anti-CD19 CAR T-cell Therapy Research Articles

The role of polyreactive memory B cells in systemic lupus erythematosus.

In systemic lupus erythematosus (SLE), the production of autoantibodies is a crucial characteristic, and B cells play a significant role in its pathogenesis. B cells are the immune cells most associated with the genetic predispositions of SLE, and recent clinical studies showing that anti-CD19 CAR-T cell therapy induces drug-free remission have underscored the importance of B cells in SLE. Meanwhile, various B cell subsets exist across different stages of differentiation, from naive B cells to plasma-cells, and identifying the important subpopulations within SLE remains a critical future challenge. Years of B cell repertoire analyses have revealed the importance of polyreactive B cell receptors (BCRs) and autoantibodies that react to a various self-antigens and microbial antigens. Particularly, memory B cells with polyreactive BCRs, which play a crucial role in biological defense during the fetal stage, are characteristically differentiated in SLE. Type I interferon-mediated expression of CXCL13 and IL21 in CD4+ T cells is associated with the development of polyreactive memory B cells. The expansion of the polyreactive B cell repertoire, vital for defending against infections such as viruses, may exert an intrinsic function in SLE.

Identification of clonally expanded γδ T-cell populations during CAR-Tcell therapy.

Anti-CD19 Chimeric Antigen Receptor (CAR)-Tcell therapies have shown promise for treating B cell malignancies, but the clinical outcome is influenced by both the CAR-T product and the patient's immune system. The role of γδ Tcells in the context of CAR-T cell therapy remains poorly understood. This study investigates the transcriptional heterogeneity, clonal expansion and dynamics of γδ Tcells in patients undergoing anti-CD19 CAR-T cell therapy. Longitudinal single cell multi-omics analysis was performed on γδ Tcells from four patients receiving anti-CD19 CAR-T cell therapy. Single cell RNA-seq, antibody-based protein profiling (AbSeq) and full-length TCRγδ sequences revealed clonally expanded populations displaying plasticity in Tcell differentiation, and temporal dynamics of large clones, suggesting ongoing expansion and differentiation. Clonally expanded γδ Tcells had heterogeneous gene expression profiles, occupying seven transcriptionally distinct clusters. Analysis of chemokine markers indicated cluster-specific homing tendencies of circulating γδ Tcells to peripheral tissues. We found unexpectedly high frequencies of Vδ1 and Vδ3 cells in the blood with distinct gene and protein expression profiles. This analysis provides insights into the dynamic and heterogeneous nature of γδ Tcells following anti-CD19 CAR-T cell therapy, contributing valuable information for optimizing CAR-T cell therapies in B cell malignancies.

CAR T-cell Therapy for Central Nervous System Lymphoma.

While anti-CD19 CAR T-cell therapy represents a major advance in systemic diffuse large B-cell lymphomas, central nervous system (CNS) lymphomas have been excluded from pivotal trials because of the fear of neurotoxicity. The purpose of this review was to assess the efficacy and tolerance of CAR T-cells in CNS lymphomas based on recently published studies. All the studies on CAR T-cell therapy for both primary and secondary CNS lymphomas reported high response rates (complete response rates ranging from 32 to 67%) in highly pre-treated patients. One-year PFS reached 40 to 60% in several studies. Neurotoxicity occurred in 36 to 68% of patients, including grade 3-4 neurotoxicity in 4.5 to 29% of patients. CAR T-cell therapy appears to be a very promising treatment in CNS lymphomas, with efficacy results close to those observed in systemic lymphomas. The toxicity profile, notably regarding neurotoxicity, is reassuring and should not prevent the development of CAR T-cells in the disease.

Anti-CD19 CAR-T cells are effective in severe idiopathic Lambert-Eaton myasthenic syndrome.

Lambert-Eaton myasthenic syndrome (LEMS) is an autoantibody-mediated disease of the neuromuscular junction characterized by muscular weakness. Autoantibodies to presynaptic P/Q-type voltage-gated calcium channels (VGCCs) induce defective neuromuscular function. In severe cases, current immunosuppressive and immunomodulatory treatment strategies are often insufficient. First reports show beneficial effects of anti-CD19 chimeric antigen receptor (CAR)-T cell therapy in patients with autoantibody-mediated myasthenia gravis. We report a patient with isolated idiopathic LEMS treated with autologous anti-CD19-CAR-T cells. In this patient, CAR-T infusion leads to expansion of predominantly CD4+ CAR-T cells with a terminally differentiated effector memory cells re-expressing CD45RA (TEMRA)-like phenotype indicating cytotoxic capabilities and subsequent B cell depletion. VGCC antibody titers decrease, resulting in a clinical improvement of LEMS symptoms, e.g., 8-fold increase in walking distance. The patient does not show relevant side effects except for cytokine release syndrome grade 2 and intermittent neutropenia suggesting that anti-CD19 CAR-T cell therapy may be a treatment option in patients with LEMS.

