Chimeric Antigen Receptor Research Articles

Single-cell analysis of the multiple myeloma microenvironment after γ-secretase inhibition and CAR T-cell therapy

AbstractChimeric antigen receptor (CAR) T cells and bispecific antibodies targeting B-cell maturation antigen (BCMA) have significantly advanced the treatment of relapsed and refractory multiple myeloma. Resistance to BCMA-targeting therapies, nonetheless, remains a significant challenge. BCMA shedding by γ-secretase is a known resistance mechanism, and preclinical studies suggest that inhibition may improve anti-BCMA therapy. Leveraging a phase 1 clinical trial of the γ-secretase inhibitor (GSI), crenigacestat, with anti-BCMA CAR T cells (FCARH143), we used single-nuclei RNA sequencing and assay for transposase-accessible chromatin sequencing to characterize the effects of GSI on the tumor microenvironment. The most significant impacts of GSI involved effects on monocytes, which are known to promote tumor growth. In addition to observing a reduction in the frequency of nonclassical monocytes, we also detected significant changes in gene expression, chromatin accessibility, and inferred cell-cell interactions after exposure to GSI. Although many genes with altered expression are associated with γ-secretase–dependent signaling, such as Notch, other pathways were affected, indicating GSI has far-reaching effects. Finally, we detected monoallelic deletion of the BCMA locus in some patients with prior exposure to anti-BCMA therapy, which significantly correlated with reduced progression-free survival (PFS; median PFS, 57 vs 861 days). GSIs are being explored in combination with the full spectrum of BCMA-targeting agents, and our results reveal widespread effects of GSI on both tumor and immune cell populations, providing insight into mechanisms for enhancing BCMA-directed therapies.

An innovative strategy harnessing self-activating CAR-NK cells to mitigate TGF-β1-driven immune suppression

The dysfunction of natural killer (NK) cells, mediated by transforming growth factor β1 (TGFβ1) within the tumor microenvironment, impedes antitumor therapy and contributes to poor clinical outcomes. Our study introduces self-activating chimeric antigen receptor (CAR)-NK cells that block TGFβ1 signaling by releasing a specifically designed peptide, P6, which targets mesothelin in pancreatic tumors. P6 originates from the interaction sites between TGFβ1 and TGFβ receptor 1 and effectively disrupts TGFβ1's inhibitory signaling in NK cells. Our analysis demonstrates that P6 treatment interrupts the SMAD2/3 pathway in NK cells, mitigating TGFβ1-mediated suppression of NK cell activity, thereby enhancing their metabolic function and cytotoxic response against pancreatic tumors. These CAR-NK cells exhibit potent antitumor capabilities, as evidenced in spheroid cultures with cancer-associated fibroblasts and in vivo mouse models. Our approach marks a substantial advancement in overcoming TGFβ1-mediated immune evasion, offering a promising avenue for revolutionizing cancer immunotherapy.

68Ga-grazytracer PET for noninvasive assessment of response to immunotherapy in solid tumors and lymphomas: a phase 1/2 clinical trial

To tackle the clinical challenge of noninvasively assessing immunotherapy efficacy in patients, here we used positron emission tomography (PET) with 68Ga-grazytracer, which targets granzyme B, a crucial effector molecule secreted by activated CD8+ T cells. In this phase 1/2 clinical trial (NCT05000372) involving a diverse cohort of 24 patients with solid tumors and lymphomas who received immunotherapies, including immune checkpoint inhibitors (either alone or with chemotherapies) and chimeric antigen receptor-T cell therapy, we examined the in vivo behaviors of 68Ga-grazytracer. Primary endpoints were safety, biodistribution, granzyme B specificity, and the predictive utility of 68Ga-grazytracer, while secondary endpoint was the relationship between 68Ga-grazytracer uptake and tumor immune phenotype. 68Ga-grazytracer exhibited a safe profile and specifically targeted granzyme B in patients. 68Ga-grazytracer PET showed superior predictive value for short-term prognosis and progression-free survival than those of conventional assessment criteria, including RECIST 1.1 and PERCIST. Moreover, the uptake of 68Ga-grazytracer in tumors was significantly higher in those with a “non-desert” immune phenotype than those with an immune “desert” phenotype, thereby meeting the primary and secondary endpoints of this trial. Collectively, we successfully visualized CD8+ T cell effector function in humans using 68Ga-grazytracer PET, offering insights for enhancing immunotherapy assessment, patient stratification and treatment planning.

