Prospective Interventional Study Exploring the Microbiota Recolonization in SR-GvHD Patients Receiving MaaT013 (ORION)

Prospective Interventional Study Exploring the Microbiota Recolonization in SR-GvHD Patients Receiving MaaT013

PrOspective inteRventional Study Exploring the mIcrobiota recolONization in Steroid-Refractory Graft-versus-Host Disease Patients Receiving MaaT013

The objective of the ORION study is to explore the changes of gut microbiota composition following MaaT013 administration and its impact on the immune system in GVHD patients.

The french regulatory authority ANSM approved in July 2019 the use of MaaT013, a pooled microbiome-based enema formulation, under a formalized named-patient use program in France called "Autorisation Temporaire d'Utilisation - ATU nominative protocolisée - ATUn" or Early Access. The ATUn is indicated to provide a benefit in the treatment of patients with grade III-IV aGVHD: In case of initial resistance to CS alone or in association or in case of failure to other treaments In first-line therapy in association with CS in case of steroid-dependance (inability to taper CS dose <0.5 mg/kg/d) In case of digestive aGvHD with overlap syndrome The objective of the ORION study is to explore the changes of gut microbiota composition following MaaT013 administration and its impact on the immune system in GVHD patients. Blood and stool samples will be collected at each visit which explained why the study is thus categorized as research involving the human person with low risks and constraints clinical trial (RIPH2).

The population of the study will be adult patients with GI-aGVHD grade III to IV undergoing MaaT013 treatment through named-patient use program ATUn (Early Access Program). Blood and stool samples will be collected at each visit to analyse the gut microbiota and the immune cells.

Diversity of gut microbiota will be evaluated using alpha-diversity metric (Simpson or Shannon or Richness indice) throughout the study

Sample comparisons will be performed using similarity metric such as Bray-Curtis, Jaccard distances, Sorensen, Pearson or Spearman indice.

Gut microbiota composition will be evaluated with phylogenetic profiling. Relative abundance of bacterial taxa will be described at each visit throughout the study.

Multiparameter analyses will be performed to identify correlations between changes in gut microbiota composition and immune parameters (Citrulline, Zonulin, ST2, 3 indoxyl sulfate, Reg3a, Total antioxidant status, TGFb1.2.3., IL-1b, IL-2, sIL-2ra, IL-6, IL-8, IL10, IL17-A, IL-18, IFNg, TNFa, sCD14, MCP1, CCL25, CCL28, sCD30, CXCL10)

Stratification of patients will be based on response to MaaT013 treatment at day 28. Then gut microbiota composition will be described in responder versus non responder patients.

Cytokines and immune parameters of interest (Citrulline, Zonulin, ST2, 3 indoxyl sulfate, Reg3a, Total antioxidant status,TGFb1.2.3., IL-1b, IL-2, sIL-2ra, IL-6, IL-8, IL10, IL17-A, IL-18, IFNg, TNFa, sCD14, MCP1, CCL25, CCL28, sCD30, CXCL10) will be measured in plasma/serum by Luminex and ELISA at each visit and compared to baseline. Results will be expressed as ratios on D0 value and heatmap. Peripheral blood mononuclear cells will be purified then analyzed by flow cytometry using specific antibodies (CD4, CD8α, CD8β,TCRαβ, CD49a, CCR6, CXCR6, CD25, CD127, CCR7, CD69, CD45RA, CD27, CD57, GITR, CD39, C. Transcriptomic analysis by single cell CITE-seq will be performed on some lymphocytes subgroups.

Inclusion Criteria: Patient ≥18 years old with Grade III-IV aGVHD with gut involvement undergoing treatment with MaaT013 through named-patient use program ATUn / Early Access Signature of informed and written consent by the subject or by the subject's legally acceptable representative for patients under guardianship or trusteeship. Affiliated or recipient from a social security scheme Exclusion Criteria: Pregnancy and breastfeeding Vulnerable patients such as: minors, persons deprived of liberty, persons in Intensive Care Unit unable to provide informed consent prior to the intervention.