Fecal microbiota transplantation (FMT): The FMT capsules are prepared from healthy donor feces screened according to international consensus guidelines. Oral administration of human-derived gut microbiota capsules, each containing no fewer than 2×10¹¹ organisms, given at a dose of 20 capsules per day for 3 consecutive days (total 60 capsules per course).No dose adjustments will be made during the study. The total treatment duration is 3 days. This is a single-arm, open-label, phase I/IIa proof-of-concept safety exploratory trial. Participants will be followed for 3 months post-FMT to assess safety, feasibility, and preliminary biological signals of immune recovery.
Study summary
Patients who undergo allogeneic hematopoietic stem cell transplantation (allo-HSCT) often experience slow and incomplete recovery of their immune system, particularly the part responsible for producing antibodies (humoral immunity). This can lead to increased risk of infections and other complications. Previous studies suggest that the gut microbiome and its metabolites, such as short-chain fatty acids (propionate and butyrate), play a critical role in immune recovery.
This study has two phases. In the first phase, we will observe changes in immune function, lymphocyte subsets, and gut metabolites (propionate and butyrate) before and at 1, 3, and 6 months after transplantation in 50-80 patients. We will compare patients with severe immune deficiency to those with normal recovery to identify differences in gut bacteria and metabolites.
In the second phase, we will perform selective fecal microbiota transplantation (FMT) in 6 patients who still have severe humoral immunodeficiency at 6 months post-transplant. The FMT capsules will be specially selected from donors whose gut bacteria are rich in both propionate-producing and butyrate-producing strains. Patients will receive 20 capsules daily for 3 consecutive days (60 capsules total). We will evaluate the safety and feasibility of this approach, and observe whether fecal secretory immunoglobulin A (sIgA) shows signs of recovery at 3 months after FMT.
The study is expected to take approximately 2 years to complete. Findings may provide a new precision microbiome-based strategy to promote immune recovery after transplantation.
Eligibility
Sex
ALL
Min age
18 Years
Max age
—
Healthy volunteers
No
Inclusion Criteria:
* Age ≥ 18 years
* Receiving first allogeneic hematopoietic stem cell transplantation (allo-HSCT) with myeloablative or reduced-intensity conditioning
* Able to complete scheduled follow-up visits and sample collections
* Willing and able to provide written informed consent
For Phase 2 (FMT intervention): participants must additionally meet all of the following criteria at 6 months post-transplant:
* Serum IgA \< 0.07 g/L with IgG and IgM not yet recovered to normal range
* No active grade III-IV acute graft-versus-host disease (GVHD)
* Off systemic antibiotics for at least 2 weeks
* Willing to receive fecal microbiota transplantation (FMT) and sign dedicated informed consent for the intervention
Exclusion Criteria:
* Early post-transplant death or loss to follow-up
* Active grade III-IV acute GVHD (at time of screening)
* Continuous use of high-dose immunosuppressants (prednisone-equivalent dose \> 1 mg/kg/day)
* Refusal to participate or inability to comply with study procedures
For Phase 2 (FMT intervention): participants meeting any of the following criteria will be excluded from the FMT phase:
* Gastrointestinal obstruction, perforation, or severe intestinal dysfunction
* Severe cardiac, hepatic, or renal insufficiency that would preclude safe FMT administration
* Known allergy or hypersensitivity to any component of the FMT preparation
Primary outcome measure(s)
Composite Endpoint of Safety and Feasibility of Selective FMT in Post-Allo-HSCT Patients — 3 months post-FMT Safety is assessed by the incidence, severity (CTCAE v5.0), and attribution of treatment-emergent adverse events (TEAEs) within 3 months post-FMT, with particular monitoring for grade ≥3 AEs, serious adverse events (SAEs), and FMT-related exacerbation of GVHD or bacteremia. Feasibility is measured by the FMT completion rate, defined as the proportion of enrolled patients who successfully receive ≥90% of the planned total dose (≥54 of 60 oral capsules). The study will be considered to have demonstrated safety and feasibility if: (a) the completion rate is ≥80% (lower bound of 95% CI \>60%); (b) the incidence of FMT-related grade ≥3 AEs is ≤15% (upper bound of 95% CI \<30%); and (c) no FMT-related SAEs occur that are definitely or probably attributed to the intervention. Independent safety review will be performed after every 5 patients, with predefined stopping rules.
Trial sites (1)
Facility
City
Region
Status
The First Affiliated Hospital of Soochow University
Suzhou
Jiangsu
More The First Affiliated Hospital of Soochow University trials in China
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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