Chimeric Antigen Receptor T-cell Products Research Articles

Advances in Hodgkin Lymphoma Treatment: From Molecular Biology to Clinical Practice

Classical Hodgkin Lymphoma (cHL) is a highly curable disease, but around 20% of patients experience progression or relapse after standard frontline chemotherapy regimens. Salvage regimens followed by autologous stem cell transplants represent the historical treatment approach for these cases. In the last decade, with the increasing understanding of cHL biology and tumor microenvironment role in disease course, novel molecules have been introduced in clinical practice, improving outcomes in the relapsed/refractory setting. The anti-CD30 antibody-drug conjugated brentuximab vedotin and PD-1/PD-L1 checkpoint inhibitors represent nowadays curative options for chemorefractory patients, and randomized trials recently demonstrated their efficacy in frontline immune-chemo-combined modalities. Several drugs able to modulate the patients’ T-lymphocytes and NK cell activity are under development, as well as many anti-CD30 chimeric antigen receptor T-cell products. Multiple tumor aberrant epigenetic mechanisms are being investigated as targets for antineoplastic compounds such as histone deacetylase inhibitors and hypomethylating agents. Moreover, JAK2 inhibition combined with anti-PD1 blockade revealed a potential complementary therapeutic pathway in cHL. In this review, we will summarize recent findings on cHL biology and novel treatment options clinically available, as well as promising future perspectives in the field.

Challenges and Lessons Learned in Autologous Chimeric Antigen Receptor T-Cell Therapy Development from a Statistical Perspective.

Chimeric antigen receptor (CAR) T-cell therapy is a human gene therapy product where T cells from a patient are genetically modified to enable them to recognize desired target antigen(s) more effectively. In recent years, promising antitumor activity has been seen with autologous CAR T cells. Since 2017, six CAR T-cell therapies for the treatment of hematological malignancies have been approved by the Food and Drug Administration (FDA). Despite the rapid progress of CAR T-cell therapies, considerable statistical challenges still exist for this category of products across all phases of clinical development that need to be addressed. These include (but not limited to) dose finding strategy, implementation of the estimand framework, use of real-world data in contextualizing single-arm CAR T trials, analysis of safety data and long-term follow-up studies. This paper is the first step in summarizing and addressing these statistical hurdles based on the development of the six approved CAR T-cell products.

Human herpesvirus 6 reactivation and disease are infrequent in chimeric antigen receptor T-cell therapy recipients

AbstractHuman herpesvirus 6B (HHV-6B) reactivation and disease are increasingly reported after chimeric antigen receptor (CAR) T-cell therapy (CARTx). HHV-6 reactivation in the CAR T-cell product was recently reported, raising questions about product and patient management. Because of overlapping manifestations with immune effector cell–associated neurotoxicity syndrome, diagnosing HHV-6B encephalitis is challenging. We provide 2 lines of evidence assessing the incidence and outcomes of HHV-6B after CARTx. First, in a prospective study with weekly HHV-6B testing for up to 12 weeks after infusion, HHV-6B reactivation occurred in 8 of 89 participants; 3 had chromosomally integrated HHV-6 and were excluded, resulting in a cumulative incidence of HHV-6B reactivation of 6% (95% confidence interval [CI], 2.2-12.5). HHV-6B detection was low level (median peak, 435 copies per mL; interquartile range, 164-979) and did not require therapy. Second, we retrospectively analyzed HHV-6B detection in the blood and/or cerebrospinal fluid (CSF) within 12 weeks after infusion in CARTx recipients. Of 626 patients, 24 had symptom-driven plasma testing, with detection in 1. Among 34 patients with CSF HHV-6 testing, 1 patient had possible HHV-6 encephalitis for a cumulative incidence of 0.17% (95% CI, 0.02-0.94), although symptoms improved without treatment. Our data demonstrate that HHV-6B reactivation and disease are infrequent after CARTx. Routine HHV-6 monitoring is not warranted.

Chimeric Antigen Receptor (CAR) T-Cell Therapy in Hematologic Malignancies: Clinical Implications and Limitations.

Chimeric antigen receptor (CAR) T-cell therapy has become a powerful treatment option in B-cell and plasma cell malignancies, and many patients have benefited from its use. To date, six CAR T-cell products have been approved by the FDA and EMA, and many more are being developed and investigated in clinical trials. The whole field of adoptive cell transfer has experienced an unbelievable development process, and we are now at the edge of a new era of immune therapies that will have its impact beyond hematologic malignancies. Areas of interest are, e.g., solid oncology, autoimmune diseases, infectious diseases, and others. Although much has been achieved so far, there is still a huge effort needed to overcome significant challenges and difficulties. We are witnessing a rapid expansion of knowledge, induced by new biomedical technologies and CAR designs. The era of CAR T-cell therapy has just begun, and new products will widen the therapeutic landscape in the future. This review provides a comprehensive overview of the clinical applications of CAR T-cells, focusing on the approved products and emphasizing their benefits but also indicating limitations and challenges.

