Prognosis of patients with acute lymphoblastic leukaemia relapsing after allogeneic stem cell transplantation

The outcomes of patients with acute lymphoblastic leukaemia (ALL) presenting relapse after allogeneic stem cell transplant (allo-SCT) are poor, with few data available in this setting. Objective and Methods: To evaluate the outcomes of patients with ALL presenting relapsed after allo-SCT, we performed a retrospective study including 132 from 11 centres in Spain. Results: Therapeutic strategies consisted of palliative treatment (n = 22), chemotherapy (n = 82), tyrosine kinase inhibitors (n = 26), immunotherapy with inotuzumab and/or blinatumumab (n = 19), donor lymphocyte infusions (n = 29 pts), second allo-SCT (n = 37) and CAR T therapy (n = 14). The probability of overall survival (OS) at 1 and 5 years after relapse was 44% (95% confidence interval [CI]: 36%; 52%) and 19% (95% CI: 11%; 27%). In the 37 patients undergoing a second allo-SCT, the 5-year estimated OS probability was 40% [22%; 58%]. Younger age, recent allo-SCT, late relapse, 1st complete remission at 1st allo-SCT and chronic graft-versus-host disease confirmed their positive impact on survival in the multivariable analysis. Conclusion: Despite the poor prognosis of patients with ALL presenting relapse after a first allo-SCT, some can be satisfactorily rescued and a second allo-SCT still remains a valid option for selected patients. Moreover, emerging therapies really might improve ALL patients outcome when relapsing after an allo-SCT.