Efficacy Of CAR-T Cell Therapy Research Articles

Oncolytic virus and CAR-T cell therapy in solid tumors.

Adoptive immunotherapy with T cells, genetically modified to express a tumor-reactive chimeric antigen receptor (CAR), is an innovative and rapidly developing life-saving treatment for cancer patients without other therapeutic opportunities. CAR-T cell therapy has proven effective only in hematological malignancies. However, although by now only a few clinical trials had promising outcomes, we predict that CAR-T therapy will eventually become an established treatment for several solid tumors. Oncolytic viruses (OVs) can selectively replicate in and kill cancer cells without harming healthy cells. They can stimulate an immune response against the tumor, because OVs potentially stimulate adaptive immunity and innate components of the host immune system. Using CAR-T cells along with oncolytic viruses may enhance the efficacy of CAR-T cell therapy in destroying solid tumors by increasing the tumor penetrance of T cells and reducing the immune suppression by the tumor microenvironment. This review describes recent advances in the design of oncolytic viruses and CAR-T cells while providing an overview of the potential combination of oncolytic virotherapy with CAR-T cells for solid cancers. In this review, we will focus on the host-virus interaction in the tumor microenvironment to reverse local immunosuppression and to develop CAR-T cell effector function.

Enhanced tumoricidal activity of PD-1 antibody-secreting c-Met CAR-T cells against pancreatic cancer cells

To construct c-Met CAR-T cells secreting PD-1 antibodies to reduce immune inhibitory effect of tumor cells and enhance the efficacy of CAR-T cell therapy against pancreatic cancer. Kaplan-Meier Plotter, GEPIA, and Timer 2.0 bioinformatics databases were used to analyze c-Met expression in pancreatic cancer and its correlation with survival and immune infiltration status. In clinical samples of pancreatic cancer and pancreatic cancer Aspc-1 cells, c-Met and PD-L1 expressions were detected using immunohistochemistry or flow cytometry. Using gene editing technology, PD-1 secretory antibodies and HIS tags were linked to second-generation c-Met CAR molecules to construct PD-1/c-Met CAR plasmids, which were then packaged into lentiviruses for infection of activated T cells. The positive rate and cell subset distribution of CAR-T cells were analyzed with flow cytometry, and secretory PD-1 antibodies in cell supernatants were detected using Western blotting. The target cell killing efficiency and proliferative activity of the modified CAR-T cells were evaluated after activation, and cytokine secretion was analyzed using ELISA. The expression of c-Met was significantly higher in pancreatic cancer than in normal tissues, and its expression level was negatively correlated with the patients' survival and positively correlated with immune cell infiltration. The clinical samples of pancreatic cancer tissues expressed significantly higher levels of c-Met and PD-L1 than the adjacent tissues, and 90.7% and 57.7% of Aspc-1 cells were positive for c-Met and PD-L1, respectively. The constructed PD-1/c-Met CAR-T cells were capable of secreting PD-1 antibodies and showed a significantly higher killing efficiency against tumor cells than c-Met CAR-T cells at an effector-to-target ratio of 20: 1, with also a higher proliferative activity after target cell stimulation and higher levels of IL-2 and TNF-α secretin. PD-1/c-Met CAR-T cells have higher killing efficiency against pancreatic cancer cells with also higher proliferative activity than c-Met CAR-T cells.

Earlier intrathecal dexamethasone effectively alleviate immune effector cell-associated neurotoxicity syndrome

Chimeric antigen receptor T cell (CAR-T) therapy is effective in treating relapsed/refractory B-cell acute lymphoblastic leukemia (R/R B-ALL). However, the side effects of immune effector cell-associated neurotoxicity syndrome (ICANS) remain a problem. The current frontline therapies for ICANS include steroids and supportive care. For the steroid-refractory and severe ICANS, several studies have reported excellent efficacy of intrathecal (IT) corticosteroids alone or in combination with chemotherapy. However, whether patients can benefit from IT dexamethasone (dex) before grade 3 or refractory ICANS remains unclear. In this study, the patients with ICANS (≥1) after CAR-T cell therapy were assigned to the IT group and non-IT group. Clinical information, laboratory parameters, and serum cytokine levels were analyzed. A significant and rapid reduction in inflammatory cytokines and biomarkers was observed after 24 h of IT dex treatment. With IT dex, 83.3 % (15/18) of patients recovered from neurotoxicity. Moreover, this option significantly shortens the recovery time of ICANS without affecting the efficacy of CAR-T cell therapy. Earlier initiation of IT dex is the optimal management of ICANS resulting from CAR-T cell therapy, but larger sample studies are needed to determine its efficacy in these settings.

