The present disclosure relates to the treatment of chronic lymphocytic leukemia. Monoclonal antibody XmAb5574 is efficacious when administered to patient at certain dosage regimens. Further disclosed are regimens including said antibody is administered at least once weekly over at least eight weeks； or/and said antibody is administered at a level that achieves a total exposure to said patient measured by area under the curve (AUG) of 14,500 ug*day/ml or more.
