Study of Cytokine Release Syndrome Prophylaxis and Treatment With Siltuximab Prior to Epcoritamab

Inclusion Criteria: * Adults 18 years of age and older * Diagnosis of non-Hodgkin lymphoma. * DLBCL (including high grade B cell lymphoma and follicular lymphoma grade 3B and transformed follicular lymphoma) treated with at least 2 lines of systemic antineoplastic therapies, including at least 1 anti-CD20 monoclonal antibody - containing therapy * FL grade 1-3A previously treated with at least 2 lines of systemic antineoplastic therapy, including at least 1 anti-CD20 monoclonal antibody - containing therapy. * At least 1 risk factor for cytokine release syndrome, including: * Age ≥ 65 years, * Elevated lactate dehydrogenase, * White blood cell count pre-anti-CD20 treatment \> 4.5x109 cells/L, * Ann Arbor Stage III/IV, * Sum of the product of the perpendicular diameters at study entry ≥3000mm2, * Cardiac comorbidity, including prior coronary disease, heart failure and other conditions that in the opinion of the investigator would increase the risk of heightened toxicity from CRS * Bone marrow infiltration, * Circulating lymphoma cells in peripheral blood * Adequate bone marrow function including: * Hemoglobin ≥ 8g/dL (unless bone marrow involvement by lymphoma) (transfusion allowed for symptomatic participants), * Absolute neutrophil count cell count ≥1000 / μL, with or without growth factor support * Platelet counts ≥ 75,000 / μL (unless bone marrow involvement by lymphoma, in which case platelet counts ≥ 50,000 / µL are required) * ECOG performa…