Safety and Efficacy of 9 Days Vein-to-Vein Decentralized Manufactured Anti-CD19 CAR T-Cell Therapy for Relapsed/Refractory B-cell Leukemia and Lymphoma: Results from the First Phase 1 Indian Trial (VELCART)

Safety and Efficacy of 9 Days Vein-to-Vein Decentralized Manufactured Anti-CD19 CAR T-Cell Therapy for Relapsed/Refractory B-cell Leukemia and Lymphoma: Results from the First Phase 1 Indian Trial (VELCART)

CT-165 Safety and Efficacy of 9 Days Veinto-Vein Decentralized Manufactured Anti-CD19 CAR T-Cell Therapy for Relapsed/Refractory B-cell Leukemia and Lymphoma: Results from the First Phase 1 Indian Trial (VELCART)

CT-165 Safety and Efficacy of 9 Days Veinto-Vein Decentralized Manufactured Anti-CD19 CAR T-Cell Therapy for Relapsed/Refractory B-cell Leukemia and Lymphoma: Results from the First Phase 1 Indian Trial (VELCART)

Anti-CD19 CAR-T Cell Therapy in Elderly Patients: Multicentric Real-World Experience from GETH-TC/GELTAMO

Chimeric antigen receptor (CAR)-T cell therapy is approved for the treatment of relapsed/refractory (R/R) large B cell lymphoma (LBCL). However, elderly patients might not be candidates for this therapy due to its toxicity, and criteria for candidate selection are lacking. Our aim was to analyze efficacy and toxicity results of CAR-T cell therapy in the population of patients 70 years and older as compared to those obtained in younger patients in the real-world setting. A multicentric retrospective study was performed including patients with R/R aggressive LBCL who received commercial CAR-T cell therapy with either tisagenlecleucel or axicabtagene ciloleucel within the Spanish Group of Hematopoietic Transplant and Cell Therapy/Spanish Group of Lymphomas and Autologous Transplant (GETH-TC/GELTAMO) centers between 2019 and 2023. As of August 2023, 442 adult patients with aggressive LBCL underwent apheresis for CAR-T cell therapy as third or subsequent line and follow-up data was collected. Of 412 infused patients, 71 (17%) were 70 years or older. Baseline characteristics, product selection, and characteristics at apheresis (including disease status, Ann Arbor stage, revised international prognosis index (R-IPI), bulky disease, lactate dehydrogenase [LDH] and ECOG [Eastern Cooperative Group performance status]) were comparable between groups. Median time from both approval to infusion and apheresis to infusion did not differ. No differences were found between groups in overall and complete response rates at 1 and 3 months. With a median follow-up of 12.2 months (range 1-44), 12-month progression-free survival (PFS) and overall survival (OS) were comparable between groups (35.2% in <70 years vs. 35.9% in ≥70 years (P = .938) and 51.1% and 52.1% (P = .885), respectively). Age ≥70 years did not affect PFS (hazard ratio (HR) 0.98, P = .941) and OS (HR 0.97, P = .890) in the univariate and multivariate analysis. Cytokine release syndrome (CRS) was observed in 82% of patients <70 years old and 84.5% in ≥ 70 years old (P = .408). Grade ≥3 CRS was more frequent in the older group (5% vs. 15%, P = .002). In the multivariate analysis, age ≥70 years was associated with an increased risk of grade ≥3 CRS (OR 3.7, P = .013). No differences were observed in terms of overall neurotoxicity (35% vs. 42%, P = .281) or grade ≥3 (12% vs. 17%, P = .33). The proportion of patients with infections, admission to the intensive care unit within the first month, and non-relapse mortality were similar between both groups. CAR-T cell therapy in patients older than 70 years showed similar efficacy to that observed in younger patients in the real-world setting. However, age ≥70 years was an independent risk factor for grades 3-4 CRS. The need for additional strategies to reduce toxicity in this population should be addressed in future studies.

A Multicenter Real-life Prospective Study of Axicabtagene Ciloleucel versus Tisagenlecleucel Toxicity and Outcomes in Large B-cell Lymphomas.

