Autologous CD4 Research Articles

Generation of Tumor-Specific Cytotoxic T Cells From Blood via InVitro Expansion Using Autologous Dendritic Cells Pulsed With Neoantigen-Coupled Microbeads.

For the past decade, adoptive cell therapy including tumor-infiltrating lymphocytes, genetically modified cytotoxic lymphocytes expressing a chimeric antigen receptor, or a novel T-cell receptor has revolutionized the treatment of many cancers. Progress within exome sequencing and neoantigen prediction technologies provides opportunities for further development of personalized immunotherapies. In this study, we present a novel strategy to deliver in silico predicted neoantigens to autologous dendritic cells (DCs) using paramagnetic beads (EpiTCer beads). DCs pulsed with EpiTCer beads are superior in enriching for healthy donor and patient blood-derived tumor-specific CD8+ T cells compared to DC loaded with whole-tumor lysate or 9mer neoantigen peptides. A dose-dependent effect was observed, with higher EpiTCer bead per DC being favorable. We concluded that CD8+ T cells enriched by DC loaded with EpiTCer beads are tumor specific with limited tumor cross-reactivity and low recognition of autologous non-activated monocytes or CD8+ T cells. Furthermore, tumor specificity and recognition were improved and preserved after additional expansion using our Good Manufacturing Process (GMP)-compatible rapid expansion protocol. Phenotypic analysis of patient-derived EpiTCer DC expanded CD8+ T cells revealed efficient maturation, with high frequencies of central memory and effector memory T cells, similar to those observed in autologous expanded tumor-infiltrating lymphocytes. These results indicate that DC pulsed with EpiTCer beads enrich for a T-cell population with high capacity of tumor recognition and elimination, which are features needed for a T-cell product to be used for personalized adoptive cell therapy.

Pre-Clinical Proof of Concept: Intra-Carotid Injection of Autologous CD34-Positive Cells for Chronic Ischemic Stroke.

This study was conducted to evaluate the safety and efficacy of human peripheral blood CD34 positive (CD34+) cells transplanted into a murine chronic stroke model to obtain pre-clinical proof of concept, prior to clinical testing. Granulocyte colony stimulating factor (G-CSF) mobilized human CD34+ cells [1 × 104 cells in 50 μl phosphate-buffered saline (PBS)] were intravenously (iv) or intra-carotid arterially (ia) transplanted 4 weeks after the induction of stroke (chronic stage), and neurological function was evaluated. In this study, severe combined immune deficiency (SCID) mice were used to prevent excessive immune response after cell therapy. Two weeks post cell therapy, the ia CD34+ cells group demonstrated a significant improvement in neurological functions compared to the PBS control. The therapeutic effect was maintained 8 weeks after the treatment. Even after a single administration, ia transplantation of CD34+ cells had a significant therapeutic effect on chronic stroke. Based on the result of this pre-clinical proof of concept study, a future clinical trial of autologous peripheral blood CD34+ cells administration in the intra-carotid artery for chronic stroke patients is planned.

Parameters of long-term response with CD28-based CD19 chimaeric antigen receptor-modified T cells in children and young adults with B-acute lymphoblastic leukaemia.

CD28-based CD19 chimaeric antigen receptor-modified (CAR-)Tcells were recently FDA-approved for adult acute lymphoblastic leukaemia (ALL). We report long-term outcome of 37 children and young adults treated with autologous CD19 CAR-T cells. The complete remission rate was 86%, of which 71% were polymerase chain reaction (PCR) minimal residual disease (MRD)-negative, 14% were MRD-negative by flow cytometry, and 14% were PCR MRD-positive. 26 patients proceeded to subsequent haematopoietic stem cell transplant (HSCT). 11 patients had a CD19-postive relapse (eight post HSCT and three without) and one had a CD19-negative relapse. All relapse events occurred within two years from cell therapy. With a median follow-up of three years, the median event-free survival (EFS) is 17months and the median overall survival (OS) is not reached. The three-year EFS is 41% and OS is 56%. Patients with >5% blasts in the bone marrow prior to lymphodepletion had an inferior EFS. All patients with a PCR MRD-positive result at day 28 had relapsed after CAR-T-cell therapy. A prior HSCT did not significantly affect outcome, but a consolidative transplant after achieving remission improved long-term results. Overall, prelymphodepletion disease burden and molecular MRD negativity following CAR-T cells are predictors of long-term outcome following CD19 CAR-T-cell therapy for ALL.

Design of experiments as a decision tool for cell therapy manufacturing

Background aimsCell therapies are costlier to manufacture than small molecules and protein therapeutics because they require multiple manipulations and are often produced in an autologous manner. Strategies to lower the cost of goods to produce a cell therapy could make a significant impact on its total cost. MethodsBorrowing from the field of bioprocess development, the authors took a design of experiments (DoE)-based approach to understanding the manufacture of a cell therapy product in pre-clinical development, analyzing main cost factors in the production process. The cells used for these studies were autologous CD4+ T lymphocytes gene-edited using CRISPR/Cas9 and recombinant adeno-associated virus (AAV) to restore normal FOXP3 gene expression as a prospective investigational product for patients with immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome. ResultsUsing gene editing efficiency as the response variable, an initial screen was conducted for other variables that could influence the editing frequency. The multiplicity of infection (MOI) of AAV and amount of single guide RNA (sgRNA) were the significant factors used for the optimization step to generate a response contour plot. Cost analysis was done for multiple points in the design space to find cost drivers that could be reduced. For the range of values tested (50 000–750 000 vg/cell AAV and 0.8–4 μg sgRNA), editing with the highest MOI and sgRNA yielded the best gene editing frequency. However, cost analysis showed the optimal solution was gene editing at 193 000 vg/cell AAV and 1.78 μg sgRNA. ConclusionsThe authors used DoE to define key factors affecting the gene editing process for a potential investigational therapeutic, providing a novel and faster data-based approach to understanding factors driving complex biological processes. This approach could be applied in process development and aid in achieving more robust strategies for the manufacture of cellular therapeutics.

Attamage-A1: Phase I/II study of autologous CD8+ and CD4+ transgenic t cells expressing high affinity MAGE-A1-specific T-cell receptor (TCR) combined with anti-PD(L)1 in patients with metastatic MAGE-A1 expressing cancer.

