Orelabrutinib Maintenance Therapy After ASCT in Primary Central Nervous System Lymphoma

Inclusion Criteria:

1. Men and women, aged 18-65;
2. Primary CNS lymphoma patients with CR were evaluated in the final stage of first-line therapy, and the virus-infected patients were balanced between the experimental and control groups;
3. Laboratory tests (blood routine, liver and kidney function) meet the following requirements:

   A) Blood routine examination: white blood cell count ≥3.0×109/L, absolute neutrophil count ≥1.5×10\^9/L, hemoglobin ≥90g/L, platelet ≥75×10\^9/L; B) Liver function: transaminase ≤2.5× upper limit of normal value, bilirubin ≤1.5× upper limit of normal value; C) Renal function: serum creatinine 44-133 mmol/L;
4. Participants' ECOG physical status score was 0-2; The subject or his/her legal representative must provide written informed consent prior to conducting a special study examination or procedure.

Exclusion Criteria:

Presence of any of the following criteria will exclude a patient from enrollment:

* Uncontrolled cardio- and cerebro-vascular disease, blood clotting disorders, connective tissue diseases, serious infectious diseases and other diseases
* Laboratory measures meet the following criteria at screening (unless caused by lymphoma):

  1. Neutrophils\<1.5×10\^9/L
  2. Platelets\<80×10\^9/L (Platelets\<50×10\^9/L in case of bone marrow involvement)
  3. ALT or AST is 2 times higher than the upper limits of normal (ULN), AKP and bilirubin are 1.5 times higher than the ULN.
  4. Creatinine is 1.5 times higher than the ULN or eGFR is lower than 40ml/min/1.73m\^2 (according to Cockcroft-Gault Equation or MDRD Equation).
* HIV-infected patients
* Left ventricular ejection fraction\<50%
* Patients with HbsAg positive are required to have HBV DNA\<1.0×10\^3 IU/ml before entering the group. In addition, if the patient is HBsAg negative but HBcAb positive (regardless of HBsAb status), HBV DNA test is also required, and HBV DNA\<1.0×10\^3 IU/ml is required before entering the group.
* Other anti-tumor treatments (lymphoma or other types of tumors) are currently in progress.
* Patients with psychiatric disorders or patients who are known or suspected to be unable to fully comply with the study protocol
* History of stroke or intracranial hemorrhage within 6 months prior to start of therapy
* Inability to swallow capsules or presence of diseases that significantly affect gastrointestinal function, such as malabsorption syndrome, post-bariatric surgery, inflammatory bowel disease and complete or incomplete intestinal obstruction
* Other medical conditions determined by the researchers that may affect the study