Collagen extracellular matrix promotes gastric cancer immune evasion by activating IL4I1-AHR signaling

BackgroundGastric cancer (GC) remains a significant global health challenge with poor prognosis, partly due to its ability to evade the immune system. The extracellular matrix (ECM), particularly collagen, plays a crucial role in tumor immune evasion, but the underlying mechanisms are not fully understood. This study investigates the role of collagen ECM in promoting immune evasion in gastric cancer by activating the IL4I1-AHR signaling pathway. MethodsWe cultured gastric cancer cells in 3D collagen gels and assessed their immune evasion capabilities by co-culturing with HER2-specific CAR-T cells. The expression of IL4I1 and its metabolites was analyzed, and the role of integrin αvβ1 in mediating the effects of collagen was explored. Additionally, the impact of IL4I1-induced AHR activation on CAR-T cell exhaustion was evaluated, both in vitro and in vivo. ResultsWe found that gastric cancer cells cultured on collagen exhibited increased resistance to CAR-T cell cytotoxicity, which was associated with upregulated immune checkpoint molecules and downregulated effector cytokines on CAR-T cells. This was linked to increased IL4I1 expression, which was further induced by integrin αvβ1 signaling within the 3D collagen environment. IL4I1 metabolites, particularly KynA, promoted CAR-T cell exhaustion by activating the AHR pathway, leading to decreased cytotoxicity and tumor growth inhibition. ConclusionsOur study reveals a novel mechanism by which the collagen ECM facilitates immune evasion in gastric cancer through the activation of IL4I1-AHR signaling, contributing to CAR-T cell exhaustion. Targeting this pathway could potentially enhance the efficacy of CAR-T cell therapy in gastric cancer.

Atlas of metastatic gastric cancer links ferroptosis to disease progression and immunotherapy response

BACKGROUND & AIMSMetastases from gastric adenocarcinoma (GAC) lead to high morbidity and mortality. Developing innovative and effective therapies requires a comprehensive understanding of the tumor and immune biology of advanced GAC. Yet, collecting matched specimens from advanced, treatment-naïve GAC patients poses a significant challenge, limiting the scope of current research, which has predominantly focused on localized tumors. This gap hinders a deeper insight into the metastatic dynamics of GAC. METHODSWe performed in-depth single-cell transcriptome and immune profiling on 68 paired, treatment-naïve, primary-metastatic tumors to delineate alterations in cancer cells and their tumor microenvironment (TME) during metastatic progression. To validate our observations, we conducted comprehensive functional studies both in vitro and in vivo, employing cell lines, multiple PDX and novel mouse models of GAC. RESULTSLiver and peritoneal metastases exhibited distinct properties in cancer cells and dynamics of TME phenotypes, supporting the notion that cancer cells and their local TMEs co-evolve at metastatic sites. Our study also revealed differential activation of cancer meta-programs across metastases. We observed evasion of cancer cell ferroptosis via GPX4 upregulation during GAC progression. Conditional depletion of Gpx4 or pharmacological inhibition of ferroptosis resistance significantly attenuated tumor growth and metastatic progression. Additionally, ferroptosis-resensitizing treatments augmented the efficacy of CAR T-cell therapy. CONCLUSIONSThis study represents the largest single-cell dataset of metastatic GACs to date. High-resolution mapping of the molecular and cellular dynamics of GAC metastasis has revealed a rationale for targeting ferroptosis defense in combination with CAR T-cell therapy as a novel therapeutic strategy with potential immense clinical implications.

RhIL-7-hyFc, a long-acting interleukin-7, improves efficacy of CAR-T cell therapy in solid tumors

BackgroundChimeric antigen receptor T-cell (CAR-T) therapy has achieved remarkable remission in patients with B-cell malignancies. However, its efficacy in treating solid tumors remains limited. Here, we investigated a combination therapy...