Sequence not salvage.

Chimeric antigen receptor T-cell (CAR-T) therapy for the treatment of multiple myeloma (MM) has fundamentally changed the relapsed and refractory therapeutic landscape, but the disease remains incurable. Two CAR-T products, idecabtagene vicleucel (ide-cel; Abecma) and ciltacabtagene autoleucel (cilta-cel, Carvykti), have been FDA- and EMA-approved for the treatment of relapsed/refractory MM (RRMM); both target B-cell maturation antigen (BCMA), a surface glycoprotein highly expressed on MM cells. Despite deep and durable responses following CAR-T therapy, most patients will need subsequent treatment, and the optimal next-line therapy is presently unclear. Commentary on: Liu etal. Outcomes in patients with multiple myeloma receiving salvage treatment after BCMA-specific CAR-T therapy: A retrospective analysis of LEGEND-2. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19340.

Abstract 49: LYL119, an investigational ROR1-targeted CAR T-cell product incorporating four novel reprogramming technologies designed for effective cell therapy for solid tumors

Abstract Effective solid tumor cell therapy requires new strategies to improve T-cell activation, persistence, and durable function. We developed four complementary T-cell reprogramming technologies to enhance chimeric antigen receptor (CAR) T-cell therapy in solid tumors: 1) overexpression of the activator protein 1 (AP-1) family transcription factor c-Jun to delay T-cell exhaustion and improve antitumor activity; 2) nuclear receptor subfamily 4A member 3 (NR4A3) gene knockout (KO) to further delay exhaustion and enhance functionality; 3) Epi-RTM manufacturing protocols to preserve stem-like characteristics; and 4) Stim-RTM technology, a novel activating reagent to improve product potency compared with standard reagents. LYL119 is an investigational ROR1-targeted CAR T-cell product that combines these technologies to create potent and durable CAR T cells. Healthy or NSCLC patient donor T cells were manufactured with the Epi-R protocols, activated with Stim-R or a standard reagent, and transduced with a vector encoding a ROR1 CAR and c-Jun. The NR4A3 gene or a control gene was edited using SpyFiTM Cas9 nuclease (Aldevron®). Cytotoxicity, cytokine production, phenotype, and single-cell transcriptomic and epigenetic profiles were evaluated in vitro after antigen restimulation assays designed to promote exhaustion. CAR T cell activity was evaluated in vivo using a ROR1+ NSCLC xenograft mouse model. Research and clinical scale LYL119 products achieved ~90% genome editing efficiency at the NR4A3 target gene resulting in a 13-fold protein reduction compared to non-edited CAR T cells. LYL119 exhibited superior cytotoxicity and cytokine production upon antigen restimulation across 7 different ROR1+ solid tumor cell lines compared to CAR T cells that lacked one or more reprogramming technologies. After repeated rounds of tumor cell killing, LYL119 displayed reduced surface expression of exhaustion-related receptors (e.g. TIM-3) and higher expression of stemness-related markers (e.g. CD127) compared to non-edited CAR T cells. Furthermore, transcriptomic analysis revealed global downregulation of exhaustion-related gene signatures and retention of unique cell subsets characterized by upregulation of memory and effector-associated gene signatures. LYL119 exhibited robust antitumor efficacy in vivo across a 10-fold dose range, including a very low dose of 1 × 105 CAR T cells. Lastly, LYL119 derived from NSCLC patient donor T cells also demonstrated enhanced cytotoxicity in vitro compared to control CAR T cells. These nonclinical data suggest LYL119, which combines c-Jun overexpression, NR4A3 KO, Epi-R protocols, and Stim-R technology, can limit exhaustion, maintain stem-like features, and has the potential to provide effective and durable CAR T-cell antitumor activity in patients with ROR1+ solid tumors. Citation Format: Viola C. Lam, Aileen Li, Meritxell Galindo Casas, Jessica Barragan, Christina Cheung, Jessica Briones, Esha Afreen, Grant Vavra, Jia Lu, Purnima Sundar, Rowena Martinez, Candace Sims, Shobha Potluri, Omar Ali, Alexander S. Cheung, Rachel C. Lynn. LYL119, an investigational ROR1-targeted CAR T-cell product incorporating four novel reprogramming technologies designed for effective cell therapy for solid tumors [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 49.