TPS592 Background: Adoptive cellular therapies can lead to durable responses in treatment refractory leukemias and lymphomas; however, these approaches are still in early stage development for metastatic solid tumors. FH-MagIC TCR-T is an autologous CD8+ and CD4+ T cell product transduced with a transgenic T cell receptor (TCR) targeting MAGE-A1. MAGE-A proteins are classified within the “testis restricted” cancer testis antigens and are broadly expressed in a wide range of malignancies, including urothelial carcinomas, triple negative breast cancers (TNBCs) and non-small cell lung cancers (NSCLCs). Importantly, MAGE-A1 is undetectable in most normal tissues exclusive of the immune privileged testes, thereby making MAGE-A1 an ideal target for T cell immunotherapy approaches. Of note, FH-MagIC TCR-T is specific to the Class I HLA A*02:01-restricted MAGE-A1 epitope. Based on preclinical studies testing FH-MagIC-T in MAGE-A1 expressing tumor models, we have launched a Phase I/II study evaluating this autologous transgenic TCR therapy. Methods: This is a Phase I/II study testing FH-MagIC TCR-T cells in patients with metastatic urothelial carcinoma, TNBC or NSCLC. Eligible patients must have HLA type HLA-A*02:01 and demonstrate expression of MAGE-A1 on archival tumor tissue (≥1+ by immunohistochemistry). Patients must have been offered or received: i) anti-PD(L)1 therapy; ii) enfortumab vedotin (urothelial carcinoma patients); and iii) FDA-approved targeted therapies (e.g. NSCLC patients with actionable mutations in EGFR, ROS1, etc.). For each dose level (DL) in the Phase 1 portion, 1 patient will be treated without lymphodepletion (LD). If no dose limiting toxicities (DLT) are observed, the next 3 patients will receive LD with cyclophosphamide 300mg/m2 and fludarabine 30mg/m2 IV days -4 to -2 before T cell infusion. The first 4 patients will be treated at DL1: 1 x 109 cells. If no DLTs are observed, the next 4 patients will be treated at DL2: 5 x 109 cells. Otherwise, if a DLT is observed at DL1, the next 4 patients will be treated at DL-1: 5 x 108 cells. The Phase 2 portion of the trial will test FH-MagIC-TCR T cell product at the RP2D with the addition of standard of care anti-PD(L)1 therapy. Primary objectives are to assess safety (Phase 1) and radiographic response rate (Phase 2) per RECIST v1.1. Secondary objectives will evaluate progression free survival, overall survival, persistence of transgenic T cells in peripheral blood and migration into tumor tissue. For the Phase 2 portion, we assume a 5% null response rate (H0). If the true response rate with TCR-transduced cells is 25% (H1), 15 patients will yield 84% power at a one-sided alpha =.05. Clinical trial information: NCT04639245.

Cigarette smoke-induced extracellular vesicles from dendritic cells alter T-cell activation and HIV replication

Despite decreased rates of tobacco smoking in many areas, cigarette smoking remains a major contributor to many health problems. Cigarette smoking can reduce immune system functioning while concurrently increasing inflammation. Dendritic cells in the lung exposed to cigarette smoke become stimulated and go on to activate T-cells. Extracellular vesicles (EVs) are nano-sized particles released by cells. They participate in intercellular communication by transferring functional proteins and nucleic acids to recipient cells and have been implicated in immune responses. For example, they can display MHC-peptide complexes to activate T-cells. In the current study, we sought to understand the role of cigarette smoke extract (CSE) on dendritic cell-derived EVs and their capacity to activate and differentiate T-cells. Primary human dendritic cells (iDCs) were exposed to CSE and EVs were separated and characterized. We exposed autologous primary CD4 + T-cells to iDC-EVs and observed T helper cell populations skewing towards Th1 and Th17 phenotypes. As HIV + individuals are disproportionately likely to be current smokers, we also examined the effects of iDC-EVs on acutely infected T-cells as well as on a cell model of HIV latency (ACH-2). We found that in most cases, iDC-CSE EVs tended to reduce p24 release from the acutely infected primary T-cells, albeit with great variability. We did not observe large effects of iDC-EVs or direct CSE exposure on p24 release from the ACH-2 cell line. Together, these data suggest that iDC-CSE EVs have the capacity to modulate the immune responses, in part by pushing T-cells towards Th1 and Th17 phenotypes.

Betibeglogene Autotemcel Gene Therapy for Non–β0/β0 Genotype β-Thalassemia

BackgroundBetibeglogene autotemcel (beti-cel) gene therapy for transfusion-dependent β-thalassemia contains autologous CD34+ hematopoietic stem cells and progenitor cells transduced with the BB305 lentiviral vector encoding the β-globin (βA-T87Q) gene.MethodsIn this open-label, phase 3 study, we evaluated the efficacy and safety of beti-cel in adult and pediatric patients with transfusion-dependent β-thalassemia and a non–β0/β0 genotype. Patients underwent myeloablation with busulfan (with doses adjusted on the basis of pharmacokinetic analysis) and received beti-cel intravenously. The primary end point was transfusion independence (i.e., a weighted average hemoglobin level of ≥9 g per deciliter without red-cell transfusions for ≥12 months).ResultsA total of 23 patients were enrolled and received treatment, with a median follow-up of 29.5 months (range, 13.0 to 48.2). Transfusion independence occurred in 20 of 22 patients who could be evaluated (91%), including 6 of 7 patients (86%) who were younger than 12 years of age. The average hemoglobin level during transfusion independence was 11.7 g per deciliter (range, 9.5 to 12.8). Twelve months after beti-cel infusion, the median level of gene therapy–derived adult hemoglobin (HbA) with a T87Q amino acid substitution (HbAT87Q) was 8.7 g per deciliter (range, 5.2 to 10.6) in patients who had transfusion independence. The safety profile of beti-cel was consistent with that of busulfan-based myeloablation. Four patients had at least one adverse event that was considered by the investigators to be related or possibly related to beti-cel; all events were nonserious except for thrombocytopenia (in 1 patient). No cases of cancer were observed.ConclusionsTreatment with beti-cel resulted in a sustained HbAT87Q level and a total hemoglobin level that was high enough to enable transfusion independence in most patients with a non–β0/β0 genotype, including those younger than 12 years of age. (Funded by Bluebird Bio; HGB-207 ClinicalTrials.gov number, NCT02906202.)

Selection and T-cell antigenicity of synthetic long peptides derived from SARS-CoV-2.

The pandemic caused by SARS-CoV-2 has led to the successful development of effective vaccines however the prospect of variants of SARS-CoV-2 and future coronavirus outbreaks necessitates the investigation of other vaccine strategies capable of broadening vaccine mediated T-cell responses and potentially providing cross-immunity. In this study the SARS-CoV-2 proteome was assessed for clusters of immunogenic epitopes restricted to diverse human leucocyte antigen. These regions were then assessed for their conservation amongst other coronaviruses representative of different alpha and beta coronavirus genera. Sixteen highly conserved peptides containing numerous HLA class I and II restricted epitopes were synthesized from these regions and assessed in vitro for their antigenicity against T-cells from individuals with previous SARS-CoV-2 infection. Monocyte derived dendritic cells were generated from these peripheral blood mononuclear cells (PBMC), loaded with SARS-CoV-2 peptides, and used to induce autologous CD4+ and CD8+ T cell activation. The SARS-CoV-2 peptides demonstrated antigenicity against the T-cells from individuals with previous SARS-CoV-2 infection indicating that this approach holds promise as a method to activate anti-SAR-CoV-2 T-cell responses from conserved regions of the virus which are not included in vaccines utilising the Spike protein.

