Key Inclusion Criteria:

        Up to 5 prior regimens for MCL. Prior therapy must have included:

          -  Anthracycline or bendamustine-containing chemotherapy and

          -  Anti-CD20 monoclonal antibody therapy and

          -  Ibrutinib or acalabrutinib

        At least 1 measurable lesion

        Platelet count ≥ 75,000/uL

        Creatinine clearance (as estimated by Cockcroft Gault) > or = to 60 mL/min

        Cardiac ejection fraction ≥ 50%, no evidence of pericardial effusion as determined by an
        echocardiogram (ECHO), and no clinically significant electrocardiogram (ECG) findings

        Baseline oxygen saturation >92% on room air.

        Key Exclusion Criteria:

          -  Known history of infection with human immunodeficiency virus (HIV) or hepatitis B
             (HBsAG positive) or hepatitis C virus (anti-HCV positive). A history of hepatitis B or
             hepatitis C is permitted if the viral load is undetectable per standard serological
             and genetic testing

          -  History of a seizure disorder, cerebrovascular ischemia/hemorrhage, dementia,
             cerebellar disease, cerebral edema, posterior reversible encephalopathy syndrome, or
             any autoimmune disease with central nervous system (CNS) involvement

          -  Presence of fungal, bacterial, viral, or other infection that is uncontrolled or
             requiring IV antimicrobials for management.

        Note: Other protocol defined Inclusion/Exclusion criteria may apply.