A Trial to Study if REGN5837 in Combination With Odronextamab is Safe for Participants With Aggressive B-cell Non-Hodgkin Lymphomas

Key Inclusion Criteria:

Have documented CD20+ aggressive B-NHL, with disease that has progressed after at least 2 lines of systemic therapy containing an anti-CD20 antibody and an alkylating agent.
Measurable disease on cross sectional imaging as defined in the protocol
Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1
Adequate bone marrow, renal and hepatic function as defined in the protocol
During dose expansion phase of the study, participant should be willing to undergo mandatory tumor biopsies, if in the opinion of the investigator, the participant has an accessible lesion that can be biopsied without significant risk to the participant.

Key Exclusion Criteria:

Prior treatments with allogeneic stem cell transplantation or solid organ transplantation, treatment with anti-CD20 x anti- CD3 bispecific antibody, such as odronextamab
Diagnosis of mantle cell lymphoma (MCL)
Primary central nervous system (CNS) lymphoma or known involvement by non-primary CNS lymphoma
Treatment with any systemic anti-lymphoma therapy within 5 half-lives or within 14 days prior to first administration of study drug, whichever is shorter
Standard radiotherapy within 14 days of first administration of study drug.
Continuous systemic corticosteroid treatment with more than 10 mg per day of prednisone or corticosteroid equivalent within 72 hours of start of odronextamab
Co-morbid conditions, as described in the protocol
Infections, as described in the protocol
Allergy/hypersensitivity: Known hypersensitivity to both allopurinol and rasburicase

NOTE: Other protocol defined inclusion / exclusion criteria apply