Non-viral vectors for chimeric antigen receptor immunotherapy

Non-viral vectors for chimeric antigen receptor immunotherapy

Non-viral vectors for chimeric antigen receptor immunotherapy

Non-viral vectors for chimeric antigen receptor immunotherapy

Exploring miRNA therapies and gut microbiome-enhanced CAR-T cells: advancing frontiers in glioblastoma stem cell targeting.

Glioblastoma multiforme (GBM) presents a formidable challenge in oncology due to its aggressive nature and resistance to conventional treatments. Recent advancements propose a novel therapeutic strategy combining microRNA-based therapies, chimeric antigen receptor-T (CAR-T) cells, and gut microbiome modulation to target GBM stem cells and transform cancer treatment. MicroRNA therapies show promise in regulating key signalling pathways implicated in GBM progression, offering the potential to disrupt GBM stem cell renewal. CAR-T cell therapy, initially successful in blood cancers, is being adapted to target GBM by genetically engineering T cells to recognise and eliminate GBM stem cell-specific antigens. Despite early successes, challenges like the immunosuppressive tumour microenvironment persist. Additionally, recent research has uncovered a link between the gut microbiome and GBM, suggesting that gut dysbiosis can influence systemic inflammation and immune responses. Novel strategies to modulate the gut microbiome are emerging, enhancing the efficacy of microRNA therapies and CAR-T cell treatments. This combined approach highlights the synergistic potential of these innovative therapies in GBM treatment, aiming to eradicate primary tumours and prevent recurrence, thereby improving patient prognosis and quality of life. Ongoing research and clinical trials are crucial to fully exploit this promising frontier in GBM therapy, offering hope to patients grappling with this devastating disease.

Application of novel CAR technologies to improve treatment of autoimmune disease.

Chimeric antigen receptor (CAR) T cell therapy has become an important treatment for hematological cancers, and its success has spurred research into CAR T cell therapies for other diseases, including solid tumor cancers and autoimmune diseases. Notably, the development of CAR-based treatments for autoimmune diseases has shown great progress recently. Clinical trials for anti-CD19 and anti-BCMA CAR T cells in treating severe B cell-mediated autoimmune diseases, like systemic lupus erythematosus (SLE), have shown lasting remission thus far. CAR T cells targeting autoreactive T cells are beginning clinical trials for treating T cell mediated autoimmune diseases. Chimeric autoantigen receptor (CAAR) T cells specifically target and eliminate only autoreactive B cells, and they have shown promise in treating mucosal pemphigus vulgaris and MuSK myasthenia gravis. Regulatory CAR T cells have also been developed, which show potential in altering autoimmune affected areas by creating a protective barrier as well as helping decrease inflammation. These new treatments are only the beginning of potential CAR T cell applications in treating autoimmune disease. Novel CAR technologies have been developed that increase the safety, potency, specificity, and efficacy of CAR T cell therapy. Applying these novel modifications to autoimmune CARs has the potential to enhance the efficacy and applicability of CAR therapies to autoimmune disease. This review will detail several recently developed CAR technologies and discuss how their application to autoimmune disease will improve this emerging field. These include logic-gated CARs, soluble protein-secreting CARs, and modular CARs that enable CAR T cell therapies to be more specific, reach a wider span of target cells, be safer for patients, and give a more potent cytotoxic response. Applying these novel CAR technologies to the treatment of autoimmune diseases has the potential to revolutionize this growing application of CAR T cell therapies.

Safety and efficacy of standard-of-care ciltacabtagene autoleucel for relapsed/refractory multiple myeloma

