Bispecific Antibodies and Autologous Chimeric Antigen Receptor T cell therapies for Treatment of Hematological Malignancies.

In recent years, the therapeutic landscape for hematological malignancies has markedly advanced, particularly since the inaugural approval of autologous chimeric antigen receptor T cell (CAR-T) therapy in 2017 for relapsed/refractory acute lymphoblastic leukemia (ALL). Autologous CAR-T therapy involves the genetic modification of a patient's T cells to specifically identify and attack cancer cells, while bispecific antibodies (BsAbs) function by binding to both cancer cells and immune cells simultaneously, thereby triggering an immune response against the tumor. The subsequent approval of various CAR-T therapies and BsAbs have revolutionized the treatment of multiple hematological malignancies, highlighting high response rates and a subset of patients achieving prolonged disease control. This review explores the mechanisms underlying autologous CAR-T therapies and BsAbs, focusing on their clinical application in multiple myeloma, ALL, and non-Hodgkin lymphoma. We provide comprehensive insights into their individual efficacy, limitations concerning broad application, and the potential of combination therapies. These upcoming strategies aim to propel the field forward, paving the way for safer and more effective therapeutic interventions in hematological malignancies.

Phase I Trial of GD2.CART Cells Augmented With Constitutive Interleukin-7 Receptor for Treatment of High-Grade Pediatric CNS Tumors.

PURPOSE: T cells modified with chimeric antigen receptors (CARTs) have demonstrated efficacy for hematologic malignancies; however, benefit for patients with CNS tumors has been limited. To enhance T cell activity against GD2+ CNS malignancies, we modified GD2-directed CART cells (GD2.CARTs) with a constitutively active interleukin (IL)-7 receptor (C7R-GD2.CARTs). METHODS: Patients age 1-21 years with H3K27-altered diffuse midline glioma (DMG) or other recurrent GD2-expressing CNS tumors were eligible for this phase I trial (ClinicalTrials.gov identifier: NCT04099797). All subjects received standard-of-care adjuvant radiation therapy or chemotherapy before study enrollment. The first treatment cohort received GD2.CARTs alone (1 × 107 cells/m2), and subsequent cohorts received C7R-GD2.CARTs at two dose levels (1 × 107 cells/m2; 3 × 107 cells/m2). Standard lymphodepletion with cyclophosphamide and fludarabine was included at all dose levels. RESULTS: Eleven patients (age 4-18 years) received therapy without dose-limiting toxicity. The GD2.CART cohort did not experience toxicity, but had disease progression after brief improvement of residual neurologic deficits (≤3 weeks). The C7R-GD2.CART cohort developed grade 1 tumor inflammation-associated neurotoxicity in seven of eight (88%) cases, controllable with anakinra. Cytokine release syndrome was observed in six of eight (75%, grade 1 in all but one patient) and associated with increased circulating IL-6 and IP-10 (P < .05). Patients receiving C7R-GD2.CARTs experienced temporary improvement from baseline neurologic deficits (range, 2 to >12 months), and seven of eight (88%) remained eligible for additional treatment cycles (range 2-4 cycles). Partial responses by iRANO criteria were observed in two of seven (29%) patients with DMG treated by C7R-GD2.CARTs. CONCLUSION: Intravenous GD2.CARTs with and without C7R were well tolerated. Patients treated with C7R-GD2.CARTs exhibited transient improvement of neurologic deficits and increased circulating cytokines/chemokines. Treatment with C7R-GD2.CARTs represents a novel approach warranting further investigation for children with these incurable CNS cancers.

Prolonged cytopenias after immune effector cell therapy and lymphodepletion in patients with leukemia, lymphoma and solid tumors.

BACKGROUND AIMS: The success of chimeric antigen receptor (CAR) T-cell therapy in treating B-cell malignancies has led to the evaluation of CAR T-cells targeting a variety of other malignancies. Although the efficacy of CAR T-cells is enhanced when administered post-lymphodepleting chemotherapy, this can trigger bone marrow suppression and sustained cytopenia after CD19.CAR T-cell therapy. Additionally, systemic inflammation associated with CAR T-cell activity may contribute to myelosuppression. Cytopenias, such as neutropenia and thrombocytopenia, elevate the risk of severe infections and bleeding, respectively. However, data on the incidence of prolonged cytopenias after immune effector therapy in the solid tumor context remain limited. OBJECTIVE: We compared the incidence of prolonged cytopenias after immune effector therapy including genetically modified T-cells, virus-specific T-cells (VSTs) and NKT-cells, as well non-gene-modified VSTs for leukemia, lymphoma, and solid tumors (ST) to identify associated risk factors. METHODS: A retrospective analysis was conducted of 112 pediatric and adult patients with relapsed and/or refractory cancers who received lymphodepleting chemotherapy followed by immune effector therapy. Patients treated with 13 distinct immune effector cell therapies through 11 single-center clinical trials and 2 commercial products over a 6-year period were categorized into 3 types of malignancies: leukemia, lymphoma and ST. We obtained baseline patient characteristics and adverse events data for each participant, and tracked neutrophil and platelet counts following lymphodepletion. RESULTS: Of 112 patients, 104 (92.9%) experienced cytopenias and 88 (79%) experienced severe cytopenias. Patients with leukemia experienced significantly longer durations of severe neutropenia (median duration of 14 days) compared with patients with lymphoma (7 days) or ST (11 days) (P = 0.002). Patients with leukemia also had a higher incidence of severe thrombocytopenia (74.1%), compared with lymphoma (46%, P = 0.03) and ST (14.3%, P < 0.0001). Prolonged cytopenias were significantly associated with disease type (63% of patients with leukemia, 44% of patients with lymphoma, and 22.9% of patients with ST, P = 0.006), prior hematopoietic stem cell transplant (HSCT) (66.7% with prior HSCT versus 38.3% without prior HSCT, P = 0.039), and development of immune effector cell-associated neurotoxicity syndrome (ICANS) (75% with ICANS versus 38% without ICANS, P = 0.027). There was no significant association between prolonged cytopenias and cytokine release syndrome. CONCLUSIONS: Immune effector recipients often experience significant cytopenias due to marrow suppression following lymphodepletion regardless of disease, but prolonged severe cytopenias are significantly less common after treatment of patients with lymphoma and solid tumors.

