Treatment-resistant acute myeloid leukemia represents one of oncology's most stubborn challenges, with patients exhausting conventional therapies often facing grim prognoses. This breakthrough suggests that precision immunotherapy could finally crack this therapeutic barrier, potentially extending survival for thousands facing relapsed blood cancers.
Researchers engineered CAR T cells with three key modifications: targeting the CD371 protein abundant on leukemia cells, incorporating a modified CD28 domain to prevent premature cellular exhaustion, and programming continuous interleukin-18 secretion to amplify immune responses. In a phase 1 trial, five patients with extensively pretreated leukemia received these modified cells. Three patients who had failed at least five previous treatment lines achieved complete disease clearance after a single low-dose infusion of 30,000 CAR T cells per kilogram body weight.
This represents a paradigm shift in CAR T cell engineering for blood cancers beyond lymphomas. Previous attempts at treating acute myeloid leukemia with cellular therapy have struggled with limited expansion and durability. The interleukin-18 modification appears to solve both problems by maintaining CAR T cell function while simultaneously activating natural killer cells and broader immune responses. The researchers observed predominantly cytotoxic CD8+ T cells persisting weeks after treatment, suggesting sustained anti-cancer activity. However, higher doses triggered severe side effects including prolonged blood count suppression and cytokine storms, emphasizing that therapeutic windows remain narrow. While promising, this represents early-phase data from just five patients, requiring validation in larger cohorts to establish whether this approach can consistently overcome treatment resistance in this notoriously difficult malignancy.