AbstractCiltacabtagene autoleucel (cilta-cel) chimeric antigen receptor (CAR) T-cell therapy was approved in 2022 for patients with relapsed/refractory multiple myeloma (RRMM). We report outcomes with cilta-cel in the standard-of-care setting. Patients with RRMM who underwent leukapheresis for cilta-cel manufacturing between 1 March 2022 and 31 December 2022 at 16 US academic medical centers were included. In terms of results, 255 patients underwent leukapheresis and 236 (92.5%) received cilta-cel. Of patients who underwent leukapheresis, 56% would not have met the CARTITUDE-1 trial eligibility criteria. Manufacturing failure rates at first attempt and overall were 6% and 1%, respectively. The median of prior lines of therapy was 6. In treated patients (n = 236), cytokine release syndrome was seen in 75% (grade ≥3, 5%), immune effector cell–associated neurotoxicity syndrome in 14% (grade ≥3, 4%), and delayed neurotoxicity in 10%. Best overall and complete response or better rates were as follows: for patients who received infusion (n = 236), 89% and 70%; patients receiving conforming CAR T-cell product (n = 191), 94% and 74%; and conforming CAR T-cell product with fludarabine/cyclophosphamide lymphodepletion (n = 152), 95% and 76%, respectively. Nonrelapse mortality was 10%, most commonly from infection. After a median follow-up of 13 months from CAR T-cell therapy, the median progression-free survival (PFS) was not reached, with the 12-month estimate being 68% (95% confidence interval, 62-74). High ferritin levels, high-risk cytogenetics, and extramedullary disease were independently associated with inferior PFS, with a signal for prior B-cell maturation antigen–targeted therapy (P = .08). Second primary malignancies excluding nonmelanoma skin cancers were seen in 5.5% and myeloid malignancies/acute leukemia in 1.7%. We observed a favorable efficacy profile of standard-of-care cilta-cel in RRMM, despite more than half the patients not meeting the CARTITUDE-1 eligibility criteria.

Developing CAR T-Cell Therapies for Pediatric Solid Tumors.

Chimeric antigen receptor (CAR) T cells have revolutionized the treatment of hematological malignancies, inducing notable and durable clinical responses. However, for solid tumors, including but not limited to pediatric tumors, several peculiar biological features posed substantial challenges for achieving comparable results. Despite sound pre-clinical evidence of the ability of CAR T cells to eradicate solid malignancies, their activity remains suboptimal when facing the in vivo complexity of solid tumors, characterized by antigen heterogeneity, scarce T-cell infiltration, and an immunosuppressive microenvironment. Neuroblastoma was amongst the first tumors to be evaluated as a potential candidate for GD2-targeting CAR T cells, which recently documented promising results in high-risk, heavily pre-treated patients. Moreover, innovative engineering strategies for generating more potent and persistent CAR T cells suggest the possibility to reproduce, and potentially improve, these promising results on a larger scale. In the next years, harnessing the full therapeutic potential of CAR T cells and other immunotherapeutic strategies may open new possibilities for effectively treating the most aggressive forms of pediatric tumors.

Enhanced tumor control and survival in preclinical models with adoptive cell therapy preceded by low-dose radiotherapy.

Effective infiltration of chimeric antigen receptor T (CAR-T) cells into solid tumors is critical for achieving a robust antitumor response and improving therapeutic outcomes. While CAR-T cell therapies have succeeded in hematologic malignancies, their efficacy in solid tumors remains limited due to poor tumor penetration and an immunosuppressive tumor microenvironment. This study aimed to evaluate the potential of low-dose radiotherapy (LDRT) administered before T-cell therapy to enhance the antitumor effect by promoting CAR-T cell infiltration. We hypothesized that combining LDRT with T-cell therapy would improve tumor control and survival compared to either treatment alone. We investigated this hypothesis using two NSG mouse models bearing GSU or CAPAN-2 solid tumors. The mice were treated with engineered CAR-T cells targeting guanyl cyclase-C (GCC) or mesothelin as monotherapy or in combination with LDRT. Additionally, we extended this approach to a C57BL/6 mouse model implanted with MC38-gp100+ cells, followed by adoptive transfer of pmel+ T cells before and after LDRT. Tumor growth and survival outcomes were monitored in all models. Furthermore, we employed atomic force microscopy (AFM) in a small cohort to assess the effects of radiotherapy on tumor stiffness and plasticity, exploring the role of tumor nanomechanics as a potential biomarker for treatment efficacy. Our results demonstrated enhanced tumor control and prolonged survival in mice treated with LDRT followed by T-cell therapy across all models. The combination of LDRT with CAR-T or pmel+ T-cell therapy led to superior tumor suppression and survival compared to monotherapy, highlighting the synergistic impact of the combined approach. Additionally, AFM analysis revealed significant changes in tumor stiffness and plasticity in response to LDRT, suggesting that the nanomechanical properties of the tumor may be predictive of therapeutic response. The findings of this study highlight the transformative potential of incorporating LDRT as a precursor to adoptive T-cell therapy in solid tumors. By promoting CAR-T and pmel+ T-cell infiltration into the tumor microenvironment, LDRT enhanced tumor control and improved survival outcomes, offering a promising strategy to overcome the challenges associated with CAR-T therapy in solid tumors. Additionally, the changes in tumor nanomechanics observed through AFM suggest that tumor stiffness and plasticity could be biomarkers for predicting treatment outcomes. These results support further investigation into the clinical application of this combined approach to improve the efficacy of cell-based therapies in patients with solid tumors.