Infarct size and long-term left ventricular remodelling in acute myocardial infarction patients subjected to transcoronary delivery of progenitor cells.

Infarct size (IS) is a fundamental determinant of left-ventricular (LV) remodelling (end-systolic and end-diastolic volume change, ΔESV, ΔEDV) and adverse clinical outcomes after myocardial infarction (MI). Our prior work found that myocardial uptake of transcoronary-delivered progenitor cells is governed by IS. To evaluate the relationship between IS, stem cell uptake, and the magnitude of LV remodelling in patients receiving transcoronary administration of progenitor cells shortly after MI. Thirty-one subjects (age 36-69 years) with primary percutaneous coronary intervention (pPCI)-treated anterior ST-elevation MI (peak CK-MB 584 [181-962] U/l, median [range]) and sustained left ventricle ejection fraction (LVEF) ≤ 45% were studied. On day 10 (median) 4.3 × 106 (median) autologous CD34+ cells (50% labelled with 99mTc-extametazime) were administered via the infarct-related artery (left anterior descending). ΔESV, ΔEDV, and mid circumferential myocardial strain (mCS) were evaluated at 24 months. Infarct mass (cMRI) was 57 [11-112] g. Cell label myocardial uptake (whole-body γ-scans) was proportional to IS (r = 0.62), with a median 2.9% uptake in IS 1st tercile (≤ 45 g), 5.2% in 2nd (46-76 g), and 6.7% in 3rd (> 76 g) (p = 0.0006). Cell uptake in proportion to IS attenuated the IS-ΔESV (p = 0.41) and IS-ΔEDV (p = 0.09) relationship. At 24 months, mCS improved in IS 2nd tercile (p = 0.028) while it showed no significant change in smaller (p = 0.87) or larger infarcts (p = 0.58). This largest human study with labelled CD34+ cell transplantation shortly after MI suggests that cell uptake (proportional to IS) may attenuate the effect of IS on LV adverse remodelling. To boost this effect, further strategies should involve cell types and delivery techniques to maximize myocardial uptake.

Madhya Pradesh sickle cell mission: An initiative for screening, counseling and treatment of sickle cell disorders among tribal communities.

Sickle cell disease (SCD) is a structural hemoglobin disorder that causes anemia in affected individuals. In addition to inhibiting a person’s natural growth, it causes extreme pain crisis, acute chest syndrome, high fever, and periodic swelling in different parts of the body. It is a hereditary disease that can be passed on from an infected parent to a child. In India, it is mainly reported among the tribal population of central and southern India.[1] In addition, 27 of the 45 districts of Madhya Pradesh fall into the sickle cell zone, and the pervasiveness of sickle hemoglobin (HbS) fluctuates between 10% and 33%. Four tribal districts of the state namely Alirajpur, Anuppur, Chhindwara, and Dindori constitute around 75% of the existing cases of sickle cell anaemia according to the annual report 2020–2021.[2] In these districts, children and pregnant women have died due to inadequate access to facilities and improper diagnosis or miscarriage. Vector borne diseases especially malaria is highly prevalent in the tribal population due to them residing in the forest areas. Malarial parasites affect only the red blood cells (RBC). To prevent malaria, RBCs have to undergo a change in shape from round to sickle shape but due to the change in the shape of RBC, the RBCs before reaching the age of 90–120 days undergo senescence. The primary treatment, hydroxyurea, has several side effects, including an increased risk of infection and tumor development. In addition, this drug is ineffective in one-third of the patients. As a result, new medicines for the successful treatment of sickle cell anemia (SCA) with low-adverse effects must be developed. Thus, new genome editing technologies like clustered regularly interspaced short palindromic repeats_(CRISPR)-Cas9 complex may be utilized to make precise alterations to SCA patients’ genomes and create a corrected gene version. Gene-corrected autologous CD34+ hematopoietic stem/progenitor cells obtained from a cohort of Indian SCA patients will also be generated and characterized, In non obese diabetic (NOD) scid gamma (NSG) mice, the functional efficiency of gene-corrected human stem cells (HSCs) will be verified.[3] The recipients will also receive customized Hemoglobinopathy genetic counseling cards developed by a doctor couple of Bhopal district. The Hemoglobinopathy Genetic Counseling Card, also known as GIPCI (Genetic Inheritance Prediction Counseling Identification), is a specially designed card for the prevention of sickle cell anemia and thalassemia that accurately predicts the monogenic disorder that will occur in the new born of a husband and wife.[4] The mission is divided into three parts: Screening, sickle patient treatment, and system strengthening. Pregnant women (door-to-door), school-aged children, and first-degree relatives of positive individuals will be actively screened. The project management team will conduct door-to-door screenings of pregnant women, school-aged children, and family members of positive cases. If a pregnant woman tests positive for an illness or characteristic, her husband is also tested. This screening is a time-consuming process that requires three team members (one auxiliary nursing midwifery (ANM), one lab technician, and one resource person). The resource person organizes daily screenings and arranges for resources (screening consumables, data collection, vehicle arrangements, etc.). Pre-screening counseling, sample collection, and antenatal care (ANC) check-ups will be handled by ANMs, and all tests will be performed by lab technicians. Two to three milliliters of blood will be transferred to the district hospital for this test. High Performance Liquid Chromatography (HPLC) test will be done on the staples in the district hospital.[5] If appropriate screening and diagnostic facilities are provided, patients will be diagnosed and, with appropriate facilities for counseling, treatment, and management, these affected patients can lead normal lives to contribute to their personal and agricultural growth and development. The genetic counseling card will play a pivotal role in early detection and timely intervention. If the couples match before marriage, the card immediately shows how likely it is that their children will develop the disease. In addition, a sickle cell couple can recognize the possibility of the disease in the next child as well. It will play an important role in family planning as well as awareness creation among tribes. Various key stakeholders at state level can also engage in dialogues based on primary results of intervention and suggest changes or modifications to expedite the mission. This step taken by the Honorable Prime Minister and the Madhya Pradesh Government will be of cardinal concern as tribal health in Madhya Pradesh has seen a setback due to SCDs in the tribes that are yet untouched and intervention programmes such as this mission will acquire a detailed picture of the disease and role of various interventions in disease prevention. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Abstract IAP0301: Bispecific T cell engagers (TCEs) for treatment of solid tumors: Challenges and opportunities

