Rifaximin versus no intervention for IgA MGUS

Rifaximin Versus No Intervention in Patients With IgA Monoclonal Gammopathy of Undetermined Significance

Phase 2 Interventional Fred Hutchinson Cancer Center · NCT07209371

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

PhasePhase 2
Study typeInterventional
Enrollment50 (estimated)
Ages18 Years and up
SexAll
SponsorFred Hutchinson Cancer Center Academic / other
Drugs / interventionschemotherapy
Locations1 site (Seattle, Washington)
Trial IDNCT07209371 on ClinicalTrials.gov

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.

Who should consider this trial

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.

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.

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 performed: This approach is novel for IgA MGUS and there is little prior clinical data showing success with rifaximin in this condition.

Eligibility criteria

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 IgA monoclonal gammopathy of undetermined significance (MGUS) based on International Myeloma Working Group (IMWG)-2014 criteria (Rajkumar et al, Lancet Oncology, 2014)
* 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

Where this trial is running

Seattle, Washington

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions IgA Monoclonal Gammopathy of Undetermined Significance
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.