• Histologically confirmed diagnosis of mantle cell lymphoma, with review of the diagnostic pathology specimen at one of the participating institutions. Whenever possible, the Ki67 fraction should be reported or evaluated, cytogenetics should be performed, and TP53 status should be assessed (preferably by next-generation sequencing; immunohistochemical staining would be next-preferred).

• No prior anti-lymphoma therapy, with the following exceptions:

‣ Prior radiotherapy for localized disease is permitted.

⁃ A course of radiotherapy for urgent symptomatic disease is also permitted. Short-course systemic corticosteroids is permissible for disease control (must be \< 7 days and ≤ 100mg/day of prednisone or ≤ 20mg/day of dexamethasone, or equivalent). Steroids must be discontinued prior to study treatment.

• Measurable disease, defined as ≥1 measurable nodal lesion (long axis \>1.5 cm or short axis \>1.0 cm) or ≥1 measurable extra-nodal lesion (long axis \>1.0 cm) on PET, CT, or magnetic resonance imaging (MRI). Disease should be FDG-avid based on PET.

• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2. (Appendix A)

• Age ≥18 years and considered a candidate for high-dose cytarabine by the treating physician.

• Adequate hematologic and organ function defined as:

‣ Absolute neutrophil count ≥ 1.0 x109/L, or ≥ 0.5 x109/L if bone marrow involvement (use of growth factor support allowed).

⁃ Hemoglobin ≥ 8 g/dL and independent of transfusion within 7 days of screening.

⁃ Platelets ≥ 100 x109/L, or ≥ 50 x109/L if bone marrow involvement, and independent of transfusion within 7 days of screening.

⁃ Estimated CrCl ≥ 30mL/min (by Cockcroft-Gault formula or by 24-hour urine collection).

⁃ AST/ALT \< 2.5 X institutional upper limit of normal (ULN), or \< 5.0 X institutional ULN if documented liver involvement of lymphoma.

⁃ Total bilirubin \< 2.0 X ULN (unless active hemolysis); for subjects with Gilbert's Syndrome, direct bilirubin \< 1.5 X ULN.

• Patients with known infection with human immunodeficiency virus (HIV) are eligible, provided all 3 of the following are true: 1) presence of controlled disease, defined as CD4 count ≥ 200/uL and an undetectable viral load, 2) disease control has been stable on anti-retroviral therapy for at least 6 months prior to study enrollment, and 3) there are no prohibitive drug-drug interactions between study drugs and the necessary anti- retroviral therapies.

• Willingness to provide a pre-treatment tumor sample by core needle or excisional surgical biopsy. A fresh biopsy is strongly encouraged, but an archival sample is acceptable if it is collected within 90 days and without intervening treatment and the following provisions are met: 1) availability of a tumor-containing formalin-fixed, paraffin-embedded (FFPE) tissue block, 2) if the tumor containing FFPE tissue block cannot be provided in total, sections from this block should be provided that are freshly cut and mounted on positively-charged glass slides. Preferably, 25 slides should be provided; if not possible, a minimum of 15 slides is required. Exceptions to this criterion may be made with approval of the Sponsor-Investigator.

• Willingness to remain abstinent or to use two effective contraceptive methods that result in a failure rate of \<1% per year from screening until at least:

‣ 6 months after the last dose of bendamustine,

⁃ 6 months after the last dose of cytarabine,

⁃ 90 days after the last dose of zanubrutinib,

⁃ 90 days after the last dose of sonrotoclax, and/or

⁃ 12 months after the last dose of rituximab, whichever of the above is longest. Examples of contraceptive methods with a failure rate of \<1% per year include:

• Tubal ligation, male sterilization, hormonal implants, established proper use of hormonal contraceptives that inhibit ovulation, hormone-releasing intrauterine devices, and copper intrauterine devices.

∙ Alternatively, two methods (e.g., two barrier methods such as a condom and a cervical cap) may be combined to achieve a failure rate of \<1% per year. Barrier methods must always be supplemented with the use of a spermicide.

∙ True abstinence is acceptable when this is in line with the preferred and usual lifestyle of the subject. In contrast, periodic abstinence (eg, calendar, ovulation, symptothermal, post-ovulation methods) and withdrawal are not acceptable methods of contraception.

• Ability to understand and the willingness to sign a written informed consent document.