Study Evaluating the Safety and Efficacy of KTE-C19 in Adult Participants With Refractory Aggressive Non-Hodgkin Lymphoma

Key Inclusion Criteria

1. Histologically confirmed:

   * Diffuse Large B Cell Lymphoma (DLBCL)
   * Primary Mediastinal Large B Cell Lymphoma (PMBCL)
   * Transformation Follicular Lymphoma (TFL)
   * High grade B-cell lymphoma (HGBCL)
2. Chemotherapy-refractory disease, defined as one of more of the following:

   * No response to last line of therapy i. Progressive disease (PD) as best response to most recent therapy regimen ii. Stable disease (SD) as best response to most recent therapy with duration no longer than 6 month from last dose of therapy OR
   * Refractory post-autologous stem cell transplant (ASCT) i. Disease progression or relapsed less than or equal to 12 months of ASCT (must have biopsy proven recurrence in relapsed individuals) ii. If salvage therapy is given post-ASCT, the individual must have had no response to or relapsed after the last line of therapy
3. Individuals must have received adequate prior therapy including at a minimum:

   * Anti-cluster of differentiate 20 (CD20) monoclonal antibody unless investigator determines that tumor is CD20-negative and
   * an anthracycline containing chemotherapy regimen
   * for individual with transformed FL must have chemorefractory disease after transformation to DLBCL.
4. At least one measurable lesion per revised international working group (IWG Response Criteria
5. Eastern cooperative oncology group (ECOG) performance status of 0 or 1
6. Absolute neutrophil count (ANC) ≥ 1000/microliters (uL)
7. Absolute lymphocyte count ≥ 100/uL
8. Platelet count ≥ 75,000/uL
9. Adequate renal, hepatic, pulmonary and cardiac function defined as:

   * Creatinine clearance (as estimated by Cockcroft Gault) \> 60 mL/min
   * Serum alanine aminotransferase (ALT)/aspartate aminotransferase (AST) \< 2.5 upper limit of normal (ULN)
   * Total bilirubin \< 1.5 mg/dL, except in individuals with Gilbert's syndrome
   * Cardiac ejection fraction \>50%, no evidence of pericardial effusion as determined by an echocardiogram (ECHO), and no clinically significant pleural effusion
   * Baseline oxygen saturation \>92% on room air
10. All individuals or legally appointed representatives/caregivers, must personally sign and date the Institutional Review Board (IRB)/Independent Ethics Committee (IEC) approved consent form before initiating any study specific procedures or activities.
11. Relapsed or refractory large B-cell lymphoma including DLBCL, PMBCL, TFL, and HGBCL after two systemic lines of therapy

Key Exclusion Criteria

1. History of malignancy other than nonmelanoma skin cancer or carcinoma in situ (e.g. cervix, bladder, breast) or follicular lymphoma unless disease free for at least 3 years
2. History of allogeneic stem cell transplantation
3. Prior chimeric antigen receptor (CAR) therapy or other genetically modified T cell therapy
4. Presence of fungal, bacterial, viral, or other infection that is uncontrolled or requiring intravenous (IV) antimicrobials for management. Simple urinary tract infection (UTI) and uncomplicated bacterial pharyngitis are permitted if responding to active treatment
5. History of human immunodeficiency virus (HIV) infection or acute or chronic active hepatitis B or C infection. Individuals with history of hepatitis infection must have cleared their infection as determined by standard serological and genetic testing per current Infectious Diseases Society of America (IDSA) guidelines
6. Individuals with detectable cerebrospinal fluid malignant cells, or brain metastases, or with a history of central nervous system (CNS) lymphoma or primary CNS lymphoma, cerebrospinal fluid malignant cells or brain metastases
7. History or presence of CNS disorder such as seizure disorder, cerebrovascular ischemia/hemorrhage, dementia, cerebellar disease, or any autoimmune disease with CNS involvement

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