Combination Study of Urelumab and Rituximab in Patients With B-cell Non-Hodgkins Lymphoma

For more information regarding BMS clinical trial participation, please visit www.BMSStudyConnect.com. Inclusion Criteria: * Clinical diagnosis of relapsed/refractory B-cell Malignancies (B-Non-Hodgkins Lymphoma (NHL)) per International Workshop Group (IWG) * Progressed or refractory to at least 1 prior line of standard therapy * Subjects in Expansion cohorts are restricted to relapsed/refractory diffuse large B-cell lymphoma (DLBCL) or Follicular Lymphoma (FL) subjects who are either relapsed or refractory to prior rituximab or ritxumab-containing chemotherapy regimens * Follicular Lymphoma (FL) must have at least 1 lesion that can be biopsied at screening and on treatment * Eastern Cooperative Oncology Group (ECOG) of 0 to 1 Exclusion Criteria: * Active or progressing brain metastases * Other concomitant malignancies (with some exceptions per protocol) * Active or history of autoimmune disease * Positive test for human immunodeficiency virus (HIV) 1\&2 or known Acquired immune deficiency syndrome (AIDS) * History of any hepatitis (A, B or C) * History of grade 3-4 drug-related hepatitis * Known current drug or alcohol abuse * Active tuberculosis (TB) * Prior therapy with any antibody/drug that targets the T cell coregulatory proteins, including but not limited to, anti-CD137, Anti Cytotoxic T lymphocyte-associated antigen 4 (anti-CTLA4) or Anti-Glucocorticoid-induced tumor necrosis factor receptor (anti-GITR). However, Anti-Programmed Death-1 (anti-PD-1), Anti-Programmed Death-Ligand1 (anti-PD-L1) are permissible as prior therapy