This real-world prospective observational study across 21 Italian centers (CART-SIE) compares axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel) outcomes in 485 patients with relapsed/refractory large B-cell lymphoma with baseline characteristics matched by stabilized inverse propensity score weighting. Axi-cel versus tisa-cel had higher all-grade cytokine release syndrome (78.6% vs. 89.3%, P = 0.0017) and neurotoxicity (9.9% vs. 32.2%, P < 0.0001) but also superior progression-free survival (PFS) at 1 year (46.5% vs. 34.1%, P = 0.0009). Even among patients who failed bridging therapy, axi-cel PFS was superior to tisa-cel (37.5% vs. 22.7%, P = 0.0059). Differences in overall survival and high-grade immune toxicities were not significant. The CAR-HEMATOTOX score not only predicted hematologic toxicity but also 1-year survival outcomes (51.5% in CAR-HEMATOTOX high vs. 77.2% in CAR-HEMATOTOX low, P < 0.0001). Twenty patients developed second primary malignancies, including two cases of T-cell neoplasms. These findings enable more informed selection of anti-CD19 CAR T-cell therapy, balancing bridging, safety, and efficacy considerations for individual patients. Significance: The findings of this study on 485 patients with relapsed/refractory large B-cell lymphoma treated with commercial axi-cel and tisa-cel indicate axi-cel's superior PFS after propensity score weighting. The predictive utility of CAR-HEMATOTOX in assessing not only toxicity but also outcomes across both CAR T-cell products may guide future risk-stratified management strategies.

Molecular Disease Monitoring in Patients With Relapsed/refractory B-Cell Lymphoma Receiving Anti-CD19 CAR T-Cell Therapy

BackgroundChimeric antigen receptor (CAR) T-cell therapy has improved the historically poor outcomes for relapsed and refractory (R/R) large B-cell non-Hodgkin's lymphoma (LBCL). However, nearly 60% of patients will either fail to respond or relapse after CAR T-cell therapy. Currently, PET/CT scans are used to assess response. Cell-free circulating tumor DNA (ctDNA) is released by tumor cells into the peripheral blood and can be measured for minimal residual disease (MRD) assessment. MethodsIn this retrospective, IRB approved pilot study, archived lymphoma tissue and ctDNA from peripheral blood samples on day 0, 14, 28, 56, 90, 180, and 365 after CAR T-cell infusion from 10 patients with R/R NHL were collected for next-generation sequencing (NGS) of clonal variable-diversity-joining (VDJ) rearrangements (Adaptive biotechnologies [Seattle, WA]). Response was assessed by PET/CT on days 90 and 365 and graded according to the Lugano 2014 criteria. The primary endpoint was to determine the feasibility of detecting ctDNA to monitor disease response after anti-CD19 CAR T-cell therapy. The secondary endpoint was to compare the sensitivity/specificity of MRD assessment from ctDNA to PET/CT imaging. ResultsNine out of 10 patients with a trackable sequence [median age 69 (range: 56-76); 55.6% male; median LDH 224], were included in this study. Each received tisagenlecleucel (tisa-cel) CAR T-cell therapy after median 2 prior treatments (range: 2-4). 7/9 patients had R/R diffuse large B-cell lymphoma (DLBCL), and 2/9 had transformed follicular lymphoma. At a median follow up of 12.7 months (range: 1.5-30 months), 4 patients were alive. By day 90, 3 patients (33.3%) achieved a radiographic complete response (CR) whilst 6 patients (66.6%) had progressive disease (PD). Detectable MRD on day 14 or day 28 had 83% sensitivity and 100% specificity for radiographic progression at any time before 1 year. For patients with PD, the median (interquartile range) MRD at day 0, 14, and 28 were 17.31 (1.01, 96.84), 9.12 (0.30, 18.8), and 23.77 (8.01, 137.53) copies per milliliter (mL), respectively. For patients with detectable MRD at day 28, mOS and mPFS were 6.7 and 1.3 months, respectively. ConclusionMonitoring MRD was a sensitive and specific method to detect poor response to tisa-cel. Additional studies evaluating MRD more frequently and with different products are warranted.

Late events after anti-CD19 CAR T-cell therapy for relapsed/refractory B-cell non-Hodgkin lymphoma.

