan
Given PO
Biospecimen CollectionProcedure or surgery
Also called Biological Sample Collection, Biospecimen Collected, Specimen Collection
Undergo blood sample collection
| Study group | Role | What they receive |
|---|---|---|
| Arm A (Rifaximin) | Experimental | Patients receive rifaximin orally (PO) three times daily (TID) for 14 days in the absence of disease progression or unacceptable toxicity. Patients undergo blood sample collection throughout the study. Receives: Drug: Rifaximin; Procedure: Biospecimen Collection |
| Arm B (No intervention) | Other | Patients undergo blood sample collection throughout the study. Receives: Procedure: Biospecimen Collection |
What is being measured
The primary outcome is the main question the study is designed to answer.
Overall response rate
Defined as the proportion of patients with > 25% decline in clonal Ig at any point within 90 days after the initiation of drug or no intervention. Logistic regression will be conducted to evaluate the association between endpoint of interest and treatment (Arm A versus [vs] B).
Measured: From the start of therapy, up to 90 days
Secondary outcomes (1)
Proportion of patients experiencing > grade 2 adverse events
Logistic regression will be conducted to evaluate the association between endpoint of interest and treatment (Arm A vs B).
Measured: From the start of therapy, up to 90 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Oct 2025
- Study start22 Jan 2026
- Primary completion1 May 2028 (estimated)
- Study completion1 May 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for IgA Monoclonal Gammopathy of Undetermined SignificanceStudies of the same condition, open and under way.
- More trials run by Fred Hutchinson Cancer CenterThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 50 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Fred Hutchinson Cancer Center
- Sponsor type
- University, hospital or other
- Collaborators
- Rising Tide Foundation
- Responsible party
- Sponsor
- Investigators
- Madhav Dhodapkar, MBBS, Principal investigator, Fred Hutch/University of Washington Cancer Consortium
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07209371
- Sponsor's protocol ID
- RG1125814
- Other IDs
- NCI-2025-06773, FHIRB0020984
- Status last verified
- Aug 2026
- First submitted
- 1 Oct 2025
- Last updated
- 17 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Rifaximin Versus No Intervention in Patients With IgG/IgA (Non-IgM) Monoclonal Gammopathy of Undetermined Significance
- ClinicalTrials.gov ID
- NCT07209371
- Acronym / sponsor ID
- RG1125814
- Conditions
- IgA Monoclonal Gammopathy of Undetermined Significance, Non-IgM Monoclonal Gammopathy of Undetermined Significance
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- Fred Hutchinson Cancer CenterUniversity, hospital or other
- Collaborators
- Rising Tide Foundation
- Study start
- 22 Jan 2026 (actual)
- Primary completion
- 1 May 2028 (estimated)
- Study completion
- 1 May 2028 (estimated)
- First posted
- 7 Oct 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This phase II trial compares the effect of rifaximin to no intervention for the treatment of IgG/IgA monoclonal gammopathy of undetermined significance (MGUS). Rifaximin is a type of antibiotic that is only used in cancer chemotherapy (antineoplastic antibiotic). It works by damaging the cell's DNA and may kill cancer cells or precancerous cells like those found with MGUS. Giving rifaximin may kill more precancerous cells in patients with IgG/IgA MGUS.
Detailed description
OUTLINE: Patients are randomized to 1 of 2 arms.
ARM A: Patients receive rifaximin orally (PO) three times daily (TID) for 14 days in the absence of disease progression or unacceptable toxicity. Patients undergo blood sample collection throughout the study.
ARM B: Patients undergo blood sample collection throughout the study.
After completion of study intervention, patients are followed up at 90 days.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Arm A (Rifaximin) | Experimental | Drug: Rifaximin, Procedure: Biospecimen CollectionPatients receive rifaximin orally (PO) three times daily (TID) for 14 days in the absence of disease progression or unacceptable toxicity. Patients undergo blood sample collection throughout the study. |
| Arm B (No intervention) | Other | Procedure: Biospecimen CollectionPatients undergo blood sample collection throughout the study. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Age ≥ 18 years
- Ability to understand and willingness to sign a written informed consent document. Legally authorized representatives may sign and give informed consent on behalf of potential study participants
- Clinical diagnosis of IgG/IgA (non-IgM) monoclonal gammopathy of undetermined significance (MGUS) based on International Myeloma Working Group (IMWG)-2014 criteria (Rajkumar et al, Lancet Oncology, 2014). It is recognized that not all patients with clinical diagnosis of MGUS undergo bone marrow biopsy. Bone marrow biopsy confirmation will not be required if not clinically indicated per treating provider
- Agree to use adequate contraception
- No antibiotic use in the preceding 2 weeks
Key exclusion criteria (4 listed)
- Participants who are receiving other investigational agents
- Pregnant women
- Known hypersensitivity to rifaximin
- Another concurrent malignancy requiring active therapy
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| RifaximinAlso: XifaxanGiven PO | Drug | Arm A (Rifaximin) |
| Biospecimen CollectionAlso: Biological Sample Collection, Biospecimen Collected, Specimen CollectionUndergo blood sample collection | Procedure or surgery | Arm A (Rifaximin), Arm B (No intervention) |
Primary outcome
Overall response rate
Time frame: From the start of therapy, up to 90 days
Defined as the proportion of patients with > 25% decline in clonal Ig at any point within 90 days after the initiation of drug or no intervention. Logistic regression will be conducted to evaluate the association between endpoint of interest and treatment (Arm A versus [vs] B).
1 secondary outcome
Proportion of patients experiencing > grade 2 adverse events
Time frame: From the start of therapy, up to 90 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Aug 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Madhav Dhodapkar, MBBS principal investigator
Fred Hutch/University of Washington Cancer Consortium
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Rifaximin and Biospecimen Collection in people with IgA Monoclonal Gammopathy of Undetermined Significance and Non-IgM Monoclonal Gammopathy of Undetermined Significance, run by Fred Hutchinson Cancer Center at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 17 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Madhav Dhodapkar, MBBS (206-606-4888, mdhodapk@fredhutch.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Overall response rate (time frame: From the start of therapy, up to 90 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Aug 2026.