Oral Pooled Fecal Microbiotherapy to Prevent Allogeneic Hematopoietic Cell Transplantation Complications (PHOEBUS Trial)

This randomized, placebo-controlled phase IIb study (PHOEBUS trial) aims to evaluate the activity of fecal microbiotherapy MaaT033 to improve survival through the prevention of transplant-related complications in eligible alloHCT patients

Inclusion Criteria:Age ≥ 50 years oldPresence of a hematologic malignancy for which an alloHCT is indicated with a reduced toxicity or reduced intensity conditioning regimenPatients with polynuclear neutrophils > 0.5 G/LPatients having received wide spectrum antibiotics within the last 90 days prior to inclusionKarnofsky index ≥ 70%Availability of a sibling donor, an unrelated stem-cell donor or a familial haploidentical donorWritten informed consentExclusion Criteria:Patients planned to receive a non-myeloablative conditioning regimen (2 Gray total body irradiation (TBI) +/- purine analog, fludarabine + cyclophosphamide or equivalent)Patients planned to receive a conventional myeloablative conditioning regimen (e.g. high dose cyclophosphamide and high dose TBI (≥10Gy); high dose busulfan (12.8 mg/kg IV) + high dose cyclophosphamide)Patients receiving a manipulated graft (in-vitro T-cell depletion)Patients planned to receive a conditioning regimen with alemtuzumabPatients planned to receive alloHCT with cord blood cellsPatients planned to receive alloHCT from unrelated donor with >= 3/10 HLA-mismatchesPatients receiving a large spectrum antibiotic at time of randomizationPatients planned to receive vedolizumab or abatacept for GvHD prophylaxisCreatinine clearance <30 mL/minBilirubin or amino-transferases abnormalities contra-indicating alloHCTCardiac ejection fraction less than 40%Pulmonary impairment with <50% lung carbon monoxide diffusing capacity (DLCO)PregnancyConfirmed or suspected intestinal ischemiaConfirmed or suspected toxic megacolon or gastrointestinal perforationAny history of gastro-intestinal surgery in the past 3 monthsAny history of chronic digestive disease (Crohn's disease, ulcerative colitis, inflammatory bowel disease or other relevant digestive condition according to physician's judgement)Known allergy or intolerance to trehalose or maltodextrinPatients with EBV-IgG negative serologyAny condition that would, in the investigator's judgment, interfere with full participation in the study, including administration of study drug and attending required study visits; pose a significant risk to the subject; or interfere with interpretation of study data.Vulnerable patients such as: persons deprived of liberty, persons in Intensive Care Unit unable to provide informed consent prior to the intervention.