CLL is an incurable disease with conventional chemotherapy. In the absence of TP53 disruption, a chemoimmunotherapy (CIT) regimen is recommended as front-line and second-line treatment in those patients who attained a long progression-free survival (PFS) with the previous regimen. Bendamustine and rituximab (BR) is one of the most widely adopted CIT regimens, including second-line treatment. Unfortunately, durations of remission following BR combination therapy tend to be short in patients with heavily pre-treated disease or who have already received rituximab. The incorporation of a maintenance following induction chemotherapy to overcome the shorter remission durations in this population is a reasonable option.

Inclusion Criteria:

• Confirmed diagnosis of CD20-positive CLL that meets the iwCLL criteria (Hallek et al, 2008).
• Relapsed or refractory status of disease after at least one prior chemotherapy regimen.
• ECOG performance status of 0-2 at study entry
• Patients have not received prior therapy with bendamustine
• Prior therapy with rituximab is permitted, even in the setting of rituximab refractory disease.

For inclusion in the research part of maintenance therapy (phase B):

• At least a partial response (PR or better; Hallek et al, 2008) must be achieved after induction of BR (phase A)

Exclusion Criteria:

• Any serious medical condition, laboratory abnormality, or psychiatric illness that would prevent the subject from signing the informed consent document or complying with the protocol treatment.
• Pregnant or breast-feeding females.
• Known to be positive for human immunodeficiency virus (HIV) or infectious hepatitis (type B or C).
• Patients are not eligible if there is a prior history or current evidence of central nervous system or leptomeningeal involvement.
• Richter syndrome or chronic prolymphocytic leukemia.
• Uncontrolled autoimmune hemolytic anemia or thrombocytopenia.
• Concurrent use of other anti-cancer agents or treatments.
• Laboratory test results within these ranges: ANC ≤ 1000/μL, Platelet count ≤ 75,000/μL.
• Total bilirubin Total bilirubin ≥ 2X upper limit laboratory normal (ULN). Patients with non-clinically significant elevations of bilirubin due to Gilbert's disease are not required to meet these criteria.
• Serum transaminases AST (SGOT) and ALT (SGPT) ≥ 3 x ULN, and/or serum alkaline phosphatase ≥ 5 X ULN.
• New York Heart Association class 3-4 heart failure.

Patients with relapsed or refractory CLL receiving treatment at the University Hematology Hospital and Ambulant clinic.