CD19 CAR T-cell therapy with axicabtagene ciloleucel (axi-cel) for relapsed or refractory (R/R) large B cell lymphoma (LBCL) may lead to durable remissions, however, prolonged cytopenias and infections may occur. In this single center retrospective study of 85 patients, we characterized immune reconstitution and infections for patients remaining in remission after axi-cel for LBCL. Prolonged cytopenias (those occurring at or after day 30 following infusion) were common with >= grade 3 neutropenia seen in 21/70 (30-0%) patients at day 30 and persisting in 3/31 (9-7%) patients at 1 year. B cells were undetectable in 30/34 (88-2%) patients at day 30, but were detected in 11/19 (57-9%) at 1 year. Median IgG levels reached a nadir at day 180. By contrast, CD4 T cells decreased from baseline and were persistently low with a median CD4 count of 155 cells/μl at 1 year after axi-cel (n=19, range 33 – 269). In total, 23/85 (27-1%) patients received IVIG after axi-cel, and 34/85 (40-0%) received G-CSF. Infections in the first 30 days occurred in 31/85 (36-5%) patients, of which 11/85 (12-9%) required intravenous antibiotics or hospitalization (“severe”) and were associated with cytokine release syndrome (CRS), neurotoxicity, tocilizumab use, corticosteroid use, and bridging therapy on univariate analyses. After day 30, 7 severe infections occurred, with no late deaths due to infection. Prolonged cytopenias are common following axi-cel therapy for LBCL and typically recover with time. Most patients experience profound and prolonged CD4 T cell immunosuppression without severe infection.

High metabolic tumor volume (MTV) predicts worse outcomes in lymphoma treated with chemotherapy. However, it is unknown if this holds for patients treated with axicabtagene ciloleucel (axi-cel), an anti-CD19 targeted chimeric antigen receptor T-cell therapy. The primary objective of this retrospective study was to investigate the relationship between MTV and survival (overall survival [OS] and progression-free survival [PFS]) in patients with relapsed/refractory large B-cell lymphoma (LBCL) treated with axi-cel. Secondary objectives included finding the association of MTV with response rates and toxicity. The MTV values on baseline positron emission tomography of 96 patients were calculated via manual methodology using commercial software. Based on a median MTV cutoff value of 147.5 mL in the first cohort (n = 48), patients were divided into high and low MTV groups. Median follow-up for survivors was 24.98 months (range, 10.59-51.02 months). Patients with low MTV had significantly superior OS (hazard ratio [HR], 0.25; 95% confidence interval [CI], 0.10-0.66) and PFS (HR, 0.40; 95% CI, 0.18-0.89). Results were successfully validated in a second cohort of 48 patients with a median follow-up for survivors of 12.03 months (range, 0.89-25.74 months). Patients with low MTV were found to have superior OS (HR, 0.14; 95% CI, 0.05-0.42) and PFS (HR, 0.29; 95% CI, 0.12-0.69). In conclusion, baseline MTV is associated with OS and PFS in axi-cel recipients with LBCL.

Axicabtagene ciloleucel (axi-cel) is a chimeric antigen receptor (CAR) T cell therapy for relapsed or refractory large B cell lymphoma (LBCL). Here, we evaluated whether immune dysregulation, present prior to CAR-T cell therapy, associated with treatment failure. Tumor expression of interferon (IFN) signaling, high blood levels of monocytic myeloid-derived suppressor cells (M-MDSCs), and high blood IL-6 and ferritin each associated with a lack of durable response. Similar to other cancers, we found that in LBCL tumor IFN signaling is associated with the expression of multiple checkpoint ligands including PD-L1, and these were higher in patients who lacked durable responses to CAR-T therapy. Moreover, tumor IFN signaling and blood M-MDSCs associated with decreased axi-cel expansion. Finally, patients with high tumor burden had higher immune dysregulation with increased serum inflammatory markers and tumor IFN signaling. These data support that immune dysregulation in LBCL promotes axi-cel resistance via multiple mechanistic programs: insufficient axi-cel expansion associated with both circulating M-MDSC and tumor IFN signaling, that also gives rise to expression of immune checkpoint ligands.

Adoptive cellular immunotherapy with chimeric antigen receptor (CAR) T cell has changed the treatment landscape of B-cell non-Hodgkin’s lymphoma (NHL), especially for aggressive B-cell lymphomas. Single-center and multicenter clinical trials with anti-CD19 CAR T-cell therapy have shown great activity and long-term remissions in poor-risk diffuse large B-cell lymphoma (DLBCL) when no other effective treatment options are available. Two CAR T-cell products [axicabtagene ciloleucel (axi-cel) and tisagenlecleucel] have obtained US Food and Drug Administration approval for the treatment of refractory DLBCL after two lines of therapy. A third product, liso-cel, is currently being evaluated in clinical trials and preliminary results appear very promising. CAR T-cell-related toxicity with cytokine-release syndrome and neurotoxicity remain important potential complications of this therapy. Here, we review the s biology, structure, clinical trial results and toxicity of two commercially approved CAR T-cell products and others currently being studied in multicenter clinical trials in B-cell NHLs.

Chimeric antigen receptor T-cell (CAR-T) therapy has proven to be a very effective cancer immunotherapy. Axicabtagene ciloleucel and Tisagenlecleucel are the first in class anti-CD19 CART cells currently available for relapsed-refractory adult large B-cell lymphoma. Tisagenlecleucel is also available for pediatric and young adult (up to age 25) patients with relapsed-refractory B-acute lymphoblastic leukemia. Cytokine release syndrome (CRS) and CAR T-cell associated encephalopathy syndrome (neurotoxicity) are the most common adverse effects associated CART cell therapy. They can lead to significant morbidity and preclude widespread use of this treatment modality. Treatment related deaths from severe CRS and cerebral edema have been reported. There is a significant heterogeneity in the side-effect profile of different CART cell products under investigation and there is a need to develop standardized guidelines for toxicity grading and management. Here, we summarize the current literature on pathogenesis, clinical presentation, and management of CRS and neurotoxicity. The different grading systems of CRS and management protocols used in different trials have made it difficult to compare the outcomes of different CART cell therapies. Several prevention strategies such as predictive biomarkers of CRS and neurotoxicity and modified CART cells with 'built-in' safety mechanisms are being studied, which has the potential to greatly expand the safety and applicability of CART cell treatment across various malignancies.