Cutting-edge approaches to B-cell depletion in autoimmune diseases.

B-cell depletion therapy (BCDT) has been employed to treat autoimmune disease for ~20 years. Immunoglobulin G1 (IgG1) monoclonal antibodies targeting CD20 and utilizing effector function (eg, antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity, antibody-dependent cellular phagocytosis) to eliminate B cells have historically been the predominant therapeutic approaches. More recently, diverse BCDT approaches targeting a variety of B-cell surface antigens have been developed for use in hematologic malignancies, including effector-function-enhanced monoclonal antibodies, chimeric antigen receptor T-cell (CAR-T) treatment, and bispecific T-cell engagers (TCEs). The latter category of antibodies employs CD3 engagement to augment the killing of target cells. Given the improvement in B-cell depletion observed with CAR-T and TCEs compared with conventional monospecific antibodies for treatment of hematologic malignancies and the recent case reports demonstrating therapeutic benefit of CAR-T in autoimmune disease, there is potential for these mechanisms to be effective for B-cell-mediated autoimmune disease. In this review, we discuss the various BCDTs that are being developed in autoimmune diseases, describing the molecule designs, depletion mechanisms, and potential advantages and disadvantages of each approach as they pertain to safety, efficacy, and patient experience. Additionally, recent advances and strategies with TCEs are presented to help broaden understanding of the potential for bispecific antibodies to safely and effectively engage T cells for deep B-cell depletion in autoimmune diseases.

Thermosensitive hyaluronic acid-manganese-capsaicin complex nanogel improving NKG2D/CAR-T melanoma treatment through adjusting tumor microenvironment

Intratumorally injection of CAR-T cells to treat melanoma can reduce the incidence of systemic side effects and ensure an adequate concentration of CAR-T cells. However, few targeting ligands and hostile tumor microenvironment (TME) inhibit the CAR-T cells' survival and infiltration. An in situ hyaluronic acid‑manganese-capsaicin complex nanogel (HA-Mn-CAP Gel) was designed by forming complex nanogel based on the main skeleton material of hyaluronic acid (HA). It targeted CD44 and TRPV1 receptors through HA and CAP, concentrated and released Mn at melanoma, subsequently relieving the hypoxia in the tumor and increasing the expression of CAR-T cells' specific ligands. Cell experiments showed that HA-Mn-CAP Gel significantly enhanced the expression of representative NKG2D ligands (MICA/B and ULBP2/5/6) >2.7 times on A375 melanoma cells. Sequential administration of HA-Mn-CAP Gel and NKG2D/CAR-T increased the tumor inhibition rate about 1.5 times that of the NKG2D/CAR-T group in melanoma-bearing NSG mice. The results of immunohistochemistry and immunofluorescence assays showed that the combined HA-Mn-CAP Gel and NKG2D/CAR-T significantly increased the proliferation and infiltration of T cells, especially for CD8+ cells. Therefore, the new promising strategy of increasing the target ligand expression and adjusting TME before administering CAR-T cells is suitable for treating solid tumors.

Role of bridging RT in relapsed/refractory diffuse large B-cell lymphoma undergoing CAR-T therapy: a multicenter study.

The optimization of bridging regimen before chimeric antigen receptor (CAR)-T cell therapy in diffuse large B-cell lymphoma (DLBCL) may impact CAR-T efficacy and outcome. This retrospective study evaluates CAR-T outcome after bridging with radiotherapy (RT) and other bridging strategies. Among 148 patients with relapsed/refractory DLBCL who underwent leukapheresis for CAR-T manufacturing, 31 received RT-bridging, 84 chemotherapy (CT), 33 no-bridging or steroid-only. CAR-T cell were infused in 96.8% of RT-group, 89.2% of CT-group and 78.8% of no-bridge-group (p = 0.079). Response to bridging was generally poor, but patients receiving RT had a significant reduction in LDH levels between pre- and post-bridging (p = 0.05). The one-year PFS was 51.2% in the RT-group, 28.2% in the CT-group, and 47.6% in the no-bridge-group (p = 0.044, CT-bridging vs RT-bridging); 1-year OS was 86.7% in the RT-group, 52.7% in the CT-group and 69% in the no-bridge-group (p = 0.025, CT-bridging vs RT-bridging). We observed a higher incidence of ICANS in patients who received CT than in others (20.0% CT-group, 3.3% RT-group, 7.7% no-bridge group; p = 0.05). In conclusion, RT-bridging is associated with lower drop-out rate and CAR-T toxicity, and it might be preferred to other bridging strategies for patients with localized disease or for those with one prevalent symptomatic site.

