Expanded Access Program for Epcoritamab

Inclusion Criteria: * Must be 18 years of age or older * R/R CD20+ mature B-cell neoplasm * Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0, 1, or 2 * ≥ 2 prior lines of antineoplastic therapy, including ≥ 1 anti-CD20 monoclonal antibody (mAb) * Fluorodeoxyglucose (FDG) positron emission tomography (PET)-avid and measurable disease by computed tomography/magnetic resonance imaging (CT/MRI) * Patients considering the EAP should have no other available therapeutic option and cannot be eligible for other epcoritamab trials. * Patients considering the EAP must be located in proximity to a US site given that the EAP is currently available only in the United States. * Prior to initiating any program-related assessments or procedures, patients (or their legally acceptable representative) must sign an informed consent form (ICF), which indicates the purpose of the program, the procedures required for the program, and confirms the patient's willingness to participate in the program. Exclusion Criteria: * Any prior therapy with an investigational bispecific antibody targeting CD3 and CD20 * Prior treatment with CAR-T therapy within 100 days prior to first epcoritamab administration * Primary central nervous system (CNS) lymphoma or known CNS involvement by lymphoma * Confirmed history of or current autoimmune disease or other diseases resulting in permanent immunosuppression or requiring permanent immunosuppressive therapy. Low-dose prednisolone for rheumatoid arthritis or similar conditions is allowed. * Active hepatitis B or hepatitis C * Known clinically significant cardiac disease * Pregnancy or breastfeeding * Known hypersensitivity to allopurinol or rasburicase