Primary resistance to CD19-directed chimeric antigen receptor T-cell therapy in T-cell/histiocyte-rich large B-cell lymphoma

Autologous stem cell transplantation in T-cell/histiocyte-rich large B-cell lymphoma: EBMT Lymphoma Working Party study

ABSTRACT

Although broadly used, consolidative autologous hematopoietic stem cell transplantation (auto-HCT) for relapsed/refractory (R/R) T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) has never been specifically investigated. Here, we have analyzed outcomes of auto-HCT for THRLBCL compared with diffuse large cell B-cell lymphoma not otherwise specified (DLBCL). Eligible for this retrospective registry study were adult patients with R/R THRLBCL and DLBCL, respectively, who underwent a first auto-HCT in a salvage-sensitive disease status as assessed by positron emission tomography-computed tomography between 2016 and 2021 and were registered with the European Society for Blood and Marrow Transplantation database. The primary end point was progression-free survival (PFS) 2 years after transplantation. A total of 201 patients with THRLBCL and 5543 with DLBCL were included. There were no significant differences in terms of disease status at HCT, pretreatment lines, and interval from diagnosis to transplant between the cohorts, but patients with THRLBCL were significantly younger, contained a higher proportion of men, and had a better performance status. Compared with DLBCL, THRLBCL was associated with significantly better 2-year PFS (78% vs 59%; P < .001) and overall survival (OS, 81% vs 74%; P = .02) because of a significantly lower 2-year relapse incidence (16% vs 35%; P < .001). On multivariate analysis, favorable relapse risk (hazard ratio [HR], 0.46; 95% confidence interval [CI], 0.31-0.7) and PFS (HR, 0.58; 95% CI, 0.41-0.82) of patients with THRLBCL remained significant, whereas OS benefits (HR, 0.78; 95% CI, 0.54-1.12) did not. These results were validated in a propensity score-matched analysis. These data prove auto-HCT as an effective treatment option for salvage-sensitive R/R THRLBCL.

CD19-directed CART therapy for T-cell/histiocyte-rich large B-cell lymphoma

ABSTRACT

T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) is a rare histologic variant of LBCL. Limited data regarding CD19-directed chimeric antigen receptor T-cell (CART) therapy in relapsed/refractory (R/R) THRLBCL suggest poor efficacy. We investigated CART outcomes for R/R THRLBCL through the Center for International Blood and Marrow Transplant Research registry. A total of 58 adult patients with R/R THRLBCL who received commercial CD19-CART therapy between 2018 and 2022 were identified. Most patients (67%) had early relapse of disease (45% primary refractory) with a median of 3 (range, 1-7) prior therapies and were treated with axicabtagene ciloleucel (69%). At median follow-up of 23 months after CART therapy, 2-year overall and progression-free survival were 42% (95% confidence interval [CI], 27-57) and 29% (95% CI, 17-43), respectively. In univariable analysis, poor performance status before CART therapy was associated with higher mortality (hazard ratio, 2.35; 95%CI, 1.02-5.5). The 2-year cumulative incidences of relapse/progression and nonrelapse mortality were 69% and 2%, respectively. Grade ≥3 cytokine release syndrome and immune effector cell-associated neurologic syndrome occurred in 7% and 15% of patients, respectively. In this largest analysis of CD19-CART therapy for R/R THRLBCL, ∼30% of patients were alive and progression free 2 years after CART therapy. Despite a high incidence of progression (69% at 2 years), these results suggest a subset of patients with R/R THRLBCL may have durable responses with CARTs.

Hemophagocytic lymphohistiocytosis in a patient with Epstein-Barr virus-positive diffuse large B-cell lymphoma treated with chimeric antigen receptor T-cell therapy

With the advent of chimeric antigen receptors T-cell therapy, understanding their role in the development of hemophagocytic lymphohistiocytosis has become increasingly complex. We describe a case of a young patient with Epstein-Barr virus-positive diffuse large B-cell lymphoma, who was treated with axicabtagene ciloleucel. The patient developed progressive cytopenia and, on Day 73 post-infusion, met criteria for hemophagocytic lymphohistiocytosis. Bone marrow evaluation revealed hemophagocytosis without evidence of clonal B cells. The patient was treated with tocilizumab, dexamethasone, etoposide and anakinra, which eventually led to improvement. Unfortunately, the patient succumbed to an infection. Disease progression was confirmed posthumously.This case report explores the differential diagnosis of hyperinflammatory syndromes following chimeric antigen receptor T-cell therapy and highlights the reduced efficacy of this treatment in patients with a T-cell/histiocyte-rich background.

