In the dose-finding part of a phase 1/2 study promoted by the Innovative Therapies for Children With Cancer in Europe (ITCC) consortium, inotuzumab ozogamicin (InO), an antibody–drug conjugate composed of a CD22-directed monoclonal antibody linked to calicheamicin, was able induce a CR/CRi (CR with incomplete hematologic recovery) in 80% of children with relapsed and refractory B-ALL. The gene discussed is CD22; the disease is acute lymphoblastic leukemia.