⁃ The subject or their legally authorized representative (guardian) understands the study and voluntarily signs the informed consent form (ICF).

⁃ Male or female, aged 3 to 65 years at the time of signing the ICF (inclusive of the cutoff values).

⁃ Expected survival of at least 12 weeks. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 at the time of signing the ICF.

⁃ At the time of signing the ICF, the patient must be diagnosed with R/R B-ALL and meet the following criteria:

• Bone marrow morphological examination at screening shows \>5% blasts in the bone marrow, and/or cerebrospinal fluid (CSF) analysis detects leukemic cells, and/or the presence of measurable extramedullary lesions, defined as:

• Any lymph node or mass with an axial diameter \>1.5 cm Any extranodal lesion with an axial diameter \>1.0 cm

• Flow cytometry confirms CD19 or CD22 positivity in tumor cells from bone marrow, peripheral blood, or cerebrospinal fluid, or pathology confirms CD19 or CD22 positivity in lymph nodes/masses or extranodal lesions.

⁃ Adequate organ function, meeting the following laboratory criteria:

• Liver function:

• Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤5× upper limit of normal (ULN) Total bilirubin ≤2× ULN

• Renal function:

⁃ Adults: Serum creatinine clearance ≥60 mL/min (using the Cockcroft-Gault formula) or creatinine ≤1.5× ULN

⁃ Children: Serum creatinine levels must not exceed the following values:

⁃ 10-13 years: ≤1.2 mg/dL Males 13-16 years: ≤1.5 mg/dL Females ≥13 years: ≤1.4 mg/dL Males ≥16 years: ≤1.7 mg/dL Blood oxygen saturation (SpO₂) \>92% on room air. Fertile male and female subjects of reproductive potential must agree to use effective contraception from the time of informed consent until 2 years after administration of the study drug.

⁃ Women of childbearing potential (WOCBP) include premenopausal women and those within 2 years post-menopause.

⁃ A negative blood pregnancy test is required for all female participants of childbearing potential at screening.