CD22 and acute lymphoblastic leukemia: Inotuzumab ozogamicin (42) is an anti-CD22 monoclonal antibody linked to a calicheamicin derivative (N-acetyl gamma-calicheamicin-dimethyl hydrazide), which received FDA approval in 2017 for treatment of relapsed or refractory CD22+ acute lymphoblastic leukemia after a Phase III clinical trial, although severe side effects were observed (Figure 13) [114].