IMMU-06. CAR DESIGN SHAPES THE BRAIN TUMOR IMMUNE MICROENVIRONMENT: IMPACT ON ACTIVITY AND PERSISTENCE OF ANTI-GLIOMA ADOPTIVE T CELL IMMUNOTHERAPY

Abstract BACKGROUND B7-H3 CAR T-cells effectively eradicate brain tumors in xenograft models and have proven safe in clinical trials, yet no objective responses were observed in patients. The limited efficacy is partly attributed to the immunosuppressive tumor microenvironment (TME), a characteristic not fully recapitulated in investigations using xenograft models. In this study, we set to optimize B7-H3 CAR structure and examine the effects of CAR design on the brain TME using an immunocompetent glioma model. METHODS We generated a panel of fully murine B7-H3 CARs with variations in transmembrane, co-stimulatory, and activation domains. This enabled us to comprehensively investigate their effector functions within the intact immune system. High-dimensional flow cytometry and single-cell RNA sequencing were then used to investigate changes in the brain TME following CAR T-cell therapy. RESULTS While five out of six B7-H3 CARs with single co-stimulatory domains exhibited potent functionality in vitro, optimizing co-stimulation and signaling failed to enhance their anti-glioma efficacy in vivo. To further enhance therapeutic effectiveness and persistence, we incorporated 4-1BB and CD28 co-stimulation through transgenic expression of 4-1BBL on CD28-based CAR T-cells. Although this design significantly improved anti-glioma efficacy in vitro, it conferred no additional benefits in vivo. Analysis of the TME revealed that CAR T-cell therapy influenced the immune composition of the brain TME. Successful anti-tumor responses were dictated by the recruitment, activation, and spatial localization of unique inflammatory ‘immune hubs’ containing specific subsets of macrophages and endogenous T-cells. Interestingly, depletion of brain macrophages using CSF1R inhibitor markedly inhibited CAR T-cell anti-tumor activity. CONCLUSION Our study highlights the critical role of CAR structural design and its modulation of the TME in mediating the efficacy of CAR T-cell therapy in brain tumors. Yet, more specific targeting and/or reprogramming of the TME is warranted for the successful design of effective adoptive immunotherapies for high-grade glioma.

Co-stimulation of CD28/CD40 signaling molecule potentiates CAR-T cell efficacy and stemness

CD19 chimeric antigen receptor T (CD19CAR-T) cells have achieved promising outcomes in relapsed/refractory B-cell malignancies. However, recurrences occur due to the loss of CAR-T cell persistence. We developed dual T/B-cell co-stimulatory molecules (CD28 and CD40) in CAR-T cells to enhance intense tumoricidal activity and persistence. CD19.28.40z CAR-T cells promoted pNF-κB and pRelB downstream signaling while diminishing NFAT signaling upon antigen exposure. CD19.28.40z CAR-T cells demonstrated greater proliferation which translated into effective anti-tumor cytotoxicity in long-term co-culture assay. Repetitive weekly antigen stimulation unveiled continuous CAR-T cell expansion while preserving central memory T-cell subset and lower expression of exhaustion phenotypes. The intrinsic genes underlying CD19.28.40z CAR-T cell responses were compared to conventional CARs and demonstrated the up-regulated genes associated with T-cell proliferation and memory as well as down-regulated genes related to apoptosis, exhaustion, and glycolysis pathway. Enrichment of genes toward T-cell stemness, particularly SELL, IL-7r, TCF7, and KLF2, was observed. Effective and continuing anti-tumor cytotoxicity in vivo was exhibited in both B-ALL and B-NHL xenograft models while demonstrating persistent T-cell memory signatures. The functional enhancement of CD37.28.40z CAR-T cell activities against CD37+ tumor cells was further validated. The modification of dual T/B-cell signaling molecules remarkably maximized the efficacy of CAR-T cell therapy.

Progress and pitfalls of gene editing technology in CAR-T cell therapy: a state-of-the-art review.