Abstract T cell-engaging bispecific antibody constructs (TCEs) have the potential to engage all cytotoxic T cells for redirected cancer cell lysis, including CD8, CD4, gamma/delta, NKT and regulatory T cells. TCEs transiently connect T cells with target cells leading to formation of a cytolytic synapse. Once activated by TCEs, T cells can adopt a serial lysis mode and increase troop size by their local proliferation. In numerous animal models, TCEs can eradicate large tumors as single-agent therapy. TCEs show a remarkable single-agent activity in hematological diseases, including ALL, NHL (DLBCL and FL) and AML. A CD19/CD3-bispecific TCE called blinatumomab (Blincyto) has been approved in 2014, and six other TCEs targeting CD20, BCMA and CD123 are in late-stage development. With complete response rates >50% and durability of responses, TCEs are in par with autologous CD19 CAR-T cells in NHL but are easier to manufacture and allow for a faster treatment start. Treatment of solid tumor indications with TCEs is not as successful as treatment of blood-borne cancers. This may be due to issues with tumor penetration, the hostile tumor microenvironment and the scarcity of T cells in cold tumors. A variety of TCEs explore their single-agent activity against solid tumors by targeting surface antigen like PSMA, GPC3, GD2, or HER-2. Enhancements in the form of combination therapy with checkpoint inhibitors, or 4-1BB and CD28 agonists are being explored as ways of augmenting solid tumor activity of TCEs. The first TCE showing robust anti-tumor activity in a solid tumor indication is targeting a gp100 peptide/MHC (developed by Immunocore). It is made from a soluble TCR fragment of very high affinity for the gp100 peptide HLA*0201 complex fused to an anti-CD3 scFv fragment. Although only few partial responses were observed in uveal melanoma patients, the single-agent treatment showed a very robust improvement in overall survival with a hazard ratio of 0.51 compared to investigators’ choice. This data will inspire the development of more TCEs that are specific for peptide/MHC complexes. This class of targets can also be addresses by TCR-mimetic antibodies. TCEs using such antibodies showed high anti-tumor activity in mouse models against MAGE-A4, p53 mutant or tyrosinase peptide/MHC complexes, all targets that are otherwise not amenable to classical TCEs. Another emerging opportunity for treating cancers are conditional TCEs. These are infused as inactive precursors. Inside tumors, the locally produced proteases convert the precursors into highly active TCEs. One example is the so called ProTriTACs, where a half-life extending albumin-binding domain masks the CD3-binding domain. The mask confers a 500-fold reduction in the cytolytic activity of the TCE. Inside tumors, the mask is cleaved off and a TCE is activated that has a very short serum half-life once it is released from the tumor. Conditional TCEs promise not only a wider therapeutic index but can also leverage as targets tumor-associated antigens that are widely expressed on tumors but also on healthy normal tissues, such as EGFR or EpCAM/TROP1. On-target toxicity of TCEs relates to the quality of target antigens. Finding more tumor-specific surface antigens, appropriate pMHC targets (e.g., mutant oncogene epitopes) and conditional T cell engagers are ways to address this challenge. Off-target toxicity of TCEs relates to T cell activation because of redirected target cell lysis. In the worst case, a cytokine release syndrome is induced. In the best case, a low-level cytokine release is contributing to the efficacy of TCEs. CRS can be managed by steroids, step dosing, anti-IL6 antibody and/or dasatinib. Another promising means is subcutaneous administration of TCEs. A dozen TCE programs currently explore this route, which allows reduction of Cmax and of the initial cytokine release. TCEs will soon become a major weapon in the arsenal of cancer therapy. They will not only work in blood-borne cancers but will soon conquer select solid tumor indications. Peptide/MHC-targeting and conditional TCEs are very promising approaches to achieve solid tumor activity of TCEs. Citation Format: Patrick A. Baeuerle. Bispecific T cell engagers (TCEs) for treatment of solid tumors: Challenges and opportunities [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr IAP0301.

Cell erythroid maturation approach: a new paradigm in the road map towards a cure for β-thalassaemia syndromes.

Cell erythroid maturation approach: a new paradigm in the road map towards a cure for β-thalassaemia syndromes.

Efficacy and Safety of Innovative Experimental Chimeric Antigen Receptor (CAR) T-cells versus Axicabtagene ciloleucel (Yescarta) for the Treatment of Relapsed/Refractory Large B-Cell Lymphoma (LBCL): Matching Adjusted Indirect Comparisons (MAICs) and Systematic Review.

Despite favorable results of CAR T-cell therapy for relapsed/refractory large B-cell lymphoma (R/R LBCL), several challenges remain, including incomplete response, immune-mediated toxicity, and antigen-loss relapse. We delineated the relative clinical benefit of the novel approaches compared to the currently approved CAR T-cell therapies. In the absence of head-to-head comparisons and randomized controlled trials, we performed Matching Adjusted Indirect Comparisons to quantify the relative efficacy and safety of experimental CARs against Axicabtagene ciloleucel (Yescarta), the first FDA-approved CAR. A total of 182R/R LBCL patients from 15 clinical trials with individual patient data (IPD) were pooled into eight populations by their CAR T-cell constructs and +/- ASCT status. The study endpoints were Progression-Free Survival (PFS), grade ≥ 3 cytokine release syndrome (CRS), and grade ≥ 3 neurotoxicity (NT). Tandem CD19.CD20.4-1BBζ CARs indicated favorable efficacy and safety, whereas the co-infusion of CD19 & CD20 with 4-1BBζ showed no clinical benefit compared to Yescarta. Third generation CD19. CD28. 4-1BBζ, and sequential administration of autologous stem cell transplantation (ASCT) and CD19. CARs presented statistically insignificant yet improved PFS and safety except for ASCT combined intervention which had suggestively higher NT risk than Yescarta. CARs with modified co-stimulatory domains to reduce toxicity (Hu19. CD8.28Zζ and CD19. BBz.86ζ) presented remarkable safety with no severe adverse events; however, both presented worse PFS than Yescarta. Third-generation CARs demonstrated statistically significantly lower NT than Yescarta. CD20. 4-1BBζ data suggested targeting CD20 antigen alone lacks clinical or safety benefit compared to Yescarta. Further comparisons with other FDA-approved CARs are needed.

