Informed consent was obtained from eligible adult patients (≥ 18 years) with relapsed or refractory CD33+ acute myeloid leukemia (AML)...These preliminary findings demonstrate initial antileukemia activity with IMGN779, a next-generation anti-CD33 ADC, in relapsed or refractory adult AML, with a toxicity profile consisting of isolated events most consistent with underlying disease and/or comorbidity.

IMGN779 was highly active against patient-derived AML cells, including those with adverse molecular abnormalities, and sensitivity correlated to CD33 expression levels. In vivo, IMGN779 displayed robust antitumor efficacy in multiple AML xenograft and disseminated disease models, as evidenced by durable tumor regressions and prolonged survival. Taken together, these findings identify IMGN779 as a promising new candidate for evaluation as a novel therapeutic in AML.