The short-term complications from chimeric antigen receptor T-cell therapy (CART) are well characterized, but the long-term complications still need to be further investigated. Therefore, herein, we will review the currently available literature published on the late adverse events following CART. We reviewed published data available from pivotal trials and real-world experiences with anti-CD19 CART (CART19) for adults with lymphoma. We defined late events as occurring or persisting beyond 1 month after CART infusion. We focused our literature review on the following late-event outcomes post-CART19: cytopenia, immune reconstitution, infections, and subsequent malignancies. Grade 3-4 cytopenia beyond 30 days occurs in 30%-40% of patients and beyond 90 days in 3%-22% of patients and is usually managed with growth-factor and transfusion support, along with neutropenic prophylaxis. B-cell aplasia and hypogammaglobulinemia are expected on-target off-tumor effects of CART19, 44%-53% of patients have IgG < 400 mg/dL, and approximately 27%-38% of patients receive intravenous immunoglobulin (IVIG) replacement. Infections beyond the initial month from CART19 are not frequent and rarely severe, but they are more prevalent and severe when patients receive subsequent therapies post-CART19 for their underlying disease. Late neurotoxicity and neurocognitive impairment are uncommon, and other causes should be considered. T-cell lymphoma (TCL) after CART is an extremely rare event and not necessarily related to CAR transgene. Myeloid neoplasm is not rare post-CART, but unclear causality given heavily pretreated patient population is already at risk for therapy-related myeloid neoplasm. CART19 is associated with clinically significant long-term effects such as prolonged cytopenia, hypogammaglobulinemia, and infections that warrant clinical surveillance, but they are mostly manageable with a low risk of non-relapse mortality. The risk of subsequent malignancies post-CART19 seems low, and the relationship with CART19 and/or prior therapies is unclear; but regardless of the possible causality, this should not impact the current benefit-risk ratio of CART19 for relapsed/refractory B-cell non-Hodgkin lymphoma (NHL).

The interim analysis of a first-in-human phase 1 trial of ET-901, a CRISPR edited allogeneic immune-cloaked anti-CD19 CAR-T cell therapy in patients with r/r B-NHL.

e19010 Background: Allogeneic CAR T-cell therapy faces challenges like limited persistence and host rejection. Current research has improved its viability by modifying genes like B2M, despite new challenges like NK cell targeting have emerged. Through CRISPR screening, we discovered a novel gene, named GeneX, and its role in enhancing T cell persistence against allogeneic attacks and AICD. GeneX influences glycan composition, affecting immune responses and AICD initiation. Engineered GeneXKO/TCRKO/anti-CD19 CAR T cells (ET-901) resisted allogeneic killing and maintained anti-tumor effects without causing GvHD, marking a significant advancement in CAR T-cell therapy. Methods: ET-901 is being tested in a phase 1 trial for r/r B-NHL at a single center, utilizing a 3+3 dose escalation scheme and planning for expansion at the recommended Phase 2 dose. Participants must have an ECOG status of 0–2, without a history of allo-HSCT or CAR-T therapy. The study's main goals are to assess ET-901's safety and establish the optimal Phase 2 dosage. Patients undergo a 3-day lymphodepletion with fludarabine (30-50 mg/m2/d) and cyclophosphamide (500-1000 mg/m2/d), followed by a single-dose infusion of ET-901 at escalating doses (DL1:1*10e6/kg, DL2:3*10e6/kg, and DL3:10*10e6/kg). Pharmacokinetic monitoring occurs during follow-up. Results: From September 2023, a total of six patients were enrolled in the escalation cohort, including 4 patients with LBCL and 2 with FL. In these patients (3 males), the median age was 53 years (range: 46–55 years), and the median number of prior treatment lines was 5. The median SPD was 7,650 mm2 (range: 2,700-43,400 mm2). Notably, two cases in DL2 exhibited unusual lymphoma infiltration sites: patient No.4 in the forearm muscle and patient No.5 in the spleen. Update to February 2024, we have completed the safety evaluation of Dose Level (DL) 1 and DL2. No DLTs were observed. The most common TRAEs of any grade included leukopenia (6/6), granulocytopenia (6/6), anemia (6/6), thrombocytopenia (6/6), CRS (6/6), infection (2/6), ICANS (2/6), and GvH like reaction (1/6). All patients achieved objective responses, with 2 cases of PR and 4 cases of CR (1 in DL1, 3 in DL2). The peak values of CAR+ cells count and VCN in peripheral blood were 36.0/μl (range: 14.0-48.0/μl, median: day 7), and 9.6e4 copies/μg (range: 7.7e4-1.2e5 copies/μg, median: day 7), respectively. In all patients, a second expansion of CAR-T cells was observed alongside B cell recovery. This confirms that GeneX knockout enables allo CAR-T cells to maintain long-term immune privilege while preserving their biological function. Conclusions: The study demonstrated the safety and feasibility of ET-901 in patients with r/r B-NHL. These findings highlight the potential of ET-901 as an effective therapeutic approach for improving outcomes for these patients. Clinical trial information: NCT06014073 .

A CRISPR-edited allogeneic anti-CD19 CAR-T cell therapy with a PD-1 knockout (CB-010) in patients with relapsed/refractory B cell non-Hodgkin lymphoma (r/r B-NHL): Updated phase 1 results from the ANTLER trial.