CAR T-cell therapy for gliomas.

To review the landscape of chimeric antigen receptor T-cell (CAR T) therapy for gliomas as seen in recently published trials and discuss on-going challenges with new cancer immunotherapy treatments. Given how CAR T therapy has revolutionized the treatment of several hematologic malignancies, there has been increasing interest in using immunotherapy, and particularly CAR T therapy for gliomas. Within the past decade, several first in human trials have published early patient experiences showing treatment is generally well tolerated but with limited efficacy, which may be improving with newer evolutions in CAR T design to overcome known resistance mechanisms in glioma treatment. CAR T therapy is a promising avenue of treatment for high-grade gliomas, which have a universally poor prognosis as well as limited therapeutics. There are a growing number of CAR T clinical trials for CNS tumors and thus, an understanding of their treatment strategies, toxicity management, and overcoming resistance mechanisms will be important for both clinical practice and to identify areas for future research.

Universal protection of allogeneic T-cell therapies from natural killer cells via CD300a agonism

AbstractImmunogenicity limits the persistence of off-the-shelf allogeneic cell therapies and transplants. Although ablation of HLA removes most T cell and humoral alloreactivity, no solution has enabled universal protection against the resulting natural killer (NK) cell response. Here, we engineered trans-antigen signaling receptors (TASRs) as a new class of NK inhibitory ligands and discovered CD300a, a previously inaccessible receptor, as a functional target. CD300a TASR outperformed leading alternative strategies in focused screens, including CD47 and HLA-E, and was solely capable of universally protecting allogeneic T cells against a large human cohort (45/45 donors), spanning diverse demographics and NK cell phenotypes. A model allogeneic T-cell therapy coexpressing an anti-CD19 chimeric antigen receptor and CD300a TASR, produced using multiplexed nonviral integration, exhibited enhanced B-cell killing potency under allogeneic immune pressure. CD300 TASR represents a universal solution to NK alloreactivity, broadening the population that could be effectively treated by next-generation allogeneic cell therapies.

Redefining chimeric antigen receptor T-cell (CAR-T) regulation: China's responses to address secondary cancer risks of CAR-T therapy.

Since the United States Food and Drug Administration (FDA) approved the first chimeric antigen receptor T-cell (CAR-T) therapy in 2017, it has marked a major breakthrough in cancer treatment, leading to a surge in global research and applications in this field. In recent years, China has made rapid progress, quickly catching up through heavy investment in CAR-T construction, preparation processes, and treatment strategies. China's CAR-T therapy market is driven by substantial pharmaceutical investment targeting its vast population, yet high therapy costs remain uncovered by basic medical insurance. In November 2023, FDA issued a warning about the risk of secondary cancers in patients undergoing CAR-T therapy, sparking global concern. In fact, the China National Medical Products Administration (NMPA) preemptively implemented a series of measures to address the safety concerns of CAR-T therapy, emphasizing the risk of secondary cancers and advising lifelong monitoring as part of the approval process for CAR-T products. Nevertheless, additional regulatory measures are needed to address emerging risks, particularly the threat of secondary cancers. The authors believe that raising the standards for Investigational New Drug (IND) approval and establishing a dynamic reporting and feedback system based on real-world data will strengthen regulatory oversight and support the sustainable growth of the CAR-T industry in China.

Impact of pre-infusion disease burden on outcomes in pediatric relapsed/refractory B-cell lymphoblastic leukemia following anti-CD19 CAR T-cell therapy

Anti-CD19 chimeric antigen receptor (CAR) T-cell therapies have demonstrated high efficacy in pediatric patients with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). Despite this success, the challenge of post-infusion relapse persists. In our study, we evaluate 116 children with R/R B-ALL who received anti-CD19 CAR T-cell therapy at our center. All patients were included in the response analysis and assessed for survival and toxicity. The CR rate was 98.3%, with 90.5% achieving minimal residual disease negative (MRD)- CR by day 28 (d28). The overall survival (OS) and event-free survival (EFS) were 69.3%±4.5% and 59.0%±4.6%, respectively, with a median follow-up duration of 47.9 months. The patients with pre-infusion MRD ≥ 1% was associated with lower 4-year OS (p = 0.006) and EFS (p = 0.027) comparing to those with MRD < 1%. The incidences of grade ≥ 3 cytokine release syndrome (CRS) and neurotoxicity were21.6 and 5.0%, respectively. Therefore, pre-infusion disease burden is a predictor of long-term outcome following anti-CD19 CAR T-cell therapy for pediatric R/R B-ALL.

