In the dose expansion cohort: Patients with relapsed/refractory DLBCL (ABC subtype) histo-pathologically confirmed by gene expression profiling (GEP) tested at a central laboratory or MCL with documented overexpression of either cyclin D1 or t(11;14), with at least 1, but not more than 3 prior lines of therapy, and measurable disease according to the Cheson criteria 2007.