Chimeric Antigen Receptor T-cell Manufacturing Research Articles

Rapidly-manufactured CD276 CAR-T cells exhibit enhanced persistence and efficacy in pancreatic cancer.

Pancreatic cancer is one of the most lethal malignancies and the lack of treatment options makes it more deadly. Chimeric Antigen Receptor T-cell (CAR-T) immunotherapy has revolutionized cancer treatment and made great breakthroughs in treating hematological malignancies, however its success in treating solid cancers remains limited mainly due to the lack of tumor-specific antigens. On the other hand, the prolonged traditional manufacturing process poses challenges, taking 2 to 6weeks and impacting patient outcomes. CD276 has recently emerged as a potential therapeutic target for anti-solid cancer therapy. Here, we investigated the efficacy of CD276 CAR-T and rapidly-manufactured CAR-T against pancreatic cancer. In the present study, CD276 CAR-T was prepared by CAR structure carrying 376.96 scFv sequence, CD8 hinge and transmembrane domain, 4-1BB and CD3ζ intracellular domains. Additionally, CD276 rapidly-manufactured CAR-T (named CD276 Dash CAR-T) was innovatively developed by shortening the duration of ex vitro culture to reduce CAR-T manufacturing time. We evaluated the anti-tumor efficacy of CD276 CAR-T and further compared the functional assessment of Dash CAR-T and conventional CAR-T in vitro and in vivo by detecting the immunophenotypes, killing ability, expansion capacity and tumor-eradicatingeffect of CAR-T. We found that CD276 was strongly expressed in multiple solid cancer cell lines and that CD276 CAR-T could efficiently kill these solid cancer cells. Moreover, Dash CAR-T was successfully manufactured within 48-72h and the functional validation was carried out subsequently. In vitro, CD276 Dash CAR-T possessed a less-differentiated phenotype and robust proliferative ability compared to conventional CAR-T. In vivo xenograft mouse model, CD276 Dash CAR-T showed enhanced anti-pancreatic cancer efficacy and T cell expansion. Besides, except for the high-dose group, the body weight of mice was maintained stable, and the state of mice was normal. In this study, we proved CD276 CAR-T exhibited powerful activity against pancreatic cancer cells in vitro and in vivo. More importantly, we demonstrated the manufacturing feasibility, acceptable safety and superior anti-tumor efficacy of CD276 Dash CAR-T generated with reduced time. The results of the above studies indicated that CD276 Dash CAR-T immunotherapy might be a novel and promising strategy for pancreatic cancer treatment.

Scalable intracellular delivery via microfluidic vortex shedding enhances the function of chimeric antigen receptor T-cells.

Adoptive chimeric antigen receptor T-cell (CAR-T) therapy is transformative and approved for hematologic malignancies, as well being developed for treatment of solid tumors, autoimmune disorders, heart disease and aging. Despite unprecedented clinical outcomes, CAR-T and other engineered cell therapies face a variety of manufacturing and safety challenges. Traditional methods, like lentivirus transduction and electroporation, result in random integration or cause significant cellular damage, which can limit the safety and efficacy of engineered cell therapies, such as CAR-T. We present hydroporation as a gentle and effective alternative for intracellular delivery. Hydroporation resulted in 1.7 to 2x higher CAR-T yields compared to electroporation with superior cell viability and recovery. Hydroporated cells exhibited rapid proliferation, robust target cell lysis and increased pro-inflammatory and regulatory cytokine secretion in addition to improved CAR-T yield by day 5 post-transfection. We demonstrated scaled-up hydroporation can process 5 × 10 8 cells in less than 10 s, showcasing the platform as a viable solution for high-yield CAR-T cell manufacturing with the potential for improved therapeutic outcomes.

Chimeric antigen receptor T-cell therapy for T-cell acute lymphoblastic leukemia.

Chimeric antigen receptor (CAR) T-cell therapy is a new and effective treatment for patients with hematologic malignancies. Clinical responses to CAR T cells in leukemia, lymphoma, and multiple myeloma have provided strong evidence of the antitumor activity of these cells. In patients with refractory or relapsed B-cell acute lymphoblastic leukemia (ALL), the infusion of autologous anti-CD19 CAR T cells is rapidly gaining standard-of-care status and might eventually be incorporated into frontline treatment. In T-ALL, however, leukemic cells generally lack surface molecules recognized by established CAR, such as CD19 and CD22. Such deficiency is particularly important, as outcome is dismal for patients with T-ALL that is refractory to standard chemotherapy and/or hematopoietic stem cell transplant. Recently, CAR T-cell technologies directed against T-cell malignancies have been developed and are beginning to be tested clinically. The main technical obstacles stem from the fact that malignant and normal T cells share most surface antigens. Therefore, CAR T cells directed against T-ALL targets might be susceptible to self-elimination during manufacturing and/or have suboptimal activity after infusion. Moreover, removing leukemic cells that might be present in the cell source used for CAR T-cell manufacturing might be problematic. Finally, reconstitution of T cells and natural killer cells after CAR T-cell infusion might be impaired. In this article, we discuss potential targets for CAR T-cell therapy of T-ALL with an emphasis on CD7, and review CAR configurations as well as early clinical results.