CAR-T cell therapy has shown remarkable promise in treating B-cell malignancies, which has sparked optimism about its potential to treat other types of cancer as well. Nevertheless, the Expectations of CAR-T cell therapy in solid tumors and non-B cell hematologic malignancies have not been met. Furthermore, safety concerns regarding the use of viral vectors and the current personalized production process are other bottlenecks that limit its widespread use. In recent years the use of gene editing technology in CAR-T cell therapy has opened a new way to unleash the latent potentials of CAR-T cell therapy and lessen its associated challenges. Moreover, gene editing tools have paved the way to manufacturing CAR-T cells in a fully non-viral approach as well as providing a universal, off-the-shelf product. Despite all the advantages of gene editing strategies, the off-target activity of classical gene editing tools (ZFNs, TALENs, and CRISPR/Cas9) remains a major concern. Accordingly, several efforts have been made in recent years to reduce their off-target activity and genotoxicity, leading to the introduction of advanced gene editing tools with an improved safety profile. In this review, we begin by examining advanced gene editing tools, providing an overview of how these technologies are currently being applied in clinical trials of CAR-T cell therapies. Following this, we explore various gene editing strategies aimed at enhancing the safety and efficacy of CAR-T cell therapy.

Phase I clinical trial of MUC1-targeted CAR-T cells with PD-1-knockout in the treatment of advanced breast cancer.

1089 Background: In the treatment of breast cancer, the therapeutic efficacy of CAR-T cell therapy remains unsatisfactory. A possible approach to enhance the efficacy of CAR-T therapy is to combine CAR-T with PD-1 inhibition. This clinical trial was designed to assess the safety and tolerability of PD-1 knockout MUC1-targeted CAR-T cells in advanced breast cancer. Methods: Patients with advanced breast cancer were recruited according to the criteria in NCT05812326. PD-1 gene knockout (KO) MUC1-targeted CAR-T cells were prepared in 2 steps. MUC1-specific CARs were first constructed using 5E5 scFv in patient-derived T cells, and then 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-T cells were infused at a starting dose of 1-2x106 CAR+ cells/kg and then escalated to 0.9-1.8x107 CAR+ cells/kg. The safety and tolerability of therapeutic cells were evaluated using CTCAE v5.0. Patients’ general condition, levels of lymphocytes, and serum cytokines (IL-1β, IL-2R, IL-6, IL-8, TNF and IL-10) were monitored. Circulating CAR-T cells were checked regularly. Changes in tumor size were examined by MRI/CT scans. The primary endpoint was to assess the safety of this treatment. We also compared the responses in patients who received single and multiple cycles of infusion of therapeutic CAR-T cells. Results: A total of 12 patients (aged 34 to 61) diagnosed with recurrent/metastatic breast cancer were included in this study. All participants received at least 1 cycle of CAR-T cell treatment. Among the 12 patients, 8 received 1 cycle, 3 received 2 cycles, 1 received 3 cycles. Adverse events (AEs) included elevated AST level (7/12, 58.3%), acute fever (6/12), elevated ALT level (5/12), skin rash (5/12), chills (4/12), anemia (4/12), lymphopenia (4/12), diarrhea, vomiting and urinary tract infection (2/12). The most serious AE was lymphopenia (grade 4 lasting 1 day in 1 patient). No grade 3-5 CRS was observed. No patients experienced neurotoxicity. No predefined dose-limiting toxicities (DLT) or serious AEs were observed. Furthermore, there were no AEs resulting in discontinuation of treatment. Of the 12 patients evaluated, 5 had stable disease (SD), indicating that MUC1 CAR-T cell therapy can control the progression of some advanced breast cancers, despite the fact that the efficacy assessment is quite preliminary. The pharmacokinetic study indicated that improved clinical outcomes are associated with a high level of circulating CAR+ copy on day 7. Conclusions: Our data suggest that treatment of patients with advanced breast cancer with PD-1 disrupted MUC1-targeted CAR-T cells is safe and well-tolerated by all patients in this phase 1 clinical trial. No serious CRS or other EA was observed throughout the study. The efficacy of this unique combined therapy is currently being assessed. Clinical trial information: NCT05812326 .

Adverse Reactions in Relapsed/Refractory B-Cell Lymphoma Administered with Chimeric Antigen Receptor T Cell Alone or in Combination with Autologous Stem Cell Transplantation.

