Table 2.

Preclinical and clinical studies of FMT in supportive oncology.

Indication	Study type and description	FMT source/screening	Preparation/dose	Route of administration	Timing/frequency of delivery	Outcome measure(s)	Key finding(s)	Reference
Gastrointestinal toxicity	Preclinical; N = 18 Male C57BL/6 mice; Ampicillin antibiotics (1 g/L days 1–7) and 5-FU chemotherapy (150 mg/kg day 8) used to mimic oncology setting	Pellets from untreated mice	Pellets resuspended in PBS (1 pellet/1 mL PBS); pellets were pooled from multiple mice	Oral gavage (200 uL/day)	Daily for 3 days beginning on day after 5-FU (day 9–11)	Microbial diversity (alpha and beta)	5-FU and ampicillin caused a decrease in microbial diversity, remaining significant for 1 week; mice that received FMT showed no detectable change in diversity	Le Bastard et al. [40]
Immunotherapy colitis	Case series; N = 2 Patient 1: 50-year old, female with high grade metaststic urothelial carcinoma (refractory to chemotherapy); treated with combined CTLA-4 and PD-1 blockade; developed steroid-resistant grade II colitis Patient 2: 78-year old male with prostate cancer refractory to chemotherapy and hormonal therapy; received two doses of ipilimumab; developed steroid-resistant grade II colitis	Single, healthy, unrelated donor; stool collected at 3 separate time points and pooled Stringent donor screening based on exclusion of blood- and stool-based pathogens and relevant medical conditions. Clear summary of exclusion criteria can be found in the supplementary files of the original publication.	150 g stool, processed within 4 h of passage; diluted 1:10 in 0.85% NaCl; prepared using Stomacher80 Master and filtered through gauze; stored at -80oC and used within 6 months of storage.	Colonoscopically administered (250 mL)	Patient 1: Once Patient 2: Twice	Endoscopic evaluation, CD4/CD8/FoxP3 immunohistochemistry, 16S microbiome analysis	Patient 1: complete resolution, return of solid daily bowel movement without bleeding; steroids were gradually removed. Endoscopic evaluation showed marked improvement, indicated by a reduction in CD+ T cells and concomitant increase in CD4+ FOXp3+. Patient 2: Partial improvement with persistent ulcers and recurrent abdominal pain. Complete resolution after second FMT. In both patients, the number of OTUs increased following FMT, with principal coordinates analyses of unweighted UniFrac distances demonstrating the microbiome composition was similar to those of the donor.	Wang et al. [45]
Infection	Retrospective clinical study; N = 10 Data was retrospectively analysed from consecutive adult patients diagnosed with hematological malignancy who received FMT during allo-SCT for multi-drug resistant bacteria colonization. All patients were on immunosuppressive medication.	Healthy related or unrelated donors aged between 18 and 65 with no digestive disorders within 3 months of donation, no chronic disease or treatments, no antibiotics in the past 3 months. Donors were also excluded if they lived in the tropics, or had been hospitalised abroad for >24 h in the year leading up to donation. Complete biological and microbiological assessment was also performed.	Minimum of 50 g of stool was prepared within 6 h of collection. 50–100 g stool mixed with 300 mL 0.9% glycerol/saline, filtered through gauze. Stored at -80oC. In some cases (N = 2), fresh stool was used with preparation occurring within 6 h of donation.	Enema (N = 8) or nasogastric (N = 2) delivery.	Once; N = 4 received before allo-SCT, N = 6 received after allo-SCT.	Degree of decolonization - Major: 3 consecutive negative microbial cultures) - Persistent: one negative microbial culture at last follow-up	Major decolonization was achieved in 7/10 patients; persistent colonization was achieved in 6/10 patients Failure occurred in three patients: - Unable to cease antibiotics - Difficulties positioning nasogastroric tube, and unable to retain enema - Insufficient stool load (43 g) N = 2 deaths reported: - Uncontrolled GvHD - Disease progression	Battipaglia et al. [49]
