TAK-901 is an investigational anti-cancer agent that functions as a selective inhibitor of the mitotic kinesin Eg5 (kinesin spindle protein), which plays a critical role in cell division by facilitating the formation of the bipolar spindle during mitosis. By inhibiting Eg5, TAK-901 disrupts proper spindle assembly, leading to cell cycle arrest and ultimately inducing apoptosis in rapidly dividing cancer cells. The compound has been evaluated in clinical trials for its potential in treating solid tumors, particularly in patients who have not responded to conventional chemotherapy. Its mechanism offers a targeted approach to halt tumor growth with a different mode of action compared to microtubule-targeting agents like taxanes or vinca alkaloids, potentially overcoming resistance to those therapies. Research has focused on determining optimal dosing, safety profile, and efficacy in various advanced malignancies. While development has faced challenges due to toxicity and narrow therapeutic window in some studies, TAK-901 contributes valuable insights into kinesin inhibitors as a class of anti-mitotic drugs in oncology drug development.