Rifaximin versus no intervention for IgA MGUS
Official title: Rifaximin Versus No Intervention in Patients With IgG/IgA (Non-IgM) Monoclonal Gammopathy of Undetermined Significance
Run by Fred Hutchinson Cancer Center · NCT07209371 · Data updated 2026-11-12
This trial tests whether a short, two-week course of the antibiotic rifaximin can reduce precancerous IgA cells in adults with IgA MGUS.
Quick facts
| Phase | Phase 2 |
|---|---|
| Study type | Interventional |
| Ages | 18 Years and up |
| Sex | All |
| Enrollment | 50 (estimated) |
| Sponsor | Fred Hutchinson Cancer Center Academic / other |
| Drugs / interventions | chemotherapy |
| Locations | 1 site (Seattle, Washington) |
| Status | Recruiting |
| Started | January 22, 2026 |
| Main results expected | May 1, 2028 |
| Study ends | May 1, 2028 |
| Registry record updated | August 17, 2026 |
| Trial ID | NCT07209371 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Adults (≥18 years) with a clinical diagnosis of IgA MGUS by IMWG-2014 criteria who can give informed consent, agree to contraception, have not used antibiotics in the prior two weeks, are not on other investigational agents, and can attend visits at the Seattle site are ideal candidates.
✕Probably not a fit
People with non-IgA MGUS, known hypersensitivity to rifaximin, pregnant women, those currently receiving other investigational agents, or those unable to travel to the Seattle site are unlikely to benefit or be eligible.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This phase II randomized trial assigns adults with IgA MGUS to either a 14-day course of oral rifaximin taken three times daily or to no intervention, with blood samples collected throughout the study for biomarker analysis. Treatment is given in the absence of disease progression or unacceptable toxicity, and all participants are followed for 90 days after the intervention period. The study uses biospecimen collection to track changes in the IgA monoclonal protein and other laboratory markers over time. The overall aim is to test whether short-term rifaximin exposure reduces precancerous cell burden compared with observation.
Why it matters
Potential benefit: If successful, this approach could reduce the number of precancerous IgA cells and potentially lower the risk of progression to multiple myeloma.
How similar studies have gone: This approach is novel for IgA MGUS and there is little prior clinical data showing success with rifaximin in this condition.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * 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 Exclusion Criteria: * Participants who are receiving other investigational agents * Pregnant women * Known hypersensitivity to rifaximin * Another concurrent malignancy requiring active therapy
Where it's running
-
Fred Hutch/University of Washington Cancer Consortium
Seattle, Washington, United States Recruiting
Study contacts
- Principal investigator: Madhav Dhodapkar, MBBS — Fred Hutch/University of Washington Cancer Consortium
- Study coordinator: Madhav Dhodapkar, MBBS
- Email: mdhodapk@fredhutch.org
- Phone: 206-606-4888
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.