Autologous bone marrow transplantation for acute myeloid leukemia following in vitro treatment with neuraminidase and monoclonal antibodies

Although monoclonal antibodies (MoAbs) to CD15, especially PM-81, react with leukemic blasts from the majority of patients with acute myeloid leukemia (AML), a small subset of patients have cells that are CD15 negative or dim. We determined previously that neuraminidase will increase the reactivity of PM-81 with AML blasts, as well as blasts from many patients with acute lymphoblastic leukemia (ALL). In this report, we describe the laboratory results and clinical course of the first patient with AML whose harvested bone marrow was treated with neuraminidase prior to MoAbs and complement treatment. Neuraminidase increased the percentage of the patient's leukemia cells that reacted with PM-81 from 18% to 90% and more than doubled the percentage of AML blasts that were lysed by PM-81 and complement. The patient suffered no acute toxicity, engrafted rapidly, and was transfusion independent by day 21 post-ABMT. This report demonstrates the probable safety and efficacy of pretreatment of bone marrow with neuraminidase, and increases the number of patients with AML or ALL who may benefit from ABMT using marrow purging with MoAb to CD15.