Rituximab, Venetoclax, and Bortezomib for the Treatment of Relapsed or Refractory Diffuse Large B-Cell Lymphoma

Inclusion Criteria: * Relapsed/refractory DLBCL defined as any of the following: * Confirmed DLBCL/Burkitt lymphoma (BL)/B-cell lymphoma, unclassifiable (BCLU) by World Health Organization (WHO) 2016 classification * Double hit lymphoma (DHL) phenotype as confirmed by FISH (fluorescent in-situ hybridization) or IHC (immunohistochemistry) * Relapsed or progression of disease after at least one prior line of standard rituximab-cyclophosphamide-hydroxydaunorubicin-oncovin-prednisone (R-CHOP), rituximab-etoposide-prednisone-oncovin-cyclophosphamide-hydroxydaunorubicin (R-EPOCH) or other R-CHOP-like therapy * Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 * No prior treatment with a proteasome inhibitor or prior BCL2 inhibitor * No cytotoxic chemotherapy within 2 weeks prior to study treatment * Patients who are not candidates for salvage stem cell transplant or patients who are not candidates for CAR-T (chimeric antigen receptor T-cell) therapy, patients who have progressed or relapsed after a salvage transplant or CAR-T therapy are eligible * Patients must give informed consent * Prior radiation therapy allowed to \< 25% of the bone marrow and patients must have recovered from the toxic effects of the treatment prior to study enrollment (except for alopecia). Patients treated with standard postoperative adjuvant radiation therapy for other cancers are allowed. Prior radiotherapy must be completed 14 days before study entry. Lesions that have been radia…