CAR-T Cell Treatment Research Articles

Efficacy and Safety of Chimeric Antigen Receptor T Cells Therapy Strategy with Dual Targeting of CD19 and CD70 to Treat Relapsed/Refractory Diffuse Large B-Cell Lymphoma

Background: Chimeric antigen receptor (CAR) T cells therapy is highly effective in the treatment of B-cell lymphoma, providing alternative therapeutic options for patients who failed to respond to conventional treatment or relapse. Despite impressive progress, more than 30-50% of patients treated with CD19 CAR-T cells experienced progressive disease. Antigen escape is one of the common causes of relapse, especially CD19-negative relapse. Absent or decreased cell surface CD19 as a mechanism of resistance after CD19 CAR-T cells treatment. CD70 is a novel and promising therapeutic target due to the restricted expression pattern in normal tissues and over expression in some lymphoma tissues. Our center explored the efficacy and safety of CAR-T cells therapy with dual targeting of CD19 and CD70 in the treatment of r/r lymphoma. Patients and Methods: The study included 8 relapsed/refractory diffuse large B-cell lymphoma patients, all patients have exhausted all available treatment options with progressive or stable disease and life expectancy >2 months were enrolled in the study. All patients expressed strong positivity of CD19 and CD70, all of patient details can be found in the table (Fig.1). Autologous T cells were apheresis collected and transduced with an apoptosis-inducible, safety-engineered lentiviral CAR with the following intracellular signaling domains: CD28/CD27/CD3z-iCasp9. All patients received cyclophosphamide/fludarabine chemotherapy conditioning 1-2 days before infusions of CAR-T cells. The quality of apheresis cells, efficiencies of gene transfer and T cell proliferation, CAR-T infusion dose and blood CAR copies were quantitatively documented. Results: In the first months after CAR-T cells infusion, 75.0% (6/8) of patients achieved complete response (CR), while 12.5% (1/8) of patients evaluated as partial response (PR) and 12.5% (1/8) of patients as progressive disease (PD), overall response rate (ORR) is 87.5% (7/8). In the evaluation of safety, 37.5% (3/8) of patients experienced cytokine release syndrome (CRS), and 25% (2/8) of patients experienced grade 1 CRS and 12.5% (1/8) of patients experienced grade 2 CRS, no case of severe CRS defined as≥grade 3 and no immune effector cell-associated neurotoxicity syndrome (ICANS) occurred. After a median follow-up of 19.9 months, 50% (4/8) of patients maintained CR, while 37.5% (3/8) of patients were relapsed, with a duration of response (DOR) of 50% (4/8), median DFS was 10.5 months and median OS was not reached (Fig.2). Conclusions: In summary, our research data confirms that the efficacy and safety of CD19/CD70 dual targeted CAR-T cells infusion, continued follow-up will determine whether the CD19/CD70 CAR-T cells therapy can obtain long term overall survival in our study. How to further improve the efficacy and safety of dual target CAR-T is still worth exploring. It's needed to optimize multi-specific targeting by CAR-T cells to improve the efficacy both in B cell malignancies and other hematological malignancies.

CAR-T Cell Therapy in Patients with Refractory Systemic Autoimmune Diseases Exhibits Less Inflammation, Toxicities and Different Cellular Dynamics Compared to Patients with B Cell Lymphoma

