Donor-derived CD19-targeted T cell infusion induces minimal residual disease-negative remission in relapsed B-cell acute lymphoblastic leukaemia with no response to donor lymphocyte infusions after haploidentical haematopoietic stem cell transplantation.

Relapse is a common cause of failure in patients with B-cell acute lymphoblastic leukaemia (B- ALL) after haploidentical haematopoietic stem cell transplantation (haplo- HSCT), and non-responders to donor lymphoblastic infusion after HSCT have a very poor prognosis. Although donor-derived CD19-directed chimeric antigen receptor-modified ( CAR) T cells can potentially cure leukaemia, their effectiveness and safety have not been confirmed in relapsed B- ALL cases after haplo- HSCT. Between January 2015 and January 2017, two and four patients each received one and two infusions of CAR T cells from haplo- HSCT donors. Five (83·33%) achieved minimal residual disease ( MRD)-negative remission; one patient was discharged automatically without evaluation after developing severe thrombotic microangiopathies. Four of five responsive patients relapsed after 2-7 months, and one died of sepsis following MRD-negative remission after a second infusion. None of the other second infusion recipients achieved a second complete remission. Five patients (83·33%) experienced eight courses of grade 1-3 cytokine release syndrome; two were treated with tocilizumab. Two (33·3%) and one patient developed grade 2 and 3 acute graft- versus-host disease ( aGVHD), respectively; the former was controlled with glucocorticoids. Donor-derived CAR T-cell infusion seems be effective and safe for relapsed B- ALL after haplo- HSCT, although larger clinical studies are needed. [ABSTRACT FROM AUTHOR]