CAR-T Cell Therapy for ALL

Inclusion Criteria: * Inclusion Criteria All of the following criteria must be met for enrolment: * 1\. Age ≥5 years and ≤50 years at the time of consent * 2\. Morphologically or immunophenotypically confirmed B-cell ALL (CD19+) meeting one or more of the following relapsed/refractory criteria: * a. Second or subsequent bone marrow relapse (BM ≥2nd relapse) * b. Any BM relapse following prior allogeneic HSCT, provided ≥6 months have elapsed from SCT to planned CAR-T infusion * c. Primary refractory disease: failure to achieve CR after ≥2 cycles of standard induction chemotherapy; or chemorefractory: failure to achieve CR after ≥1 cycle of standard salvage chemotherapy for relapsed ALL * d. Philadelphia chromosome-positive (Ph+) ALL: intolerant to or failed ≥2 lines of TKI therapy, or TKI contraindicated * e. Ineligibility for allo-HSCT due to: comorbid disease, lack of suitable donor, contraindication to conditioning, or patient refusal after documented discussion with a BMT physician not part of the study team * 3\. CD19 expression on tumour cells confirmed by multi-parameter flow cytometry within 3 months of enrolment (≥20% CD19-positive blasts required) * 4\. Bone marrow blast burden ≥5% by morphological assessment at screening * 5\. Adequate organ function at screening: * a. Renal: Age-adjusted serum creatinine within normal limits per CTCAE paediatric reference tables, or GFR ≥30 mL/min/1.73m² (MDRD/CKD-EPI) * b. Hepatic: ALT/AST ≤5× ULN; Total bilirub…