An Open-Label Study Comparing Glofitamab and Polatuzumab Vedotin + Rituximab, Cyclophosphamide, Doxorubicin, and Prednisone Versus Pola-R-CHP in Previously Untreated Patients With Large B-Cell Lymphoma

Inclusion Criteria:

* Previously untreated participants with CD20-positive LBCL
* Ability to provide tumor tissue
* International prognostic index (IPI) score 2-5
* Eastern cooperative oncology group (ECOG) performance status of 0, 1, or 2
* At least one bi-dimensionally measurable lesion, defined as \> 1.5 cm in its longest dimension as measured by CT or MRI
* Left ventricular ejection fraction (LVEF) \>/=50% on cardiac multiple-gated acquisition (MUGA) scan or cardiac echocardiogram (ECHO)
* Adequate hematologic function
* Negative HIV test at screening with exceptions as defined by the protocol
* Negative SARS-CoV-2 antigen or PCR test

Exclusion Criteria:

* Contraindication to any of the individual components of Pola-R-CHP or glofitamab, including prior receipt of anthracyclines, or history of severe allergic or anaphylactic reactions to humanized or murine monoclonal antibodies, or known sensitivity or allergy to murine products
* Prior solid organ transplantation
* Participants receiving systemic immunosuppressive agent such as, but not limited to cyclosporin, azathioprine, methotrexate, thalidomide, and anti-tumor necrosis factor agents within 4 weeks prior to first dose of study treatment
* Current Grade \> 1 peripheral neuropathy by clinical examination or demyelinating form of Charcot-Marie-Tooth disease
* History of indolent lymphoma (e.g., Follicular Lymphoma, Marginal Zone Lymphoma, Waldenstrom macroglobulinemia)
* Current diagnosis of the following: Follicular lymphoma grade 3B; transformations of indolent B-cell lymphomas (e.g., de novo transformed follicular lymphoma); mediastinal grey zone lymphoma; primary mediastinal (thymic) large B-cell lymphoma; Burkitt lymphoma; primary large B-cell lymphoma of immune-privileged sites (encompassing primary diffuse large B-cell lymphoma of the CNS, primary large B-cell lymphoma of the vitreoretina and primary large B-cell lymphoma of the testis); primary effusion DLBCL; and primary cutaneous DLBCL, leg type
* Primary or secondary CNS lymphoma at the time of recruitment or history of CNS lymphoma
* Prior treatment with systemic immunotherapeutic agents
* Prior use of any monoclonal antibody for the purposes of treating cancer within 3 months of the start of Cycle 1
* Any investigational therapy for the purposes of treating cancer within 28 days prior to the start of Cycle 1
* Prior radiotherapy to the mediastinal/pericardial region
* Prior therapy for LBCL, with the exception of corticosteriods
* Corticosteroid use \> 30 mg/day of prednisone or equivalent, for purposes other than lymphoma symptom control
* History of other malignant or non-malignant diseases that could affect compliance with the protocol or interpretation of results
* Significant or extensive history of cardiovascular disease
* Recent major surgery (within 4 weeks prior to the start of Cycle 1), other than for diagnosis
* Current or past history of central nervous system (CNS) disease, such as stroke, epilepsy, CNS vasculitis, or neurodegenerative disease
* Known or suspected chronic active Epstein-Barr viral infection
* Known or suspected history of hemophagocytic lymphohistiocytosis (HLH)
* Active autoimmune disease requiring treatment
* Clinically significant liver disease
* Live, attenuated vaccine within 4 weeks before study treatment infusion on Day 1 of Cycle 1 or anticipation that such a live, attenuated vaccine will be required during the study. Live vaccines during the study and until participants B cells recover are prohibited
* Any active infection within 7 days prior to Cycle 1 Day 1 that would impact participant safety
* Suspected active or latent tuberculosis
* Positive test results for chronic hepatitis B infection, hepatitis C, or the human T-lymphotropic virus type 1 (HTLV-1)
* History of progressive multifocal leukoencephalopathy