Abstract 37: IL-4 drives CART cell exhaustion in a CD4 independent manner

Abstract While chimeric antigen receptor T (CART) cell therapy has shown remarkable success, the development of exhaustion limits durable response. We identified a role for interleukin (IL)-4 in the development of CART cell exhaustion through three independent approaches including: 1) a genome-wide CRISPR knockout screen using healthy donor CART cells in an in vitro model for exhaustion, 2) RNA and ATAC sequencing on freshly produced and chronically stimulated healthy donor CART cells, and 3) RNA and ATAC sequencing on pre-infusion CART cell products from responders and non-responders in the Zuma-1 clinical trial that led to the FDA approval of axi-cel. Further, in vitro validation studies revealed that CD19 directed CART (CART19) cells chronically stimulated in the presence of human recombinant IL-4 (hrIL-4) displayed signs of exhaustion such as 1) decreased proliferation (p = 0.01), 2) increased coexpression of inhibitory receptors (p = 0.01), and 3) decreased production of IL-2 and interferon (IFN)-γ (p= 0.02, p = 0.002). Encouragingly, CART19 cells combined with an IL-4 monoclonal antibody improved antitumor activity (p = 0.045) and expansion (p = 0.01) while also decreasing the co-expression of inhibitory receptors (p = 0.02) in a mantle cell lymphoma xenograft mouse model. Building on these results, we asked if IL-4 driven exhaustion results from a direct impact of IL-4 on CART cells. To test this, we used a tumor-free assay where CART19 cells were chronically stimulated with CD19 beads in the presence of hrIL-4 or diluent. CART cells treated with hrIL-4 displayed an exhausted phenotype characterized by increased co-expression of inhibitory receptors (p = 0.04) and decreased production of IL-2 (p = 0.01). Next, we asked if IL-4 driven CART cell exhaustion is dependent on the costimulatory domain. We tested the impact of IL-4 on both CD28ζ and 41BBζ costimulated CART19 cells. Similar to our previous studies with CART19-28ζ cells, chronic stimulation of CART19-BBζ cells in the presence of hrIL-4 enhanced the exhausted phenotype as seen by increased co-expression of inhibitory receptors (p = 0.04) and decreased production of IL-2 and IFN-γ (p = 0.08 and p = 0.007). Finally, we asked if IL-4 induces exhaustion independently of its classic role in Th2 polarization of CD4 CART cells. Following CART production, we isolated CD8 cells and chronically stimulated them in the presence of hrIL-4 or diluent. CD8 CART cells treated with hrIL-4 displayed an enhanced exhausted profile as seen by 1) decreased proliferative ability (p < 0.0001), 2) increased co-expression of inhibitory receptors (p = 0.01), and 3) decreased production of IL-2 and IFN-γ (p < 0.0001, p = 0.004). Together, our data indicates a novel role for IL-4 in the development of CART cell exhaustion that is independent of tumor cells, costimulatory domain, and CD4 cells. As such, we believe IL-4 neutralization may be a widely applicable and actionable approach to improve the durable response to CART cell therapy. Citation Format: Carli M. Stewart, Elizabeth L. Siegler, Truc N. Huynh, R. Leo Sakemura, Brooke Kimball, Long Mai, Kun Yun, James H. Girsch, Jennifer Feigin, Omar Gutierrez Ruiz, Makena Rodriguez, Ekene Ogbodo, Ismail Can, Claudia Manriquez Roman, Olivia Sirpilla, Hong Xia, Jenny Kim, Justin Budka, Mike Mattie, Nathalie Scholler, Simone Filosto, Saad S. Kenderian. IL-4 drives CART cell exhaustion in a CD4 independent manner [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 37.

Cryopreserved leukapheresis material can be transferred from controlled rate freezers to ultracold storage at warmer temperatures without affecting downstream CAR-T cell culture performance and in-vitro functionality

Chimeric antigen receptor (CAR) T-cell therapies are increasingly adopted as a commercially available treatment for hematologic and solid tumor cancers. As CAR-T therapies reach more patients globally, the cryopreservation and banking of patients’ leukapheresis materials is becoming imperative to accommodate intra/inter-national shipping logistical delays and provide greater manufacturing flexibility. This study aims to determine the optimal temperature range for transferring cryopreserved leukapheresis materials from two distinct types of controlled rate freezing systems, Liquid Nitrogen (LN2)-based and LN2-free Conduction Cooling-based, to the ultracold LN2 storage freezer (≤−135 °C), and its impact on CAR T-cell production and functionality. Presented findings demonstrate that there is no significant influence on CAR T-cell expansion, differentiation, or downstream in-vitro function when employing a transfer temperature range spanning from −30 °C to −80 °C for the LN2-based controlled rate freezers as well as for conduction cooling controlled rate freezers. Notably, CAR T-cells generated from cryopreserved leukapheresis materials using the conduction cooling controlled rate freezer exhibited suboptimal performance in certain donors at transfer temperatures lower than −60 °C, possibly due to the reduced cooling rate of lower than 1 °C/min and extended dwelling time needed to reach the final temperatures within these systems. This cohort of data suggests that there is a low risk to transfer cryopreserved leukapheresis materials at higher temperatures (between −30 °C and −60 °C) with good functional recovery using either controlled cooling system, and the cryopreserved materials are suitable to use as the starting material for autologous CAR T-cell therapies.

