Here we report the development and
preclinical characterization of a novel CD123 - targeting ADC, IMGN632, which utilizes a highly potent DNA - alkylating payload, resulting in an ADC with
robust preclinical activity in multiple
models of AML.
However, ADCs that use derivatives of calicheamicin, which promotes double - stranded DNA breaks, such as GO and inotuzumab ozogamicin, 40,41 have limited activity in cells with high multidrug resistance protein activity, a phenotype found in a significant fraction of AML patients.42 Another ADC, SGN - CD123A, comprising an engineered form of the CD123 - targeting 7G3 antibody conjugated to a synthetic pyrrolobenzodiazepine dimer, which acts via DNA crosslinking, has entered clinical trials after showing
robust activity in
preclinical models of AML, including those with multidrug resistance.33