(1) Background: The combination of CAR-T with ASCT has been observed to enhance the efficacy of CAR-T cell therapy. However, the impact of this combination on adverse reactions is still uncertain. (2) Methods: Between January 2019 and February 2023, 292 patients diagnosed with r/r B-cell lymphoma received either CAR-T therapy alone or in combination with ASCT at our institution. We evaluated the incidence of CRS and CRES and utilized a logistic regression model to identify factors contributing to severe CRS (grade 3-4) and CRES (grade 3-4). (3) Results: The overall incidence of CRS and CRES was 78.9% and 8.2% in 147 patients receiving CAR-T alone, and 95.9% and 15.2% in 145 patients receiving CAR-T combined with ASCT, respectively. The incidence of overall CRS (p < 0.0001) and mild CRS (grade 1-2) (p = 0.021) was elevated in the ASCT combined with CAR-T group. No significant difference was observed in severe CRS and CRES between the groups. Among the 26 cases of lymphoma involving the central nervous system (CNS), 96.2% (25/26) developed CRS (15.4% grade 3-4), and 34.6% (9/26) manifested CRES (7.7% grade 3-4). Female patients had a lower incidence of severe CRS but a higher incidence of severe CRES. Lymphomas with CNS involvement demonstrated a higher risk of CRES compared to those without central involvement. (4) Conclusions: The combination of ASCT with CAR-T demonstrated a preferable option in r/r B-cell lymphoma without an increased incidence of severe CRS and CRES.

Efficacy of CAR T-cell therapy is not impaired by previous bispecific antibody treatment in large B-cell lymphoma

AbstractIn this retrospective study, chimeric antigen receptor T cells remained effective in patients with relapsed/refractory large B-cell lymphoma after prior exposure to bispecific antibodies (BsAbs) targeting different antigens. These results are relevant to clinical practice, particularly given the increasing use of BsAbs in earlier treatment lines.

Mesothelin CAR-T cells expressing tumor-targeted immunocytokine IL-12 yield durable efficacy and fewer side effects

Chimeric antigen receptor (CAR)-modified T cell therapy has achieved remarkable efficacy in treating hematological malignancies, but it confronts many challenges in treating solid tumors, such as the immunosuppressive microenvironment of the solid tumors. These factors reduce the antitumor activity of CAR-T cells in clinical trials. Therefore, we used the immunocytokine interleukin-12 (IL-12) to enhance the efficacy of CAR-T cell therapy. In this study, we engineered CAR-IL12R54 T cells that targeted mesothelin (MSLN) and secreted a single-chain IL-12 fused to a scFv fragment R54 that recognized a different epitope on mesothelin. The evaluation of the anti-tumor activity of the CAR-IL12R54 T cells alone or in combination with anti-PD-1 antibody in vitro and in vivo was followed by the exploration of the functional mechanism by which the immunocytokine IL-12 enhanced the antitumor activity. CAR-IL12R54 T cells had potency to lyse mesothelin positive tumor cells in vitro. In vivo studies demonstrated that CAR-IL12R54 T cells were effective in controlling the growth of established tumors in a xenograft mouse model with fewer side effects than CAR-T cells that secreted naked IL-12. Furthermore, combination of PD-1 blockade antibody with CAR-IL12R54 T cells elicited durable anti-tumor responses. Mechanistic studies showed that IL12R54 enhanced Interferon-γ (IFN-γ) production and dampened the activity of regulatory T cells (Tregs). IL12R54 also upregulated CXCR6 expression in the T cells through the NF-κB pathway, which facilitated T cell infiltration and persistence in the tumor tissues. In summary, the studies provide a good therapeutic option for the clinical treatment of solid tumors.

Chimeric antigen receptor (CAR) modified T Cells in acute myeloid leukemia: limitations and expectations.