Enrichment of T-lymphocytes from leukemic blood using inertial microfluidics toward improved chimeric antigen receptor-T cell manufacturing

Chimeric antigen receptor cell therapy is a successful immunotherapy for the treatment of blood cancers. However, hurdles in their manufacturing remain including efficient isolation and purification of the T-cell starting material. Herein, we describe a one-step separation based on inertial spiral microfluidics for efficient enrichment of T-cells in B-cell acute lymphoblastic leukemia (ALL) and B-cell chronic lymphocytic leukemia patient's samples. In healthy donors used to optimize the process, the lymphocyte purity was enriched from 65% (SD ± 0.2) to 91% (SD ± 0.06) and T-cell purity was enriched from 45% (SD ± 0.1) to 73% (SD ± 0.02). Leukemic samples had higher starting B-cells compared to the healthy donor samples. Efficient enrichment and recovery of lymphocytes and T-cells were achieved in ALL samples with B-cells, monocytes and leukemic blasts depleted by 80% (SD ± 0.09), 89% (SD ± 0.1) and 74% (SD ± 0.09), respectively, and a 70% (SD ± 0.1) T-cell recovery. Chronic lymphocytic leukemia samples had lower T-cell numbers, and the separation process was less efficient compared to the ALL. This study demonstrates the use of inertial microfluidics for T-cell enrichment and depletion of B-cell blasts in ALL, suggesting its potential to address a key bottleneck of the chimeric antigen receptor-T manufacturing workflow.

Evolving Evidence-Based Value Assessment of One-Time Therapies: Tisagenlecleucel as a Case Study.

Economic evaluation of one-time therapies during reimbursement decision-making is challenging due to uncertain long-term outcomes. The availability of 5-year outcome data from the ELIANA trial and real-world evidence of tisagenlecleucel, the first chimeric antigen receptor T-cell (CAR-T) therapy, presents an opportunity to re-evaluate the predictions of prior cost-effectiveness analyses (CEAs). To conduct a systematic literature review (SLR) of prior CEAs of tisagenlecleucel for pediatric/young adult relapsed or refractory acute lymphoblastic leukemia (r/r ALL) and evaluate the impact of recently available 5-year efficacy data from ELIANA and advances in CAR-T manufacturing in an updated CEA model. OVID MEDLINE/Embase and health technology assessment (HTA) databases were searched for full-text economic evaluations in English reporting cost-effectiveness results for tisagenlecleucel for r/r ALL. Evaluations with publicly reported incremental cost-effectiveness ratios (ICERs) were included in the SLR. Study screening and data abstraction were conducted following PRISMA guidelines. Data extracted included the country/currency, perspective, clinical trial evidence, model structures, long-term efficacy extrapolation approaches (i.e., overall survival [OS]), time horizon, discount rates, and outcomes (i.e., life years [LY], quality-adjusted LY [QALY], and ICERs). The CEA model reported in Wakase et al. was updated using 5-year OS data from ELIANA and the CAR-T infusion rate informed by real-world practice. Sixteen records corresponding to 15 unique studies were included in the SLR (11 publications and 5 HTA reports); all were conducted from the health care system perspective of the respective countries. Most studies found tisagenlecleucel to be cost effective, but all studies' projected 3- and 5-year OS rates for tisagenlecleucel were lower than the observed 3- and 5-year rates, respectively, derived from 5-year ELIANA data. When applying updated OS projections from the most recent ELIANA data cut and higher infusion rates of 92.5% (per the real-world infusion rate)-96.0% (per the manufacturer success rate) to theCEA of Wakase et al., the associated QALYs for tisagenlecleucel increased from 11.6 to 14.6-15.0, andLYs increased from 13.3 to 17.0-17.5. Accordingly, the ICERs for tisagenlecleucel decreased from ¥2,035,071 to ¥1,787,988-¥1,789,048 versus blinatumomab and from ¥2,644,702 to ¥2,257,837-¥2,275,181 versus clofarabine combination therapy in the updated CEA model. Projections at launch of the likely cost effectiveness of tisagenlecleucel appear to have underestimated its ultimate economic value given more recent trial and real-world data. To balance uncertainty in initial valuation with the need to provide access to novel oncology therapies, payers can consider flexible reimbursement policies alongside ongoing assessments as new data emerge.

Applications and Opportunities for Immune Cell CAR Engineering in Comparative Oncology.

