Inclusion Criteria:

- histopathologically confirmed diagnosis of typical or atypical mantle cell lymphoma,
except for blastoid type.

- documented relapsed/refractory mantle cell lymphoma.

- CD20 positive B cells in the lymph node biopsy or other lymphoma pathology specimen.

- adequate hematologic function according to specific trial parameters.

- bidimensionally measurable disease with at least 1 lesion measuring 2.0 cm or more in
a single dimension, or the patient is in the leukemic phase of the disease.

- patient has Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or
2.

- patient has an estimated life expectancy of at least 3 months.

- women of childbearing potential (not surgically sterile or 2 years postmenopausal)
must use a medically accepted method of contraception and must agree to continue use
of this method for the duration of the study and for 30 days after participation in
the study.

- men not surgically sterile or who are capable of producing offspring must practice
abstinence or use a barrier method of birth control, and must agree to continue use
of this method for the duration of study drug treatment and for 30 days after
participation in the treatment period.

Exclusion Criteria:

- has received more than 3 previous standard chemotherapy regimens.

- has the blastoid subtype of mantle cell lymphoma.

- documented history of central nervous system (CNS) lymphomatous involvement.

- a history of previous high-dose chemotherapy with allogeneic stem cell
transplantation (history of autologous stem cell transplantation is allowed).

- previous treatment with bendamustine.

- has an active malignancy other than MCL, or has had a malignancy other than MCL
within the past 3 years, except for controlled prostate cancer without evidence of
bone metastases, localized bladder cancer, cervical carcinoma in situ, breast cancer
in situ, or non-melanoma skin cancer.

- has New York Heart Association (NYHA) Class III or IV heart failure, arrhythmias or
unstable angina, electrocardiographic evidence of active ischemia or active
conduction system abnormalities, or myocardial infarction within the last 6 months.

- has serum creatinine of more than 2.0 mg/dL or creatinine clearance of less than 30
mL/min based on the Cockcroft-Gault method or from a 24-hour urine collection.

- does not have adequate hepatic organ function as evidenced by specific trial
parameters.

- has known human immunodeficiency virus (HIV) infection.

- has active hepatitis B infection. Hepatitis B surface antigen must be tested.

- a pregnant or lactating woman. (Any women becoming pregnant during the study will be
withdrawn from the study.)

- has received corticosteroids within 28 days of study entry unless chronically
administered (prednisone ≤20 mg/day) for indications other than lymphoma or
lymphoma-related complications.

- any serious uncontrolled, medical or psychological disorder that would impair the
ability of the patient to participate in or complete this study.

- any condition which places the patient at unacceptable risk or confounds the ability
of the investigators to interpret study data.

- patient has received other investigational agent(s) within 28 days of study entry.

- patient has received chemotherapy within the prior 28 days.

- patient has a known hypersensitivity to bendamustine, mannitol, or rituximab.