Network meta-analysis of CAR T-Cell therapy for the treatment of 3L+ R/R LBCL after using published comparative studies.

INTRODUCTION: Studies have compared chimeric antigen receptor (CAR) T-cell therapies and salvage chemotherapy in relapsed/refractory large B-cell lymphoma (LBCL) patients, but further evidence of their relative effectiveness is warranted. METHODS: Our systematic review identified studies comparing efficacy and safety outcomes of axicabtagene ciloleucel (axi-cel), lisocabtagene maraleucel (liso-cel) and tisagenlecleucel (tisa-cel) trials to salvage chemotherapy cohorts in LBCL patients with ≥2 prior lines of treatment; and an extended evidence network included indirect comparisons comparing CAR T-cell therapies. We conducted network meta-analyzes using Bayesian hierarchical modeling. RESULTS: Three studies comparing ZUMA-1 (axi-cel), TRANSCEND (liso-cel) and JULIET (tisa-cel) trials to salvage chemotherapy within the SCHOLAR-1 cohort were identified. Axi-cel (odds ratio [OR]:5.63; 95% credible interval [CrI]:2.66-12.42) and liso-cel (OR:4.26; 95%CrI:2.33-7.93) showed a significant increased overall response rate compared to tisa-cel, but not to one-another. Axi-cel demonstrated significant improvements in overall survival relative to liso-cel (hazard ratio [HR]:0.54; 95%CrI:0.37-0.79) and tisa-cel (HR:0.47; 95%CrI:0.26-0.88). Higher rates of grade ≥3 neurological events were observed with axi-cel than with tisa-cel and liso-cel. CONCLUSIONS: We highlight important differences in clinical outcomes between CAR T-cell therapies. Axi-cel demonstrated improved overall survival compared to tisa-cel and liso-cel, and both axi-cel and liso-cel showed higher response rates compared to tisa-cel.

Benefit of axicabtagene ciloleucel versus chemoimmunotherapy in older patients and/or patients with poor ECOG performance status with relapsed or refractory large B-cell lymphoma after 2 or more lines of prior therapy.

Axicabtagene ciloleucel (axi-cel) in trials has demonstrated favorable efficacy compared with historical controls after ≥2 lines of therapy for the treatment of relapsed or refractory (R/R) large B cell lymphoma (LBCL). Herein, we compared the real-world effectiveness of axi-cel with efficacy and effectiveness of chemoimmunotherapy (CIT) in patients aged ≥65 years and patients with Eastern Cooperative Oncology Group performance status (ECOG PS) of 2. A total of 1146 patients treated with commercial axi-cel for R/R LBCL with ≥2 lines of prior therapy were included from the Center for International Blood and Marrow Transplantation Research prospective observational study, and 469 patients treated with CIT for R/R LBCL after ≥2 lines of prior therapy were included from SCHOLAR-1 (an international, multicohort, retrospective study). After propensity score matching, at a median follow-up of 24 months for patients receiving axi-cel and 60 months for patients receiving CIT, 12-month overall survival rates were 62% and 28%, respectively (hazard ratio, 0.30 [95% CI, 0.24-0.37]). Objective response rate (ORR) was 76% (complete response [CR] rate 58%) in patients receiving axi-cel versus 28% (CR rate 16%) for those receiving CIT. A 57% difference in ORR (55% difference in CR rate) favoring axi-cel over CIT was observed among patients aged ≥65 years. Increased magnitude of benefit in response rates for axi-cel versus CIT was also observed among patients with ECOG PS = 2. These findings further support the broader use of axi-cel in older patients and patients with ECOG PS = 2 with R/R LBCL.

A Comparison of 3-Year Follow-up of ZUMA-5 (Axicabtagene Ciloleucel) With SCHOLAR-5 in Relapsed/Refractory Follicular Lymphoma.