Preliminary Safety and Efficacy Results from Precizn-1: An Ongoing Phase 1/2 Study on Zinc Finger Nuclease-Modified Autologous CD34+ HSPCs for Sickle Cell Disease (SCD)

▪IntroductionSickle cell disease (SCD) is caused by pathologic variants in both alleles of the β-globin gene, affecting ~100,000 patients in the US (Strouse. Handb Clin Neurol 2016;138:311-24). Elevated fetal hemoglobin (HbF) levels ameliorate symptoms and improve survival in patients with SCD (Hebert. Am J Hematol 2020;95:1235-45). SAR445136 (BIVV003) is a novel therapeutic product comprising autologous CD34+ HSPCs modified ex vivo by zinc finger nucleases (ZFN) and targeting the BCL11A gene erythroid-specific enhancer (ESE) to increase endogenous HbF production.MethodsPRECIZN-1 (NCT03653247) is an ongoing first-in-human, open label, single arm, multi-site study evaluating safety and tolerability of SAR445136 (n=8; aged 18-40 years), with severe SCD across 6 US sites. Eligible subjects underwent mobilization and apheresis with plerixafor 240 ug/kg/day for up to 3 days to collect autologous CD34+ HSPCs to achieve a minimum of 10 × 10 6 CD34+ HSPC/kg for manufacturing of the SAR445136 dose. Additional apheresis cycles were allowed to achieve the minimum cell dose and rescue aliquots. Autologous HSPCs were transfected ex vivo with ZFN mRNAs targeting the ESE region of the BCL11A locus to manufacture SAR445136. A single IV infusion of 3-20 × 10 6 CD34+ HSPC/kg was administered at least 72 hours after the final busulfan myeloablation dose. Subjects were monitored for stem cell engraftment and hematopoietic recovery, adverse events (AEs), clinical and laboratory hemolysis markers, total Hb and HbF, percentage of F cells and sickle-cell related events post-SAR445136 infusion. Health-related quality of life (HRQoL) was assessed via the PROMIS-57 survey at screening, Weeks 26 and 52, and early termination visit.ResultsOf the 7 subjects that underwent mobilization and apheresis to date (25 June 2021), 5 achieved successful target yields ranging from 3.4-13.8 x 10 6 CD34+ HSPC/kg per apheresis day (mean: 6.49 x10 6 CD34+ HSPC/kg per apheresis day) in one apheresis cycle (4.45-10.9 x 10 6 CD34+ HSPC/kg per 2-day cycle). One subject failed to mobilize; one discontinued due to intercurrent cholangitis. Baseline patient characteristics of the 4 patients infused are in Table 1.Pre-apheresis peripheral blood WBC ranged from 23.2-36.9 x 10 3/μL (mean: 28.7 x 10 3/μL) and % CD34+ was 0.09-0.36% (0.22%) with absolute CD34+ counts of 20-80/μL (mean: 60/μL). Four of the mobilized subjects were successfully infused with SAR445136 at a single dose ranging from 3.2-9.7 x 10 6 CD34+ HSPC/kg (mean: 5.17 x 10 6 CD34+ HSPC/kg). All 4 subjects engrafted with a median time to neutrophil and platelet recovery of 21.5 and 24.5 days, respectively. No rescue doses were required.All 4 patients improved clinically since SAR445136 infusion, with no recurrence of previous vaso-occlusive crises (VOCs). Total Hb stabilized at 9-10 g/dL by week 26 post SAR445136 infusion along with improvements in the clinical markers of hemolysis in all 4 subjects. Percent HbF levels were 1-11% at screening, increasing to 15-29% by Week 13 in all 4 subjects, to 14-39% by Week 26 in the 3 subjects with at least 26 weeks follow up; and persisting at 35% in 1 subject with 65 weeks follow up (Figure 1). Percent F cells increased to 49-94% in 3 subjects with at least 26 weeks follow up, persisting at 90% in 1 subject with 65 weeks follow up. The fourth subject had 87.5% F cells at 13 weeks follow up.Although preliminary, a trend of improvement exceeding the proposed minimally clinically important difference in all PROMIS-57 HRQoL domains except sleep disturbance was observed in the 3 subjects with 26 weeks follow up, whose scores were “worse” than the norm at baseline (≤2 points per domain).SAR445136 was generally well tolerated with no infusion related reactions. The AEs reported were consistent with plerixafor mobilization and busulfan myeloablation therapy. No AEs or SAEs were reported as related to SAR445136.ConclusionsAs of 25 June 2021, these preliminary proof-of-concept efficacy and safety results confirm the potential therapeutic value of ZFN-mediated modification of the BCL11A ESE region and SAR445136 infusion to address current unmet needs of patients with SCD. All 4 infused patients had no SCD related events including VOCs following SAR445136 infusion, as well as increases in total Hb, HbF, and %F cells, and clinical improvements in PROMIS-57 domains. SAR445136 is generally well tolerated in the 4 subjects infused to date, with no related AEs or SAEs reported. [Display omitted] DisclosuresAbedi: BMS/Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Seattle Genetics: Speakers Bureau; Abbvie: Speakers Bureau. Galeon: Sanofi: Current Employment. Reiner: Sanofi: Current Employment. Smith: Sanofi: Current Employment. Wang: Sanofi: Current Employment. Ramezi: Sanofi: Current Employment. Rendo: Sanofi: Current Employment, Other: May hold shares and/or stock options . Walters: AllCells, Inc: Consultancy; Vertex pharmaceuticals: Consultancy; Ensoma, Inc.: Consultancy; BioLabs, Inc: Consultancy.

Utilization of External Control Arm to Contextualize Clinical Efficacy of Tisagenlecleucel Treated Among Patients with Relapsed/Refractory Follicular Lymphoma from the Single-Arm Elara Trial

Utilization of External Control Arm to Contextualize Clinical Efficacy of Tisagenlecleucel Treated Among Patients with Relapsed/Refractory Follicular Lymphoma from the Single-Arm Elara Trial

TEM-GBM: An Open-Label, Phase I/IIa Dose-Escalation Study Evaluating the Safety and Efficacy of Genetically Modified Tie-2 Expressing Monocytes to Deliver IFN-α within Glioblastoma Tumor Microenvironment

