CPI-169 is primarily used in research settings as a potent and selective inhibitor of the menin-MLL (mixed lineage leukemia) protein-protein interaction. This interaction plays a critical role in the development and progression of certain types of leukemia, particularly MLL-rearranged (MLL-r) leukemias. By disrupting this interaction, CPI-169 has shown promise in suppressing the growth of leukemia cells in preclinical models. It is commonly applied in studies aimed at understanding the molecular mechanisms of MLL-fusion-driven leukemogenesis. Researchers use CPI-169 to evaluate the therapeutic potential of targeting the menin-MLL interface, making it a valuable tool compound in oncology drug discovery. Its high selectivity and cellular activity support its use in in vitro and in vivo experiments to assess anti-leukemic effects, often in combination with other targeted agents. Due to its ability to induce differentiation and apoptosis in leukemia cell lines, CPI-169 is also used to explore epigenetic regulation in cancer. While still in the investigational stage, it serves as a lead candidate for the development of novel therapies for acute leukemias with MLL rearrangements.