Gene mutations and pretransplant minimal residual disease predict risk of relapse in adult patients after allogeneic hematopoietic stem-cell transplantation for T cell acute lymphoblastic leukemia.

We retrospectively analyzed outcomes of 120 hematopoietic stem cell transplantation (HSCT) patients with T cell acute lymphoblastic leukemia (T-ALL), with emphases on gene mutations and pre-transplant minimal residual disease (MRD). Patients with NOTCH1/FBXW7 (N/F) mutations but no RAS or PTEN abnormalities were considered genetic low risk (gLoR), whereas those with RAS/PTEN alterations or no N/F mutations were considered high risk (gHiR). The gLoR and gHiR groups differed significantly in 3-year CIR (gLoR: 12.4%, gHiR: 41.2%, p = .026) and RFS (gLoR: 80.7%, gHiR: 35.2%, p = .025). Patients with MRD at transplantation had significantly higher CIR rates than those with no MRD (56.7% vs 22.6%, p < .001). Among the 57.5% of patients with no MRD, 3-year CIR and RFS differed significantly between the gHiR and gLoR groups (CIR-gHiR: 38.7%, gLoR: 6.7%, p = .039; RFS-gHiR: 42.3%, gLoR: 86.1%, p = .012). Gene mutations and pretransplant MRD predict high risk of relapse and worse RFS in patients with T-ALL after HSCT.