CD33 and acute lymphoblastic leukemia: Similarly, gemtuzumab ozogamicin and inotuzumab ozogamicin, antibodies respectively targeting CD33 and CD22 that are each conjugated to the payload ozogamicin (an antitumor, antibiotic calicheamicin derivative), have shown efficacy in pediatric acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL), respectively (Aplenc et al. 2008, Bhojwani et al. 2018, de Vries et al. 2012, Gamis et al. 2014, Guest et al. 2017, Rytting et al. 2014, Tarlock et al. 2016).