7025 Background: CB-010 is an allogeneic anti-CD19 CAR-T cell therapy derived from healthy donor T cells using CRISPR hybrid RNA-DNA (chRDNA) technology. This technology is used to introduce 3 genome edits: (1) knockout of TRACto eliminate TCR expression and reduce risk of GvHD, (2) insertion of a CD19-specific CAR (scFv FMC63) into the TRAC locus, and (3) knockout of PD-1 to prevent premature CAR-T cell exhaustion and potentially enhance antitumor activity. Methods: ANTLER is a Phase 1 clinical trial (NCT04637763) with a 3+3 dose escalation phase and a dose expansion phase designed to evaluate safety, tolerability, and antitumor activity of CB-010 in patients (pts) with r/r B-NHL and determine RP2D. In dose escalation, pts must have received ≥2 prior lines of chemoimmunotherapy or had primary refractory disease to 1L therapy. Pts received lymphodepletion with sequential cyclophosphamide (60 mg/kg/day x 2 days) and fludarabine (25 mg/m2/day x 5 days) followed by a single CB-010 infusion. Results: 16 pts with r/r B-NHL (10 LBCL, 3 MCL, 2 FL with POD24, 1 MZL) received CB-010 at 40 x 106 CAR-T cells (dose level 1; N=8), 80 x 106 CAR-T cells (dose level 2; N=5), or 120 x 106 CAR-T cells (dose level 3; N=3) during dose escalation. Median age was 66 years (range 55-82). Median time since first diagnosis was 2.4 years (range 0.2-16.4). Median prior lines of therapy was 2 (range 1-8). CB-010 was generally well tolerated. No GvHD was seen. CRS occurred in 7/16 (44%) pts (no CRS grade ≥3). Median time to CRS onset was 3.5 days and median duration was 3 days. ICANS occurred in 4/16 (25%) pts (13% grade ≥3). Median time to ICANS onset was 7.5 days and median duration was 2 days. The 3 most common TEAEs grade ≥3 were thrombocytopenia (11/16; 69%), neutropenia (9/16; 56%), and anemia (8/16; 50%). One grade 3 infection (antecubital cellulitis) occurred unrelated to CB-010. After a single CB-010 infusion, 15/16 (94%) pts achieved an overall response, 11/16 (69%) achieved a CR, and 7/16 (44%) achieved a CR at ≥6 months. Median time to CR was 28 days. Among LBCL pts (n=10), 9 (90%) achieved an overall response, 7 (70%) achieved a CR, and 5 (50%) achieved a CR at ≥6 months. To date,2 pts have completed the 24-month study period with ongoing CR. Peak expansion of CB-010 occurred at days 7-10 post-infusion. T and NK cells recovered rapidly in peripheral blood (&lt;3 weeks) after lymphodepletion, and B cells remained below the limit of quantification beyond 3 months, supporting specific targeting of B cells by CB-010. Conclusions: CB-010 showed a manageable safety profile and promising efficacy for treatment of pts with r/r B-NHL, including aggressive subtypes. The dose escalation phase is complete. Enrollment of 2L LBCL pts in dose expansion is ongoing. Initial dose expansion data at the CB-010 RP2D and translational data will be presented for the first time at the meeting. Clinical trial information: NCT04637763 .

A study of a new mechanism: Intracellular retention allo-CART safety and efficacy for extranodal bulky B-NHL.

