Panobinostat is an inhibitor of histone deacetylase (HDAC), thus preventing the deacetylation of histone and non-histone proteins, which are involved in switching the activity of genes on and off within cells. Overexpression of HDACs in multiple myeloma cells can cause a closed chromatin structure, in turn decreasing the expression of key tumor suppressor genes. Therefore, panobinostat works to promote an open chromatin structure and damages DNA, which in turn drives the expression of critical genes that suppress growth and division of cancer cells. This prevents cancer cells from dividing and activates apoptosis. Its use as a multiple myeloma treatment is synergistic with other therapies, such as bortezomib and dexamethasone.