Chimeric antigen receptor (CAR) T-adoptive cell therapy has transformed the treatment of human hematologic malignancies. However, its application for the treatment of solid tumors remains challenging. An exciting avenue for advancing this field lies in the use of pet dogs, in which cancers that recapitulate the biology, immunological features, and clinical course of human malignancies arise spontaneously. Moreover, their large size, outbred genetic background, shared environment with humans, and immunocompetency make dogs ideal for investigating and optimizing CAR therapies before human trials. Here, we will outline how challenges in early clinical trials in patients with canine lymphoma, including issues related to autologous CAR T-cell manufacturing, limited CAR T-cell persistence, and tumor antigen escape, mirrored challenges observed in human CAR T trials. We will then highlight emerging adoptive cell therapy strategies currently under investigation in dogs with hematological and solid cancers, which will provide crucial safety and efficacy data on novel CAR T regimens that can be used to support clinical trials. By drawing from ongoing studies, we will illustrate how canine patients with spontaneous cancer may serve as compelling screening platforms to establish innovative CAR therapy approaches and identify predictive biomarkers of response, with a specific emphasis on solid tumors. With increased funding for canine immunotherapy studies, multi-institutional investigations are poised to generate highly impactful clinical data that should translate into more effective human trials, ultimately benefiting both human and canine cancer patients.

Optimizing lentiviral vector formulation conditions for efficient ex vivo transduction of primary human T cells in chimeric antigen receptor T-cell manufacturing

Background aimsChimeric antigen receptor (CAR) T-cell products are commonly generated using lentiviral vector (LV) transduction. Optimal final formulation buffer (FFB) supporting LV stability during cryostorage is crucial for cost-effective manufacturing. MethodsTo identify the ideal LV FFB composition for ex vivo CAR-T production, primary human T cells were transduced with vesicular stomatitis virus G-protein (VSV-G) -pseudotyped LVs (encoding a reporter gene or an anti-CD19-CAR). The formulations included phosphate-buffered saline (PBS), HEPES, or X-VIVOTM 15, and stabilizing excipients. The functional and viral particle titers and vector copy number were measured after LV cryopreservation and up to 24 h post-thaw incubation. CAR-Ts were produced with LVs in selected FFBs, and the resulting cells were characterized. ResultsPost-cryopreservation, HEPES-based FFBs provided higher LV functional titers than PBS and X-VIVOTM 15, and 10% trehalose-20 mM MgCl2 improved LV transduction efficiency in PBS and 50 mM HEPES. Thawed vectors remained stable at +4°C, while a ≤ 25% median decrease in the functional titer occurred during 24 h at room temperature. Tested excipients did not enhance LV post-thaw stability. CAR-Ts produced using LVs cryopreserved in 10% trehalose- or sucrose-20 mM MgCl2 in 50 mM HEPES showed comparable transduction rates, cell yield, viability, phenotype, and in vitro functionality. ConclusionA buffer consisting of 10% trehalose-20 mM MgCl2 in 50 mM HEPES provided a feasible FFB to cryopreserve a VSV-G -pseudotyped LV for CAR-T-cell production. The LVs remained relatively stable for at least 24 h post-thaw, even at ambient temperatures. This study provides insights into process development, showing LV formulation data generated using the relevant target cell type for CAR-T-cell manufacturing.

Optimizing the CAR T-Cell Therapy Experience in Multiple Myeloma: Clinical Pearls From an Expert Roundtable

Chimeric antigen receptor T-cell (CAR-T) therapies offer substantial advancement in the treatment of multiple myeloma (MM). However, the CAR-T therapy process involves complex decision-making that is informed by many variables. This review aims to provide an overview of the patient selection and administration process for CAR-T therapy for MM from the perspective of experienced healthcare providers (HCPs), including considerations for each step in the CAR-T therapy process. Referring HCPs should initiate conversations with HCPs at CAR-T capable centers earlier in the treatment journey, even before patients are eligible for CAR-T therapy, particularly for patients from underserved populations and patients with high-risk disease, to ensure adequate time for logistical planning and patient education. Patient selection for CAR-T therapy may be guided by factors such as performance status, rate of disease progression, and logistical considerations. Some anticancer therapies may affect T-cell fitness and therefore impact CAR-T manufacturing and patient outcomes; however, additional research is needed to confirm this in MM. Bridging therapies should be tailored to the needs of the patient and ideally halted 1 week or longer before CAR-T infusion, contingent upon the agent(s) used. Lymphodepletion regimens may need to be modified for patients with renal insufficiency. Collaboration with HCPs at both the treating and referring centers is important to optimize coordinated care of patients. Collaboration with and guidance from experienced HCPs throughout patient selection, referral, and CAR-T administration is instrumental in optimizing patient outcomes as access to CAR-T therapies expands.

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.

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.

