Used in the treatment of multiple myeloma, particularly in patients who have received prior therapy including bortezomib and immunomodulatory drugs. It functions as a histone deacetylase (HDAC) inhibitor, helping to restore normal gene expression in cancer cells, leading to cell cycle arrest and apoptosis. Often administered in combination with other agents like bortezomib and dexamethasone to enhance efficacy. Its application is primarily in relapsed or refractory cases where other treatments have failed.