The Implementation of Chimeric Antigen Receptor (CAR) T-cell Therapy in Pediatric Patients: Where Did We Come From, Where Are We Now, and Where are We Going?

CD19-directed Chimeric Antigen Receptor (CAR) T-cell therapy has revolutionized the treatment of patients with B-cell acute lymphoblastic leukemia (B-ALL). Somewhat uniquely among oncologic clinical trials, early clinical development occurred simultaneously in both children and adults. In subsequent years however, the larger number of adult patients with relapsed/refractory (r/r) malignancies has led to accelerated development of multiple CAR T-cell products that target a variety of malignancies, resulting in six currently FDA-approved for adult patients. By comparison, only a single CAR-T cell therapy is approved by the FDA for pediatric patients: tisagenlecleucel, which is approved for patients  25 years with refractory B-cell precursor ALL, or B-cell ALL in second or later relapse. Tisagenlecleucel is also under evaluation in pediatric patients with relapsed/refractory B-cell non-Hodgkin lymphoma, but is not yet been approved for this indication. All the other FDA-approved CD19-directed CAR-T cell therapies available for adult patients (axicabtagene ciloleucel, brexucabtagene autoleucel, and lisocabtagene maraleucel) are currently under investigations among children, with preliminary results available in some cases. As the volume and complexity of data continue to grow, so too does the necessity of rapid assimilation and implementation of those data. This is particularly true when considering “atypical” situations, e.g. those arising when patients do not precisely conform to the profile of those included in pivotal clinical trials, or when alternative treatment options (e.g. hematopoietic stem cell transplantation (HSCT) or bispecific T-cell engagers (BITEs)) are also available. We have therefore developed a relevant summary of the currently available literature pertaining to the use of CD19-directed CAR-T cell therapies in pediatric patients, and sought to provide guidance for clinicians seeking additional data about specific clinical situations.

CAR-T Cell Therapy for T-Cell Malignancies.

Chimeric antigen receptor T-cell (CAR-T) therapy has revolutionized the treatment of B-cell lymphoid neoplasia and, in some instances, improved disease outcomes. Thus, six FDA-approved commercial CAR-T cell products that target antigens preferentially expressed on malignant B-cells or plasma cells have been introduced in the therapy of B-cell lymphomas, B-ALLs, and multiple myeloma. These therapeutic successes have triggered the application of CAR-T cell therapy to other hematologic tumors, including T-cell malignancies. However, the success of CAR-T cell therapies in T-cell neoplasms was considerably more limited due to the existence of some limiting factors, such as: 1) the sharing of mutual antigens between normal T-cells and CAR-T cells and malignant cells, determining fratricide events and severe T-cell aplasia; 2) the contamination of CAR-T cells used for CAR transduction with malignant T-cells. Allogeneic CAR-T products can avoid tumor contamination but raise other problems related to immunological incompatibility. In spite of these limitations, there has been significant progress in CD7- and CD5-targeted CAR-T cell therapy of T-cell malignancies in the last few years.

Chimeric Antigen Receptor-T (CAR-T) Cells as “Living Drugs”: A Clinical Pharmacist Perspective