Chimeric antigen receptor (CAR) T-cell therapies have shown high efficacy in the treatment of B cell non-Hodgkin lymphoma (NHL) and acute lymphoblastic leukemia (ALL) and are established as a standard treatment for patients with hematological malignancies. Aside from malignant B cells, autoreactive B cells can also cause great harm in patients with autoimmune diseases (AID), resulting in chronic inflammation, organ damage, and increased mortality. We have recently demonstrated that CD19-directed CAR-T cell therapy is feasible and effective in patients with refractory systemic lupus erythematosus (Mougiakakos et al, 2021; Mackensen et al., 2022), antisynthetase syndrome (Müller et al., 2023) and systemic sclerosis (Bergmann et al., 2023). Despite these promising data, there are many uncertainties in the treatment of AID patients with cellular therapies, which were primarily developed for the treatment of cancer patients. Here, we analyzed the occurrence and severity of toxicities, inflammatory markers, and the cellular dynamics of 15 AID patients and 40 NHL patients undergoing CAR-T cell therapy. All patients were treated in our center with either commercial CAR-T cell products (Axicabtagenee ciloleucel, Tisagenlecleucel, Lisocabtagen maraleucel) or with the investigational medicinal product MB-CART19.1 (in-house manufactured 2 nd generation anti-CD19 CAR-T cells with a 4.1BB co-stimulatory domain; Kretschmann et al., 2023). Average peak expansion was reached at day 7 in both patient groups. Despite comparable average peak levels, patients with AID showed lower incidence and severity of cytokine-release syndrome (CRS) and immune-effector cell associated neurotoxicity syndrome (ICANS) compared to the NHL cohort. Consistent with reduced toxicity, AID patients received less tocilizumab and glucocorticoid treatment. Bone marrow toxicity with severe and/or prolonged cytopenia is a frequent long-term CAR-T cell related adverse event. Of interest, AID patients demonstrated a less profound decrease of neutrophils, platelet counts, and hemoglobin after CAR-T cell therapy compared to NHL patients and a faster recovery to normal values. Occurrence and duration of severe neutropenia (<500 neutrophils/µl) also differed between both patient cohorts. There was no late bone marrow toxicity in AID patients, whereas 19 of 40 patients with NHL showed at least one > grade 3 blood count reduction. In line with the Hematotox-Score predicting bone marrow toxicity, baseline inflammation (e.g. C-reactive protein, ferritin) prior to CAR-T cell treatment was higher in lymphoma patients than in AID patients. While AID patients quickly returned to normal ferritin values, elevated ferritin levels often persisted in the NHL cohort after CAR-T cell therapy. Given that AID patients showed fewer late toxicity and lower long-term inflammation, we speculated that persistence of CAR-T cells was lower. In line, longitudinal monitoring of the patient's immune cells including CAR-T cell kinetics demonstrated a typical contraction of CAR-T cell numbers with low-level persistence in both cohorts. We did not observe a difference in absolute CAR-T cell numbers or dynamics within the first three months after treatment. In contrast to NHL patients in remission, AID patients did not develop long-term persistence of CAR-T cells as most patients lost CAR-T cells within 1 year after cell infusion. Consistent with this observation, all AID patients showed B-cell reconstitution after loss of CAR-T cell persistence. Taken together, we observed less toxicities and severe adverse events in AID patients than in NHL patients despite similar CAR-T cell expansion and dynamics. The lack of CAR-T cell persistence and the early recurrence of B cells in AID patients is so far not explained and could provide novel insights in the biological processes controlling long-term CAR-T cell persistence.

Immunoengineering via Chimeric Antigen Receptor-T Cell Therapy: Reprogramming Nanodrug Delivery.

Following its therapeutic effect in hematological metastasis, chimeric antigen receptor (CAR) T cell therapy has gained a great deal of attention during the last years. However, the effectiveness of this treatment has been hampered by a number of challenges, including significant toxicities, difficult access to tumor locations, inadequate therapeutic persistence, and manufacturing problems. Developing novel techniques to produce effective CARs, administer them, and monitor their anti-tumor activity in CAR-T cell treatment is undoubtedly necessary. Exploiting the advantages of nanotechnology may possibly be a useful strategy to increase the efficacy of CAR-T cell treatment. This study outlines the current drawbacks of CAR-T immunotherapy and identifies promising developments and significant benefits of using nanotechnology in order to introduce CAR transgene motifs into primary T cells, promote T cell expansion, enhance T cell trafficking, promote intrinsic T cell activity and rewire the immunosuppressive cellular and vascular microenvironments. Therefore, the development of powerful CART cells can be made possible with genetic and functional alterations supported by nanotechnology. In this review, we discuss the innovative and possible uses of nanotechnology for clinical translation, including the delivery, engineering, execution, and modulation of immune functions to enhance and optimize the anti-tumor efficacy of CAR-T cell treatment.

Releasing the brake: CTLA-4 loss turbocharges CAR T cells

Immune checkpoint receptor-induced Tcell dysfunction is a major cause of CAR Tcell treatment failure. In this issue, Agarwal etal. report that CRISPR/Cas9 deletion of CTLA4, but not PDCD1 or CTLA4 and PDCD1, enhances CD28 signaling, restoring fitness and antitumor function of CAR Tcells, including those derived from patients who failed CAR Tcell therapy.

Characterization of Lymphopenia during Bridging Radiation Therapy Prior to CAR-T Cell Therapy in Patients with Aggressive B Cell Lymphomas

