This is a randomized, open-label study in adult patients who have completed standard first line therapy for large B-cell lymphoma (LBCL) and achieved a complete response or partial response suitable for observation, but who have minimal residual disease (MRD) as detected by the Foresight CLARITY Investigational Use Only (IUO) MRD test, powered by PhasED-Seq. The purpose of the trial is to assess the efficacy and safety of consolidation with cemacabtagene ansegedleucel (cema-cel), an allogeneic CD19 CAR T product, as compared to standard of care observation.

In this study, participants with MRD are randomized 1:1 to treatment with cema-cel or an observation arm. Treatment includes cema-cel following a lymphodepletion regimen of fludarabine and cyclophosphamide.

Prior to August 2025, participants may also have received an anti-CD52 monoclonal antibody, ALLO-647, as part of their lymphodepletion regimen.

This is an expanded access protocol that will be conducted at sites qualified and approved to treat subjects with lisocabtagene maraleucel. Sometimes when lisocabtagene maraleucel is manufactured the drug does not pass all the testing results to be called lisocabtagene maraleucel. When this happens the drug is called nonconforming lisocabtagene maraleucel. The expanded access protocol will be used to allow subjects to receive nonconforming lisocabtagene maraleucel only if the potential benefit is better than the potential risk. This expanded access protocol is restricted to those subjects who were prescribed lisocabtagene maraleucel as part of their routine care.

Subjects will first receive a lymphodepleting chemotherapy regimen and then be treated with nonconforming lisocabtagene maraleucel as the treatment plan.

The goal of this clinical trial is to reduce the duration of ICANS and incidence of G3 or great ICANS in participants who receive axi-cel. The main questions the study aims to answer are: Efficacy of IT therapy to reduce high-grade ICANS in participants who receive axi-cel in NHL compared to historical experience.

This phase II trial tests how well giving intrathecal (IT) cytarabine and hydrocortisone works for the early treatment of immune effector cell associated neurotoxicity syndrome (ICANS) in patients undergoing chimeric antigen response (CAR) t cell therapy for the treatment of non Hodgkin Lymphoma that has come back after a period of improvement (recurrent) or that has not responded o previous treatment (refractory). CAR T-cell therapy can sometimes cause an overactive immune response and inflammation. This can cause a side effect called ICANS that affects the rain and may lead to symptoms such as confusion, difficulty speaking, or other neurological problems. Giving cytarabine and hydrocortisone directly into the fluid around the brain and spinal cord (called intrathecal treatment) may help lower the body's immune response and reduce inflammation. Giving IT cytarabine and hydrocortisone may be effective for early treatment of CANS in patients undergoing CAR T cell therapy for relapsed or refractory non Hodgkin Lymphoma.

This phase II trial tests the effect of nemtabrutinib in combination with brexucabtagene autoleucel (brexu-cel) in treating patients with mantle cell lymphoma that has come back after a period of improvement (relapsed) or that has not responded to previous treatment (refractory). Nemtabrutinib, a BTK inhibitor, may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Chimeric antigen receptor (CAR) T-cell therapy, such as brexu-cel, is a type of treatment in which a patient's T cells (a type of immune system cell) are changed in the laboratory so they will attack cancer cells. T cells are taken from a patient's blood. Then the gene for a special receptor that binds to a certain protein on the patient's cancer cells is added to the T cells in the laboratory. The special receptor is called a CAR. Large numbers of the CAR T cells are grown in the laboratory and given to the patient by infusion for treatment of certain cancers. Chemotherapy, such as fludarabine and cyclophosphamide, are given before CAR T cell therapy to help kill cancer cells in the body and help make room for the CAR T cells. Giving nemtabrutinib in combination with brexu-cel may be safe, tolerable, and/or effective in treating patients with relapsed or refractory mantle cell lymphoma.