Background. Chimeric antigen receptor (CAR) T cell therapy, a “living drug” immunotherapy, harnesses the power of T-cells from a patient (autologous) or healthy donor (allogeneic) to target and kill cancer cells and has shown unprecedented outcomes in patients with relapsed and refractory malignancies. Treatment with CAR-T cells requires the application of unique skillsets in recognised specialist centres for successful outcomes and requires management by the multidisciplinary team incorporating the specialist pharmacist. Method. A multimodal research strategy was employed for this literature review whereby PubMed, Google Scholar, Embase, Stella Library Search, EMA website, and EBMT website were sources of information. The search was limited from 2020 onwards with key terms referring to CAR-T cell therapy. Results and Discussion. There are six CAR-T cell products currently approved by the European Medicines Agency (EMA) and Food and Drug Administration (FDA) which target haematological malignancies with abundant clinical trials underway exploring new and improved CAR designs and antigen targets. As CAR-T cell therapy is an advanced therapy medicinal product (ATMP), there is need for an extensive regulatory framework underpinning its safety and efficacy. The clinical pharmacist plays an integral role in the provision of safe and effective CAR-T cell therapy including governance, operational and clinical aspects of treatment. Pharmacists may also be involved through provision of “Qualified Person” (QP) expertise in clinical trials and for release within hospitals under certain circumstances. There is a need for harmonised and accessible guidance on the clinical delivery of ATMPs such as CAR-T cells, with fully delineated responsibilities of pharmacists involving the oversight and supervision of CAR-T cell treatment. Conclusion. There is an unmet need to provide suitable and applicable literature for clinical pharmacists who are involved in the delivery of CAR-T cells. We have provided an overview of T-cell biology and an explanation of CAR-T cell design and the biomanufacturing process. We reviewed the complex and multifaceted treatment cycle requiring considerable logistics, and described the involvement of the clinical pharmacist in each part of this cycle from patient selection to postinfusion care. Finally, we look to the challenges and future opportunities that will require the involvement of the clinical pharmacist.

Healthcare cost and utilization for chimeric antigen receptor (CAR) T-cell therapy in the treatment of pediatric acute lymphoblastic leukemia: A commercial insurance claims database analysis.

B-lineage acute lymphoblastic leukemia (B-ALL) is the most common malignancy of childhood. With the introduction of novel cellular therapies, cost of care is a critical component and the financial burden experienced by patients and society requires evaluation. This study aims to assess the utilization and cost of care for chimeric antigen receptor T-cell (CAR-T) therapy for pediatric ALL patients with commercial insurance coverage in the United States. Using de-identified commercial insurance data from the OptumLabs® Data Warehouse, a cohort of 37 patients, aged 1-25 years, with B-ALL treated with CAR-T therapy between Oct 2016 and Dec 2021 in the United States was identified. Cost was evaluated for a 90 day period encompassing CAR-T infusion and by administration and complication characteristics. Among the 37 identified B-ALL patients that received a CAR-T product infusion, 14 patients were female, median age at administration was 13 years. The median 90-day total cost was $620,500 (Mean: $589,108). Inpatient cost accounted for approximately 71% of the total cost with an average of 28 inpatient days per patient. Although inpatient cost was slightly higher in the older age group (aged 10-25 years) and in patients with a code for cytokine release syndrome (CRS), these differences were not statistically significant. This real-world cost analysis shows for the first time the encompassing cost of CAR-T therapy for pediatric B-ALL patients in the US with commercial insurance. This study provides a valuable benchmark that can be used to analyze the financial implications of CAR-T therapy for pediatric B-ALL therapy on health systems.

Current development of chimeric antigen receptor T-cell therapy for diffuse large B-cell lymphoma and high-grade B-cell lymphoma.

Chimeric antigen receptor (CAR) T-cell therapy has become a commercially available treatment option for relapsed or refractory (r/r) diffuse large B-cell lymphoma (DLBCL) with two or more lines of prior therapies, and recently for high-risk r/r DLBCL with one prior line of therapy. The successful development of CAR T-cell therapy for multiple relapsed DLBCL has led to a boom in subsequent trials that investigated its utility in patients with other r/r B-cell lymphoma subtypes. However, CAR T-cell therapy is a multistep process that includes leukapheresis and manipulation which take several weeks. Therefore, patients with rapidly progressing or bulky disease may not be able to complete the therapeutic regimen involving CAR T-cell products. This raises the question of the generalizability of the results of pivotal studies to the entire population. In this review, we summarize the development of CAR-T cell therapy for B-cell lymphoma and discuss strategies to further improve the clinical outcomes of this treatment.

Chimeric antigen receptor T-cell therapy-induced nervous system toxicity: a real-world study based on the FDA Adverse Event Reporting System database

