Among patients who are undergoing allogeneic hematopoietic cell transplantation (HCT) for blood cancers including acute myeloid leukemia (AML), fecal microbiota transplantation (FMT) appears both safe and shows promise in ameliorating intestinal dysbiosis, according to research published in the Journal of Clinical Oncology. The treatment did not, however, reduce the risk of infection compared with placebo.

Clinical data have repeatedly shown that HCT disrupts patients’ intestinal microbiota, which may lead to dysbiosis. In the case of dysbiosis, there is an increased risk of acute graft vs host disease (GVHD), disease relapse, and mortality among patients undergoing HCT.

It has, however, also been previously demonstrated that FMT may decrease the risk of dysbiosis, and moreover help to treat some cases of acute GVHD. For this randomized phase 2 study ( Identifier: NCT03678493), researchers aimed to establish whether FMT reduces infection incidence among patients undergoing allogeneic HCT.

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The study included 2 cohorts: an HCT cohort and an AML cohort. Overall, in the HCT cohort, 74 patients were enrolled, of whom 49 were randomly assigned to the FMT group while 25 were assigned to receive placebo. The mean age at transplant was 52.4 years, 56.8% of patients were male sex, and 66.2% of patients had a matched unrelated donor. The most common diagnosis in the cohort was acute leukemia (71.6%). In the AML cohort, 26 patients were enrolled, of whom 18 were randomly assigned to receive FMT while 8 were assigned to receive placebo.

Analysis showed that the 4-month infection density was 0.74 events per 100 patient-days in the FMT arm vs 0.91 in the placebo arm, corresponding to an infection rate ratio of 0.83 (P =.49). The infection rate ratio in the AML cohort was 0.74 (P =.48).

Further analysis showed that, following FMT, unique donor bacterial sequences made up between 25% and 30% of patient fecal microbiota. FMT also appeared to improve post-antibiotic recovery of microbiota diversity.

The amount of expanded genera Enterococcus, Streptococcus, Veillonella, and Dialister detected among patients who received FMT was also lower.

“FMT trials targeting such patients who also have significant antibiotic exposure and likely develop dysbiosis will be of interest,” the authors wrote. “Finally, a larger total microbiota dose delivered over several days might improve engraftment and potentially treatment efficacy.”

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, or device companies. Please see the original reference for a full list of disclosures.


Rashidi A, Ebadi M, Rehman TU, et al. Randomized double-blind phase II trial of fecal microbiota transplantation versus placebo in allogeneic hematopoietic cell transplantation and AML. J Clin Oncol. Published online May 26, 2023. doi:10.1200/JCO.22.02366