Signed IRB-approved informed consent.

Greater than 18 years of age

Proof of CD23+ CLL or small lymphocytic lymphoma (SLL)

Progressive disease after at least 1 course of chemotherapy

Acceptable hematologic status, liver function, renal function, and pulmonary function

Patients of reproductive potential must agree to follow accepted birth control methods during treatment and for 3 months after completion of treatment

Safety and Efficacy of IDEC-152 in the Treatment of Chronic Lymphocytic Leukemia (CLL)

What this study is about