CD19 targeted CAR-T therapy versus chemotherapy in re-induction treatment of refractory/relapsed acute lymphoblastic leukemia: results of a case-controlled study

Chimeric antigen receptor modified T cells against CD19 (CART19s) have potent anti-leukemia activities in patients with refractory/relapsed acute lymphoblastic leukemia (R/R ALL). This study was designed to investigate the correlation between safety/efficacy and therapeutic modalities including chemotherapy and CART19 therapy. Total 23 and 69 patients were enrolled in the CART19 group and in the chemotherapy group, respectively. The safety and efficacy profiles of 66 and 22 patients in the 2 groups were evaluated. The complete remission (CR) rate was higher in the CART19 group than that in the chemotherapy group (90.9 vs 37.9%, P = 0.000). For patients relapsed after allo-HSCT and chemotherapy, CR rates were 100% (8/8) vs 48.0% (12/25) (P = 0.009) and 85.7% (12/14) vs 31.7% (13/41) (P = 0.000), respectively. Moreover, a higher percentage in the CART19 group had results below the threshold for minimal residual disease (100 vs 7.58%, P = 0.000). In survival analysis, the overall survival rate at 12 months was higher in the CART19 group than that in the chemotherapy group (60.9 vs 10.1%, P = 0.000). For post-transplant patients achieving CR, 25.0% (2/8) and 75.0% (9/12) complicated with GVHD (P = 0.04) in the CART19 group and chemotherapy group, respectively. For all CR patients, the median duration of absolute neutrophil count less than 500/mu L and platelet count less than 20,000/mu L were longer in the CART19 group than in the chemotherapy group (p = 0.0047 and 0.0003, respectively). Our data demonstrated that patients with CART19s therapy acquired higher rates of remission and longer survival, confirming the encouraging application of CART19 therapy in R/R ALL.