Second allogeneic stem cell transplantation in patients with acute lymphoblastic leukaemia: a study on behalf of the Acute Leukaemia Working Party of the European Society for Blood and Marrow Transplantation

Summary Although second allogeneic haematopoietic cell transplantation (allo‐ HCT 2) is a therapeutic option for patients relapsing after first HCT (allo‐ HCT 1), there is limited data on allo‐ HCT 2 in patients with acute lymphoblastic leukaemia ( ALL ). We retrospectively studied 245 patients receiving allo‐ HCT 2 as a salvage treatment for relapse following allo‐ HCT 1 between the 2000 and 2017. The median age at allo‐ HCT 2 was 34·6 years (range: 18–74). One hundred and one patients (41%) received sibling donor and 144 (59%) unrelated donor allo‐ HCT 2. Acute graft‐versus‐host disease ( GVHD ) grade II – IV and III – IV occurred in 33% and 17% of the patients, respectively. The incidence of 2‐year total and extensive chronic GVHD was 38% and 19%, respectively. The 2‐ and 5‐year cumulative incidence of non‐relapse mortality, relapse incidence, leukaemia‐free survival, overall survival and GVHD ‐free, relapse‐free survival ( GRFS ) were 24% and 26%, 56% and 62%, 20% and 12%, 30% and 14% and 12% & 7%, respectively. In multivariate analysis, factors associated with overall survival were age, time from allo‐ HCT 1 to relapse, conditioning for allo‐ HCT 1, Karnofsky score at allo‐ HCT 2 and donor type for allo‐ HCT 2. In conclusion, outcomes of allo‐ HCT 2 in ALL patients were poor, with only 14% overall survival and 7% GRFS at 5 years with very high relapse incidence.