Compare the efficacy and safety of Orelabrutinib plus bendamustine+ rituximab versus bendamustine + rituximab in previously untreated patients with mantle cell lymphoma (MCL)

Inclusion Criteria:

1. Subjects ≥ 65 of age, or ≥ 60 and < 65 years old who are ineligible for stem cell transplant or have refused stem cell transplantation due to reason(s) including: Have not received prior systemic therapies for MCL.
2. Modified Ann Arbor stage II-IV. Patients with stage II require systemic treatment to be eligible, at the discretion of the investigator.
3. Histopathological confirmed MCL, expression of Cyclin D1 and/or t (11; 14) chromosomal translocation. Either fresh tissue or FFPE for diagnosis must be sent to central lab for final confirmation after randomization.
4. At least one measurable site of disease (the longest axis of the lymph node lesion is > 1.5 cm, or the longest diameter of the extranodal lesion is > 1.0 cm).
5. ECOG PS score of 0 to 2.

Exclusion Criteria:

1. Existing or prior history of other malignant tumor and no evidence of recurrence and metastasis within 2 years before screening.
2. Subjects with evident gastrointestinal dysfunction that may affect drug intake, transport or absorption, or subjects who have undergone total gastrectomy.
3. Subjects for whom the goal of therapy is tumor debulking prior to stem cell transplant.
4. Use of strong inhibitors or strong inducers of cytochrome P450 3A within 14 days or 5 half-lives, whichever is longer, before the first dose of study treatment; or plan to use strong inhibitors or strong inducers of CYP3A during the study.
5. Known central nervous system lymphoma.