LFB-R603 Dose Finding in Patients With Advanced Stage B-Chronic Lymphocytic Leukemia

Inclusion Criteria: * Signed informed consent * Relapsed or refractory B-CLL after at least one prior course of therapy with fludarabine * Circulating lymphocytes expressing CD20 * Peripheral blood lymphocyte count \> 5,000/µL * ECOG performance status ≤ 2 * Life expectancy ≥ 3 months * Negative blood pregnancy test before inclusion for women of childbearing potential * Medically acceptable method of birth control throughout the study for women of childbearing potential * Being considered as reliable and capable of adhering to the protocol and compliant with study procedures * Covered by healthcare insurance Exclusion Criteria: * Transformation of CLL into a high grade lymphoma * Allogeneic stem cell transplantation \< 6 months before enrolment * Prior treatment with anti-CD20 monoclonal antibodies \< 6 months before enrolment * Prior treatment with alemtuzumab \< 2 months before enrolment * Treatment with any IMP or participation in a clinical study within 30 days prior to enrolment * Known severe anaphylactic or other hypersensitivity reactions secondary to a prior exposure to murine antibodies or to any component of LFB-R603 * Patient with prior treatment or concomitant medication that may interfere with the interpretation of the study data * Patient with a concomitant malignancy other than basal cell carcinoma of the skin, or in situ carcinoma of the cervix or the breast * Patient with serious non-malignant disease, active infection requiring systemic antibiotic, antifungal or antiviral drug or physical examination or laboratory abnormalities, that would compromise protocol objectives * Positive serology to HIV, HCV or presence of HBs Ag * Creatinine clearance, calculated according to Cockroft -Gault formula \< 60 mL/min * ALT and /or AST level \> 1.5 times the upper limit of normal * Pregnancy or breastfeeding