KDU691 is primarily used in research settings as a potent and selective inhibitor of the enzyme dihydroorotate dehydrogenase (DHODH). This inhibition plays a critical role in blocking the de novo pyrimidine biosynthesis pathway, which is essential for DNA and RNA synthesis in rapidly dividing cells. Due to this mechanism, KDU691 has gained attention for its potential therapeutic applications in oncology, particularly in the treatment of acute myeloid leukemia (AML) and other hematological malignancies. It demonstrates strong anti-proliferative effects in cancer cell lines by inducing cell cycle arrest and apoptosis. In addition to its anticancer properties, KDU691 is being explored for antiviral applications. Studies suggest it can inhibit the replication of certain RNA viruses by depriving them of nucleotide precursors needed for viral genome synthesis. Its broad-spectrum activity has been observed in models of flavivirus infections, including dengue and Zika virus. KDU691 is also valued in immunology research for its immunomodulatory effects, as DHODH inhibition can suppress activated T-cell proliferation, indicating potential in autoimmune disease models. Its high selectivity and favorable pharmacokinetic profile make it a useful tool compound in preclinical drug development.