BackgroundNervous system toxicity (NST) is one of the most frequent and dangerous side effects of chimeric antigen receptor T-cell (CAR-T) therapy, which is an effective treatment for related tumors in most relapsed/refractory (r/r) hematologic malignancies. Current clinical trial data do not fully reflect the real-world situation. Therefore, this study evaluated the NST of CAR-T therapy using the FDA Adverse Event Reporting System (FAERS).MethodsData were retrieved from FAERS for the period from January 1, 2017 to March 31, 2023. Disproportionality analysis and Bayesian analysis were used for data mining. The reporting odds ratio (ROR) for NST with 95% confidence interval (CI) was calculated for each CAR-T product. The time to onset (TTO) and clinical outcomes due to CAR-T therapy-associated NST were assessed.ResultsOverall, 6946 cases of NST associated with CAR-T therapy were identified. The patients had a median age of 61 years (interquartile range [IQR]: 47–69 years). Significant signals were observed for all CAR-T products (ROR: 2.19, 95% CI: 2.13–2.44). Anti-CD19 CAR-T products showed a higher NST signal than anti-B cell maturation antigen (BCMA) CAR-T products (ROR025 2.13 vs. 1.98). Brexucabtagene autoleucel (ROR: 3.17, 95% CI: 2.90–3.47) and axicabtagene ciloleucel (ROR: 2.92, 95% CI: 2.81–3.03) had the two highest NST signals. For the preferred term “brain edema,” the highest signals were obtained for CD28 CAR-T products. The median TTO of NST for all CAR-T products was 7 days (IQR: 3–17 days). The proportion of death, life-threatening and hospitalization adverse events associated with NST was 20.06%, 7.21%, and 32.70%, respectively. The proportion of death outcomes was higher in patients treated with tisagenlecleucel (30.36%) than in those treated with other CAR-T products, except ciltacabtagene autoleucel (P < 0.001). The proportion of hospitalizations was significantly higher for lisocabtagene maraleucel-associated NST (53.85%) than for other drugs, except for ciltacabtagene autoleucel (P < 0.001).ConclusionsNST is more closely associated with anti-CD19 CAR-Ts and CAR-Ts containing CD28. Serious NST (brain oedema) is likely to occur with CAR-Ts that contain CD28. CAR-T-related NST warrants greater attention owing to the high proportion of serious adverse events and delayed NST.

Allogeneic CAR-T cells with of HLA-A/B and TRAC disruption exhibit promising antitumor capacity against B cell malignancies

BackgroundAlthough chimeric antigen receptor T (CAR-T) cells have been proven to be an effective way of treating B cell malignancies, a lot of patients could not benefit from it because of failure in CAR-T cell manufacturing, disease progression, and unaffordable price. The study aimed to explore universal CAR-T cell products to extend the clinical accessibility.MethodsThe antitumor activity of CRISPR/Cas9-edited allogeneic anti-CD19 CAR-T (CAR-T19) cells was assessed in vitro, in animal models, and in patients with relapsed/refractory (R/R) acute B cell lymphoblastic leukemia (B-ALL) or diffuse large B cell lymphoma.ResultsB2M−/TRAC− universal CAR-T19 (U-CAR-T19) cells exhibited powerful anti-leukemia abilities both in vitro and in animal models, as did primary CD19+ leukemia cells from leukemia patients. However, expansion, antitumor efficacy, or graft-versus-host-disease (GvHD) was not observed in six patients with R/R B cell malignancies after U-CAR-T19 cell infusion. Accordingly, significant activation of natural killer (NK) cells by U-CAR-T19 cells was proven both clinically and in vitro. HLA-A−/B−/TRAC− novel CAR-T19 (nU-CAR-T19) cells were constructed with similar tumoricidal capacity but resistance to NK cells in vitro. Surprisingly, robust expansion of nU-CAR-T19 cells, along with rapid eradication of CD19+ abnormal B cells, was observed in the peripheral blood and bone marrow of another three patients with R/R B-ALL. The patients achieved complete remission with no detectable minimal residual disease 14 days after the infusion of nU-CAR-T19 cells. Two of the three patients had grade 2 cytokine release syndrome, which were managed using an IL-6 receptor blocker. Most importantly, GvHD was not observed in any patient, suggesting the safety of TRAC-disrupted CAR-T cells generated using the CRISPR/Cas9 method for clinical application.ConclusionsThe nU-CAR-T19 cells showed a strong response in R/R B-ALL. nU-CAR-T19 cells have the potential to be a promising new approach for treating R/R B cell malignancies.

Lymphodepletion - an essential but undervalued part of the chimeric antigen receptor T-cell therapy cycle.

Lymphodepletion (LD) or conditioning is an essential step in the application of currently used autologous and allogeneic chimeric antigen receptor T-cell (CAR-T) therapies as it maximizes engraftment, efficacy and long-term survival of CAR-T. Its main modes of action are the depletion and modulation of endogenous lymphocytes, conditioning of the microenvironment for improved CAR-T expansion and persistence, and reduction of tumor load. However, most LD regimens provide a broad and fairly unspecific suppression of T-cells as well as other hematopoietic cells, which can also lead to severe side effects, particularly infections. We reviewed 1271 published studies (2011-2023) with regard to current LD strategies for approved anti-CD19 CAR-T products for large B cell lymphoma (LBCL). Fludarabine (Flu) and cyclophosphamide (Cy) (alone or in combination) were the most commonly used agents. A large number of different schemes and combinations have been reported. In the respective schemes, doses of Flu and Cy (range 75-120mg/m2 and 750-1.500mg/m2) and wash out times (range 2-5 days) differed substantially. Furthermore, combinations with other agents such as bendamustine (benda), busulfan or alemtuzumab (for allogeneic CAR-T) were described. This diversity creates a challenge but also an opportunity to investigate the impact of LD on cellular kinetics and clinical outcomes of CAR-T. Only 21 studies explicitly investigated in more detail the influence of LD on safety and efficacy. As Flu and Cy can potentially impact both the in vivo activity and toxicity of CAR-T, a more detailed analysis of LD outcomes will be needed before we are able to fully assess its impact on different T-cell subsets within the CAR-T product. The T2EVOLVE consortium propagates a strategic investigation of LD protocols for the development of optimized conditioning regimens.

