Clinical Trial of CD19 and CD22 CAR Sequential Therapy Versus Single CD19 CAR Bridging to HSCT for r/r B-ALL Patients

Inclusion criteria

• . Patients who were diagnosed as primary refractory or relapsed B-ALL. (Criterion-reference: NCCN, version 2.2023); All the patients matched the diagnostic criteria of ALL according to the NCCN guideline (≥20% bone marrow lymphoblasts on hematopathology review of bone marrow aspirate and biopsy materials, which were confirmed by comprehensive flow cytometric immunophenotyping, minimal residual disease analysis and karyotyping of G-banded metaphase chromosomes). Molecular characterization could be obtained via interphase fluorescence in situ hybridization (FISH) testing, reverse transcriptase polymerase chain reaction (RT-PCR) testing, comprehensive testing by next-generation sequencing (NGS) for gene fusions and pathogenic mutations, etc. Determination of the World Health Organization ALL subtypes and cytogenetic and clinical risk groups were also allowed. B-ALL patients who did not achieve a complete remission after previous therapy (including the various treatment response scenarios shown in Table 1), who did not achieve a complete remission after at least two lines of TKI agents (including the various treatment response scenarios shown in Table 1), or who had ≥1 relapses were defined as having refractory or relapsed disease. Patients who were diagnosed as CD19- and CD22-positive high-risk B-ALL with continuous positive minimal residual disease (MRD) for more than three months after last therapy were also eligible. Patients had positive CD19 and CD22 expression on leukemia blasts by FCM (\>80% CD19 and CD22 positive);