In the pivotal ZUMA-5 trial, axicabtagene ciloleucel (axi-cel; an autologous anti-CD19 chimeric antigen receptor T-cell therapy) demonstrated high rates of durable response in relapsed/refractory follicular lymphoma patients. SCHOLAR-5 is an external control cohort designed to act as a comparator to ZUMA-5. Here, we present an updated comparative analysis of ZUMA-5 and SCHOLAR-5, using the 36-month follow-up data and the intent-to-treat population of ZUMA-5. Using propensity-score methods, 127 patients in ZUMA-5 were compared to 129 patients in SCHOLAR-5. At this extended follow-up, axi-cel continues to demonstrate clinically meaningful benefits in survival compared to historically available treatments in this population.

Bridging therapy with axicabtagene ciloleucel for large B-cell lymphoma: results from the US Lymphoma CAR-T Consortium.

ABSTRACT: During the manufacturing period of autologous chimeric antigen receptor (CAR) T-cell therapy, patients may experience a decline in their condition due to cancer progression. In this study, we investigated the impact of bridging therapy (BT) on the outcome of patients with relapsed/refractory large B-cell lymphoma who received antilymphoma treatment between leukapheresis and axicabtagene ciloleucel (axi-cel) infusion. We conducted our analysis using data from the multicenter US Lymphoma CAR-T Consortium, with a median follow-up of 33 months (range, 4.3-42.1). Out of the 298 patients who underwent leukapheresis, 275 patients received axi-cel. A total 52% of patients (n = 143) who received BT had a higher baseline risk profile than patients who did not receive BT, and these patients, as a group, had inferior outcomes compared with those who did not receive BT. However, after propensity score matching between the 2 groups, there were no statistically significant differences in overall response rate (77% vs 87%; P = .13), complete response rate (58% vs 70%; P = .1), progression-free survival (hazard ratio [HR], 1.25; P = .23), and overall survival (HR, 1.39; P=.09) between the BT group and the no-BT group, respectively. Analyzing the effects of BT in the whole cohort that underwent leukapheresis regardless of receiving axi-cel (intention-to-treat analysis) showed similar results. Radiation BT resulted in outcomes similar to those observed with nonradiation BT. Our findings suggest that BT may be safe without a significant impact on long-term survival for patients who require disease stabilization during the manufacturing period. Moreover, our results suggest that there is no clear advantage to using radiation-based BT over nonradiation-based BT.

Three-year follow-up analysis of axicabtagene ciloleucel in relapsed/refractory indolent non-Hodgkin lymphoma (ZUMA-5).

ABSTRACT: Axicabtagene ciloleucel (axi-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for relapsed/refractory (R/R) follicular lymphoma (FL). Approval was supported by the phase 2, multicenter, single-arm ZUMA-5 study of axi-cel for patients with R/R indolent non-Hodgkin lymphoma (iNHL; N = 104), including FL and marginal zone lymphoma (MZL). In the primary analysis (median follow-up, 17.5 months), the overall response rate (ORR) was 92% (complete response rate, 74%). Here, we report long-term outcomes from ZUMA-5. Eligible patients with R/R iNHL after ≥2 lines of therapy underwent leukapheresis, followed by lymphodepleting chemotherapy and axi-cel infusion (2 × 106 CAR T cells per kg). The primary end point was ORR, assessed in this analysis by investigators in all enrolled patients (intent-to-treat). After median follow-up of 41.7 months in FL (n = 127) and 31.8 months in MZL (n = 31), ORR was comparable with that of the primary analysis (FL, 94%; MZL, 77%). Median progression-free survival was 40.2 months in FL and not reached in MZL. Medians of overall survival were not reached in either disease type. Grade ≥3 adverse events of interest that occurred after the prior analyses were largely in recently treated patients. Clinical and pharmacokinetic outcomes correlated negatively with recent exposure to bendamustine and high metabolic tumor volume. After 3 years of follow-up in ZUMA-5, axi-cel demonstrated continued durable responses, with very few relapses beyond 2 years, and manageable safety in patients with R/R iNHL. The ZUMA-5 study was registered at www.clinicaltrials.gov as #NCT03105336.

Safety and efficacy of ibrutinib in combination with rituximab and lenalidomide in previously untreated follicular and marginal zone lymphoma: An open label, phase 2 study.

