CASCADE: A phase 3, randomized, double-blind study of vadastuximab talirine (33A) versus placebo in combination with azacitidine or decitabine in the treatment of older patients with newly diagnosed acute myeloid leukemia (AML).

TPS7066Background: AML is associated with poor survival rates in patients (pts) who are not eligible for intensive chemotherapy or allogeneic stem cell transplant (allo-SCT) due to advanced age, comorbidities, and/or disease risk factors. Non-intensive therapies, such as the hypomethylating agents (HMAs) azacitidine and decitabine, are frequently employed in this setting; however, response rates and survival remain suboptimal in this pt population. Vadastuximab talirine (33A) is a CD33-directed antibody conjugated to pyrrolobenzodiazepine (PBD) dimers. Upon binding, 33A is internalized and transported to the lysosomes where PBD is released via proteolytic cleavage of the linker, leading to DNA crosslinking and cell death. In preclinical studies, HMA priming followed by 33A exposure upregulated CD33 expression, increased DNA incorporation of the PBD dimer, and enhanced cytotoxicity. In a phase 1 study, 33A plus HMA was generally well tolerated without a significant pattern of off-target toxicity. Activity ...