Efficacy and safety of humanized anti‐CD19‐CAR‐T therapy following intensive lymphodepleting chemotherapy for refractory/relapsed B acute lymphoblastic leukaemia

We studied the efficacy and safety of humanized CAR‐T therapy following intensive chemotherapy for refractory/relapsed (R/R) acute lymphoblastic leukaemia (B‐ALL). Twenty‐three patients with R/R B‐ALL were pretreated with intensive chemotherapy (fludarabine combined with medium‐dose cytarabine) 12 days before CAR‐T therapy. Adverse events (AEs), curative effects, infection indicators and cytokine release syndrome (CRS) were monitored. Each of the 23 patients received a dose of 1·0 × 10(6) cells/kg CAR‐T cell infusion on day 0. After 14 days, 19 patients (82·61%) achieved complete response (CR) or CR with incomplete count recovery. No survival benefit was achieved with consolidative haematopoietic stem‐cell transplantation (HSCT), with a median follow‐up of 14·0 months (range, 1·5–21·0 months). The notable AEs were grade 1–2 CRS in 18 patients, while the other five patients were grade 3 CRS. No patients died of CRS. Only one patient died of respiratory failure due to cytomegalovirus infection 24 days after infusion. The proportion of leukaemic cells in bone marrow on infusion day and the peaks of IL‐6, TNF‐α and IL‐8 levels were correlated with CRS levels. A lower disease burden was achieved by intensive lymphodepleting chemotherapy, and the subsequent CAR‐T therapy had a high response and manageable toxicity. Trial registration: The patients were enrolled in a clinical trial of ChiCTR‐ONN‐16009862, and ChiCTR1800019622.