BACKGROUND: Follicular lymphoma (FL) and marginal zone lymphoma (MZL) are indolent non-Hodgkin lymphomas (iNHL). Median survival for iNHL is approximately 20 years. Because standard treatments are not curative, patients often receive multiple lines of therapy with associated toxicity-rationally designed, combination therapies with curative potential are needed. The immunomodulatory drug lenalidomide was evaluated in combination with rituximab for the frontline treatment of FL in the phase 3 RELEVANCE study. Ibrutinib, an oral Bruton tyrosine kinase inhibitor, is active in NHL and was evaluated in combination with lenalidomide, rituximab, and ibrutinib (IRR) in a phase 1 study. METHODS: The authors conducted an open-label, phase 2 clinical trial of IRR for previously untreated FL and MZL. The primary end point was progression-free survival (PFS) at 24 months. RESULTS: This study included 48 participants with previously untreated FL grade 1-3a (N = 38), or MZL (N = 10). Participants received 12, 28-day cycles of lenalidomide (15 mg, days 1-21 cycle 1; 20 mg, cycles 2-12), rituximab (375 mg/m2 weekly in cycle 1; day 1 cycles 2-12), and ibrutinib 560 mg daily. With a median follow-up of 65.3 months, the estimated PFS at 24 months was 78.8% (95% confidence interval [CI], 68.0%-91.4%) and 60-month PFS was 59.7% (95% CI, 46.6%-76.4%). One death occurred unrelated to disease progression. Grade 3-4 adverse events were observed in 64.6%, including 50% with grade 3-4 rash. CONCLUSIONS: IRR is highly active as frontline therapy for FL and MZL. Compared to historical results with lenalidomide and rituximab, PFS is similar with higher grade 3-4 toxicity, particularly rash. The study was registered with ClinicalTrials.gov (NCT02532257).

Effect of delayed cell infusion in patients with large B-cell lymphoma treated with chimeric antigen receptor T-cell therapy.

Complications occurring after lymphodepleting chemotherapy (LDC) may delay chimeric antigen receptor (CAR) T-cell infusion. The effect of these delays on clinical outcomes is unclear. We performed a retrospective analysis of 240 patients with relapsed/refractory large B-cell lymphoma treated with standard-of-care axicabtagene ciloleucel (axi-cel) and identified 40 patients (16.7%) who had delay in axi-cel infusion. Of these, 85% had delay due to infection. At time of LDC initiation, patients with delayed infusion had lower absolute neutrophil count (p=0.006), lower platelets (p=0.004), lower hemoglobin (p5 days (4.6 vs. 8.2 months; p=0.036), but not 1 day (5.7 vs. 8.2 months; p=0.238). Following propensity score matching, patients with delayed infusion continued to have shorter median PFS (3.5 vs. 6.0 months; p=0.015). Levels of proinflammatory cytokines on day of infusion were significantly higher in patients with delayed infusion. Together, these findings suggest that delays in CAR T-cell administration after initiation of LDC are associated with inferior outcomes. Further studies are needed to guide strategies to improve efficacy in such patients.

Chimeric antigen receptor T cells to target CD79b in B-cell lymphomas.

