A drug used with bortezomib and dexamethasone to treat multiple myeloma. It is used in patients who have already been treated with bortezomib and an immunomodulating agent. It is also being studied in the treatment of other types of cancer. LBH589 blocks certain enzymes needed for cells to grow and divide and may kill cancer cells. It may also prevent the growth of new blood vessels that tumors need to grow. It is a type of histone deacetylase inhibitor and a type of antiangiogenesis agent.