Subcutaneous Epcoritamab With or Without Lenalidomide as First Line Therapy for Diffuse Large B-Cell Lymphoma (EPCORE DLBCL-3)

Inclusion Criteria: Must have newly diagnosed CD20+ large cell lymphoma. Is ineligible for anthracycline-based therapy/cytotoxic chemotherapy due to: Being age ≥80 years; AND/OR Being age ≥75 years and having important comorbid condition(s), which are likely to have a negative impact on tolerability of anthracycline-based therapy/cytotoxic chemotherapy. Have Immune Effector Cell-Associated Encephalopathy (ICE) score of at least 8 out of 10. Have Ann Arbor Stage II-IV disease. Have ECOG PS of 0, 1, or 2; (ECOG PS of 3 may be considered if impairment is attributed to current lymphoma/DLBCL and if pre-phase treatment during the screening phase results in an improvement of ECOG PS to ≤2 prior to enrollment). Have measurable disease as per Lugano criteria. Have acceptable organ function based on baseline bloodwork. Must have fresh (preferred) or archival biopsy material at screening. Exclusion Criteria: Has known active, clinically significant bacterial, viral, fungal, mycobacterial, parasitic, or other infection at trial enrollment, including COVID-19 infection. Has severe cardiovascular disease (other than those eligibility criteria that preclude the subject from receiving anthracycline-based therapy/cytotoxic chemotherapy), Has been exposed to/received any of the following prior therapies, treatments, or procedures within the specified timeframes: Major surgery within 4 weeks prior to the first dose of epcoritamab; Non-investigational antineoplastic agents (except anti-CD20 monoclonal antibodies) or any investigational drug within 4 weeks or 5 half-lives, whichever is shorter, prior to the first dose of epcoritamab; Autologous hematopoietic stem cell transplantation (HSCT), CAR-T, allogeneic stem cell transplantation, or solid organ transplantation; Live, attenuated vaccines within 30 days prior to initiation of epcoritamab; Investigational vaccines within 28 days before the planned first dose of epcoritamab (ie, experimental and/or non-authorized SARS-CoV-2 vaccinations and therapies are not allowed); Invasive investigational medical device use within 28 days before the planned first dose of epcoritamab. Has primary central nervous system (CNS) tumor or known CNS involvement or intracranial involvement as confirmed by mandatory brain magnetic resonance imaging/computed tomography (MRI/CT) scan at screening and, if clinically indicated, by lumbar puncture. Has a seizure disorder requiring anti-epileptic therapy or experienced a seizure within 6 months of signing an informed consent form. Has known past or current malignancy other than inclusion diagnosis, with exceptions as stated in protocol. Has known or suspected allergies, hypersensitivity, or intolerance to either of the trial treatments or has known or suspected contraindication to the use of all locally available anti-cytokine therapies per local guidelines for management of cytokine release syndrome (CRS). Has active hepatitis B virus (HBV) (DNA polymerase chain reaction [PCR]-positive) or hepatitis C virus (HCV) (RNA PCR-positive) infection, current alcohol abuse, or cirrhosis. Has active cytomegalovirus (CMV) infection (DNA PCR-positive) requiring treatment. Has suspected active or inadequately treated latent tuberculosis. Has a known history of seropositivity for HIV. Note: HIV testing is required at screening only if required per local health authorities or institutional standards. Note: Other protocol defined inclusion/exclusion criteria may apply.