|Inclusion Criteria:||1) Male or female >/= 18 years of age|
2) Diagnosis of B-cell CLL, with diagnosis established according to International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria and documented within medical records
3) CLL that warrants treatment (consistent with accepted IWCLL criteria for initiation of therapy). Any of the following conditions constitute CLL that warrants treatment: a) Evidence of progressive marrow failure as manifested by the onset or worsening of anemia and/or thrombocytopenia b) Massive (ie, lower edge of spleen >/=6 cm below the left costal margin), progressive, or symptomatic splenomegaly, or c) Massive (ie, >/=10 cm in the longest diameter), progressive, or symptomatic lymphadenopathy, or d) Progressive lymphocytosis in the absence of infection, with an increase in blood absolute lymphocyte count (ALC) >/=50% over a 2-month period or lymphocyte doubling time of <6 months (as long as initial ALC was >/=30,000/L), or e) Autoimmune anemia and/or thrombocytopenia that is poorly responsive to corticosteroids or other standard therapy, or
4) (Continued) f) Constitutional symptoms, defined as any one or more of the following disease-related symptoms or signs occurring in the absence of evidence of infection: i) Unintentional weight loss of >/=10% within the previous 6 months, or ii) Significant fatigue (>/=Grade 2), or iii) Fevers >100.5°F or 38.0°C for >/=2 weeks, or iv) Night sweats for >1 month.
5) Presence of measurable lymphadenopathy (defined as the presence of >/=1 nodal lesion that measures >/=2.0 cm in the longest dimension and >/=1.0 cm in the longest perpendicular dimension as assessed by computed tomography or magnetic resonance imaging
6) Prior treatment for CLL comprising: a) >/=2 cycles of a regimen containing a purine analog (eg, fludarabine, pentostatin, cladribine) or bendamustine, and b) >/=2 doses with a regimen containing an anti-CD20 monoclonal antibody (eg, rituximab, ofatumumab, GA-101). Note: Prior cytotoxic drugs or anti-CD20 antibodies may have been administered as single agents or as components of combination therapies. Subjects may also have received other commercially available therapies (eg, alemtuzumab, lenalidomide, corticosteroids, or others) or non-excluded investigational therapies. Each repeated but separated therapeutic application of the same single-agent or combination is considered an independent regimen.
7) Documentation of CLL progression <36 months since the completion of the last prior therapy for CLL.
8) Discontinuation of all therapy (including radiotherapy, chemotherapy, immunotherapy, systemic corticosteroids, or investigational therapy) for the treatment of CLL >/=3 weeks before randomization.
9) All acute toxic effects of any prior antitumor therapy resolved to Grade </=1 before randomization (with the exception of alopecia (Grade 1 or 2 permitted), neurotoxicity (Grade 1 or 2 permitted), or bone marrow parameters (Grades 1 or 2 permitted).
10) Karnofsky performance score of >/=60.
11) Required baseline laboratory data (within 4 weeks prior to randomization). Note: Confirmation should be considered for out-of range values to determine if the abnormality is real or artifactual. Values should be obtained within the screening period and should generally be the most recent measurement obtained. CLL peripheral blood or bone marrow evaluations within 12 weeks (FISH, DNA mutational analysis, flow cytometry, and cytology).
12) For female subjects of childbearing potential, willingness to abstain from heterosexual intercourse or use a protocol-recommended method of contraception from the screening visit (Visit 1) throughout the study treatment period and for 30 days following the last doe of study drug. Note: A female subject is considered to be of childbearing potential unless she has had a hysterectomy, bilateral tubal ligation, or bilateral oophorectomy; has medically documented ovarian failure (with serum estradiol and follicle-stimulating hormone (FSH) levels within the institutional postmenopausal range and a negative serum or urine BHCG); or is menopausal (age greater than or equal to 55 years with amenorrhea for greater than or equal to 6 months).
13) For male subjects of childbearing potential having intercourse with females of childbearing potential, willingness to abstain from heterosexual intercourse or use a protocol-recommended method of contraception from the randomization visit (Visit 2) throughout the study treatment period and for 90 days following the last dose of study drug and to refrain from sperm donation from randomization (Visit 2) throughout the study treatment period and for 90 days following the last dose of study drug. Note: A male subject is considered able to father a child unless he has had a bilateral vasectomy with documented aspermia or a bilateral orchiectomy, or has ongoing testicular suppression with a depot luteinizing hormone-releasing hormone (LH-RH) agonist (eg, goserelin acetate (Zoladex), leuprolide acetate (Lupron), or triptorelin pamoate (Trelstar).
14) In the judgment of the investigator, participation in the protocol offers an acceptable benefit-to-risk ratio when considering current CLL disease status, prior treatment history, medical condition, and the potential benefits and risks of alternative treatments for CLL. Note: Investigators should consider whether a study subject is an appropriate candidate for bendamustine-containing therapy based on the number and severity of comorbid conditions; subjects with a baseline Cumulative Illness Rating Scale (CIRS) score of </=6 may be particularly appropriate candidates for this trial.
15) Willingness and ability to comply with scheduled visits, drug administration plan, imaging studies, laboratory tests, other study procedures, and study restrictions. Note: Psychological, social, familial, or geographical factors that might preclude adequate study participation should be considered.
16) Evidence of a personally signed informed consent indicating that the subject is aware of the neoplastic nature of the disease and has been informed of the procedures to be followed, the experimental nature of the therapy, alternatives, potential benefits, possible side effects, potential risks and discomforts, and other pertinent aspects of study participation.