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy with a poor prognosis despite the advent of novel therapies. Consequently, a major need exists for new therapeutic options, particularly for patients with relapsed/refractory (R/R) AML. In recent years, it has been possible to individualize the treatment of a subgroup of patients, particularly with the emergence of multiple targeted therapies. Nonetheless, a considerable number of patients remain without therapeutic options, and overall prognosis remains poor because of a high rate of disease relapse. In this sense, cellular therapies, especially chimeric antigen receptor (CAR)-T cell therapy, have dramatically shifted the therapeutic options for other hematologic malignancies, such as diffuse large B cell lymphoma and acute lymphoblastic leukemia. In contrast, effectively treating AML with CAR-based immunotherapy poses major biological and clinical challenges, most of them derived from the unmet need to identify target antigens with expression restricted to the AML blast without compromising the viability of the normal hematopoietic stem cell counterpart. Although those limitations have hampered CAR-T cell therapy translation to the clinic, there are several clinical trials where target antigens, such as CD123, CLL-1 or CD33 are being used to treat AML patients showing promising results. Moreover, there are continuing efforts to enhance the specificity and efficacy of CAR-T cell therapy in AML. These endeavors encompass the exploration of novel avenues, including the development of dual CAR-T cells and next-generation CAR-T cells, as well as the utilization of gene editing tools to mitigate off-tumor toxicities. In this review, we will summarize the ongoing clinical studies and the early clinical results reported with CAR-T cells in AML, as well as highlight CAR-T cell limitations and the most recent approaches to overcome these barriers. We will also discuss how and when CAR-T cells should be used in the context of AML.

Current challenges and therapeutic advances of CAR-T cell therapy for solid tumors.

The application of chimeric antigen receptor (CAR) T cells in the management of hematological malignancies has emerged as a noteworthy therapeutic breakthrough. Nevertheless, the utilization and effectiveness of CAR-T cell therapy in solid tumors are still limited primarily because of the absence of tumor-specific target antigen, the existence of immunosuppressive tumor microenvironment, restricted T cell invasion and proliferation, and the occurrence of severe toxicity. This review explored the history of CAR-T and its latest advancements in the management of solid tumors. According to recent studies, optimizing the design of CAR-T cells, implementing logic-gated CAR-T cells and refining the delivery methods of therapeutic agents can all enhance the efficacy of CAR-T cell therapy. Furthermore, combination therapy shows promise as a way to improve the effectiveness of CAR-T cell therapy. At present, numerous clinical trials involving CAR-T cells for solid tumors are actively in progress. In conclusion, CAR-T cell therapy has both potential and challenges when it comes to treating solid tumors. As CAR-T cell therapy continues to evolve, further innovations will be devised to surmount the challenges associated with this treatment modality, ultimately leading to enhanced therapeutic response for patients suffered solid tumors.

Self-regulating CAR-T cells modulate cytokine release syndrome in adoptive T-cell therapy.

Cytokine release syndrome (CRS) is a frequently observed side effect of chimeric antigen receptor (CAR)-T cell therapy. Here, we report self-regulating T cells that reduce CRS severity by secreting inhibitors of cytokines associated with CRS. With a humanized NSG-SGM3 mouse model, we show reduced CRS-related toxicity in mice treated with CAR-T cells secreting tocilizumab-derived single-chain variable fragment (Toci), yielding a safety profile superior to that of single-dose systemic tocilizumab administration. Unexpectedly, Toci-secreting CD19 CAR-T cells exhibit superior in vivo antitumor efficacy compared with conventional CD19 CAR-T cells. scRNA-seq analysis of immune cells recovered from tumor-bearing humanized mice revealed treatment with Toci-secreting CD19 CAR-T cells enriches for cytotoxic T cells while retaining memory T-cell phenotype, suggesting Toci secretion not only reduces toxicity but also significantly alters the overall T-cell composition. This approach of engineering T cells to self-regulate inflammatory cytokine production is a clinically compatible strategy with the potential to simultaneously enhance safety and efficacy of CAR-T cell therapy for cancer.

Abstract CT069: Targeting EpCAM via CAR T-cells is an effective treatment for gastric cancer patients and subsequent toll-like receptor signaling activation in CD36+ monocyte underlies the resulting cytokine release syndrome