Bridging RT (bRT) may be used as a strategy for disease control in patients with relapsed/refractory aggressive B cell lymphoma treated with anti-CD19-directed chimeric antigen receptor T-cell therapy (CART). The correlation of treatment-related lymphopenia with adverse outcomes in patients has been widely documented in several malignancies. Here, we assessed lymphocyte kinetics during bRT and impact on clinical outcome. After IRB-approval, records were retrospectively reviewed for adults with DLBCL who received bRT for axicabtagene ciloleucel 11/2017-12/2022. Clinical/treatment characteristics, lab values, and outcomes were extracted. ALC Δ RT was computed by subtracting pre-RT ALC from post-RT ALC count. Survival was modeled using Kaplan-Meier for events distributed over time, or binary logistic regression for disease response. Fisher's Exact Test or Mann-Whitney U methods were used. Forty patients met inclusion criteria. Fourteen (35%) received bRT with systemic therapy. Thirty-two (80%) patients received bRT that started post-leukapheresis. bRT was delivered with a median dose of 30 Gy (range: 4-46) in 10 fractions (range: 2-23). Twenty-three patients (57.5%) had CR at 30 days post-CART infusion. Nine had PR (22.5%), and 8 patients (20%) had PD or SD. Median PFS was 8.9 months and median OS was 22 months. The pre-RT ALC mean ± SD was 0.74 ± 0.49 K/µL, and post-RT was 0.43 ± 0.35 K/µL. The absolute ALC Δ RT was 0.31 ± 0.43 K/µL, and ratio post-RT/pre-RT was 0.74 ± 0.64. Stratifying by receipt of bRT alone or with systemic therapy, there was no statistically significant difference in ALC count post-RT (chemoRT: 0.33 ± 0.23 vs. RT: 0.48 ± 0.4, p = 0.2), but there was a lower ALC count pre-RT in the chemoRT group (0.5 ± 0.3 vs. 0.87 ± 0.52 for RT alone, p = 0.02). Post-RT ALC was not significantly associated with CR/PR vs. PD/SD, or with DSS, PFS, or OS. A greater drop in ALC Δ RT trended towards association with improved 90-day response (p = 0.066), without correlation with DSS, OS, or response at 30 days. Median dose per fraction was lower among patients that got pre-leukapheresis RT (2.25 vs. 2.5, p = 0.04), but total dose of bRT or number of fractions was not significantly different. Otherwise, the groups were similar in terms of stage, disease bulk, or comprehensive vs. focal bRT. The average decrease in ALC post-RT for patients who received bRT prior to apheresis was 0.215 K/µL, compared to 0.268 K/µL for patients who received bRT post-apheresis (p = 0.75). Treatment with pre-leukapheresis bRT or ALC Δ RT among these patients were not associated with worse DFS, PFS, or OS (p>0.15). Post-bRT ALC and reduction in ALC during bRT is not associated with worse treatment response or survival outcomes after CAR-T cell treatment in aggressive B cell lymphoma. Pre-leukapheresis bRT did not appear to substantially impact ALC, and ALC Δ RT among these patients were not associated with worse outcomes.

Longitudinal Serum Proteomics Characterization of CD19-CAR-T Cell Therapy for B-Cell Malignancies.

Chimeric antigen receptor (CAR)-modified T cells have demonstrated remarkable efficacy in treating B-cell leukemia. However, treated patients may potentially develop side effects, such as cytokine release syndrome (CRS), the mechanisms of which remain unclear. Here, we collected 43 serum samples from eight patients with B-cell acute lymphoblastic leukemia (B-ALL) before and five time points after CD19-specific CAR-T cell treatment. Using TMTpro 16-plex-based quantitative proteomics, we quantified 1151 proteins and profiled the longitudinal proteomes analysis of each patient. Seven days after therapy, we found the most dysregulated inflammatory proteins. Lipid metabolism proteins, including APOA1, decreased after therapy, reached their minimum after 7 days, and then gradually recovered. Hence, APOA1 has been selected as a potential biomarker of the CRS disease progression. Furthermore, we identified CD163 as a potential biomarker of CRS severity. These two biomarkers were successfully validated using targeted proteomics in an independent cohort. Our study provides new insights into CAR-T cell therapy-induced CRS. The biomarkers we identified may help develop targeted drugs and monitoring strategies.

Genetically Stable and Scalable Nanoengineering of Human Primary T Cells via Cell Mechanoporation.

Effective tumor regression has been observed with chimeric antigen receptor (CAR) T cells; however, the development of an affordable, safe, and effective CAR-T cell treatment remains a challenge. One of the major obstacles is that the suboptimal genetic modification of T cells reduces their yield and antitumor activity, necessitating the development of a next-generation T cell engineering approach. In this study, we developed a nonviral T cell nanoengineering system that allows highly efficient delivery of diverse functional nanomaterials into primary human T cells in a genetically stable and scalable manner. Our platform leverages the unique cell deformation and restoration process induced by the intrinsic inertial flow in a microchannel to create nanopores in the cellular membrane for macromolecule internalization, leading to effective transfection with high scalability and viability. The proposed approach demonstrates considerable potential as a practical alternative technique for improving the current CAR-T cell manufacturing process.

Chimeric antigen receptor-natural killer cells: a promising sword against insidious tumor cells.

Natural killer (NK) cells are a critical component of innate immunity, particularly in initial cancer recognition and inhibition of additional tumor growth or metastasis propagation. NK cells recognize transformed cells without prior sensitization via stimulatory receptors and rapidly eradicate them. However, the protective tumor microenvironment facilitates tumor escaping via induction of an exhaustion state in immune cells, including NK cells. Hence, genetic manipulation of NK cells for specific identification of tumor-associated antigens or a more robust response against tumor cells is a promising strategy for NK cells' tumoricidal augmentation. Regarding the remarkable achievement of engineered CAR-T cells in treating hematologic malignancies, there is evolving interest in CAR-NK cell recruitment in cancer immunotherapy. Innate functionality of NK cells, higher safety, superior in vivo maintenance, and the off-the-shelf potential move CAR-NK-based therapy superior to CAR-T cells treatment. In this review, we have comprehensively discussed the recent genetic manipulations of CAR-NK cell manufacturing regarding different domains of CAR constructs and their following delivery systems into diverse sources of NK cells. Then highlight the preclinical and clinical investigations of CAR-NK cells and examine the current challenges and prospects as an optimistic remedy in cancer immunotherapy.

