Patients were randomly assigned ( 1:1 ) via an interactive web-based and voice response system , stratified by number of previous treatment lines and by previous use of bortezomib , to receive 21 day cycles of placebo or panobinostat ( 20 mg ; on days 1 , 3 , 5 , 8 , 10 , 12 , orally ) , both in combination with bortezomib ( 13 mg/m ( 2 ) on days 1 , 4 , 8 , 11 , intravenously ) and dexamethasone ( 20 mg on days 1 , 2 , 4 , 5 , 8 , 9 , 11 , 12 , orally ) .