Epcoritamab With Dose Adjusted Etoposide, Cyclophosphamide, Vincristine, Doxorubicin, Prednisone and Rituximab (EPOCH-R) for the Treatment of Aggressive B-Cell Non-Hodgkin Lymphoma

Inclusion Criteria: * Untreated aggressive large-B cell lymphoma (non-Hodgkin lymphoma) with adverse features that may predict sub-optimal response to R-CHOP and in the opinion of the investigator would be treated with dose adjusted (DA)-EPOCH-R as standard of care. Subjects must be planned to receive full course (6 cycles) chemoimmunotherapy as per clinical standard of care. 1 prior cycle of chemoimmunotherapy may be allowed. Composite lymphomas are not excluded provided that the subject has not received prior systemic therapy for the indolent component and would receive DA-EPOCH-R as the standard of care regimen for the aggressive component. Eligible histologies based on 2016 World Health Organization (WHO) classification include: * High grade B-cell lymphoma with MYC and BCL2 and/or BCL6 translocations * High grade B-cell lymphoma, not otherwise specified (NOS) * Diffuse large b-cell lymphoma (DLBCL) NOS * Primary mediastinal B-cell lymphoma * T-cell/histiocyte-rich large-B-cell lymphoma * Epstein Barr virus (EBV) + DLBCL, NOS * Burkitt lymphoma * B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and classical Hodgkin lymphoma * Be willing and able to provide written informed consent for the trial * Be ≥ 18 years of age on day of signing informed consent * Have measurable disease, including at least 1 nodal site measuring 1.5 cm or 1 extranodal site measuring 1.0 cm in longest dimension on CT or FDG-PET * Have a performance status of 0-2 on the Eastern Cooperative Oncology Group (ECOG) performance scale (PS) at time of enrollment * Left ventricular ejection fraction (LVEF) ≥ 50% on cardiac multiple-gated acquisition (MUGA) scan or cardiac echocardiogram (ECHO) * Absolute neutrophil count (ANC) ≥ 1,000/μL except in cases of marrow infiltration by lymphoma * Platelets ≥ 75,000 / mcL except in cases of marrow infiltration by lymphoma or hypersplenism * Hemoglobin ≥ 8 g/dL except in cases of marrow infiltration by lymphoma without red blood cell (RBC) transfusion within 14 days of first treatment * Measured or calculated\* creatinine clearance (glomerular filtration rate \[GFR\] can also be used in place of creatinine clearance \[CrCl\]) ≥ 45 mL/min * Creatinine clearance should be calculated per institutional standard * Serum total bilirubin ≤ 1.5 X upper limit of normal (ULN) (Patients with documented Gilbert disease may be enrolled if total bilirubin ≤ 3.0 x ULN) OR direct bilirubin ≤ ULN for subjects with total bilirubin levels \> 1.5 ULN * Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\]) and alanine aminotransferase (ALT) (serum glutamic pyruvic transaminase \[SGPT\]) ≤ 2.5 X ULN OR ≤ 5 X ULN for subjects with liver involvement * International Normalized Ratio (INR) ≤ 1.5 X ULN unless subject is receiving anticoagulant therapy as long as PT or PTT is within therapeutic range of intended use of anticoagulants or prothrombin Time (PT) ≤ 1.5 X ULN unless subject is receiving anticoagulant therapy * For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive methods that result in a failure rate of ≤ 1% per year during the treatment period and for at least 12 months after the last dose of study treatment. Women must refrain from donating eggs during this same period. A woman is considered to be of childbearing potential if she is post-menarcheal, has not reached a postmenopausal state (≤ 12 continuous months of amenorrhea with no identified cause other than menopause), and has not undergone surgical sterilization (removal of ovaries and/or uterus). The definition of childbearing potential may be adapted for alignment with local guidelines or requirements. Examples of contraceptive methods with a failure rate of ≤ 1% per year include bilateral tubal ligation, male sterilization, hormonal contraceptives that inhibit ovulation, hormone-releasing intrauterine devices, and copper intrauterine devices. The reliability of sexual abstinence should be evaluated in relation to the duration of the clinical trial and the preferred and usual lifestyle of the patient. Periodic abstinence (e.g., calendar, ovulation, symptothermal, or post-ovulation methods) and withdrawal are not acceptable methods of contraception * For women of childbearing potential, a negative serum pregnancy test result during screening period. Women who are considered not to be of childbearing potential are not required to have a pregnancy test * For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use a condom, and agreement to refrain from donating sperm, as defined below: With female partners of childbearing potential or pregnant female partners, men must remain abstinent or use a condom during the treatment period and for at least 6 months after the last treatment. Men must refrain from donating sperm during this same period. The reliability of sexual abstinence should be evaluated in relation to the duration of the clinical trial and the preferred and usual lifestyle of the patient. Periodic abstinence (e.g., calendar, ovulation, symptothermal, or postovulation methods) and withdrawal are not acceptable methods of preventing drug exposure. Male patients considering preservation of fertility should bank sperm before study treatment Exclusion Criteria: * Contraindication to any of the individual components of EPOCH-R, including, or history of severe allergic or anaphylactic reactions to humanized or murine monoclonal antibodies, or known sensitivity or allergy to murine products or if receiving an additional 6 cycles of anthracycline would place patient over the anthracycline lifetime cumulative dose (400 mg/m\^2) * Prior systemic treatment for lymphoma. Prior radiotherapy is allowed provided that this site is not used as a measurable site to assess response * Transformation from indolent lymphoma is allowed provided that the subject has not received