One Step to a Cure Outcomes of Experimental Treatments for Non-Hodgkins Lymphomas, A Systematic Review

Non-Hodgkins lymphomas are malignant lymphatic tumors, mainly affecting B cells. Generally occur in children and young adults with different forms of treatment, however most treatments are accompanied by tumoral relapse.Recently, many researches have been made to identify the best treatment with positive long-term outcomes. In that regard, CAR-T cell treatment has been recognized for its accessibility and effect, it utilizes T cells with chimeric antigen receptors, facilitating cancerous cells detection after non-response to the regular R-CHOP treatment. As data-base 26 research papers were found, with 23 of them being utilized.

Idecabtagene Vicleucel Is Well Tolerated and Effective in Relapsed/Refractory Myeloma Patients with Prior Allogeneic Stem Cell Transplantation

BCMA-specific chimeric-antigen receptor cells have led to high response rates and durable remissions in patients with relapsed refractory multiple myeloma. However, little data are available for patients after prior allogeneic transplantation, where patient T-cells are chimeric. Our objective was to assess safety and efficacy of patient-derived donor CAR-T cell treatment in myeloma patients with prior allogeneic stem cell transplantation, in particular with regard to Graft versus Host Disease (GvHD). We demonstrate a comprehensive clinical analysis of 3 patients, who had previously received allogeneic transplantation for high-risk myeloma, treated with idecabtagene vicleucel (ide-cel) at our institution. Ide-cel was well tolerated with no clinically relevant immune effector cell-associated neurotoxicity syndrome or cytokine release syndrome observed in any patient. Importantly, no new GvHD was observed although all patients had a history of GvHD. All patients responded to treatment with at least a very good partial remission. Two patients relapsed within 6 months and one patient is still in sCR. We demonstrate that treatment with ide-cel is feasible, very well tolerated and effective in patients with relapsed/refractory multiple myeloma after prior allogeneic stem cell transplantation.

Glofitamab for Relapsed/Refractory Diffuse Large B-Cell Lymphoma

Glofitamab for Relapsed/Refractory Diffuse Large B-Cell Lymphoma

IMMU-01. EVALUATING THE IMPACT OF CAR DESIGN ON THE TUMOR IMMUNE MICROENVIRONMENT AND ANTI-TUMOR RESPONSE IN SYNGENEIC GLIOMA MODELS

Abstract B7-H3 CAR T-cells have limited efficacy in immunocompetent mouse models indicating a suppressive role of the tumor immune microenvironment (TIME). In this study, we set to optimize B7-H3 CAR structure and examine the effects of CAR design on brain TIME. We generated a panel of second-generation B7-H3-specific CARs with different transmembrane (CD8, CD28), costimulatory (CD28, 4-1BB), and activation (ζ, mutζ) domains. We then compared the cytolytic activity, expansion, and anti-tumor activity of T-cells expressing these CARs. Results showed that T-cells expressing B7-H3 CARs with CD28 transmembrane/costimulatory domains have superior efficacy in vitro. Yet, providing optimized costimulation and signaling did not induce superior anti-glioma efficacy of B7-H3 CAR T-cells in vivo. Additionally, incorporating 4-1BB signaling into CD28-based CAR T-cells by expressing 4-1BBL on their cell surface enhances the therapeutic efficacy and persistence of B7-H3 CAR T-cells in vitro. However, transgenic expression of 4-1BBL in CD28-based CARs was not associated with further enhanced anti-glioma efficacy of B7-H3 CAR T-cells in vivo. Next, using high-dimensional flow cytometry and spatial transcriptomic analyses, we show that suppressive tumor-associated macrophages (TAMs) infiltrate tumors in non-responder mice and they predominantly surround the tumor edges. Additionally, minimal T-cell infiltrates were observed in these tumors with predominantly exhausted and dysfunctional phenotypes. Analysis of gene-expression signatures early after CAR T-cell treatment revealed that tumors treated with CD28-based CARs differentially upregulate genes associated with inflammatory myeloid responses. While treatment with other signaling domains’ containing CARs upregulates pathways predictive of suppressive TAM and regulatory/dysfunctional T-cell responses. We show that global depletion of brain macrophages using CSF1R inhibitor exacerbates CAR T-cell anti-tumor activity. In summary, our results show that specific CAR domains induce an early inflammatory immune hub predictive of potent anti-tumor responses. Additionally, inflammatory macrophages are needed for successful CAR T-cell activation and anti-glioma responses.