Abstract EpCAM is highly expressed in various cancer types of the gastrointestinal system and at metastatic sites. It serves as a promising prognostic marker and therapeutic target. We conducted a first-in-human, open-label, single-arm, multicenter, phase 1 clinical trial following the classical "3+3" dose escalation design. The endpoints of this clinical trial are to assess the safety, efficacy, and pharmacokinetic (PK)/pharmacodynamic (PD) profile of EpCAM CAR-T. The trial is still ongoing, and our interim analysis results revealed a favorable safety profile of EpCAM CAR-T. No treatment-related deaths were observed within the 4-week follow-up period after infusion. 2 (12.5%) patients in high dose group (3*106) experienced dose-limiting toxicity (DLT) and 8 (50%) patients experienced grade 1-3 CRS. EpCAM CAR-T showed promising efficacy in gastric cancer. In gastric cancer group, the overall response rate (ORR) and disease control rate (DCR) reached 20.0% and 90.0%, respectively. However, the efficacy of EpCAM CAR-T in treating colorectal cancer was suboptimal, with an objective response rate (ORR) of 0% and disease control rate (DCR) of 50%. In our study, we observed that patients in gastric cancer (GC) group who developed cytokine release syndrome (CRS) had a weak response to CAR-T cell therapy, which is consistent with previous observations in animal models. We employed single-cell RNA sequencing (scRNA-seq) to analyze peripheral blood mononuclear cells (PBMCs) from GC group patients receiving EpCAM CAR-T treatment to explore the potential antagonism between CRS and treatment efficacy. Our findings underscore the significant role of monocytes in the regulation of CRS and treatment response. Specifically, we identified an increased abundance of Toll-like receptor (TLR)-dependent CD36+ monocytes in non-responders experiencing CRS. In a mouse model, we demonstrated that blocking TLR signaling in monocytes attenuated CRS induced by EpCAM CAR-T cells. Conversely, CD16+ monocytes were enriched in responders, displaying upregulated antigen presentation pathways and enhanced tumor infiltration capacity. In vivo, experiments revealed that blocking the antigen presentation pathway or inhibiting tumor infiltration of CD16+ monocytes resulted in reduced anti-tumor response of EpCAM CAR-T cells. Our findings highlight the critical role of intrinsic monocyte subpopulations as determinants of CAR-T efficacy and CRS. These insights may provide valuable strategies for predicting and enhancing the safety and efficacy of CAR-T cell therapy for solid tumors. Citation Format: TIanhang Luo, Zhengmao Lu, Zhongen Wu, Yuxuan Dong, Yuanyuan Zhu, Mei Feng, Shenglin Mei, Weijia Fang, Di Zhu. Targeting EpCAM via CAR T-cells is an effective treatment for gastric cancer patients and subsequent toll-like receptor signaling activation in CD36+ monocyte underlies the resulting cytokine release syndrome [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 CT069.

Safety and efficacy of chimeric antigen receptor T-cell therapy for acute myeloid leukemia: A subgroup based meta-analysis

IntroductionAcute myeloid leukemia (AML) is a significant hematological malignancy in the United States, with a high mortality rate and limited treatment options. CAR T-cell therapy, a new and promising treatment, is being investigated for its efficacy and safety in AML. This meta-analysis aims to assess the safety and efficacy of CAR T-cell therapy in AML, considering various subgroups such as study location, study design, prior transplantation status, conditioning regimen, and CAR T-cell source. MethodsWe conducted a comprehensive literature review across multiple databases, adhering to PRISMA guidelines and focusing on studies concerning CAR T-cell therapy in AML. We included original articles in English and excluded non-original reviews, abstracts, and non-English studies. The risk of bias was assessed using the Cochrane ROBINS-I tool. Statistical analysis involved meta-analysis with Cochrane’s Q-test and I² statistic, using both fixed-effect and random-effects models, and assessed for publication bias. ResultsOur search yielded studies encompassing 57 AML patients treated with CAR T-cell therapy. The meta-analysis revealed a 48% incidence of complete remission with CAR T-cell therapy, varying significantly across subgroups based on study design, location, prior transplantation, conditioning regimen, and CAR T-cell source. The highest complete remission rates were observed in patients from China, those who had undergone prior hematopoietic cell transplantation, and those treated with fludarabine and cyclophosphamide conditioning regimen. Adverse events included graft-versus-host disease (7%) and cytokine release syndrome (53%). ConclusionsThis meta-analysis highlights the potential of CAR T-cell therapy in AML treatment, especially when integrated with certain prior treatments and conditioning regimens. The findings suggest a higher efficacy in patients with previous hematopoietic cell transplantation and specific conditioning regimens. Further large-scale, randomized trials are essential to confirm these findings and establish CAR T-cell therapy as a standard treatment for AML.