Background: We developed a macrophage-based treatment relying on ex vivo transduction of autologous hematopoietic stem and progenitor cells (HSPC) to express immune-payloads within the TME. Our ATMP (Temferon) targets IFN-a, an immune-modulatory molecule counteracting also neo-angiogenesis and tumor growth, to a subset of Tie2-expressing, tumor-infiltrating macrophages known as TEMs.Materials and Methods: TEM-GBM is an open-label, Phase I/IIa dose-escalation study evaluating safety and efficacy of Temferon in up to 21 newly diagnosed glioblastoma patients with unmethylated MGMT promoter. Key eligibility criteria include age 18-70 years, ECOG 0-1 and KPS >70%, and adequate cardiac, renal, hepatic and pulmonary function. Important exclusion criteria include the presence of active autoimmune disease or receipt of any oral or parenteral chemotherapy or immunotherapy within 2 years of screening. Autologous CD34+ HSPC are mobilized with lenograstim and plerixafor, collected by apheresis, purified and transduced ex vivo with a 3 rd generation lentiviral vector encoding for IFN-a2. Transgene expression is confined to TEMs by the Tie2 promoter and post-transcriptional regulation by microRNA-126 thus achieving tumor specificity. The study evaluates safety and biological activity of Temferon in 7 cohorts of three patients each, where escalating doses of Temferon are co-administered with a fixed CD34+ cell dose of non-manipulated supporter cells following a sub-myeloablative conditioning regimen (Thiotepa + BCNU or + Busulfan).The primary endpoints for this study are: •Engraftment of Temferon over the first 90 Days•The proportion of patients achieving hematologic recovery by Day +30 from ASCT•Short-term tolerability of Temferon; stable blood counts and absence of cytopenias, absence of significant organ toxicities (> grade 2); absence of Replication Competent LentivirusThe figure below reports the TEM-GBM study design.Results: As of 28th June 2021, 18 patients have been enrolled; 15 received Temferon (D+0) with follow-up of 30 - 697 days. There was rapid engraftment and hematological recovery after the conditioning regimen. Median neutrophil and platelet engraftment occurred at D+13 and D+12 for patients in cohort 1-3 and D+16 and D+15 for patients assigned to cohort 4 and 5, respectively. Temferon-derived differentiated cells, as determined by the presence of vector genomes in the DNA of peripheral blood and bone marrow cells, were found within 14 days post treatment and persisted subsequently, albeit at lower levels (up to 18 months). Very low concentrations of IFNa were detected in the plasma (average 7.8 pg/ml at D+30; baseline < LLOQ) and in the cerebrospinal fluid (average 1.6 pg/ml at D+30; baseline < LLOQ), suggesting tight regulation of transgene expression. Seven deaths occurred: six at D+241, +322, +340, +402, +478, +646 after Temferon administration due to disease progression, and one at D+60 due to complications following the conditioning regimen. Nine patients had progressive disease (PD; range D-12 to +239). SAEs include infections, venous thromboembolism, brain abscess, hemiparesis, GGT elevation and poor performance status compatible with autologous stem cell transplantation, concomitant medications and PD. Four patients underwent second surgery. These recurrent tumors had gene-marked cells present and increased expression of IFN-responsive gene signatures compared to diagnosis, indicative of local IFNa release by TEMs. In one patient, a stable lesion (as defined by MRI) had a higher proportion of T cells and TEMs within the myeloid infiltrate and an increased IFN-response signature than in a progressing lesion. The T-cell immune repertoire changed with evidence for expansion of tumor-associated clones. Tumor microenvironment characterization by scRNA and TCR sequencing is ongoing.Conclusion: These interim results show that Temferon is generally well tolerated by patients, with no dose limiting toxicities identified to date. The results provide initial evidence of Temferon's potential to activate the immune system and reprogram the tumor microenvironment (TME), as predicted by preclinical studies. [Display omitted] DisclosuresNaldini: Genenta Science: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees, Other: Founder.

Safety and Efficacy of Aru-1801 in Patients with Sickle Cell Disease: Early Results from the Phase 1/2 Momentum Study of a Modified Gamma Globin Gene Therapy and Reduced Intensity Conditioning

▪Introduction: Sickle cell disease (SCD) is a genetic red blood cell (RBC) disorder that causes chronic hemolytic anemia, progressive organ damage, and life-threatening acute complications such as painful vaso-occlusive crises. Allogeneic hematopoietic stem cell transplant (allo-HSCT) with myeloablative conditioning remains the only curative therapy for SCD but has several limitations including low donor availability and conditioning-related toxicity. Genetic modification of autologous hematopoietic system cells (HSCs) with reduced-intensity conditioning (RIC) using a high-potency drug product may address these limitations.ARU-1801 is a gene therapy that uses a modified γ-globin lentiviral vector to produce HbF G16D within autologous CD34+ HSCs. Preclinical studies in SCD mice have shown the G16D mutation enables γ-globin G16D to bind α-globin with higher affinity; lentiviral transfer of γ-globin G16D resulted in 1.5-2x more HbF per vector copy number (VCN) compared to analogous wild-type γ-globin vector. Early studies also suggested HbF G16D may be more potent for anti-sickling than HbF, lowering reticulocyte counts in SCD mice to a greater extent at similar protein levels. We hypothesize ARU-1801 with RIC could lessen toxicities and resource utilization relative to myeloablative approaches, allowing expanded access to gene therapy for a broader group of SCD patients. Updated data from patients in the ongoing Phase 1/2 study (NCT02186418) including laboratory and clinical markers of efficacy are presented here.Methods: Adults (18-45 years old) with severe SCD (defined by recurrent vaso-occlusive events [VOE] and acute chest syndrome) were screened for eligibility. Prior to ARU-1801 drug product (DP) infusion, all patients received a single IV dose of RIC melphalan (140 mg/m 2). Endpoints included measures of safety, engraftment, VCN, hemoglobin sub-fractions, and SCD-related outcomes. Patients were weaned off transfusions 3-6 months after DP infusion. Levels of anti-sickling globins (including HbF G16D) are presented as proportions of non-transfused total hemoglobin.Results: As of 28 July 2021, four patients (mean, 26 [19-35] years old) have been treated with ARU-1801 gene therapy for SCD with three patients followed for ≥12 months post-transplant. Transient neutropenia and thrombocytopenia were the predominant adverse events, lasting a median seven days each. There have been no other serious adverse events related to chemotherapy or ARU-1801 to date.At 36 months post-transplant, Patient 1 has shown stable HbF expression (27%) and 64% F-cells. Patient 2 has maintained 14% HbF and 37% F-cells at 36 months despite lower engraftment of ARU-1801 due to renal hyperfiltration (eGFR = 200 mL/min/1.73 m 2) at time of conditioning, which resulted in lower melphalan exposure. Both patients saw marked improvements in SCD manifestations, including 93% and 85% fewer annualized VOEs, respectively, in the two years after receiving ARU-1801 gene therapy compared to two years prior.Patient 3 received ARU-1801 manufactured with several process modifications (including improvements of HSC collection timing and lentiviral production) and has maintained 36% HbF at month 15 with pancellular distribution (96% F-cells). To date, Patient 3 has had no VOEs since ARU-1801 administration, representing 100% reduction from baseline.Conclusion: Amelioration of SCD phenotype and engraftment of ARU-1801 gene-modified HSCs is possible with a single RIC dose of melphalan, as demonstrated in three patients. The first patient shows 27% HbF expression at three years, and 93% reduction in VOEs. The second patient had lower HSC engraftment due to below-target melphalan exposure (likely caused by renal hyperfiltration), with 14% HbF and 5% HbA2 at three years. Nonetheless, an 85% reduction in VOEs in Patient 2 demonstrates significant clinical benefit. Dose-adjusted melphalan has the potential to improve engraftment in SCD patients with renal hyperfiltration. Following manufacturing process improvements, the third patient has shown the highest HbF (36%) at one year, the highest F-cells (96%), and no VOEs since receiving ARU-1801. ARU-1801, with RIC melphalan conditioning, is a promising alternative to myeloablative transplants for achieving durable responses with a favorable safety profile in patients with severe SCD. Longer follow-up and additional patients will be presented. [Display omitted] DisclosuresAsnani: Avicanna Ltd.: Research Funding; Aruvant Sciences: Research Funding. Lutzko: Aruvant Sciences: Patents & Royalties: preclinical vector development. Quinn: Forma Therapeutics: Consultancy; Emmaus Medical: Research Funding; Novo Nordisk: Consultancy; Aruvant: Research Funding. Lo: Aruvant Sciences: Current Employment. Little: Aruvant Sciences: Current Employment. Dong: Aruvant Sciences: Current Employment. Malik: Aruvant Sciences: Consultancy; Forma Therapeutics: Consultancy; Aruvant Sciences: Patents & Royalties; CSL Behring: Patents & Royalties. OffLabel Disclosure:Plerixafor was used for stem cell mobilization. Melphalan was used as chemotherapy conditioning prior to autologous transplant with ARU-1801