e19007 Background: Extranodal bulky lesions, a significant adverse prognostic factor in lymphoma, commonly denote a more aggressive disease course, mandating prompt and intensified treatment strategies. In response, we developed ThisCART19A, a non-genetic editing and off-the-shelf anti-CD19 CAR T-cell therapy incorporating intracellular retention of membrane proteins, representing a novel approach that downregulates surface expression of TCRαβ/CD3 complexes. ThisCART19 has exhibited a favorable safety profile and promising efficacy in patients with relapsed/refractory bulky B-cell Non-Hodgkin Lymphoma. Methods: This is an investigator-initiated trial employing an open-label, dose escalation, and expansion design to evaluate the safety and efficacy of ThisCART19A in patients with relapsed or refractory bulky B-cell non-Hodgkin lymphoma (B-NHL). Bulky disease was defined as the longest diameter of the mass &gt;5 cm at baseline. Results: Between June, 2021, and June, 2023, 13 extranodal bulky disease were enrolled in the studies and successfully received ThisCART19A. The median age was 56 (range, 37~67) years. All 13 patients had 3 median prior lines of therapy (range, 2-5). All patients received anti-CD20 and multi- agent chemotherapy. 8 (61.54%) patients had prior auto CART. mSPD was 48 (range, 16~162) cm². mTMTV was 114.9 (range, 14~483) ml. As of February 2024, The most common adverse events were CRS (100%) , infections (30.77%), ICANS (23.08%) and cytopenias(100%); This is no grade 3 or higher CRS occurred;only 1(7.69%)patient experienced grade 4 ICANS and relieved after intravenous dexamethasone treatment. This is no treatment-related deaths occurred. Among the 13 patients, 10 were evaluable, with an ORR and CR of 90% and 80%, respectively, at 28 days post-infusion. mPFS was 62 days (range, 28~227). The patient who achieved a PR received chemotherapy and radiotherapy as consolidation, As of February 5th, 2024, the patient has survived for 263 days and is still under follow-up. Additionally, two patients progressed after CR received sequential chemotherapy and BCL-2 Inhibitor, with an average OS of 326.5 days, still being under follow-up. In 13 evaluable patients, the mean C-max was 1043.13 cells/μL(range, 0.59~10045.4), and the mean AUC0-28d was 1542.23 cells/μL × day(range, 0.91~11724).In this cohort, two patients received low-dose infusions at 1×106 cells/kg and still achieved excellent expansion, the respective C-max were 726.432 cells/μL and 336.67 cells/μL. Conclusions: This CART19A exhibited favorable safety, remarkable expansion potential, and efficacy profiles in the treatment of r/r bulky lymphoma. Notably, it achieved a high ORR of 90%, providing a favorable window of opportunity for subsequent consolidation and intensification treatments. Moreover, this transition from a bulky to a non-bulky disease state reduces the intricacy of follow-up treatments. Clinical trial information: NCT04384393 .

Outcomes of patients aged ≥26 years with relapsed or refractory B-cell acute lymphoblastic leukemia in ZUMA-3 and historical trials

Brexucabtagene autoleucel (brexu-cel) is an autologous anti-CD19 CAR T-cell therapy approved in the USA and European Union (EU) for adults with relapsed or refractory B-cell acute lymphoblastic leukemia (R/R B-ALL; aged ≥26 years in EU). Here, outcomes for patients with R/R B-ALL aged ≥26 years in ZUMA-3 treated with brexu-cel were compared with historical standard-of-care (SOC) therapy. After median follow-up of 26.8 months, the overall complete remission (CR) rate among patients treated with brexu-cel in Phase 2 (N = 43) was 72% and median overall survival (OS) was 25.4 months (95% CI, 15.9-NE). Median OS was improved in Phase 2 patients versus matched historical SOC-treated patients. Compared with aggregate historical trial data, Phase 1 and 2 patients had improved OS versus blinatumomab, inotuzumab, and chemotherapy in a matching-adjusted indirect comparison (MAIC) study. These data demonstrate clinical benefit of brexu-cel relative to SOC in patients ≥26 years with R/R B-ALL.

In silico and in vivo analysis reveal impact of c-Myc tag in FMC63 scFv-CD19 protein interface and CAR-T cell efficacy

Anti-CD19 CAR-T cell therapy represents a breakthrough in the treatment of B-cell malignancies, and it is expected that this therapy modality will soon cover a range of solid tumors as well. Therefore, a universal cheap and sensitive method to detect CAR expression is of foremost importance. One possibility is the use of epitope tags such as c-Myc, HA or FLAG tags attached to the CAR extracellular domain, however, it is important to determine whether these tags can influence binding of the CAR with its target molecule. Here, we conducted in-silico structural modelling of an FMC63-based anti-CD19 single-chain variable fragment (scFv) with and without a c-Myc peptide tag added to the N-terminus portion and performed molecular dynamics simulation of the scFv with the CD19 target. We show that the c-Myc tag presence in the N-terminus portion does not affect the scFv’s structural equilibrium and grants more stability to the scFv. However, intermolecular interaction potential (IIP) analysis reveals that the tag can approximate the complementarity-determining regions (CDRs) present in the scFv and cause steric impediment, potentially disturbing interaction with the CD19 protein. We then tested this possibility with CAR-T cells generated from human donors in a Nalm-6 leukemia model, showing that CAR-T cells with the c-Myc tag have overall worse antitumor activity, which was also observed when the tag was added to the C-terminus position. Ultimately, our results suggest that tag addition is an important aspect of CAR design and can influence CAR-T cell function, therefore its use should be carefully considered.