Update on the current and future use of CAR-T to treat multiple myeloma.

Chimeric antigen receptor T-cell (CAR-T) therapy has become an important intervention in the management of relapsed and relapsed/refractory multiple myeloma (MM). Currently, B-cell maturation antigen (BCMA) is the most targeted surface protein due to its ubiquitous expression on plasma cells, with increasing expression of this essential transmembrane protein on malignant plasma cells as patients develop more advanced disease. This review will explore the earliest CAR-T trials in myeloma, discuss important issues involved in CAR-T manufacturing and processing, as well as review current clinical trials that led to the approval of the two commercially available CAR-T products, Idecabtagene vicleucel and ciltacabtagene autoleucel. The most recent data from trials investigating the use of CAR-T as an earlier line of therapy will be presented. Finally, the problem of relapses after CAR-T will be presented, including several theories as to why CAR-T therapies fail and possible clinical caveats. The next generation of MM-specific CAR-T will likely include new targets such as G-protein-coupled receptor class C, Group 5, member D (GPRC5D) and signaling lymphocyte activation molecular Family 7 (SLAMF7). The role of CAR-T in the treatment of MM will undoubtedly increase exponentially in the next decade.

Enhancing CAR-T cells: unleashing lasting impact potential with phytohemagglutinin activation in in vivo leukemia model.

Chimeric antigen receptor T (CAR-T) cell therapy holds great promise as an innovative immunotherapeutic approach for cancer treatment. To optimize the production and application of CAR-T cells, we evaluated the in vivo stability and efficacy capacities of CAR-T cells developed under different conditions. In this study, CAR-T cells were activated using Phytohemagglutinin (PHA) or anti-CD3&anti-CD28 and were compared in an in vivo CD19+B-cell cancer model in mouse groups. Our results demonstrated that CAR-T cells activated with PHA exhibited higher stability and anti-cancer efficacy compared to those activated with anti-CD3&anti-CD28. Specifically, CAR19BB-T cells activated with PHA exhibited continuous proliferation and long-term persistence without compromising their anti-cancer efficacy. Kaplan-Meier survival analysis revealed prolonged overall survival in the CAR-T cell-treated groups compared to the only tumor group. Furthermore, specific LTR-targeted RT-PCR analysis confirmed the presence of CAR-T cells in the treated groups, with significantly higher levels observed in the CAR19BB-T (PHA) group compared to other groups. Histopathological analysis of spleen, kidney, and liver tissue sections indicated reduced inflammation and improved tissue integrity in the CAR-T cell-treated groups. Our findings highlight the potential benefits of using PHA as a co-stimulatory method for CAR-T cell production, offering a promising strategy to enhance their stability and persistence. These results provide valuable insights for the development of more effective and enduring immunotherapeutic approaches for cancer treatment. CAR-T cells activated with PHA may offer a compelling therapeutic option for advancing cancer immunotherapy in clinical applications.

CAR-modified Cellular Therapies in Chronic Lymphocytic Leukemia: Is the Uphill Road Getting Less Steep?

The clinical development of chimeric antigen receptor (CAR) T-cell therapy has been more challenging for chronic lymphocytic leukemia (CLL) compared to other settings. One of the main reasons is the CLL-associated state of immune dysfunction that specifically involves patient-derived T cells. Here, we provide an overview of the clinical results obtained with CAR T-cell therapy in CLL, describing the identified immunologic reasons for the inferior efficacy. Novel CAR T-cell formulations, such as lisocabtagene maraleucel, administered alone or in combination with the Bruton tyrosine kinase inhibitor ibrutinib, are currently under investigation. These approaches are based on the rationale that improving the quality of the T-cell source and of the CAR T-cell product may deliver a more functional therapeutic weapon. Further strategies to boost the efficacy of CAR T cells should rely not only on the production of CAR T cells with an improved cellular composition but also on additional changes. Such alterations could include (1) the coadministration of immunomodulatory agents capable of counteracting CLL-related immunological alterations, (2) the design of improved CAR constructs (such as third- and fourth-generation CARs), (3) the incorporation into the manufacturing process of immunomodulatory compounds overcoming the T-cell defects, and (4) the use of allogeneic CAR T cells or alternative CAR-modified cellular vectors. These strategies may allow to develop more effective CAR-modified cellular therapies capable of counteracting the more aggressive and still incurable forms of CLL.