BACKGROUND: Chimeric antigen receptor (CAR) T cells targeting CD19 mediate potent and durable effects in B-cell malignancies. However, antigen loss or downregulation is a frequent cause of resistance. Here, we report development of a novel CAR T-cell therapy product to target CD79b, a pan B-cell antigen, widely expressed in most B-cell lymphomas. METHODS: We generated a novel anti-CD79b monoclonal antibody by hybridoma method. The specificity of the antibody was determined by testing against isogenic cell lines with human CD79b knock-in or knock-out. A single-chain variable fragment derived from the monoclonal antibody was used to make a panel of CD79b-targeting CAR molecules containing various hinge, transmembrane, and co-stimulatory domains. These were lentivirally transduced into primary T cells and tested for antitumor activity in in vitro and in vivo B-cell lymphoma models. RESULTS: We found that the novel anti-CD79b monoclonal antibody was highly specific and bound only to human CD79b and no other cell surface protein. In testing the various CD79b-targeting CAR molecules, superior antitumor efficacy in vitro and in vivo was found for a CAR consisting CD8α hinge and transmembrane domains, an OX40 co-stimulatory domain, and a CD3ζ signaling domain. This CD79b CAR specifically recognized human CD79b-expressing lymphoma cell lines but not CD79b knock-out cell lines. CD79b CAR T cells, generated from T cells from either healthy donors or patients with lymphoma, proliferated, produced cytokines, degranulated, and exhibited robust cytotoxic activity in vitro against CD19+ and CD19- lymphoma cell lines and patient-derived lymphoma tumors relapsing after prior CD19 CAR T-cell therapy. Furthermore, CD79b CAR T cells were highly efficient at eradicating pre-established lymphoma tumors in vivo in three aggressive lymphoma xenograft models, including two cell line-derived xenografts and one patient-derived xenograft. Notably, these CAR T cells did not demonstrate any significant tonic signaling activity or markers of exhaustion. CONCLUSION: Our results indicated that this novel CD79b CAR T-cell therapy product has robust antitumor activity against B-cell lymphomas. These results supported initiation of a phase 1 clinical trial to evaluate this product in patients with relapsed or refractory B-cell lymphomas.

A single-cell atlas of CD19 chimeric antigen receptor T cells.

Li et al. present a resource of single-cell RNA sequencing (scRNA-seq) data from the infusion products of relapsed or refractory large B cell lymphoma (rrLBCL) patients treated with standard-of-care axicabtagene ciloleucel and identify features that are significantly different between products from responders and non-responders at 3-month followup by PET/CT, an important landmark for long-term outcomes.

Prolonged cytopenia following CD19 CAR T cell therapy is linked with bone marrow infiltration of clonally expanded IFNγ-expressing CD8 T cells.

Autologous anti-CD19 chimeric antigen receptor T cell (CAR T) therapy is highly effective in relapsed/refractory large B cell lymphoma (rrLBCL) but is associated with toxicities that delay recovery. While the biological mechanisms of cytokine release syndrome and neurotoxicity have been investigated, the pathophysiology is poorly understood for prolonged cytopenia, defined as grade ≥3 cytopenia lasting beyond 30 days after CAR T infusion. We performed single-cell RNA sequencing of bone marrow samples from healthy donors and rrLBCL patients with or without prolonged cytopenia and identified significantly increased frequencies of clonally expanded CX3CR1hi cytotoxic T cells, expressing high interferon (IFN)-γ and cytokine signaling gene sets, associated with prolonged cytopenia. In line with this, we found that hematopoietic stem cells from these patients expressed IFN-γ response signatures. IFN-γ deregulates hematopoietic stem cell self-renewal and differentiation and can be targeted with thrombopoietin agonists or IFN-γ-neutralizing antibodies, highlighting a potential mechanism-based approach for the treatment of CAR T-associated prolonged cytopenia.

Targeting CXCR4 abrogates resistance to trastuzumab by blocking cell cycle progression and synergizes with docetaxel in breast cancer treatment.

