Patients refractory to first-line therapy or who relapse within 12 months of receiving salvage therapy (including bone marrow transplant) for recurrent disease have had poor prognoses with median overall survival rates of 3.3 and 6.3 months, respectively. The prognosis of these patients appears to be improved by using CAR-T therapy. Chimeric antigen receptor T cell (i.e. CAR-T) adoptive cellular immunotherapy has emerged as a recent advance in treating refractory and relapsed DLBCL, NOS (tisagenlecleucel, axicabtagene ciloleucel, lisocabtagene maraleucel). Chimeric antigen receptor T cells are genetically engineered to express: 1) an artificial T-cell receptor consisting of antigen-recognition and attached hinge domains expressed on their surface membranes; 2) a surface membrane-spanning domain; 3) an intracellular domain which, when the antigen-recognition domain binds its targeted antigen, activates signaling pathways that cause the T-cell to attack and kill cells that bear the recognized antigen on their surface membranes; and 4), in more recently devised second generation CAR-T strategies, an associated intracellular co-stimulating molecule (e.g. CD28 or 4-1BB) which augments activation of the cell-killing signaling pathways. CAR-T therapy, as it pertains to DLBCL, NOS, kills a patients neoplastic B-cells by isolating this patients T-cells; genetically engineering these cells to express an artificial T-cell receptor designed to bind an antigen expressed on the surface of their neoplastic B-cells; and infusing these cells back into the donor patient. The targeted antigen has usually been CD19, a surface membrane protein expressed on virtually all B-cells including the neoplastic cells in DLBCL, NOS.
The regimen achieves cure, relapse following remission, and unresponsive rates of 60–70%, 30–40% and <10%, respectively, in GBC variant cases. Relapses generally occur within the first 3 years of diagnosis with few cases doing so after 5 years. Patients who are refractory to, relapse within 1 year of diagnosis before starting, relapse within 6 months after completing, or progress within 2 years of starting R-CHOP have poorer prognoses. R-CHOP is less effective and not recommended for patients who have MYC, BL2, and/or BL6 rearrangements regardless of their GBC, ABC, or non-GBC type. One recommendation for treating these DH/THL cases is the DA-R-EPOCH regimen (dose-adjusted rituximab, etoposide, prednisolone, oncovin, cyclophosphamide, and hydroxydaunorubicin). S-R-EPOCH achieves 2 year survival rates of 40–67% compared to a ~25% survival rate for R-CHOP in these cases. DA-R-EPOCH has also been recommended for patients with double expresser lymphoma although some experts recommend treating this variant more like a typical DLCBL, NOS. First-line therapy for patients with the ABC, undetermined, or non-GBC variants has been the DA-R-EPOCH regimen. Patients with these variants (including those with double expresser lymphoma) have had a ~40% cure rate when treated with it. A randomized clinical trial conducted in France reported that a R-ACVBP chemotherapy regimen (rituximab, adriamycin, cyclophosphamide, vindesine, bleomycin, and cytarabine followed by sequential consolidation therapy with systemic methotrexate, ifosfamide, and etoposide, and then cytarabine) achieved significantly better response rates than R-CHOP in ABC/NGC variant cases lymphoma.