CAR-T Phenotype and Efficacy Is Impaired By Lymphoma-Associated CD39 + T Cells

Background: Autologous chimeric antigen receptor (CAR) T-cell therapy is standard of care for patients with relapsed or refractory Large B cell Lymphoma (R/R LBCL). Each patient's CAR T product is unique, and the patient-specific determinants of CAR T-cell quality are poorly understood. CD39 is an ectonucleosidase that participates in the conversion of ATP and ADP and is upregulated in cancer. On T-cells, CD39 is expressed on CD4+ Tregs and on exhausted CD8+ T-cells that are prone to apoptosis. Methods: This is a retrospective single-center cohort study (N=72) of patients who received CD19 CAR T-cell therapy for LBCL (axi-cel n=52; tisa-cel n=20). Leukapheresis material was obtained from n=51 patients and flow cytometry was performed to phenotype CD4+ and CD8+ stem-central memory, memory, and effector T-cell subsets (using CCR7 and CD45RO), and for immune checkpoint expression (PD-1, LAG3, TIGIT, and CD39). 10x multiome (ATAC and RNA) single cell sequencing (scRNA-seq) was performed on n=8 leukapheresis products for deeper characterization. Serum metabolomics was performed on paired samples from n=21 patients. 10X Genomics Chromium scRNAseq was also performed on n=57 CAR T-cell infusion products, including n=36 with paired leukapheresis material previously phenotyped by flow cytometry. In vitro CAR T-cells were manufactured from starting patient T-cells and analyzed for CAR T-cell phenotype and function. Results: In the leukapheresis material of patients that did not achieve long-term remission after CAR T-cell therapy, and in those with high tumor burden, we found higher numbers of CD4+CD39+ and CD8+CD39+ T-cells ( Figs. 1 and 2). 10X multiome sequencing confirmed that CD39+ T-cells exhibit characteristics of exhaustion. Recent platinum-based chemotherapy did not affect CD39+ T-cell levels. In n=21 patients with paired serum analyzed by metabolomics, high CD8+CD39+ T-cells associated with reduced metabolites in the inosine-hypoxanthine pathway, which are downstream of the ectonucleotidase function of CD39 (inosine; P=0.006; hypoxanthine P=0.07). Increased numbers of CD39+ T-cells in the starting leukapheresis material translated into manufactured CAR T-cells having less favorable product characteristics, including higher CD39 expression and fewer memory cells in both paired patient samples and in experiments of in vitro CAR T-cell manufacturing. ScRNA-seq of the infused CAR T-cell product revealed differential gene signatures, both globally and in association with response, between axi-cel and tisa-cel CAR T-cell products, highlighting the profound product-specific differences. Nonetheless, both products were adversely affected by high CD39+ T-cells in the leukapheresis material used for manufacture. Conclusions: CD39+ T-cells, found in patients with high lymphoma tumor burden and an unfavourable immunometabolic environment, associate with poor CAR T-cell quality and adverse patient outcomes in R/R LBCL. Strategies are needed to improve patient T-cell quality prior to leukapheresis and/or improve CAR T-cell manufacturing from patients with high levels of exhausted CD39+ T-cells. Figure 1: Progression-free survival (PFS) stratified by leukapheresis CD8+CD39+ T-cells in the leukapheresis product. Blue - below cohort median percentage of CD8+T-cells that are CD39+ (low); Red - above median percentage of CD8+T-cells that are CD39+ (high). P-value by Log-Rank test. Overall survival (not shown) P-value 0.01. Figure 2: Proportion of CD8+CD39+ T-cells found in patients with low or high baseline metabolic tumor volume (MTV) based on a previously established cutoff (Dean et al. Blood Adv. 2020). MTV was measured on the pre-CAR T-cell PET/CT. P-value by T-test. MDJ, XY, and RMA are co-first authors with equal contribution.

Type I Interferon Blockade Enhances Transduction Efficiency and Efficacy of Non-Activated CAR T Cells