Restoring Iron Homeostasis in Pts Who Achieved Transfusion Independence after Treatment with Betibeglogene Autotemcel Gene Therapy: Results from up to 7 Years of Follow-up

Restoring Iron Homeostasis in Pts Who Achieved Transfusion Independence after Treatment with Betibeglogene Autotemcel Gene Therapy: Results from up to 7 Years of Follow-up

CHOP but Not Bendamustine Reverses EZH2 Y641 Mutation Induced MHC-I/II Loss in Human Lymphoma Models

Chemotherapy combined with anti-CD20 antibodies is the standard treatment for patients with symptomatic advanced stage follicular lymphoma (FL). We have previously shown that EZH2 gene mutations were predictive of differential efficacy of the chemotherapy backbone within the GALLIUM trial (NCT01332968; Jurinovic, ASH 2019). Specifically, patients with EZH2 mutant FL had significantly longer progression free survival with CHOP-based immunochemotherapies as compared to patients with EZH2 wild type FL. In contrast, the EZH2 mutation status was not predictive of treatment outcome in patients receiving bendamustine-based regimens. The underlying biology is unclear.Mutations in EZH2, a histone methyltransferase, occur in 25-30% of FL and mostly affect the Y641 residue within the catalytic domain, resulting in more efficient conversion of H3K27me2 to H3K27me3. First, we tested differences in chemosensitivity in lymphoma cell lines that harbor the FL-hallmark translocation t(14;18)[BCL2/IGH] and intrinsic EZH2 mutations (Karpas422, OCI-Ly1, SU-DHL4, DB) or no EZH2 mutation (SU-DHL16, WSU-FSCCL, OCI-Ly8, OCI-Ly19). Treatment with CHOP (4-hydroperoxycyclophosphamide (4-HC), doxorubicin, vincristine, and prednisone), alone or in combination, or bendamustine revealed marked differences in IC50 for cell viability (CellTiter Glo) and apoptosis (Annexin V) between cell lines, but no correlation with EZH2 mutation status. To better control for cell line specific effects, we stably expressed EZH2 Y641N or wild type (WT) in the EZH2 WT cell line SU-DHL16. EZH2 mutant cells indeed showed significantly increased H3K27me3 levels compared to EZH2 WT cells. However, we did not observe differences in global cellular phenotypes, including cell proliferation and cell cycle phases. Furthermore, IC50 for cell viability and apoptosis with CHOP and bendamustine treatment were not significantly different.As we could not identify differences in direct cytotoxic responses, we hypothesized that EZH2 mutations might indirectly affect treatment efficacy, by altering the interaction of FL cells with their tumor microenvironment (TME) in response to chemotherapy. In a mouse model, Ennishi et al. had previously shown that Ezh2 mutant lymphomas have reduced MHC expression and T-cell infiltrates (Cancer Discovery, 2019). Here, we could show that expression of mutant EZH2 in human SU-DHL16 cells also leads to almost complete MHC-I loss by flow cytometry (Fig A). MHC-I loss was fully reversible when cells were treated with increasing doses of tazemetostat, a specific EZH2 inhibitor, or interferon-gamma. Interestingly, treatment with 4-HC, prednisone, doxorubicin and CHOP also resulted in increasing restoration of MHC-I expression in EZH2 mutant cells, while bendamustine (and vincristine alone) had no impact on MHC expression (Fig B,C).Next, we used a fully human B-cell co-culture model (modified from Caeser et al., Nat Comm 2019) for validation and functional studies. Mirroring the TME-dependence of FL, germinal-center (GC) B-cells from human tonsils immortalized by transduction with BCL2 and MYC absolutely require follicular dendritic cell (FDC) support plus IL21 and CD40L for sustained growth. Stable expression of EZH2 Y641N in these GC-B-cells led to increased H3K27me3 levels as compared to EZH2 WT and empty vector (ev) controls, but did not result in FDC+IL21/CD40L independent growth. Again, we observed significantly lower MHC-I/II expression on EZH2 mutant cells (Fig D). Importantly, we show that EZH2 mutation-induced MHC loss resulted in reduced CytoStim-stimulated conjugate formation when cells were co-cultured with autologous CD4 T-cells isolated from the same tonsils (Fig E). Finally, treatment with doxorubicin but not bendamustine resulted in significant upregulation of MHC-I/II on EZH2 mutant GC-B cells (Fig F). Co-culture experiments with autologous CD4 and CD8 T-cells with and without doxorubicin, CHOP and bendamustine treatment are ongoing to analyze the EZH2 mutation-specific chemotherapy effects on T-cell activation, recruitment, and T-cell mediated killing.In conclusion, our data indicates that the particular chemosensitivity of EZH2 mutant FL to CHOP is not the result of differences in direct cytotoxicity, but -unlike bendamustine- is rather mediated by restoring EZH2 mutation-induced MHC-I/II loss, thereby potentially promoting cytotoxic T-cell responses. [Display omitted] DisclosuresHodson: Astra Zeneca: Research Funding. von Bergwelt: Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding, Speakers Bureau; Astellas: Honoraria, Research Funding, Speakers Bureau; Roche: Honoraria, Research Funding, Speakers Bureau; Miltenyi: Honoraria, Research Funding, Speakers Bureau; Mologen: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau; MSD Sharpe & Dohme: Honoraria, Research Funding, Speakers Bureau. Subklewe: MorphoSys: Research Funding; Novartis: Consultancy, Research Funding, Speakers Bureau; Seattle Genetics: Consultancy, Research Funding; Roche: Research Funding; Janssen: Consultancy; Klinikum der Universität München: Current Employment; Takeda: Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Miltenyi: Research Funding; Gilead: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Research Funding, Speakers Bureau; BMS/Celgene: Consultancy, Research Funding, Speakers Bureau. Weigert: Janssen: Speakers Bureau; Roche: Research Funding; Epizyme: Membership on an entity's Board of Directors or advisory committees.