GvHD	Case series; N = 4 Adult patients with steroid resistant (N = 3) or steroid-dependent (N = 1) gastrointestinal acute GvHD All patients on immunosuppressive medication.	Related donor aged 20–64 years; no tattoos/piercings, no sexual intercourse with a new partner for 3 months, no blood transfusion for 3 months, no travel to tropical areas in 3 months, no antibiotics in last month, no history of malignancy or inflammatory bowel disease, no abdominal symptomology on day of donation. All samples were screened for transmissible diseases.	Fresh, collected on day of donation; store day 4oC under anaerobic conditions until preparation. 200–300 mL sterile saline was added to fecal sample (weight unknown); fecal slurry was filtered through sterile metal sieve and leached through gauze. Sample was prepared under ambient conditions.	Nasogastric tube	Once, however patients without newly developed adverse events were offered a second FMT between 4 and 14 days after the first at the discretion of the physician.	Efficacy: gut GvHD grade (assessed using validated criteria) - Complete response: resolution of all intestinal signs and symptoms - Partial response: decrease in severity of gut GvHD by minimum of one stage - Progression: worsened gut GvHD symptoms - No change: no significant change in gut GvHD FMT was considered effective if the patient achieved CR or PR in steroid-resistant cases, or a reduction of ≥40% in the dose of steroid in steroid-dependent cases. Safety: Adverse events that first occurred or progressed within 1 week of infusion.	FMT was effective in all patients, with complete response in 3/4 patients and partial response in 1/4 patients. Adverse events were largely mild and transient; the possibility of an association between FMT and some adverse events could not be completely ruled out.	Kakihana et al. [50,69]
	Case report; N = 1 21-year old female with acute, stage III, steroid refractory gastrointestinal GvHD,	Related donor (sister); no tattoos/piercings, no sexual intercourse with a new partner for 3 months, no blood transfusion for 3 months, no travel to tropical areas in 3 months, no antibiotics in last month, no history of malignancy or inflammatory bowel disease, no abdominal symptomology on day of donation. All samples were screened for transmissible diseases.	71–144 g donated feces were homogenised with sterile saline; fecal suspension as passed through a metal sieve and filtered through sterile gauze; sample was centrifuged to isolate microbial pellet which was resuspended in 10% glycerol/saline. 450 uL concentrate was encapsulated into a #1 hypomellose capsule and rapidly frozen in liquid nitrogen; stored at -80oC.	Capsules	15 capsules per day on days 125, 130, 133 and 144 after transplantation, followed by a second round of FMT on days 173, 181 and 189.	Colonization and uptake of donor microbiome determined by 16S sequencing.	Recipients microbiome composition rapidly reflected that of the donor, increasing in diversity with a high abundance of Lactobacillus. Enterococcus re-emerged at 4 weeks, and the participant was offered another FMT. Second FMT resulted in partial resolution of symptoms, decreasing to grade I GvHD.	Kaito et al. [51]
	Feasibility study; N = 8 Adult patients with steroid refractory gastrointestinal GvHD All patients on immunosuppressive medication.	Donor FMT prepared from N = 2 healthy female donors, aged 23. No information regarding screening.	40–50 mL of frozen fecal microbiota resuspended in 200 mL of warm saline. No further information provided on preparation.	Nasogastric tube	Once	Efficacy: severity of GvHD symptoms (abdominal pain, diarrhea, presence of bloody purulent stools); clinical remission defined if diarrhea and intestinal spasms and/or bleeding disappeared, or stool volume decreased by 500 mL in 3 days. Safety: presentation of adverse events during FMT procedure or at follow up. Durability: 16S sequencing of recipient microbiota.	All patients achieved symptomatic remission after the FMT. At second follow up, 4/8 patients maintained full cure and 1/8 remained in remission. Improvements in GvHD symptoms seen in 1/8 patients. 2/8 patients relapsed at follow-up. No adverse events were reported. Progression free survival was enhanced in FMT recipients compared to historical controls (no FMT).	Qi et al. [52]