Immune checkpoint blockade and CAR T-cell therapy in T-cell/histiocyte-rich large B-cell lymphoma: Challenges and opportunities

T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) is a highly aggressive large B-cell lymphoma defined by a paucity of malignant B cells amidst a dense infiltrate of reactive T cells and histiocytes. The unique tumor microenvironment (TME) of THRLBCL, marked by extensive immune infiltration and high PD-L1 expression, poses significant challenges for immunotherapies. This review explores the therapeutic potential and resistance mechanisms of immune checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR) T-cell therapy in THRLBCL. While ICIs show promise due to the immune-suppressive nature of the TME, CAR T-cell therapy has demonstrated limited efficacy, often hindered by primary resistance and early relapse. Combining CAR T-cell therapy with ICIs and Bruton tyrosine kinase (BTK) inhibitors and developing novel CAR constructs targeting multiple antigens are potential strategies to enhance treatment outcomes. Further prospective studies are essential to corroborate these strategies and improve the prognosis for this challenging lymphoma subtype.

CAR T-cell therapy in aggressive lymphomas-identifying prognostic and predictive markers

We discuss different pre-infusion, post-infusion and post-CAR T-cell relapse prognostic factors influencing the outcomes of anti-CD19 CAR T-cell therapy in patients with relapsed or refractory large B-cell lymphomas. Despite the overall positive results of anti-CD19 CAR T-cell therapy, a significant percentage of patients relapse. We summarize the efforts made to identify predictive factors for response and durable remissions and survival. In the pre-infusion setting, the patient-related factors discussed include Eastern Cooperative Oncology Group performance status, age, and comorbidities. Disease-related factors like tumor burden, histology, and biological features are also considered. In addition, inflammation-related factors and CAR T-cell product-related factors are considered. After CAR T-cell infusion, factors such as disease response assessed by 18FDG-PET/CT scan, liquid biopsy monitoring, and CAR T-cell expansion become crucial in predicting survival outcomes. Response to 18FDG-PET/CT scan is a widely used test for confirming response and predicting survival. Liquid biopsy, in combination with 18FDG-PET/CT scan, has shown potential in predicting outcomes. CAR T-cell expansion and persistence have shown mixed effects on survival, with some studies indicating their association with response. In the setting of post-CAR T-cell relapse, prognostic factors include refractory disease, time of relapse, and elevated lactate dehydrogenase levels at CAR T-cell infusion. Enrollment in clinical trials is crucial for improving outcomes in these patients. Overall, we discuss a comprehensive overview of prognostic factors that can influence the outcomes of anti-CD19 CAR T-cell therapy in patients with relapsed or refractory large B-cell lymphomas, highlighting the need for personalized approaches in treatment decision-making.

CD19-directed CAR T cells as first salvage therapy for large B-cell lymphoma: towards a rational approach

The approval of CD19-directed chimeric antigen receptor (CAR) T-cell therapies for the second-line treatment of high-risk large B-cell lymphoma (LBCL) has greatly affected salvage algorithms for this condition, and such therapies could have the potential to improve the course of relapsed or refractory LBCL. In this Review, we provide guidance for a rational management approach to the use of commercial CD19-directed CAR T cells in the second-line treatment of LBCL, addressing crucial questions regarding eligible histologies; age, comorbidity, and tumour biology restrictions; the handling of very aggressive tumour behaviour; and holding and bridging therapies. The guidance was developed in a structured manner and, for each question, consists of a description of the clinical issue, a summary of the evidence, the rationale for a practical management approach, and recommendations. These recommendations could help to decide on the optimal management of patients with relapsed or refractory LBCL who are considered for second-line CAR T-cell treatment.

[Efficacy and safety of fourth-generation CD19 CAR-T expressing IL7 and CCL19 along with PD-1 monoclonal antibody for relapsed or refractory large B-cell lymphoma]

