A Phase II Study of Oral Panobinostat (LBH589) and Rituximab to Treat Diffuse Large B Cell Lymphoma (DLBCL)

This is a randomized Phase II, multi-center study of LBH589 given alone (Arm A) or in combination with rituximab (Arm B). The objectives of this study are: * To investigate the efficacy of LBH589 alone and in addition to rituximab in patients with relapsed or refractory DLBCL. * To investigate the safety and tolerability of single agent LBH589 therapy and combination therapy of LBH589 with rituximab. * To identify potential biological factors that might correlate with efficacy. LBH589 will be given at a dose of 30mg orally every Monday, Wednesday and Friday, as in other studies of this agent. Rituximab will be given as a single 375mg/m2 dose intravenously on day 1 of each cycle. Treatment may be administered up to 6 cycles. Treatment beyond 6 cycles will be discussed with the Sponsor. Each cycle will last 21 days. A Phase I, dose-escalation component to the study, to determine the recommended phase II dose of rituximab in combination with LBH589, is not considered necessary as the respective toxicity profiles of these two drugs do not predict for overlapping toxicity. Dose de-escalation of LBH589 will be performed for toxicity. No dose escalations will be permitted. If patients experience grade 2 or more toxicity not returning to grade \< 1 within 4 weeks after stopping therapy, they will not be allowed to continue on therapy. If more than two dose interruptions are required for toxicity, this will also be a reason to be removed from the study. An interim analysis for safety and futility will be performed after a total of 10 patients in each arm have been enrolled.