Abstract LB092: Novel tumor gene expression signatures predictive of outcome in large B cell lymphoma treated with CAR T cell therapy (axicabtagene ciloleucel)

Abstract We leveraged ZUMA-7, the first and largest, phase III randomized CAR-T cell clinical study of relapsed/refractory large B cell lymphoma (LBCL) in the 2nd line setting, to discover tumor gene expression (GE) signatures associated with outcome to anti-CD19 CAR-T cell therapy, Axicabtagene Ciloleucel (axi-cel). We performed GE profiling on pre-treatment LBCL tumor samples from 134 axi-cel-treated (safety dataset) patients using IO-360 Nanostring panel (769 genes). Multivariate analysis with penalized Cox models was conducted to identify genes whose expression (transcripts) associated with event-free survival (EFS), progression-free survival (PFS), and duration of response (DOR), leading to identification of two predictive GE signatures. For technical validation, the predictive value of these signatures was reproduced in a subset of ZUMA-7 samples profiled by RNA-seq (n=124). High levels (&amp;gt; median) of a favorable 6-transcript GE signature (6-GES) composed of CD19, CD45RA, CCL22, KLRK1, SOX11, and SIGLEC5 positively correlated with EFS (HR: 0.27, 95% CI: 0.16–0.44; P=1.82 × 10−8) and PFS (HR: 0.27, 95% CI: 0.16–0.46; P=1.35 × 10−7) in patients treated with axi-cel. The 6-GES may capture lymphomas with abundant adhesion molecules, a relatively low inflammation, and abundant expression of the targeted antigen (CD19). Conversely, high levels of an unfavorable 17-transcript GE signature (17-GES; CD45RO, BCL2, IL-18R1, TNFSF4 [OX40L], KLRB1 [CD161], KIR3DL2, ITGB8, DUSP5, GPC4, PSMB5, RPS6KB1, SERPINA9, NBN, GLUD1, ESR1, ARID1A, and SLC16A1) negatively correlated with Axi-cel EFS (HR: 6.19, 95% CI: 3.60–10.65; P=1.51 × 10−13) and PFS (HR: 7.58, 95% CI: 4.16–13.81; P=2.70 × 10−14). The 17-GES signature is consistent with a high level of immune infiltration and inflammation paralleled by the activation of immune-escape mechanisms, such as the upregulation of anti-apoptotic genes. Notably, the 17-GES was elevated at progression after axi-cel treatment (n=18). These signatures did not associate with outcome to 2nd-line SOC from ZUMA-7 (n = 122 for nanostring and n = 125 for ZUMA-7 RNAseq datasets, respectively), nor with outcome to 1st -line R-CHOP from two online datasets, indicating their predictive rather than prognostic value. In conclusion, our transcriptomic analysis of ZUMA-7 dataset identified novel GE signatures predictive of outcome with axi-cel. These GE signatures could support risk-stratification of LBCL patients. Citation Format: Yuan Tian, Justin Budka, Frederick L. Locke, Jason R. Westin, Christina To, Shilpa Shahani, Davide Bedognetti, Rhine R. Shen, Jorge Andrade, Simone Filosto. Novel tumor gene expression signatures predictive of outcome in large B cell lymphoma treated with CAR T cell therapy (axicabtagene ciloleucel) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB092.

Abstract 3867: Identification of novel biomarkers of immune toxicity from CAR T-cell therapy using ultrasensitive NULISA™ proteome technology

Abstract Introduction: The efficacy of anti-CD19 chimeric antigen receptor (CAR) T-cell therapy in patients with relapsed/refractory large B-cell lymphoma (LBCL) is limited by acute toxic events, most notably cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Identification of biomarkers of toxicities can allow for selection of high-risk patients and elucidate targetable mechanisms for mitigation. Previous biomarker studies have been constrained by relatively narrow panels of potential mediators and limited time points. Here, we employed NULISA, a novel ultrasensitive assay capable of simultaneously quantifying 204 inflammatory proteins from a single sample, to identify temporal proteome associations with acute toxicities in anti-CD19 CAR T-cell treated patients. Methods: Baseline and post-treatment peripheral blood samples from 80 patients with LBCL who underwent anti-CD19 CAR-T cell therapy were collected within specific time intervals. Plasma samples (n=480) were analyzed with NULISA. CRS and ICANS were graded according to ASTCT consensus criteria. Patients were grouped according to their maximum CRS and ICANS scores. Differential protein abundance across the toxicity groups was assessed using linear mixed effects models fit for each protein, including a time by toxicity group interaction. Proteins showing significant associations were subjected to pathway enrichment and network analysis. Results: Severe CRS and ICANS patient groups showed proteome upregulation beginning on day 1-2 and peaking at day 6-9, followed by extensive downregulation on day 11-16. The strongest upregulated pathway associations of severe CRS and ICANS were inflammatory response, IL-17 signaling, non-genomic action of vitamin D3, regulation of leukocyte proliferation, and cellular extravasation. Downregulated pathways included anti-microbial humoral response and TNFs binding to receptors. In addition to the previously identified inflammatory proteins IL-6, IFNγ, sIL-2Rα, CXCL8, CCL2, our analysis revealed significant association of several novel immune regulators and mediators. These included upregulated Th2 cytokines, IL-17A, IL-22, GZMB, CTLA4, IFNA1;IFNA13, and downregulated S100A12, IL-12B, CCL22, BDNF and TNFSFs, revealing exquisite temporal orchestration of lymphoid and myeloid activities during CRS and ICANS development. Conclusions: This study represents the most comprehensive characterization of immune response to CAR T-cell therapy to date. Using the novel NULISA technology, we identified new proteins and functional pathways associated with CAR T-cell-induced toxicity, implicating them as potential biomarkers. These previously unidentified factors also provide a platform to further investigate the causative immune mechanisms of acute toxicities in CAR-T cell therapy. Citation Format: Riley Kirkpatrick, Joanne Beer, Manishkumar S. Patel, Akansha Jalota, Agrima Mian, Ishara S. Ariyapala, Qinyu Hao, Wei Feng, Xiao-Jun Ma, Yuling Luo, Brian T. Hill, Neetu Gupta. Identification of novel biomarkers of immune toxicity from CAR T-cell therapy using ultrasensitive NULISA™ proteome technology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3867.

