Clearance of alemtuzumab in selected patients treated intravenously. In patients with minimal residual disease (by flow cytometry) at the end of therapy, clearance was slow and single phase (▵). Patients who still had a small amount of CLL cells showed biphasic clearance (▿) and patients who still had bulky disease cleared the antibody rapidly (•). However, in each case the terminal half-life was roughly similar.