Allogeneic CAR-T cells for cancer immunotherapy.

Autologous chimeric antigen receptor (CAR)-modified T (CAR-T) cell therapy has displayed high efficacy in the treatment of hematological malignancies. Up to now, 11 autologous CAR-T cell products have been approved for the management of malignancies globally. However, the application of autologous CAR-T cell therapy has many individual limitations, long time-consuming, highly cost, and the risk of manufacturing failure. Indeed, some patients would not benefit from autologous CAR-T cell products because of rapid disease progression. Allogeneic CAR-T cells especially universal CAR-T (U-CAR-T) cell therapy are superior to these challenges of autologous CAR-T cells. In this review, we describe basic study and clinical trials of U-CAR-T cell therapeutic methods for malignancies. In addition, we summarize the problems encountered and potential solutions.

Silencing of SIRPα enhances the antitumor efficacy of CAR-M in solid tumors

The potential of macrophage-mediated phagocytosis as a cancer treatment is promising. Blocking the CD47–SIRPα interaction with a CD47-specific antibody significantly enhances macrophage phagocytosis. However, concerns regarding their toxicity to nontumor cells remain substantial. Here, we engineered chimeric antigen receptor macrophages (CAR-Ms) by fusing a humanized single-chain variable fragment with FcγRIIa and integrating short hairpin RNA to silence SIRPα, thereby disrupting the CD47–SIRPα signaling pathway. These modified CAR-shSIRPα-M cells exhibited an M1-like phenotype, superior phagocytic function, substantial cytotoxic effects on HER2-positive tumor cells, and the ability to eliminate patient-derived organoids. In vivo, CAR-M cells significantly inhibited tumor growth and prolonged survival in tumor-bearing mice. Notably, CAR-shSIRPα-M cells enhanced cytotoxic T-cell infiltration into tumors, thereby enhancing the antitumor response in both the humanized immune system mouse model and immunocompetent mice. Mechanistically, SIRPα inhibition activated inflammatory pathways and the cGAS-STING signaling cascade in CAR-M cells, leading to increased production of proinflammatory cytokines, reactive oxygen species, and nitric oxide, thereby enhancing their antitumor effects. These findings underscore the potential of SIRPα inhibition as a novel strategy to increase the antitumor efficacy of CAR-M cells in cancer immunotherapy, particularly against solid tumors.

Therapeutic advantage of combinatorial CAR T cell and chemo-therapies.

Chimeric antigen receptor (CAR) T cell therapies have transformed outcomes for many patients with hematological malignancies. However, some patients do not respond to CAR T cell treatment, and adapting CAR T cells for solid and brain tumors has been met with many challenges including a hostile tumor microenvironment and poor CAR T cell persistence. Thus, it is unlikely that CAR T cell therapy alone will be sufficient for consistent, complete tumor clearance across cancer patients. Combinatorial therapies of CAR T cells and chemotherapeutics are a promising approach for overcoming this as chemotherapeutics could augment CAR T cells for improved anti-tumor activity or work in tandem with CAR T cells to clear tumors. Herein, we review efforts towards achieving successful CAR T cell and chemical drug combination therapies. We focus on combination therapies with approved chemotherapeutics as these will be more easily translated to the clinic, but also review non-approved chemotherapeutics and drug screens designed to reveal promising new CAR T cell and chemical drug combinations. Together, this review highlights the promise of CAR T cell and chemotherapy combinations with specific focus on how combinatorial therapy overcomes challenges faced by either monotherapy and supports the potential of this therapeutic strategy to improve outcomes for cancer patients. Significance Statement Improving currently available CAR T cell products via combinatorial therapy with chemotherapeutics has the potential to drastically expand the types of cancers and number of patients that could benefit from these therapies when neither alone has been sufficient to achieve tumor clearance. Herein, we provide a thorough review of the current efforts towards studying CAR T and chemotherapy combinatorial therapies and provide perspectives on optimal ways to identify new and effective combinations moving forward.