Chimeric antigen receptor (CAR) T-cell therapies have revolutionized the treatment of advanced hematologic cancers, showing impressive response rates in pivotal trials. Despite this success, challenges in CAR T-cell adoption persist due to tumor resistance mechanisms, manufacturing failures, and limitations in CAR T-cell persistence and effector function. Strategies that promote T-cell persistence, proliferation, and cytotoxic activity are essential to improving long-term outcomes of CAR T therapy. The most common protocol for CAR T-cell manufacturing involves lentiviral vector transduction of activated T-cells followed by ex vivo culture. However, this approach may drive terminal T-cell differentiation and exhaustion, compromising therapeutic efficacy. In contrast, non-activated CAR T-cell manufacturing has shown promise in enhancing T-cell differentiation and tumor control. Yet, the low transduction efficiency of quiescent T-cells remains a challenge. In this study, we explore the role of type I interferon (IFN)-mediated innate immune responses in limiting CAR T manufacturing efficiency. We hypothesize that blocking these responses using the vaccinia virus-encoded type I interferon-binding protein can enhance transduction efficiency and promote less-differentiated CAR T-cell phenotypes, including naïve and central memory-like differentiation. Our findings demonstrate that lentiviral vector transduction triggers an innate immune response in non-activated T-cells, resulting in reduced transduction efficiency, and altered T-cell differentiation. Inhibiting the anti-viral response via anti-IFN leads to improved T-cell differentiation and exhaustion characteristics. Importantly, anti-IFN exposure supports the enrichment of naive-like T cells: a subset noted for superior clinical efficacy. Anti-IFN also reduces LAG3 expression. Collectively, these findings position anti-IFN as a novel means to enhance CAR T-cell persistence and anti-tumor function. We further investigate the influence of sustained anti-IFN exposure by designing lentiviral transfer plasmids encoding both a CAR and secreted type I interferon-binding protein. These cells showed enhanced cytolytic activity and cytokine production against target cells. Our studies in mice show promising results, suggesting that the protein secretion enhance therapeutic activity against tumors employing sustained type I interferon signaling for immune escape. Overall, targeting the type I interferon response during non-activated CAR T-cell manufacturing offers a potential solution to improve transduction efficiency and enhance CAR T-cell functionality. Given the therapeutic promise of non-activated CAR T cells, our findings have immediate translational relevance for broadening their appeal against cancer. Figure 1. Exposure to anti-IFN increases transduction efficiency and naïve-like differentiation of lentivirus-transduced non-activated T-cells A) Freshly isolated human T-cells were incubated in media with aIFN or vehicle, for one hour at room temperature. The cells were resuspended in complete media and then transduced with lentiviral vector encoding iRFP. Expression of iRFP was evaluated 96 h after transduction by flow cytometry. b, Human T-cells were isolated and prepared as above. At 96 h post-transduction, cells were stained with anti-CD45RO and anti-CCR7 antibodies and samples were evaluated by flow cytometry. Data for A and B are representative of multiple experiments with three independent donors.

Attrition after Referral for Chimeric Antigen Receptor T-Cell (CAR-T) Products in Multiple Myeloma (MM)

Introduction: Chimeric antigen receptor T-cell (CAR-T) products have shown an impressive response in relapsed/refractory MM patients (pts). The pivotal KarMMa-3 (Otero-Rodriguez P et al, NEJM, 2023) and CARTITUDE-4 (San Miguel J, et al, NEJM, 2023) studies showed that infusion of idecabtagene vicleucel (ide-cel) and ciltacabtagene autoleucel (cilta-cel) was superior to other standard of care therapies. However, some pts in these studies were unable to receive CAR-T even after being deemed eligible for apheresis. In KarMMa-3, 12/140 pts who completed apheresis did not receive their cells, 3 due to disease progression/death and 1 due to a true manufacturing failure. In CARTITUDE-4, 16/113 pts who completed apheresis did not receive their cells, with 9 dying prior to infusion and 0 having true manufacturing failures. Other studies have shown that factors like peripheral CD3 count (PCD3) affected the probability of a successful apheresis (Rytlewski et al, ASCO 2022). Known reasons for CAR-T attrition include lack of available spots, true manufacturing failures, death post-apheresis but prior to infusion (PAD; due to infection and/or disease progression), and cell product issues necessitating an expanded access program (EAP). This study aimed to find patient- and disease-specific variables associated with increased rates of CAR-T attrition. Methods: We retrospectively reviewed the medical records of all pts who were approved for either ide-cel or cilta-cel as standard of care (SOC) treatment for MM at MD Anderson between August 2021 and June 2023. The study was approved by the Institutional Review Board at MD Anderson. Pts were classified by CAR-T product received, and the number of apheresis procedures required to produce viable product. They were then classified based on need for EAP. Descriptive statistics including mean, standard deviation, median, and range for continuous variables such as age and lab measurements, and frequency counts and percentages for categorical variables such as stage, gender, comorbidity, treatment, and response were obtained. Fisher's exact test or Chi-square test was used to evaluate the association between two categorical variables. Wilcoxon rank sum test or Kruskal-Wallis test was used to evaluate the difference in a continuous variable between or among patient groups. Kaplan-Meier method was used to estimate overall survival and progression free survival for the pts who received CAR-T infusion. Statistical software SAS 9.4 (SAS, Cary, NC) and S-Plus 8.2 (TIBCO Software Inc., Palo Alto, CA) were used for all the analyses. Results: Data from 153 pts were included. High-risk features, defined as the presence of high-risk cytogenetics, extramedullary disease, or R-ISS stage III, were present in 125 (81.7%), and 84 (54.9%) were penta-refractory. CAR-T cells were infused successfully in 86 (56.2%) pts, including 5 who were infused via EAP. Of the 67 pts who did not get infused, 26 (38.2%) died prior to apheresis, 8 (11.9%) were PAD, 10 (14.9%) were treated with a bispecific agent due to lack of available manufacturing slots, and 3 (4.5%) had true manufacturing failures. Of the 8 patients that were PAD, 2 died due to progression of disease, 4 died from complications of inpatient bridging chemo, and 2 died from complications from lymphodepleting chemo. For all pts with manufacturing failures, their apheresis had a low dose, with 2 out of 3 having PCD3 < 5%. The mean absolute lymphocyte count (ALC) at apheresis was significantly higher in the EAP group (n=5) compared with the non-EAP group, but significantly lower in the manufacturing failures group (n=3) compared with the successful CAR-T manufacturing (n=86) group (Table 1). For the overall cohort of pts receiving CAR-T (n=86), the median progression-free (PFS) and overall survival (OS) rates were 11.7 and 18.8 months, respectively (Figure 1). Conclusion: The PFS and OS for all pts, including those who received their CAR-T through EAP, were excellent. ALC at the time of apheresis was a predictor of true manufacturing failure. Surprisingly, pts successfully treated on EAP had an increased ALC compared with those receiving SOC. Further comparative studies of pts with barriers to CAR-T are needed to identify other variables that increase adverse outcomes so that these can be addressed. Hopefully, with a better understanding of the barriers patients have, we can ensure that more pts get access to this efficacious treatment.

