Rifaximin for Infection Prophylaxis in Hematopoietic Stem Cell Transplantation

This study is for patients who will be having a blood/marrow transplant (BMT) to treat
leukemia, lymphoma or other cancer of the blood. The blood or marrow cells will come from
another person (donor)—allogeneic BMT. Bacterial infections and acute graft versus host
disease (AGVHD) are frequent complications of allogeneic BMT. Bacterial infections sometimes
happen because injury to the gut during transplant allows gut bacteria to cross the injured
gut barrier and get to the blood. AGVHD happens when certain white blood cells, called
T-cells, in the donor cells (the graft) attack the patient's body.

Primary purpose of the study is to see if rifaximin can improve the balance of bacteria
within the gut, which has been shown to improve transplant outcomes. It will also assess
whether rifaximin can reduce the risk of infection in blood/marrow transplant (BMT).

Inclusion Criteria:

1. Allogeneic HSCT recipients between the ages of 2 and 21 years.

2. Underlying hematologic malignancy, regardless of donor type or graft source.

3. Myeloablative conditioning regimen.

Exclusion Criteria:

1. Known hypersensitivity to rifaximin, or other rifamycin antimicrobial agents.

2. Minimally toxic conditioning regimen (e.g. low dose TBI based). Since these regimens
induce minimal myelosuppression and gut injury, patients receiving them probably stand
little to gain from antibiotic prophylaxis.

3. Patients with ongoing bacterial, viral or fungal active infections are not eligible
for this study. Patients who remain on broad spectrum antibiotics for the treatment of
a previous infection are not eligible.

4. The use of prophylactic antibiotics is not permitted.

5. Following the standard practice in blood and marrow transplantation, pregnant or
breast feeding patients will be excluded