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Introduction: Allogeneic stem cell transplantation (alloSCT) was the only curative option for younger patients (pts) with relapsed/ refractory (r/ r) LBCL (DLBCL, tFL, PMBCL). Anti-CD19 CAR T-cells (CART) entered the clinical arena around 5 years ago now being considered standard of care for such patients. As >50% of LBCL pts progress or relapse after CART treatment we were interested in identifying prognostic factors for both modalities and their relative role in the treatment of advanced r/r LBCL. Methods: Pts registered with the EBMT database from 1/2016 to 5/2021 having received either a first alloSCT or commercially available CART therapy (Yescarta® or Kymriah ®) as ≥3rd therapy of LBCL were analyzed. To correct for imbalances in patient characteristics we did propensity score analyses considering only pts with complete information on IPI including LDH at the time of cell therapy. We performed multivariate analyses in patients with either low- or high-risk r/r LBCL according to LDH level at cell therapy in pts treated with alloSCT or CART. Results: We identified 515 pts with full information on IPI at cell therapy (212 alloSCT and 303 CART). Patient groups differed significantly in median age, IPI score, and disease status at cell therapy. Median follow up was 46.3 months after alloSCT and 22.1 months after CART treatment. In univariate analysis, type of cell therapy, disease status, and IPI at cell therapy had a significant impact on OS. Amongst IPI risk factors LDH, performance status, and number of extranodal sites had a significant impact on OS, PFS an RI. At 24 months, OS was 41% after allo SCT and 49% after CART. In a propensity score analysis using all IPI factors as covariates, CART was superior to alloSCT in terms of OS (HR 0.62, 95% CI: 45–0.84, p = 0.0193) but not PFS, RI or NRM. In multivariate analysis patients with IPI (o-2) low risk at cell therapy show better OS (HR 0.81, 95% CI 0.59–1.1, p < 0.0001) and PFS (HR 0.62, CI: 0.46–0.83, p = 0.00145), comparable RI and lower NRM (HR 0.21 CI: 0.11–0.42, p = 0.00001) with CART compared to allo SCT. In IPI (3–5) high-risk patients, CART showed significantly higher RI (HR 1.45, CI: 1.03–2.04, p = 0.03549) but lower NRM (HR 0.21, CI: 0.11–0.42), p = 0.00001) compared to allo SCT. OS and PFS did not significantly differ. Refractory disease was an independent adverse prognostic factor for OS (HR 1.74, CI: 1.3–2.33, p = 0.0002), PFS (HR 1.61 CI: 1.23–2.1, p = 0.0006) and RI (HR 1.79 CI: 1.29–2.49, p = 0.0006) but not for NRM. Results at 2 years are given in Table 1. Conclusion: IPI assessed at cell therapy is of prognostic impact for both CART and allo SCT. Overall, pts given CART for ≥3rd line treatment of DLBCL showed better OS than pts treated with alloSCT. In patients with high intermediate/high IPI results of CART must be improved and allogeneic SCT remains a valuable treatment strategy due to its high anti-lymphoma activity. Keyword: Cellular therapies Conflicts of interests pertinent to the abstract. B. Glass Consultant or advisory role: Kite, BMS, Novartis, Milteneyi, Roche, Janssen, Jazz, Abbvie Honoraria: Kite, BMS, Novartis, Milteneyi, Roche, Janssen, Jazz, Abbvie Research funding: Roche, Riemser A. Sureda Consultant or advisory role: Takeda, MSD, BMS, Novartis, Janssen, Roche, Sanofi, Gilead P. Dreger Consultant or advisory role: Kite, Novartis P. Corradini Honoraria: Abbvie, Amgen, Celgene, Giled, Incyte, Janssen, Takeda, R. Ram Honoraria: Novartis, Gilead, Takeda, BMS G. Wulf Consultant or advisory role: Gilead, Novartis A. M. García-Sancho Consultant or advisory role: Roche, BMS, Kyowa Kirin, Clinigen, Eusa Pharma, Novartis, Kite Gilead, Servier, Incyte, Lilly, Takeda, ADC Therapeutics America, Miltenyi, Kern M. Stelljes Consultant or advisory role: Medac, Pfizer, Jazz, Novartis, MSD, Amgen, BMS, Kite D. Blaise Consultant or advisory role: Jazz E. Forcade Consultant or advisory role: Gilead, Jazz, Novartis, GSK, Sanofi, MSD I. Hilgendorf Consultant or advisory role: Novartis, Abbvie J. A. Perez-Simon Consultant or advisory role: Novartis, Janssen, Gilead, Jazz, Alexion, Abbvie, Pfizer W. Bethge Consultant or advisory role: Gilead, Novartis, Miltenyi, Janssen, Celgene N. Schmitz Consultant or advisory role: Allogene Stock ownership: BMS Honoraria: Allogene Research funding: Janssen, Roche Educational grants: Allogene, Milteneyi