Efficacy of Chimeric Antigen Receptor T-Cell Therapy Is Not Impaired By Previous Bispecific Antibody Treatment in Patients with Large B-Cell Lymphoma

Introduction: Potential T-cell exhaustion after bispecific antibody (BsAb) treatment remains an open question, raising the theoretical concern that prior BsAb exposure could affect subsequent chimeric antigen receptor (CAR) T-cell efficacy. Clinical data on CAR T-cell outcomes after prior BsAb treatment in the setting of large B-cell lymphoma (LBCL) are scarce and highly awaited to better define treatment sequencing in relapsed/refractory (R/R) patients. Methods: We conducted a retrospective, international study including R/R LBCL patients treated with CD19-targeted CAR T-cells at 15 centers between July 2018 and January 2023 who had been exposed to BsAbs prior to apheresis. Then, we identified a control cohort from patients included in the DESCAR-T Registry (n=764). We carried out a 1:1 propensity score matching (PSM) to achieve balance between cohorts; 13 baseline covariates were included in the PSM. We compared response rates, survival outcomes and toxicity after CAR T-cell therapy, according to previous BsAb exposure. Results: We identified 47 LBCL patients who received BsAb therapy prior to CAR T-cell apheresis. Median age was 65 years (range 31-82), with a male predominance (66%), and median prior lines of therapy before BsAb were 2 (IQR 2-3) (Table). The BsAbs targeted CD20/CD3 (91%) or CD22/CD3 (9%), either in monotherapy (n=41, 87%) or in combination with other agents (n=6, 13%) (lenalidomide [n=2], polatuzumab [n=1], chemotherapy [n=2], missing [n=1]). The median time on BsAb treatment was 98 days (IQR 56-160) with a best overall (complete) response rate (ORR [CRR]) of 47% (19%). Median progression-free survival (PFS) and duration of response (DOR) were 3.1 months (95% CI 2.7-4.4 months) and 8.8 months (95% CI 2.2-NR), respectively. Cytokine release syndrome (CRS) occurred in 59% of patients (grade 3 in 4%). No neurologic toxicity (NT) was reported. In 26 (55%) patients, bispecific antibody was the last line before CAR T-cell therapy. Median washout between the last BsAb dose and lymphocyte apheresis for CAR T-cell manufacturing was 43 days (range 34-103 days). In terms of the subsequent CAR T-cell therapy, patients received axi-cel (n=22, 47%), tisa-cel (n=20, 43%) or liso-cel (n=5, 11%). Most patients developed CRS after infusion (79%, 6% grade >2), with a low rate of NT (23%, 2% grade >2). Neutropenia and thrombocytopenia grade >2 were reported in 66% and 45% of patients, respectively. Regarding efficacy, ORR after infusion was 83% (CR 43%). Median PFS and overall survival (OS) were 6.6 months (95% CI 2.6-not reached [NR]) and NR (95% CI 9.0-NR), respectively. The rate of overall (complete) response was similar between patients who had previously responded (CR or PR) or not (SD or PD) to BsAb therapy (82% [41%] vs 84% [44%], respectively, p=0.64). However, all 9 patients achieving CR after BsAb achieved subsequent response to CAR T-cells. Given the wide variability in the washout between last BsAb dose and lymphocyte apheresis, we evaluated the impact of this interval on CAR T-cell efficacy. The 6-month PFS and OS of patients previously exposed to BsAb within 45 days of lymphocyte apheresis was similar to patients who had a longer washout (59% vs 47% [p=0.25] and 83% vs 67% [p=0.21], respectively). In the second part of the analysis, we matched our cohort with a control group of CAR T-cell recipients not previously exposed to BsAbs. The final analysis included 2 sets of 42 patients with comparable characteristics. Median follow-up from CAR T-cell infusion was 11.5 months for the BsAb cohort (CI 95% 6.4-19.0 months) and 18.8 months for the control cohort (CI 95% 10.9-23.0 months). Patients with previous BsAb exposure showed a similar PFS (p=0.10, Figure) and OS (p=0.08) after CAR T-cell infusion in comparison to the control group. In terms of toxicity, there were no differences in the incidence of CRS (p=0.41) or NT (p=1.0) after infusion. Conclusions: Previous exposure to bispecific antibody treatment targeting different antigens does not have a negative impact on survival outcomes after CAR T-cell therapy. Lack of response to a previous BsAb does not predict for lower response rates after CAR T-cell infusion.

