Study to Compare Axicabtagene Ciloleucel With Standard of Care Therapy as First-line Treatment in Participants With High-risk Large B-cell Lymphoma

Key Inclusion Criteria:

* Histologically confirmed large B cell lymphoma (LBCL) based on 2016 World Health Organization (WHO) classification by local pathology lab assessment, including of the following:

  * Diffuse large B-cell lymphoma (DLBCL), not otherwise specified (NOS)
  * High-grade B-cell lymphoma (HGBL)
* Note: Transformed DLBCL from follicular lymphoma or from marginal zone lymphoma is eligible if no prior treatment with anthracycline-containing regimen.
* High-risk disease defined as an International Prognostic Index (IPI) score of 4 or 5 at initial diagnosis.
* Have received only 1 cycle of rituximab plus chemotherapy (R-chemotherapy).
* Adequate bone marrow, renal, hepatic, pulmonary, and cardiac function.
* Females of childbearing potential must have a negative serum or urine pregnancy test.

Key Exclusion Criteria:

* The following WHO 2016 subcategories by local assessment:

  * T-cell/histiocyte-rich LBCL
  * Primary DLBCL of the central nervous system (CNS)
  * Primary mediastinal (thymic) LBCL
  * B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and classical Hodgkin lymphoma
  * Burkitt lymphoma
  * History of Richter's transformation of chronic lymphocytic leukemia
* Presence of detectable cerebrospinal fluid (CSF)-malignant cells, brain metastases, or a history of CNS involvement of lymphoma.
* Presence of cardiac lymphoma involvement.
* Any prior treatment for LBCL other than the 1 cycle of R-chemotherapy.
* History of severe immediate hypersensitivity reaction to any of the agents used in this study.
* Presence of CNS disorder. History of stroke, transient ischemic attack, or posterior reversible encephalopathy syndrome (PRES) within 12 months prior to enrollment.
* History of acute or chronic active hepatitis B or C infection.
* Positive for human immunodeficiency virus (HIV) unless taking appropriate anti-HIV medications, with an undetectable viral load by PCR and with a cluster of differentiation 4 (CD4) count \> 200 cells/uL.
* Medical conditions or residual toxicities from prior therapies likely to interfere with assessment of safety or efficacy of study treatment. Please refer to protocol for further details.
* History of clinically significant cardiac disease within 12 months before enrollment.
* History of any medical condition requiring maintenance systemic immunosuppression/systemic disease modifying agents within the last 2 years.

Note: Other protocol defined Inclusion/Exclusion criteria may apply.