BACKGROUND: Although trastuzumab and other HER2-targeted therapies have significantly improved survival in patients with HER2 overexpressed or amplified (HER2+) breast cancer, a significant proportion of patients do not respond or eventually develop clinical resistance. Strategies to reverse trastuzumab resistance remain a high clinical priority. We were the first to report the role of CXCR4 in trastuzumab resistance. The present study aims to explore the therapeutic potential of targeting CXCR4 and better understand the associated mechanisms. METHODS: Immunofluorescent staining, confocal microscopy analysis, and immunoblotting were used to analyze CXCR4 expression. BrdU incorporation assays and flow cytometry were used to analyze dynamic CXCR4 expression. Three-dimensional co-culture (tumor cells/breast cancer-associated fibroblasts/human peripheral blood mononuclear cells) or antibody-dependent cellular cytotoxicity assay was used to mimic human tumor microenvironment, which is necessary for testing therapeutic effects of CXCR4 inhibitor or trastuzumab. The FDA-approved CXCR4 antagonist AMD3100, trastuzumab, and docetaxel chemotherapy were used to evaluate therapeutic efficacy in vitro and in vivo. Reverse phase protein array and immunoblotting were used to discern the associated molecular mechanisms. RESULTS: Using a panel of cell lines and patient breast cancer samples, we confirmed CXCR4 drives trastuzumab resistance in HER2+ breast cancer and further demonstrated the increased CXCR4 expression in trastuzumab-resistant cells is associated with cell cycle progression with a peak in the G2/M phases. Blocking CXCR4 with AMD3100 inhibits cell proliferation by downregulating mediators of G2-M transition, leading to G2/M arrest and abnormal mitosis. Using a panel of trastuzumab-resistant cell lines and an in vivo established trastuzumab-resistant xenograft mouse model, we demonstrated that targeting CXCR4 with AMD3100 suppresses tumor growth in vitro and in vivo, and synergizes with docetaxel. CONCLUSIONS: Our findings support CXCR4 as a novel therapeutic target and a predictive biomarker for trastuzumab resistance in HER2+ breast cancer.

Single cell clonotypic and transcriptional evolution of multiple myeloma precursor disease.

Multiple myeloma remains an incurable disease, and the cellular and molecular evolution from precursor conditions, including monoclonal gammopathy of undetermined significance and smoldering multiple myeloma, is incompletely understood. Here, we combine single-cell RNA and B cell receptor sequencing from fifty-two patients with myeloma precursors in comparison with myeloma and normal donors. Our comprehensive analysis reveals early genomic drivers of malignant transformation, distinct transcriptional features, and divergent clonal expansion in hyperdiploid versus non-hyperdiploid samples. Additionally, we observe intra-patient heterogeneity with potential therapeutic implications and identify distinct patterns of evolution from myeloma precursor disease to myeloma. We also demonstrate distinctive characteristics of the microenvironment associated with specific genomic changes in myeloma cells. These findings add to our knowledge about myeloma precursor disease progression, providing valuable insights into patient risk stratification, biomarker discovery, and possible clinical applications.

Immortalized B Cells Transfected with mRNA of Antigen Fused to MITD (IBMAM): An Effective Tool for Antigen-Specific T-Cell Expansion and TCR Validation.

Peripheral mononuclear blood cells (PBMCs) are the most widely used study materials for immunomonitoring and antigen-specific T-cell identification. However, limited patient PBMCs and low-frequency antigen-specific T cells remain as significant technical challenges. To address these limitations, we established a novel platform comprised of optimized HLA-matched immortalized B cells transfected with mRNA of a prototype viral or tumor antigen conjugated to MHC class-I trafficking domain protein (MITD) to increase the efficiency of epitope expression in antigen-presenting cells (APCs) essential to expanding antigen-specific T cells. When applied to CMV as a model, the IBMAM platform could successfully expand CMV-specific T cells from low-frequency CMV PBMCs from seropositive donors. Additionally, this platform can be applied to the validation of antigen specific TCRs. Together, compared to using APCs with synthesized peptides, this platform is an unlimited, highly efficient, and cost-effective resource in detecting and expanding antigen-specific T cells and validating antigen-specific TCRs.

A non-antibiotic-disrupted gut microbiome is associated with clinical responses to CD19-CAR-T cell cancer immunotherapy.

