First-Line Consolidation Therapy with CD19/CD22 Bispecific CAR-T Cells for MRD Positive B-ALL Maybe Feasible

Measurable residual disease (MRD) persistence after induction or early intensive therapy has proved to be the strongest independent prognostic indicator for B-cell acute lymphoblastic leukemia (B-ALL). Here we presented a phase I study to evaluate the safety and efficacy of CD19/CD22 bispecific targeted chimeric antigen receptor (CAR) T-cells for MRD positive B-ALL, especially as first-line consolidation therapy for primary patients. The primary objective was to assess the safety and the secondary objective was for its efficacy. The most common adverse events (AEs) were hematologic related, including anemia of 93.3%(14/15), leukopenia of 100% (15/15), decreased neutrophil count of 100% (15/15), and decreased lymphocyte count of 100% (15/15).Cytokine release syndrome (CRS) occurred in 4 patients (26.7%) and all of them were grade 1 or 2. One patient (6.7%) developed delayed later neurotoxicity and related symptoms were obviously alleviated after treatments with prednisone. The overall MRD response rate was 100% at day 28. With a median follow-up of 15.5 months (range, 2.5-33), the median RFS and OS were not reached. For all patients, the 2-year RFS and OS were 77% (95% CI, 55-99) and 86% (95% CI, 68-104), respectively, while for patients in first-line consolidation group, the 2-year RFS and OS 77.8% (95% CI, 51-105) and 80.8% (95% CI, 57-105), respectively. The results suggested that CD19/CD22 bispecific CAR-T cells as first-line consolidation therapy might be feasible for MRD positive patients. This trial was registered at clinicaltrials.org (NCT: 03919526).

No relevant conflicts of interest to declare.