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Introduction: Central nervous system (CNS) involvement in patients with refractory or relapsed large B-cell lymphoma (LBCL) is associated with an extremely poor prognosis. Autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy is an approved treatment for patients with refractory or relapsed (R/R) LBCL that has changed the prognosis of patients with chemoresistant LBCL. However, data regarding efficacy and safety of CART cell treatment in patients with active CNS involvement are limited since they are excluded from most of clinical trials. Methods: We retrospectively collected data from 75 patients with LBCL, treated with CART cells from January 2020 to January 2023 in Henri Mondor Hospital. We identified 13 patients with active CNS involvement at the time of CAR-T cell treatment decision: 12/13 had abnormal neurological examination, 8/11 had head and/or medullar MRI abnormalities consistent with lymphoma and 9/10 had detectable lymphoma cells in the cerebrospinal fluid. We compared the characteristics of the 13 patients with CNS involvement (CNS+) with 62 patients without evidence of active CNS disease (CNS-). Median age was 69 and 59 years, respectively (p = 0.05). CNS+ patients received a median of 2 previous lines of treatment versus 3 for CNS- patients (p = 0.34). Performance status prior to CART-cell injection was 2 or more in 9/13 (69%) and 11/62 (18%) p < 0.001, respectively. 5/13 (38%) CNS+ patients had high grade B-cell lymphomas versus 11/62 (18%) CNS- (p = 0.13). CAR-T-cell was axi-cel in 10/13 (77%) CNS+ patients versus 42/62 (68%) CNS– (p = 0.74). It is noteworthy that 7/13 (54%) CNS+ patients had pre-existing low-grade B-cell lymphomas versus 15/62 (24%) CNS- (p = 0.046). Results: The best overall response rate was identical in both groups: 12/13 (92%) in CNS+ patients versus 51/61 (92%) in CNS-, including 11/13 (85%) and 44/61(72%) complete metabolic response. As shown in the figure, median progression free survival and overall survival was 5.5 and 8.4 months, respectively in CNS+ patients versus 11.5 and 21 months in CNS- patients (not significant). Regarding safety, 13/13 (100%) CNS+ patients had a cytokine release syndrome (10 grade 1–2 and 3 grade 3) versus 54/62 (87%) CNS- (49 grade 1–2 and 5 grade 3–4) and 10/13 (77%) experienced ICANS (6 grade 1–2 and 4 grade 3–4) versus 28/62 (45%) CNS- (27 grade 1–2 and 1 grade 3–4) (p = 0.06 and 0.02 for grade 3–4). Transfer into an intensive care unit occurred in 4/13 (31%) CNS+ patients versus 9/62 (15%) CNS- (p = 022). Median time of hospitalization was 37 days for CNS+ patients versus 20 days for CNS- patients (p = 0.007). Six CNS+ patients died from which 5 died of progression and 1 of infection. Keywords: Aggressive B-cell non-Hodgkin lymphoma, Cellular therapies, Immunotherapy Conflicts of interests pertinent to the abstract. F. Lemonnier Consultant or advisory role: BMS, Kiowa, Miltenyi Educational grants: Gilead, Janssen, Roche L. Roulin Educational grants: Kite gilead, Novartis, Bristol myers squibb

Phase I clinical trial using a unique immunotherapeutic combination of MUC1-targeted CAR-T cells with PD-1-knockout in the treatment of patients with advanced esophageal cancer.

e16061 Background: Combining CAR-T with programmed cell death-1 (PD-1) inhibition may be a more efficacious approach for treatment of solid tumors. This clinical study was designed to assess the safety and tolerability of PD-1 knockout MUC1-Targeted CAR-T engineered Cells to treat advanced esophageal cancer. Methods: Patients with advanced esophageal cancer were recruited according to the criteria in NCT03706326. PD-1 gene knockout (KO) MUC1-targeted CAR-T cells were prepared by constructing MUC1-specific CARs using the SM3 scFv in patient-derived T-cells, and PD-1 gene KO was achieved in these CAR positive T cells using the CRISPR-Cas9 system. Efficiency and validation were confirmed by sequencing and flow cytometry. MUC1-CAR+/PD-1- KO engineered T cells at a starting dose of 5x107 were infused over 60 min. The dose was escalated to 5x109 cells. Following treatment, the safety and tolerability of dose of the therapeutic cells were assessed using CTCAE v4.0. Patients’ general condition, levels of lymphocytes, IL-6, hs-CRP, PCT, CYFRA21, NSE(E), and SCC were monitored at regular intervals. Circulating CART cells were checked regularly. Tumor size were examined by MRI/CT scans. Efficacy was also assessed. Results: A total of 9 patients (aged 48 to 80) diagnosed with esophageal cancer/esophageal squamous cell carcinoma (IIIb to IV), were included in this study. All participants received at least one cycle of CART cell treatment. Among the 9 treated patients, 4 received 1 cycle, other 5 received 2, 3, 4, 7 and 10 cycles, respectively. The most common adverse events (AE) were acute fever (8 patients, 38.0-40.5 C◦), chills (5 patients, occurred in the subsequent cycle of infusion), skin rash (4 patient). No grade 3-5 AEs were found, and no cytokine release syndrome (CRS) was observed. Of the 9 assessed patients, 6 had stable disease (SD) while 3 had progressive disease. All patients had significant symptom improvements after infusion. Circulating CART cells gradually declined after infusion; the number dropped down to approximately 25% in 4 months after one cycle treatment indicating the necessity of receiving more cycles. Patients who received multiple cycles of infusion showed long-term and steady SD status. Two patients who received a multiple cycle of CAR-T cells had an overall survival (OS) of 24 months. Conclusions: Our data suggests that the treatment of patients with advanced esophageal cancer with PD-1 disrupted MUC1-targeted CAR-T cells is safe and well-tolerated by all patients. No CRS and other serious EAs were observed throughout the study. The efficacy of this unique combined therapy is currently being assessed. Our limited data indicate that the OS of the patients extended significantly in the treated patients. Two out of 6 patients with an OS of greater than 24 months, an outstanding clinical outcome. Clinical trial information: NCT03706326 .