PD-1 downregulation enhances CAR-T cell antitumor efficiency by preserving a cell memory phenotype and reducing exhaustion

BackgroundDespite the encouraging outcome of chimeric antigen receptor T cell (CAR-T) targeting B cell maturation antigen (BCMA) in managing relapsed or refractory multiple myeloma (RRMM) patients, the therapeutic side effects...

Abstract 6327: Impact of G-CSF on safety and efficacy of CAR T-cell therapy in non-Hodgkin lymphoma

Abstract Introduction: Chimeric antigen receptor T-cell (CAR-T) therapy is an established treatment modality for the management of refractory and/or relapsed non-Hodgkin lymphoma (NHL). Despite restrictions on granulocyte colony-stimulating factor (G-CSF) use in registration clinical trials due to potential worsening of cytokine release syndrome (CRS), G-CSF is often prescribed for neutrophil recovery post-CAR-T in clinical practice. We conducted a retrospective study to assess the association between G-CSF use and the safety and efficacy of CAR-T. Methods: Following Institutional Review Board approval, we retrospectively analyzed NHL patients receiving commercial CD19-targeted CAR-T across Mayo Clinic sites (Arizona, Florida, and Minnesota) between October 2017 and May 2023. Demographics, labs, and post CAR-T events were collected. Electronic medical records were reviewed for G-CSF exposure within Day 1 - 100 post-CAR T. Differences by G-CSF status were examined using a Chi-square test and Kruskal Wallis tests. Hazard ratios (HR) and 95% confidence intervals (CI) for overall survival (OS) were calculated using Cox model. Results: Among 270 CAR-T patients; 106 received G-CSF within 30 days and 164 did not. Median age was 56.9 with G-CSF and 58.3 without G-CSF. Most were male (75.2% G-CSF, 62.6% no G-CSF). Diffuse large B cell lymphoma was the predominant NHL subtype (67.0% G-CSF, 65.2% no G-CSF). G-CSF within 30 days was not associated with reduced incidence of neutropenic fever (11.7% G-CSF vs 9.9% no G-CSF, p = 0.6593) or documented infection (22.1% vs 18.3%, p = 0.4439). G-CSF correlated with decreased profound neutropenia duration (ANC &amp;lt; 100 μL, 0 vs 2 days, p &amp;lt; 0.0001) and incidence within 30 days ( 31.7% vs 60.4%, p &amp;lt; 0.0001) as well as incidence of protracted profound neutropenia (&amp;gt; 7 days, 3.8% vs 22.8%, p &amp;lt; 0.0001). G-CSF was associated with a higher incidence of cytopenias between days 30 -100: severe neutropenia (ANC &amp;lt; 500/uL, 28.8% vs 15.2%, p = 0.0075), severe anemia (Hb &amp;lt; 8 g/dL, 21% vs 9.7%, p = 0.0114), and severe thrombocytopenia (Plt &amp;lt; 50 g/L, 35.2% vs 20.9%, p = 0.0099). Logistic regression analysis showed that none of the examined covariates, including prior autologous stem cell transplant, ECOG PS score, and receipt of bridging therapy, were associated with severe neutropenia likelihood. G-CSF was associated with a higher CRS incidence (89.6% vs 79.9%, p = 0.0343), but grade 3 CRS or higher (4.7% vs 3.7%, p = 0.6675) was no different. No difference in complete response rates (66% vs 61.1%, p = 0.4707) or 2-year OS (p = 0.523) was observed between the 2 groups. Conclusion: G-CSF within 30 days was associated with reduced duration and incidence of profound neutropenia without a significant impact on incidence of neutropenic fever or documented infections. There was a signal of association between G-CSF and increased incidence of low-grade CRS and delayed cytopenias (day 30-100) that warrants confirmation in larger studies. Citation Format: Lay She Ng, Claire I. Yee, Radhika Bansal, Mohamed A. Kharfan-Dabaja, Grzegorz S. Nowakowski, Allison C. Rosenthal, Javier Munoz, Januario Castro, Wern Lynn Ng, Hemant S. Murthy, Yi Lin, Matthew R. Buras, Madiha Iqbal, Yucai Wang, Talal Hilal. Impact of G-CSF on safety and efficacy of CAR T-cell therapy in non-Hodgkin lymphoma [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 6327.