Aptevo Therapeutics announced that the first patient has been dosed in a Phase 1/1b clinical trial of APVO436, a novel anti-CD123 by anti-CD3 bispecific antibody based on Aptevo's Adaptir technology, which is being developed for the treatment of patients with Acute Myeloid Leukemia, or AML, and High-Grade Myelodysplastic Syndrome, or MDS. As an immunotherapy, APVO436 is designed to engage the immune system to mount a targeted response against CD123-expressing hematological tumors. Cytokine release syndrome, or CRS, is a concern with T-cell activating therapies and has been associated with severe complications in clinical trials. In preclinical studies, APVO436 induced lower levels of several key T-cell cytokines, including IFNg, IL-2, IL-6, and TNFa. Aptevo believes that the improved cytokine activation profile observed in preclinical studies of APVO436 suggest that it could offer a potential safety advantage with reduced toxicities compared to other CD123 x CD3 T-cell engagers at comparable or higher doses.
