A Randomized, Open-Label Study Evaluating the Efficacy and Safety of Cemacabtagene Ansegedleucel in Participants with Minimal Residual Disease After Response to First Line Therapy for Large B-cell lymphoma.

Key Inclusion Criteria: 1. LBCL per WHO 2017 including diffuse large B-cell lymphoma, high-grade B-cell lymphoma, and primary mediastinal B-cell lymphoma histologically confirmed by pathology report. 2. Participant has completed a full course of standard first line therapy (e.g., R-CHOP, dose-adjusted EPOCH-R, Pola-R-CHP) as intended. Participants cannot have received additional lines of therapy. 3. Participant achieved CR, or PR suitable for observation at the end of first line therapy based on PET/CT evaluation 4. Foresight CLARITY™ IUO MRD test, powered by PhasED-Seq™, is positive. 5. Adult participants ≥18 years of age. 6. Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 or 1. 7. Adequate hematological, renal, hepatic, pulmonary, and cardiac function 8. Non-hematologic toxicities related to prior therapy must be recovered to baseline or grade ≤1. Key Exclusion Criteria: 1. LBCL with history of central nervous system involvement, transformed from other malignancy (e.g., transformed follicular lymphoma or marginal zone lymphoma, Richter's transformation), or T-cell/histiocyte rich LBCL. 2. Prior treatment with anti-CD19 targeted therapies. 3. Anti-cancer treatment, including radiation, after end of treatment PET/CT and/or MRD testing is performed. 4. Active and clinically significant autoimmune disease. 5. Active systemic bacterial, fungal, or viral infections requiring systemic treatment (e.g., HIV). 6. History of another primary malignancy or bone marrow disorder (e.g., myelofibrosis, smoldering multiple myeloma) within 3 years prior to enrollment.