FOXO1 Inhibition Generates Potent Nonactivated CAR T Cells against Solid Tumors.

Chimeric antigen receptor (CAR) T cells have shown promising results in the treatment of B-cell malignancies. Despite the successes, challenges remain. One of them directly involves the CAR T-cell manufacturing process and especially the ex vivo activation phase. While this is required to allow infection and expansion, ex vivo activation dampens the antitumor potential of CAR T cells. Optimizing the nature of the T cells harboring the CAR is a strategy to address this obstacle and has the potential to improve CAR T-cell therapy, including for solid tumors. Here, we describe a protocol to create CAR T cells without ex vivo preactivation by inhibiting the transcription factor FOXO1 (CAR TAS cells). This approach made T cells directly permissive to lentiviral infection, allowing CAR expression, with enhanced antitumor functions. FOXO1 inhibition in primary T cells (TAS cells) correlated with acquisition of a stem cell memory phenotype, high levels of granzyme B, and increased production of TNFα. TAS cells displayed enhanced proliferative and cytotoxic capacities as well as improved migratory properties. In vivo experiments showed that CAR TAS cells were more efficient at controlling solid tumor growth than classical CAR T cells. The production of CAR TAS from patients' cells confirmed the feasibility of the protocol in clinic.

Metabolic PET/CT analysis of aggressive Non-Hodgkin lymphoma prior to Axicabtagene Ciloleucel CAR-T infusion: predictors of progressive disease, survival, and toxicity

PET/CT is used to evaluate relapsed/refractory non-Hodgkin lymphoma (NHL) prior to chimeric antigen receptor T-cell (CAR-T) infusion at two time points: pre-leukapheresis (pre-leuk) and pre-lymphodepletion chemotherapy (pre-LD). We hypothesized that changes in PET/CT between these time points predict outcomes after CAR-T. Metabolic tumor volume (MTV), total lesion glycolysis (TLG), and other metrics were calculated from pre-leuk and pre-LD PET/CT scans in patients with NHL who received axicabtagene ciloleucel, and assessed for association with outcomes. Sixty-nine patients were analyzed. While single time point PET/CT characteristics were not associated with risk of PD or death, increases from pre-leuk to pre-LD in parenchymal MTV, nodal MTV, TLG of the largest lesion, and total number of lesions were associated with increased risk of death (p < 0.05 for all). LASSO analysis identified increasing extranodal MTV and increasing TLG of the largest lesion as strong predictors of death (AUC 0.74). Greater pre-LD total MTV was associated with higher risk of grade 3+ immune effector cell-associated neurotoxicity syndrome (ICANS) (p = 0.042). Increasing metabolic disease burden during CAR-T manufacturing is associated with increased risk of progression and death. A two variable risk score stratifies prognosis prior to CAR-T infusion and may inform risk-adapted strategies.

Biomaterials for chimeric antigen receptor T cell engineering.

Chimeric antigen receptor T (CAR-T) cells have achieved breakthrough efficacies against hematological malignancies, but their unsatisfactory efficacies in solid tumors limit their applications. The prohibitively high prices further restrict their access to broader populations. Novel strategies are urgently needed to address these challenges, and engineering biomaterials can be one promising approach. The established process for manufacturing CAR-T cells involves multiple steps, and biomaterials can help simplify or improve several of them. In this review, we cover recent progress in engineering biomaterials for producing or stimulating CAR-T cells. We focus on the engineering of non-viral gene delivery nanoparticles for transducing CAR into T cells ex vivo/in vitro or in vivo. We also dive into the engineering of nano-/microparticles or implantable scaffolds for local delivery or stimulation of CAR-T cells. These biomaterial-based strategies can potentially change the way CAR-T cells are manufactured, significantly reducing their cost. Modulating the tumor microenvironment with the biomaterials can also considerably enhance the efficacy of CAR-T cells in solid tumors. We pay special attention to progress made in the past five years, and perspectives on future challenges and opportunities are also discussed. STATEMENT OF SIGNIFICANCE: Chimeric antigen receptor T (CAR-T) cell therapies have revolutionized the field of cancer immunotherapy with genetically engineered tumor recognition. They are also promising for treating many other diseases. However, the widespread application of CAR-T cell therapy has been hampered by the high manufacturing cost. Poor penetration of CAR-T cells into solid tissues further restricted their use. While biological strategies have been explored to improve CAR-T cell therapies, such as identifying new cancer targets or integrating smart CARs, biomaterial engineering provides alternative strategies toward better CAR-T cells. In this review, we summarize recent advances in engineering biomaterials for CAR-T cell improvement. Biomaterials ranging from nano-, micro-, and macro-scales have been developed to assist CAR-T cell manufacturing and formulation.

