The Gut Microbiome Changes in FMS-like Tyrosine Kinase 3 (FLT3) Negative Acute Leukemia (AL) Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation (Allo-HSCT) With or Without Sorafenib Maintenance Post-transplantation

Acute leukemia is a heterogeneous group of clonal diseases. Leukemia relapse remains the main cause of treatment failure, including the patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Sorafenib, an inhibitor of multiple kinases including FLT3, has shown promising activity in FLT3-ITD-positive AML. The investigator's previous studies demonstrated that sorafenib maintenance post-transplantation could improve the outcomes of FLT3-ITD positive AML patients, which was associated with sorafenib enhancing the graft-versus-leukemia (GVL) effect. Recent studies have shown that sorafenib is also effective in patients with FLT3-negative acute leukemia. The investigator's previous exploratory study found that salvage therapy such as sorafenib combined with chemotherapy and donor lymphocyte infusion could significantly improve the CR rate and survival in patients with recurrent FLT3-negative acute leukemia after allo-HSC. More and more studies have shown that sorafenib and allo-HSCT have synergistic GVL effect. Some studies have demonstrated that gut microbiome is associated with graft-versus-host-disease (GVHD) and GVL. However, the exact mechanism of sorafenib enhancing the GVL effect and the influence of gut microbiome on sorafenib maintenance after allo-HSCT in FLT3 negative acute leukemia patients remain unknown.