CORRELATION BETWEEN SOMATIC MUTATIONS AND PROGNOSIS IN PEDIATRIC MATURE B‐CELL LYMPHOMA

Introduction: To investigate the prognostic factors of childhood mature B-cell lymphoma (MBL), especially the significance of somatic mutations in the clinical features and prognosis, by analyzing the clinical chartacteristics, genetic mutation results and prognosis of 133 children with MBL. Methods: Children and adolescents (≤18 years old) with MBL who were admitted from November 2017 to February 2023 were enrolled, and patients with somatic mutations were detected using next-generation sequencing (NGS). The diagnosis includes the completion of pathological examination and center consultation, and the staging is based on the international children's St. Jude staging system, primary patients were treated with the modified LMB89/96 protocol. Refractory or recurrent (r/r) patients were treated with second-line chemotherapy based on ICE and/or CAR-T-cell sequential therapy with different B-cell targets. The factors related to curative effect and prognosis, especially the correlation between the gene mutation spectrum and prognosis, were analyzed. Results: The mutant gene spectrum of 133 patients is shown in Fig.a. According to the time of specimen collection, there were 77 cases of initial diagnosis (initial treatment group) and 56 cases of r/r patients (r/r group). The clinical feature and survival of the 133 patients are summarized in Figure b, c, d, e (P < 0.001) and g. The results showed that patients with a large tumor focus, serous cavity effusion and delayed chemotherapy during treatment had significant difference in prognosis and significantly shortened survival. The top three genes in the initial treatment group were ID3 (53%), TP53 (47%), and CCND3 (30%) (Figure h). The top three genes in the r/r group were TP53 (82%), ID3 (58%), and ARID1A (40%) (Figure j). TP53 was significantly different between the initial treatment group and r/r patients (P < 0.001). Of the 133 patients grouped by efficacy, 70 progressed/relapsed, and 59/70 received CAR T therapy, with an overall response rate (ORR) of 83%. Survival analysis is shown in the figure f. A total of 11/70 patients received second-line chemotherapy, and only 1 patient survived to receive treatment. Compared with second-line chemotherapy, CAR T-cell treatment significantly improved the survival rate (P = 0.008). ARID1Awas significant in patients with poor prognosis after CAR T therapy (P = 0.00081) (Figure k). Keywords: Chemotherapy, Diagnostic and Prognostic Biomarkers, Non-Hodgkin (Pediatric, Adolescent, and Young Adult) No conflicts of interests pertinent to the abstract.

Intratumoral pan-ErbB targeted CAR-T for head and neck squamous cell carcinoma: interim analysis of the T4 immunotherapy study

BackgroundLocally advanced/recurrent head and neck squamous cell carcinoma (HNSCC) is associated with significant morbidity and mortality. To target upregulated ErbB dimer expression in this cancer, we developed an autologous CD28-based...

Exploratory study on the efficacy of bortezomib combining mitoxantrone or CD22-CAR T therapy targeting CD19-negative relapse after CD19-CAR T cell therapy with a simpler cell-line-based model.

Target-negative relapse after CD19 chimeric antigen receptor engineered (CAR) T cell therapy for patients with B lineage acute lymphoblastic leukemia (B-ALL) presents limited treatment options with dismal outcomes. Although CD22-CAR T cells mediate similarly potent antineoplastic effects in patients with CD19dim or even CD19-negative relapse following CD19-directed immunotherapy, a high rate of relapse associated with diminished CD22 cell surface expression has also been observed. Therefore, it is unclear whether any other therapeutic options are available. Mitoxantrone has shown significant antineoplastic activity in patients with relapsed or refractory leukemia over the past decades, and in some cases, the addition of bortezomib to conventional chemotherapeutic agents has demonstrated improved response rates. However, whether this mitoxantrone and bortezomib combination therapy is effective for those patients who have relapsed B-ALL after receiving CD19-CAR T cell therapy remains to be elucidated. In this study, we established a cellular model system using a CD19-positive B-ALL cell line Nalm-6 to investigate the treatment options for CD19-negative relapsed B-ALL after CD19-CAR T cell therapy. In addition to CD22-CAR T therapy, we observed that the combination of bortezomib and mitoxantrone exhibited effective anti-leukemia activity in the CD19-negative Nalm-6 cell line by downregulating p-AKT and p-mTOR. These results suggest that this combination therapy is a possible option for target-negative refractory leukemia cells after CAR-T cell treatment.