Objective: This study systematically explore the efficacy and safety of fourth-generation chimeric antigen receptor T-cells (CAR-T), which express interleukin 7 (IL7) and chemokine C-C motif ligand 19 (CCL19) and target CD19, in relapsed or refractory large B-cell lymphoma. Methods: Our center applied autologous 7×19 CAR-T combined with tirelizumab to treat 11 patients with relapsed or refractory large B-cell lymphoma. The efficacy and adverse effects were explored. Results: All 11 enrolled patients completed autologous 7×19 CAR-T preparation and infusion. Nine patients completed the scheduled six sessions of tirolizumab treatment, one completed four sessions, and one completed one session. Furthermore, five cases (45.5%) achieved complete remission, and three cases (27.3%) achieved partial remission with an objective remission rate of 72.7%. Two cases were evaluated for disease progression, and one died two months after reinfusion because of uncontrollable disease. The median follow-up time was 31 (2-34) months, with a median overall survival not achieved and a median progression-free survival of 28 (1-34) months. Two patients with partial remission achieved complete remission at the 9th and 12th months of follow-up. Therefore, the best complete remission rate was 63.6%. Cytokine-release syndrome and immune effector cell-associated neurotoxicity syndrome were controllable, and no immune-related adverse reactions occurred. Conclusion: Autologous 7×19 CAR-T combined with tirelizumab for treating relapsed or refractory large B-cell lymphoma achieved good efficacy with controllable adverse reactions.

Efficacy of checkpoint inhibition after CAR-T failure in aggressive B-cell lymphomas: outcomes from 15 US institutions

Checkpoint inhibitor (CPI) therapy with anti-PD-1 antibodies has been associated with mixed outcomes in small cohorts of patients with relapsed aggressive B-cell lymphomas after CAR-T failure. To define CPI therapy efficacy more definitively in this population, we retrospectively evaluated clinical outcomes in a large cohort of 96 patients with aggressive B-cell lymphomas receiving CPI therapy after CAR-T failure across 15 US academic centers. Most patients (53%) had diffuse large B-cell lymphoma, were treated with axicabtagene ciloleucel (53%), relapsed early (≤180 days) after CAR-T (83%), and received pembrolizumab (49%) or nivolumab (43%). CPI therapy was associated with an overall response rate of 19% and a complete response rate of 10%. Median duration of response was 221 days. Median progression-free survival (PFS) and overall survival (OS) were 54 and 159 days, respectively. Outcomes to CPI therapy were significantly improved in patients with primary mediastinal B-cell lymphoma. PFS (128 vs 51 days) and OS (387 vs 131 days) were significantly longer in patients with late (>180 days) vs early (≤180 days) relapse after CAR-T. Grade ≥3 adverse events occurred in 19% of patients treated with CPI. Most patients (83%) died, commonly because of progressive disease. Only 5% had durable responses to CPI therapy. In the largest cohort of patients with aggressive B-cell lymphoma treated with CPI therapy after CAR-T relapse, our results reveal poor outcomes, particularly among those relapsing early after CAR-T. In conclusion, CPI therapy is not an effective salvage strategy for most patients after CAR-T, where alternative approaches are needed to improve post-CAR-T outcomes.

The identification of TCF1+ progenitor exhausted T cells in THRLBCL may predict a better response to PD-1/PD-L1 blockade

T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) is a rare and aggressive variant of diffuse large B-cell lymphoma (DLBCL) that usually affects young to middle-aged patients, with disseminated disease at presentation. The tumor microenvironment (TME) plays a key role in THRLBCL due to its peculiar cellular composition (<10% neoplastic B cells interspersed in a cytotoxic T-cell/histiocyte-rich background). A significant percentage of THRLBCL is refractory to rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (RCHOP)-based regimens and to chimeric antigen receptor T-cell therapy; thus, the development of a specific therapeutic approach for these patients represents an unmet clinical need. To better understand the interaction of immune cells in THRLBCL TME and identify more promising therapeutic strategies, we compared the immune gene expression profiles of 12 THRLBCL and 10 DLBCL samples, and further corroborated our findings in an extended in silico set. Gene coexpression network analysis identified the predominant role of the programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) axis in the modulation of the immune response. Furthermore, the PD-1/PD-L1 activation was flanked by the overexpression of 48 genes related to the functional exhaustion of T cells. Globally, THRLBCL TME was highly interferon-inflamed and severely exhausted. The immune gene profiling findings strongly suggest that THRLBCL may be responsive to anti–PD-1 therapy but also allowed us to take a step forward in understanding THRLBCL TME. Of therapeutic relevance, we validated our results by immunohistochemistry, identifying a subset of TCF1⁺ (T cell–specific transcription factor 1, encoded by the TCF7 gene) progenitor exhausted T cells enriched in patients with THRLBCL. This subset of TCF1⁺ exhausted T cells correlates with good clinical response to immune checkpoint therapy and may improve prediction of anti–PD-1 response in patients with THRLBCL.