Organisational and methodological challenges of CAR-T manufacturing in the Russian Federation

Despite their widespread clinical implementation, chimeric antigen receptor T-cell (CAR-T) therapy products, including those manufactured by industrial processes, are still not legally available or used in the Russian Federation.The aim of the study was to describe the current challenges associated with specific aspects of CAR-T manufacturing in the Russian Federation and the potential ways to overcome them.This article discusses the regulatory, legal, organisational, and methodological challenges of CAR-T manufacturing. It analyses differences in the interpretation of CAR-T therapy products under national and supranational law. According to Russian Federal Law No. 180-FZ “On Biomedical Cell Products” of 23 June 2016, CAR-T therapy products are considered biomedical cell products. However, according to Decision No. 78 of the Council of the Eurasian Economic Commission “On the Rules of Marketing Authorisation and Assessment of Medicinal Products for Human Use” of 3 November 2016, CAR-T therapy products are considered advanced therapy medicinal products (ATMPs). This article provides a detailed overview of the difficulties in obtaining starting biological materials (i.e. the inability to consider the patient as a donor) and transferring the materials for CAR-T manufacturing (i.e. the inapplicability of national law). In addition, this article describes export aspects specific to biological materials. The authors reckon that CAR-T therapy products should be categorised as ATMPs and that the corresponding active pharmaceutical ingredients, genetically modified autologous lymphocytes, should be defined as starting materials. Therefore, genetically modified autologous lymphocytes should be regulated under the requirements for starting materials for the manufacturing of active pharmaceutical ingredients that are set forth in Decision No. 77 of the Council of the Eurasian Economic Commission “On the Adoption of the Rules of Good Manufacturing Practice of the Eurasian Economic Union” of 3 November 2016. In conclusion, the authors recognise the need for national and supranational law harmonisation. For this task, it is necessary to establish expert groups that will include clinicians, legal experts, and representatives from the relevant authorities and the pharmaceutical industry.

Risk factors for CAR-T cell manufacturing failure among DLBCL patients: A nationwide survey in Japan.

For successful chimeric antigen receptor T (CAR-T) cell therapy, CAR-T cells must be manufactured without failure caused by suboptimal expansion. In order to determine risk factors for CAR-T cell manufacturing failure, we performed a nationwide cohort study in Japan and analysed patients with diffuse large B-cell lymphoma (DLBCL) who underwent tisagenlecleucel production. We compared clinical factors between 30 cases that failed (7.4%) with those that succeeded (n = 378). Among the failures, the proportion of patients previously treated with bendamustine (43.3% vs. 14.8%; p < 0.001) was significantly higher, and their platelet counts (12.0 vs. 17.0 × 104 /μL; p = 0.01) and CD4/CD8 T-cell ratio (0.30 vs. 0.56; p < 0.01) in peripheral blood at apheresis were significantly lower than in the successful group. Multivariate analysis revealed that repeated bendamustine use with short washout periods prior to apheresis (odds ratio [OR], 5.52; p = 0.013 for ≥6 cycles with washout period of 3-24 months; OR, 57.09; p = 0.005 for ≥3 cycles with washout period of <3 months), low platelet counts (OR, 0.495 per 105 /μL; p = 0.022) or low CD4/CD8 ratios (<one third) (OR, 3.249; p = 0.011) in peripheral blood at apheresis increased the risk of manufacturing failure. Manufacturing failure remains an obstacle to CAR-T cell therapy for DLBCL patients. Avoiding risk factors, such as repeated bendamustine administration without sufficient washout, and risk-adapted strategies may help to optimize CAR-T cell therapy for DLBCL patients.

Release Assays and Potency Assays for CAR T-Cell Interventions.

Chimeric antigen receptor (CAR) T-cells are considered "living drugs" and offer a compelling alternative to conventional anticancer therapies. Briefly, T-cells are redirected, using gene engineering technology, toward a specific cancer cell surface target antigen via a synthetic chimeric antigen receptor (CAR) protein. CARs have a modular design comprising four main structures: an antigen-binding domain, a hinge region, a transmembrane domain, and one or more intracellular signaling domains for T-cell activation. A major challenge in the CAR T-cell manufacturing field is balancing product quality with scalability and cost-effectiveness, especially when transitioning from an academic clinical trial into a marketed product, to be implemented across many collection, manufacturing, and treatment sites. Achieving product consistency while circumnavigating the intrinsic variability associated with autologous products is an additional barrier. To overcome these limitations, a robust understanding of the product and its biological actions is crucial to establish a target product profile with a defined list of critical quality attributes to be assessed for each batch prior to product certification. Additional challenges arise as the field progresses, such as new safety considerations associated with the use of allogenic T-cells and genome editing tools. In this chapter, we will discuss the release and potency assays required for CAR T-cell manufacturing, covering their relevance, current challenges, and future perspectives.