Increasing evidence suggests that the gut microbiome may modulate the efficacy of cancer immunotherapy. In a B cell lymphoma patient cohort from five centers in Germany and the United States (Germany, n = 66; United States, n = 106; total, n = 172), we demonstrate that wide-spectrum antibiotics treatment ('high-risk antibiotics') prior to CD19-targeted chimeric antigen receptor (CAR)-T cell therapy is associated with adverse outcomes, but this effect is likely to be confounded by an increased pretreatment tumor burden and systemic inflammation in patients pretreated with high-risk antibiotics. To resolve this confounding effect and gain insights into antibiotics-masked microbiome signals impacting CAR-T efficacy, we focused on the high-risk antibiotics non-exposed patient population. Indeed, in these patients, significant correlations were noted between pre-CAR-T infusion Bifidobacterium longum and microbiome-encoded peptidoglycan biosynthesis, and CAR-T treatment-associated 6-month survival or lymphoma progression. Furthermore, predictive pre-CAR-T treatment microbiome-based machine learning algorithms trained on the high-risk antibiotics non-exposed German cohort and validated by the respective US cohort robustly segregated long-term responders from non-responders. Bacteroides, Ruminococcus, Eubacterium and Akkermansia were most important in determining CAR-T responsiveness, with Akkermansia also being associated with pre-infusion peripheral T cell levels in these patients. Collectively, we identify conserved microbiome features across clinical and geographical variations, which may enable cross-cohort microbiome-based predictions of outcomes in CAR-T cell immunotherapy.

PD-L1+ macrophages are associated with favorable features in primary mediastinal (thymic) large B-cell lymphoma.

Primary mediastinal (thymic) large B-cell lymphoma (PMBCL) is a rare, aggressive subtype of non-Hodgkin lymphoma and has a complex inflammatory microenvironment. Although most patients can be cured with standard-of-care immunochemotherapy, patients who have disease relapse have an unfavorable prognosis. Pre-treatment prognostic biomarkers in PMBCL are needed. In this retrospective study, we analyzed the clinical features and outcomes of PMBCL patients and their association with immune cell subpopulations identified by multiplex immunofluorescence at initial diagnosis. Two different antibody panels were used to assess macrophages in tissue biopsy specimens collected before the initiation of induction therapy. Twelve PMBCL patients, including five patients who had disease relapse, were included in the analysis. At a median follow-up time of 32.2 months, the median progression-free and overall survival durations were not reached. Our findings suggest that a high density of PD-L1+ macrophages is associated with favorable features, such as early disease stage and the absence of B-symptoms, and indicate that a high percentage of PD-L1+ macrophages and high densities of CD30+PD-L1+ cells and CD30+ cells might be associated with a lower risk of relapse within 12 months of therapy initiation. Further studies are needed to develop a biomarker signature predictive of treatment response with therapeutic consequences for patients with newly diagnosed PMBCL.

Immune Effector Cell-Associated Hemophagocytic Lymphohistiocytosis-Like Syndrome.

T cell-mediated hyperinflammatory responses, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), are now well-established toxicities of chimeric antigen receptor (CAR) T cell therapy. As the field of CAR T cells advances, however, there is increasing recognition that hemophagocytic lymphohistiocytosis (HLH)-like toxicities following CAR T cell infusion are occurring broadly across patient populations and CAR T cell constructs. Importantly, these HLH-like toxicities are often not as directly associated with CRS and/or its severity as initially described. This emergent toxicity, however ill-defined, is associated with life-threatening complications, creating an urgent need for improved identification and optimal management. With the goal of improving patient outcomes and formulating a framework to characterize and study this HLH-like syndrome, we established an American Society for Transplantation and Cellular Therapy panel composed of experts in primary and secondary HLH, pediatric and adult HLH, infectious disease, rheumatology and hematology, oncology, and cellular therapy. Through this effort, we provide an overview of the underlying biology of classical primary and secondary HLH, explore its relationship with similar manifestations following CAR T cell infusions, and propose the term "immune effector cell-associated HLH-like syndrome (IEC-HS)" to describe this emergent toxicity. We also delineate a framework for identifying IEC-HS and put forward a grading schema that can be used to assess severity and facilitate cross-trial comparisons. Additionally, given the critical need to optimize outcomes for patients experiencing IEC-HS, we provide insight into potential treatment approaches and strategies to optimize supportive care and delineate alternate etiologies that should be considered in a patient presenting with IEC-HS. By collectively defining IEC-HS as a hyperinflammatory toxicity, we can now embark on further study of the pathophysiology underlying this toxicity profile and make strides toward a more comprehensive assessment and treatment approach.