Table 1

Secondary objectives/outcomes from the MAST study

Objectives	Outcome
Determine the feasibility and tolerability of capsule IMT prior to HCT in a multicentre setting.	Tolerability and acceptability of IMT/placebo (as assessed via patient perspective questionnaires, ie, EQ-5D-5L and EORTC QLQ-C30 questionnaires).
Evaluate microbiological/infective, haematological, and quality of life-related clinical outcomes of administering IMT prior to HCT.	Gut microbiome endpoints: Assessment of changes in inverse Simpson’s index and other measures of gut microbiome diversity across all time points assessed, including alpha diversity and richness (ie, as measured via Chao-1, Shannon, Faith’s PD) and beta-diversity (Aitchinson’s distance). Assessment of changes in gut microbiome taxonomic composition across all time points assessed(using shallow shotgun sequencing).
	Clinical endpoints: Markers of general health across all time points measured, including days on the intensive treatment unit; presence and severity of mucositis; use of (and length of time that requiring) parenteral nutrition; severe acute kidney injury and severe liver dysfunction. Infective/microbiological outcomes across all time points measured, including days of fever post-HCT (corrected for length of admission); days on antibiotics (including use of carbapenem specifically); number and length of bloodstream infections; urinary tract infections; colonisation with multidrug-resistant bacteria (including extended-spectrum beta-lactamases, vancomycin-resistant enterococci and carbapenemase-producing Enterobacteriales) and use of antibiotics. Haematological outcomes across all time points measured, including: non-relapse mortality, relapse incidence; occurrence and severity of graft-versus-host disease (GvHD), overall and GvHD-free relapse-free survival and quality of life.
Explore the potential for pre-HCT IMT to impact on HCT engraftment and immune reconstitution.	Neutrophil and platelet engraftment data as defined by EBMT will be routinely collected. Recovery of T-cell chimerism, T-cell count assessed by the lymphocyte subset analysis and immunoglobulin levels will be recorded at follow-up assessments.

EBMT, European Society for Blood and Marrow Transplantation; EORTC QLQ-C30, European Organisation for Research and Treatment of Cancer Core Quality of Life Questionnaire 30; EQ-5D-5L, EuroQol-5 descriptive-5 level; HCT, haematopoietic cell transplantation; IMT, intestinal microbiota transplant; MAST, Microbiota Transplant Prior to Allogeneic Stem Cell Transplant.