Mylotarg is directed against the CD33 antigen expressed by hematopoietic cells. Binding of the anti-CD33 antibody portion of Mylotarg with the CD33 antigen results in the formation of a complex that is internalized. Upon internalization, the calicheamicin derivative is released inside the lysosomes of the myeloid cell. The released calicheamicin derivative binds to DNA in the minor groove resulting in DNA double strand breaks and cell death.
Used for the treatment of acute myeloid leukemia (AML), mylotarg binds to the CD33 antigen, which is expressed on the surface of leukemic cells in more than 80% of patients with AML. The CD33 antigen is not expressed on pluripotent hematopoietic stem cells or nonhematopoietic cells. This gives mylotarg the selectivity needed to target leukemic cells.
Most likely removed by opsonization via the reticuloendothelial system.
The most frequently reported toxicities are myelosuppression and hepatic veno-occlusive disorder.