Inclusion Criteria:

          -  Men and women, ≥ 65 years of age.

          -  Pathologically confirmed MCL, with documentation of a chromosome translocation
             t(11;14)(q13;q32) and/or overexpression of cyclin D1 in association with other
             relevant markers (eg, CD5, CD19, CD20, PAX5) .

          -  MCL requiring treatment and for which no prior systemic anticancer therapies have been
             received.

          -  Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 2.

          -  Agreement to use highly effective forms of contraception during the study and 6 months
             after the last dose of bendamustine, or 12 months after the last dose of rituximab,
             whichever is longest .

        Exclusion Criteria:

          -  Significant cardiovascular disease such as uncontrolled or symptomatic arrhythmias,
             congestive heart failure, or myocardial infarction within 6 months of first dose of
             study drug, or any Class 3 or 4 cardiac disease as defined by the New York Heart
             Association Functional Classification, or corrected QT interval (QTc) > 480 msec
             (calculated using Friderica's formula: QT/RR0.33) at screening. Exception: Subjects
             with controlled, asymptomatic atrial fibrillation during screening are allowed to
             enroll on study.

          -  Malabsorption syndrome, disease significantly affecting gastrointestinal function,
             resection of the stomach, extensive small bowel resection that is likely to affect
             absorption, symptomatic inflammatory bowel disease, partial or complete bowel
             obstruction, or gastric restrictions and bariatric surgery, such as gastric bypass.

          -  Uncontrolled active systemic fungal, bacterial, viral, or other infection (defined as
             exhibiting ongoing signs/symptoms related to the infection and without improvement,
             despite appropriate antibiotics or other treatment), or intravenous anti infective
             treatment within 2 weeks before first dose of study drug.

          -  Concurrent participation in another therapeutic clinical trial.