Primary vs. pre-emptive anti-seizure medication prophylaxis in anti-CD19 CAR T-cell therapy

IntroductionSeizures may occur in up to 30% of non-Hodgkin lymphoma patients who received anti-CD19 CAR T-cell therapy, yet the optimal anti-seizure medication (ASM) prevention strategy has not been thoroughly investigated.MethodsConsecutive patients affected by refractory non-Hodgkin lymphoma who received anti-CD19 CAR T-cells were included. Patients were selected and assessed using similar internal protocols. ASM was started either as a primary prophylaxis (PP-group) before CAR T-cells infusion or as a pre-emptive therapy (PET-group) only upon the onset of neurotoxicity development.ResultsOne hundred fifty-six patients were included (PP-group = 88, PET-group = 66). Overall, neurotoxicity and severe neurotoxicity occurred in 45 (29%) and 20 (13%) patients, respectively, equally distributed between the two groups. Five patients experienced epileptic events (PET-group = 3 [4%]; PP-group = 2 [2%]). For all the PET-group patients, seizure/status epilepticus occurred in the absence of overt CAR-T-related neurotoxicity, whereas patients in the PP-group experienced brief seizures only in the context of critical neurotoxicity with progressive severe encephalopathy. ASMs were well-tolerated by all patients, even without titration. No patients developed epilepsy or required long-term ASMs.ConclusionOur data suggest that both primary and pre-emptive anti-seizure prophylaxis are safe and effective in anti-CD19 CAR T-cell recipients. Clinical rationale suggests a possible more favourable profile of primary prophylaxis, yet no definitive conclusion of superiority between the two ASM strategies can be drawn from our study.

Subsequent malignant neoplasms in patients previously treated with anti-CD19 CAR T-cell therapy

Subsequent malignant neoplasms in patients previously treated with anti-CD19 CAR T-cell therapy

Efficacy and Safety of Children With Relapsed/Refractory B-Cell Acute Lymphoblastic Leukemia After Anti-CD19 CAR T-Cell Therapy Without Bridging Transplantation

Anti-CD19 chimeric antigen receptor (CAR) T-cell therapies have demonstrated significant efficacy in achieving complete remission (CR) in pediatric patients with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). However, a considerable number of patients experience relapse within 1 year after CAR T-cell therapy, leading to an extremely poor prognosis, particularly in patients without bridging transplantation. In our study, we investigated 42 children with R/R B-ALL who underwent anti-CD19 CAR T-cell therapy without bridging transplantation at our center. All patients were included in the response analysis and evaluated for survival and toxicity. The cohort that received the CAR T-cell infusion exhibited a 100% CR rate by day 28 (d28). The overall survival (OS) at 4 years was 61.3% ± 8.5%, and the event-free survival (EFS) was 55.9% ± 7.9%, with a median follow-up duration of 50.1 months. Minimal residual disease (MRD) ≥1% was associated with inferior outcomes, resulting in lower 4-year OS (P = .033) and EFS (P = .014) compared to MRD<1%. The incidences of grade≥3 cytokine release syndrome (CRS) and neurotoxicity were 26.8% and 23.8%, respectively. Furthermore, MRD≥1% was identified as an independent factor associated with increased severity of CRS and occurrence of neurotoxicity. These findings suggest that reducing the preinfusion MRD could serve as an effective treatment strategy to enhance the outcomes of CAR T-cell therapy.