Faecal microbiota transplantation to prevent complications after allogeneic stem cell transplantation for haematological malignancies: a study protocol for a randomised controlled phase-II trial (the FMT-allo study)

Abstract

Introduction: Allogeneic haematopoietic stem-cell transplantation (allo-HSCT) is a major treatment for many haematological malignancies. The procedure has a good success rate but high transplant-related toxicity (TRM). TRM is mostly related to graft-versus-host disease (GvHD) and infectious complications. Alterations of the intestinal microbiota plays a major role in the development of allo-HSCT complications. The gut microbiota could be restored by faecal microbiota transplantation (FMT). However, there are no published randomised studies assessing the efficacy of FMT for GvHD prophylaxis.

Methods and analysis: This prospective, open-label, multi-centre, parallel-group, randomised phase-II clinical trial has been designed to assess the effect of FMT on toxicity in patients treated with myeloablative allo-HSCT for haematological malignancy. Based on Fleming's single-stage sample size estimation procedure, the design plans to include 60 male and female patients aged 18 or over per arm, to be randomly assigned to two groups, one with and one without (control group) FMT. The primary endpoint is GvHD-free relapse-free survival rate at 1 year after allo-HSCT. Secondary endpoints are outcome measures of the impact of FMT on allo-HSCT-related morbidity and mortality (overall survival and progression-free survival at 1 and 2 years, haematological parameters, infectious complications, tolerance and safety of FMT). The primary endpoint will be evaluated according to assumptions of the single-stage Fleming design, compared between groups by a log-rank test and further investigated in a multivariate marginal structural Cox model taking into account centre effect. The proportional-hazard hypothesis will be verified using Schoenfeld's test and by plotting residuals.

Ethics and dissemination: The local institutional review board (CPP Sud-Est II, France) issued approval on 27 January 2021. The French national authorities issued approval on 15 April 2021. The outcome of the study will be disseminated via peer-reviewed publications and at congresses.

Trial registration number: NCT04935684.

Keywords: Bone marrow transplantation; Leukaemia; Lymphoma; Myeloma.

Figure 1

Patient timeline. Patients will be screened for eligibility during the pretransplantation consultation. The inclusion visit will take place during the first day of hospitalisation for eligible patients who have signed the consent form. The patient will have a complete clinical examination, the usual biological check-up, a stool sample for microbiota analysis and a blood sample for serum collection. The period D7 to D1 corresponds to completion of the myeloablative conditioning regimen followed by the reinjection of haematopoietic stem cells which, by convention, is called D0. During the entire hospitalisation period, the patient will be followed as per usual standard-of-care practice with daily clinical and biological monitoring. Randomisation will be done at the end of engraftment (and maximum 4 weeks after), provided the patient does not present exclusion criteria at that time. Both patient groups will have a stool sample for the microbiota analysis and blood samples for serum collection within these 4 weeks (before the FMT for patients randomised to the ‘FMT group’). Follow-up will continue either in day hospital or in consultation at least once a month for a year. The evaluation criteria for the primary and secondary endpoints will be measured throughout routine clinical and biological follow-up until 2 years. A stool sample for microbiota analysis and a blood sample for serum collection will be collected at M1, M3 and 1 year after engraftment. allo-HSCT, allogeneic haematopoietic stem-cell transplantation; FMT, faecal microbiota transplantation.