Recovery-model: A model for CAR T-cell-related thrombocytopenia in relapsed/refractory multiple myeloma

BackgroundPatients with multiple myeloma (MM) treated with anti-B cell maturation antigen (BCMA) and chimeric antigen receptor (CAR) T-cell therapy tend to show delayed platelet recovery. Patients and methodsThis single-center retrospective observational study included a cohort of patients with MM treated with anti-BCMA CAR-T cells in ChiCTR-OPC-16009113, ChiCTR1800018137, and ChiCTR1900021153. ResultsFifty-eight patients with MM treated with anti-BCMA CAR-T cells were included. Delayed platelet recovery (platelet count not recovering to 50 × 109/L within 28 days) was observed in 36 % of patients. Regression analysis identified several factors that influenced platelet recovery, and accordingly, a Recovery-Model was developed. A high Recovery-Model score indicates a greater risk of delayed platelet recovery after CAR-T cell infusion and reflects the risk of hematologic toxicity. The model's predictive biomarkers included baseline platelet count, baseline hemoglobin level, logarithm of baseline Ferritin level, and cytokine release syndrome grade. Finally, survival analysis showed a significant relationship between overall survival, delayed platelet recovery (p = 0.0457), and a high Recovery-Model score (p = 0.0011). ConclusionsInflammation-related factors and bone marrow reserves are associated with delayed platelet recovery. Therefore, we developed a model to predict the risk of delayed platelet recovery and hematological toxicity in relapsed/refractory patients with MM after anti-BCMA CAR-T cell treatment.

Identification of potential resistance mechanisms and therapeutic targets for the relapse of BCMA CAR-T therapy in relapsed/refractory multiple myeloma through single-cell sequencing

BackgroundBCMA CAR-T is highly effective for relapsed/refractory multiple myeloma(R/R-MM) and significantly improves the survival of patients. However, the short remission time and high relapse rate of MM patients treated with BCMA CAR-T remain bottlenecks that limit long-term survival. The immune microenvironment of the bone marrow (BM) in R/R-MM may be responsible for this. The present study aims to present an in-depth analysis of resistant mechanisms and to explore potential novel therapeutic targets for relapse of BCMA CAR-T treatment via single-cell RNA sequencing (scRNA-seq) of BM plasma cells and immune cells.MethodsThis study used 10X Genomic scRNA-seq to identify cell populations in R/R-MM CD45+ BM cells before BCMA CAR-T treatment and relapse after BCMA CAR-T treatment. Cell Ranger pipeline and CellChat were used to perform detailed analysis.ResultsWe compared the heterogeneity of CD45+ BM cells before BCMA CAR-T treatment and relapse after BCMA CAR-T treatment. We found that the proportion of monocytes/macrophages increased, while the percentage of T cells decreased at relapse after BCMA CAR-T treatment. We then reclustered and analyzed the alterations in plasma cells, T cells, NK cells, DCs, neutrophils, and monocytes/macrophages in the BM microenvironment before BCMA CAR-T treatment and relapse after BCMA CAR-T treatment. We show here that the percentage of BCMA positive plasma cells increased at relapse after BCMA CAR-T cell therapy. Other targets such as CD38, CD24, SLAMF7, CD138, and GPRC5D were also found to be expressed in plasma cells of the R/R-MM patient at relapse after BCMA CAR-T cell therapy. Furthermore, exhausted T cells, TIGIT+NK cells, interferon-responsive DCs, and interferon-responsive neutrophils, increased in the R/R-MM patient at relapse after BCMA CAR-T cell treatment. Significantly, the proportion of IL1βhi Mφ, S100A9hi Mφ, interferon-responsive Mφ, CD16hi Mφ, MARCO hi Mφ, and S100A11hi Mφ significantly increased in the R/R-MM patient at relapse after BCMA CAR-T cell therapy. Cell–cell communication analysis indicated that monocytes/macrophages, especially the MIF and APRIL signaling pathway are key players in R/R-MM patient at relapse after BCMA CAR-T cell therapy.ConclusionTaken together, our data extend the understanding of intrinsic and extrinsic relapse of BCMA CAR-T treatment in R/R-MM patient and the potential mechanisms involved in the alterations of antigens and the induced immunosuppressive microenvironment, which may provide a basis for the optimization of BCMA CAR-T strategies. Further studies should be performed to confirm these findings.