Orelabrutinib Combined With Rituximab and Chemotherapy for Relapsed/Refractory B-Cell Lymphoma Patients With Central Nervous System Involvement

Inclusion Criteria: * 14 to 80 years old; * Histopathologically confirmed CD20 positive B-cell lymphoma according to the 5th edition of the World Health Organization (WHO) Classification of Haematolymphoid Tumours; * After systemic treatment of the CNS lesions; * Life expectancy of \> 3 months (in the opinion of the investigator); * No non-haematologic adverse events, except alopecia, higher than grade 1 according to Common Terminology Criteria for Adverse Events (CTCAE) v5.0; * Absolute Neutrophil Count (ANC) ≥ 1.0×10\^9/L, Platelet Count ≥ 50×10\^9/L and Haemoglobin ≥ 60 g/L, without transfusion or any use of pharmacologically hematopoietic drugs in 2 weeks; * Serum Creatinine (SCr) ≤ 1.5 times the Upper Limit of Normal (ULN) or Creatinine Clearance Rate (CCR) ≥ 30 mL/min; * Serum total Bilirubin (tBil) ≤ 1.5 × ULN and both Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT) ≤ 2.5 × ULN without hepatic metastases, otherwise tBil ≤ 3 × ULN and AST, ALT ≤ 5 × ULN respectively; * International Normalized Ratio (INR) ≤ 1.5 and activated Partial Thromboplastin Time (aPTT) ≤ 1.5 × ULN; * Left Ventricular Ejection Fraction (LVEF) ≥ 50%; * Agreeing to provide written informed consent prior to any special examination or procedure for the research on their own or legal representative. Exclusion Criteria: * Pregnant or lactating women; * Known Hepatitis B Virus (HBV) and/or Hepatitis C Virus (HCV) infection (HBV infection refers to HBV-DNA \> detectable limit); * With acquired or congenital immunodeficiency; * With congestive heart failure in 6 months before enrollment, New York Heart Association (NYHA) heart function class III or IV, or LVEF \< 50%; * Known to be allergic to the test drug ingredients; * Diagnosed with or being treated for malignancy other than lymphoma; * With severe infection; * Substance abuse, medical, psychological, or social conditions that may interfere with the subjects' participation in the study or evaluation of the study results; * Deemed unsuitable for the group.