CAR-T Followed by Bispecific Antibodies

This trial is studying whether adding bispecific antibody drugs (drugs that help the immune system attack cancer from two directions at once) after CAR-T cell therapy can improve outcomes for patients with certain types of aggressive B-cell lymphoma that have come back or stopped responding to treatment. **You may be eligible if...** - You have relapsed or treatment-resistant large B-cell lymphoma (including transformed follicular lymphoma) - You have already received CAR-T cell therapy at least 30 days ago - Your cancer still shows measurable disease on imaging after CAR-T - You have a life expectancy of at least 12 weeks and adequate organ function **You may NOT be eligible if...** - You had serious toxicity from CAR-T therapy (severe immune reaction or neurological side effects) - You have a history of autoimmune disease (like lupus, rheumatoid arthritis, or multiple sclerosis) - You are pregnant, breastfeeding, or planning to become pregnant - You have had a solid organ transplant - You have an active serious infection or significant heart or lung disease - You have a history of progressive multifocal leukoencephalopathy (a serious brain infection) Talk to your doctor to see if this trial is right for you.