(R)-Filanesib is primarily investigated for its potential in cancer therapy, particularly in the treatment of multiple myeloma. It functions as a selective inhibitor of kinesin spindle protein (KSP), which is essential for cell division. By inhibiting KSP, it disrupts the formation of the mitotic spindle, leading to cell cycle arrest and apoptosis in rapidly dividing cancer cells. Its (R)-enantiomer is specifically studied due to its enhanced potency and reduced off-target effects compared to its counterpart. Clinical trials have explored its efficacy as a monotherapy or in combination with other chemotherapeutic agents, aiming to improve outcomes for patients with relapsed or refractory multiple myeloma. Research continues to evaluate its safety profile and therapeutic potential in other malignancies.