Positron Emission Tomography Evaluation in Relapsed/Refractory B-Cell Lymphoma Patients Treated with Anti-19 Chimeric Antigen Receptor (CAR) T-Cells in the CART-SIE Observational Study

Background: CD19 direct chimeric antigen receptor (CAR) T-cell therapy is an efficacious therapy for patients (pts) affected by relapsed/refractory (R/R) large B-cell lymphomas (LBCL). The role of early evaluation by Positron emission tomography/computed tomography (PET/CT) is still undefined. The study's objective was to analyze the role of early PET/CT according to histology and CAR T-cell product administered. Methods:CART-SIE is an ongoing prospective and retrospective observational study evaluating the outcome of lymphoma pts treated with CAR T-cells. From March 2019 to June 2023, 659 patients were enrolled. In this study, we included only pts with adequate follow-up (30 days) and an FDG-PET/CT before infusion (PET-0) and at least one month (PET-1) after CAR-T cells infusion. A landmark analysis based on PET-1 and PET-3 (3 months evaluation) results was performed for Progression-free survival (PFS) and Overall Survival (OS) estimation. Results: Three hundred twenty-seven pts with R/R LBCL [n= 189 (58%) Diffuse large B-cell lymphomas, n= 59 (18%) High-grade B-cell lymphomas (HGBCL), n= 41 (13%) Primary Mediastinal B-cell lymphomas (PMBCL), n= 38 (11%) Mantle Cell Lymphoma (MCL)] received CAR T-cell treatment with axicabtagene-ciloleucel [n=161(49%), axicel], tisagenlecleucel [n=128 (39%), tisacel] or brexucabtagene autoleucel [n=38(12%), brexucel]. The median age of the pts was 58 years (90 pts were older than 65 years). Most pts [n=280, (85,6%)] were treated with a bridging therapy. Bulky and extranodal disease were observed in 108 (33%) and 177 (54,1%) pts, respectively. Pts who received tisacel were significantly older (p&amp;lt;0.0001), had a longer time from lymphocyte apheresis to the infusion (&amp;lt;0.0001), and did not include PMBCL. The median follow-up time was 12 months [IQR, 6,09-22,37]. At the time of PET-1, 180 pts (55%) showed a PET with DS1-3, 82(25%) had a PET with DS4 (n=61 PR, n=21 SD), and 65(20%) with DS5 (n=13 SD, n=47 PD, n=5 PR). The results of early PET were significantly different according to the histology (p&amp;lt;0.0005): the percentage of DS 4 and DS 5 was 22% and 23% for DLBCL, 30% and 31% for HGBCL, 39% and 7% for PMBCL, and 16% and 0% for MCL, respectively. Overall, 1-year PFS based on PET-1 was 67%, 42%, and 8% for DS1-3, DS4, and DS5 (p&amp;lt;0,0001), respectively. The prognostic role of DS 4 varied with histology: 1-year PFS was 36%, 58%, and 44% for DLBCL, PMBCL, and HGBCL (&amp;lt;0.0001), respectively. The outcome of early PET was significantly influenced by CAR T-cell product (also excluding PMBCL): 1-year PFS for pts with DS1-3 and DS4 at PET-1 was 66% and 51% for axicel and 58,7% and 32% for those treated with tisacel (p&amp;lt;0.0001). The 1-year OS based on PET-1 was 88%, 82%, and 33% for DS1-3, DS4, and DS5 (p&amp;lt;0,0001), respectively. At 90 days, only 219 pts were evaluable; 21 of 82 (26%) DS4 and 5 of 65 (8%) DS5 at PET-1 converted in CR. Overall, 1-year PFS and OS based on PET-3 was 80% and 93% for DS1-3, 64% and 93% for DS4, and 8% and 56% for DS5, respectively. Multivariable analyses identified DS4 and DS5 values on PET-1 and CAR T-cell product Tisacel associated with increasing risk of failure [HR: 1,95 (95%CI;1,01-3,76) for DS4; HR: 9,63 for DS5 (95%CI:6,13-15,13); p&amp;lt; 0,0001; HR: 1,53 for Tisacel vs Axicel; (95%CI:1,06-2,22); p&amp;lt;0.0231]. Conclusion: Early evaluation by PET significantly influenced the prognosis. Estimating the risk of failure must be integrated with CAR T- cell product.