Comparison of Efficacy and Safety Profile of Allogeneic Versus Autologous CD19 Chimeric Antigen Receptor T Cell Therapy in Hematological Malignancies: A Systematic Review and Meta-Analysis

IntroductionChimeric antigen receptor T cell (CAR-T) therapy is an adoptive immunotherapy employing genetically modified T cells. Autologous CD19 CAR-T cell therapy is currently approved for adults with relapsed or refractory non-Hodgkin lymphoma (NHL) and children and young adults (<26yo) with relapsed or refractory acute lymphoblastic leukemia (ALL), dramatically improving outcomes for these diseases. “Off the shelf” allogeneic CAR-T cells derived from the third party healthy donors may overcome several barriers to autologous CAR-T cells, including increased fitness of the construct's T-cells, and reducing therapy delays or failures resulting from manufacturing issues. However, allogeneic CAR-T cells may come with added risks such as graft versus host disease (GvHD) and increased rates of donor rejection. We performed a systematic review and meta-analysis to assess and compare the safety and efficacy of allogeneic versus autologous CAR-T cell therapy.MethodsWeb of Science/MEDLINE/PubMed, Embase, and Cochrane Registry of Controlled Trials were searched following the PRISMA guidelines using MeSH terms and keywords for “Receptors, Chimeric antigen” OR “Artificial-T-cell receptor” OR “immunotherapy, adoptive” OR “CD-19”. Our search produced 3506 articles, and after removing duplicates, 2243 records were screened. We included 98 prospective trials of CD-19 CAR-T enrolling two or more patients from Jan 1, 2013 to Nov 1, 2020. Pooled analysis was done using the ‘meta’ package (R Studio software), and a random-effects model was used to estimate the pooled prevalence with 95% confidence intervals (CI).ResultsWe looked at 98 articles in total including 8 articles for allogenic, 86 for autologous, 4 for donor CAR-T cell. Due to considerable heterogeneity in study populations among these three groups, a comparative analysis was not feasible. (Table 1)Universal “off the shelf” CARTA total of 68 patients from 8 studies were evaluated. Median age was 22.5 (4.8-64) years and 64% were males (n= 9/14). The median follow-up time was 10 (2-18) months. Underlying diagnosis was ALL 72% (n= 49), chronic lymphocytic leukemia (CLL) 9% (n= 6), and NHL 19% (n= 13). The pooled overall response rate (ORR) was 77% (95%CI 0.63-0.89, I 2 =22%, p=0.25, n=68) with complete response (CR) of 75% (95%CI 0.57-0.90, I 2 =48%, p=0.07, n=65). The pooled incidence of cytokine reactivity syndrome (CRS) grade I/II and grade III/IV was 53% (95%CI 0.16-0.89, I 2 =89%, p<0.01, n=65) and 10% (95%CI 0.01-0.25, I 2 =50%, p=0.06, n=65) respectively. Neurotoxicity (NT) grade I/II was 12% (95%CI 0.01-0.30, I 2 =47%, p=0.09, n=47) and GvHD grade I/II was 8% (95%CI 0.01-0.19, I 2 =0%, p=0.57 n=53).Donor CAR-TA total of 43 patients from 4 studies were evaluated. The median age was 44.5 (3-68) years and 57% were males (n=16/28). Underlying diagnosis was ALL 56% (n=24), NHL 24% (n=10), and CLL 21% (n= 9), The pooled ORR was 47% (95%CI 0.30-0.64, I 2 =0%, p=0.58 n=36), CR was 40% (95%CI 0.26-0.55, I 2 =0%, p=0.48 n=49), PR was 6% (95%CI 0.00-0.16, I 2 =0%, p=0.47 n=49). CRS and NT were not observed except in one study, where 28.5% of the patients experienced grade I/II CRS.Autologous CAR-TA total of 2553 patients from 86 studies were evaluated. Median age was 37.5 (9-72) years with the median follow-up time of 8.8 (1.12-57.9) months. The pooled ORR was 80% (95%CI 0.75-0.84, I 2 =79%, p<0.01 n=2000), CR was 68% (95%CI 0.63-0.74, I 2 =85%, p<0.01 n=2441), PR was 15% (95%CI 0.11-0.20, I 2 =70%, p<0.01 n=1337). The pooled incidence of CRS grade I/II and grade III/IV was 47% (95%CI 0.39-0.56, I 2 =91%, p<0.01 n=1965) and 11% (95%CI 0.07-0.14, I 2 =79%, p<0.01 n=2136) respectively. The pooled incidence of NT grade I/II was 11% (95%CI 0.07-0.17, I 2 =83%, p<0.01 n=1347) and NT grade III/IV was 13% (95%CI 0.10-0.18, I 2 =75%, p<0.01 n=1730).ConclusionCAR-T Allogeneic third party “off the shelf” constructs are currently in phase I and dose escalation trials, and early reported data so far shows promising efficacy signals with similar rates of CRS and NT. While there is a risk of GvHD with the allogeneic constructs (universal and donor derived) the GvHD was mostly low grade (grade I-II). Given these promising features, readily available “off the shelf” third party constructs, which are still early in development, therefore offer an attractive potential option to overcome manufacturing and access barriers with present day autologous CAR-T therapy. [Display omitted] DisclosuresHoffmann: TG Therapeutics: Consultancy, Honoraria; Pharmcyclics: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; celgene: Consultancy, Honoraria. McGuirk: Pluristem Therapeutics: Research Funding; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Bellicum Pharmaceuticals: Research Funding; Gamida Cell: Research Funding; EcoR1 Capital: Consultancy; Novartis: Research Funding; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; Allovir: Consultancy, Honoraria, Research Funding; Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau; Novartis: Research Funding; Astelllas Pharma: Research Funding; Fresenius Biotech: Research Funding.