| Inclusion Criteria: | 1) Male or female patient age >/= 18 and </= 80 years at the time of study entry
2) Signed informed consent
3) Females of child bearing potential must agree to abstain from sexual activity or to use a medically approved contraceptive measure/regimen during and for 3 months after the treatment period or be surgically sterile. Women of child bearing potential must have a negative serum pregnancy test at the time of enrollment. Acceptable methods of birth control include oral contraceptive, intrauterine device (IUD), transdermal/implanted or injected contraceptives and abstinence
4) (Continued from Inclusion 3 above). Males must agree to abstain from sexual activity or agree to utilize a medically approved contraception method during treatment and for 3 months after the treatment period or be surgically sterile.
5) Diagnosis of CLL or SLL, relapsed from at least one prior therapy, satisfying at least one of the following: * Progressive splenomegaly and/or lymphadenopathy by physical examination or radiology *Anemia (hemoglobin <11 g/dL) or thrombocytopenia (platelet count <100 × 10^9/L) due to bone marrow involvement * Presence of unintentional weight loss > 10% over preceding 6 months * NCI CTCAE grade 2 or 3 fatigue * Fevers >100.5°F or night sweats for >2 weeks w/out evidence of infection * Progressive lymphocytosis w/ increase of > 50% over 2 month period or anticipated doubling time of <6 months
6) CLL/SLL cells expressing CD20 documented during screening
7) Eastern Cooperative Oncology Group (ECOG) performance status of </=2
8) Life expectancy of at least 12 weeks
9) Serum creatinine </=2.0 mg/dL
10) Total bilirubin </= 2.0 mg/dL
11) Alanine aminotransaminase (ALT) and aspartate aminotransaminase (AST) </=2 × upper limit of normal (ULN); for patients with liver involvement of CLL/SLL disease, this limit is increased to</=5 × ULN
12) At the time of enrollment, patients must be >4 weeks since major surgery, radiotherapy, chemotherapy (>6 weeks if they were treated with a nitrosourea, mitomycin, or monoclonal antibodies such as bevacizumab), immunotherapy, biotherapy/targeted or investigational therapies and recovered from the toxicity of prior treatment to </= grade 1, exclusive of alopecia. For patients who received long-acting agents, a treatment-free interval of 2 half-lives should be considered. Steroid therapy for control of disease is permitted up to time of enrollment. |