In 2000, Mylotarg, a humanized IgG4 anti-CD33 antibody (hP67.6) conjugated to Calicheamicin via a hydrazone linker on lysine residues, was the first ADC to be approved by the FDA for the treatment of acute myeloid leukemia (AML) patients. The gene discussed is CD33; the disease is acute myeloid leukemia.