Eighteen-year survival after GD2-directed Chimeric Antigen Receptor-Modified Immune Effector Cell Treatment for Neuroblastoma.

We report long-term outcomes up to 18 years of a clinical trial treating children with neuroblastoma with EBV-specific T lymphocytes and CD3-activated T cells - each expressing a first-generation chimeric antigen receptor targeting GD2 with barcoded transgenes to allow tracking of each population. Of 11 patients with active disease at infusion, three patients achieved a complete response that was sustained in 2, one for 8 years until lost to follow up and one for 18+ years. Of eight patients with a history of relapse or at high risk of recurrence, five are disease-free at their last follow-up between 10-14 years post-infusion. Intermittent low levels of transgene were detected during the follow up period with significantly greater persistence in those who were long-term survivors. In conclusion, patients with relapsed/refractory neuroblastoma achieved long-term disease control after receiving GD2 CAR-T cell therapy including one patient now in remission of relapsed disease for >18 years.

Autologous HER2-specific CAR T cells after lymphodepletion for advanced sarcoma: a phase 1 trial.

In this prospective, interventional phase 1 study for individuals with advanced sarcoma, we infused autologous HER2-specific chimeric antigen receptor T cells (HER2 CAR T cells) after lymphodepletion with fludarabine (Flu) ± cyclophosphamide (Cy): 1 × 108 T cells per m2 after Flu (cohort A) or Flu/Cy (cohort B) and 1 × 108 CAR+ T cells per m2 after Flu/Cy (cohort C). The primary outcome was assessment of safety of one dose of HER2 CAR T cells after lymphodepletion. Determination of antitumor responses was the secondary outcome. Thirteen individuals were treated in 14 enrollments, and seven received multiple infusions. HER2 CAR T cells expanded after 19 of 21 infusions. Nine of 12 individuals in cohorts A and B developed grade 1-2 cytokine release syndrome. Two individuals in cohort C experienced dose-limiting toxicity with grade 3-4 cytokine release syndrome. Antitumor activity was observed with clinical benefit in 50% of individuals treated. The tumor samples analyzed showed spatial heterogeneity of immune cells and clustering by sarcoma type and by treatment response. Our results affirm HER2 as a CAR T cell target and demonstrate the safety of this therapeutic approach in sarcoma. ClinicalTrials.gov registration: NCT00902044 .

Interleukin-15-armored GPC3-CAR T cells for patients with solid cancers.

Interleukin-15 (IL15) promotes the survival of T lymphocytes and enhances the antitumor properties of CAR T cells in preclinical models of solid neoplasms in which CAR T cells have limited efficacy1-4. Glypican-3 (GPC3) is expressed in a group of solid cancers5-10, and here we report the first evaluation in humans of the effects of IL15 co-expression on GPC3-CAR T cells. Cohort 1 patients (NCT02905188/NCT02932956) received GPC3-CAR T cells, which were safe but produced no objective antitumor responses and reached peak expansion at two weeks. Cohort 2 patients (NCT05103631/NCT04377932) received GPC3-CAR T cells that co-expressed IL15 (15.CAR), which mediated significantly increased cell expansion and induced a disease control rate of 66% and antitumor response rate of 33%. Infusion of 15.CAR T cells was associated with increased incidence of cytokine release syndrome, which was rapidly ameliorated by activation of the inducible caspase 9 safety switch. Compared to non-responders, tumor-infiltrating 15.CAR T cells from responders showed repression of SWI/SNF epigenetic regulators and upregulation of FOS and JUN family members as well as genes related to type I interferon signaling. Collectively, these results demonstrate that IL15 increases the expansion, intratumoral survival, and antitumor activity of GPC3-CAR T cells in patients.

Human platelet lysate enhances in vivo activity of CAR-Vδ2 T cells by reducing cellular senescence and apoptosis.

BACKGROUND AIMS: Vγ9Vδ2 T cells are an attractive cell platform for the off-the-shelf cancer immunotherapy as the result of their lack of alloreactivity and inherent multi-pronged cytotoxicity, which could be further amplified with chimeric antigen receptors (CARs). In this study, we sought to enhance the in vivo longevity of CAR-Vδ2 T cells by modulating ex vivo manufacturing conditions and selecting an optimal CAR costimulatory domain. METHODS: Specifically, we compared the anti-tumor activity of Vδ2 T cells expressing anti-CD19 CARs with costimulatory endodomains derived from CD28, 4-1BB or CD27 and generated in either standard fetal bovine serum (FBS)- or human platelet lysate (HPL)-supplemented medium. RESULTS: We found that HPL supported greater expansion of CAR-Vδ2 T cells with comparable in vitro cytotoxicity and cytokine secretion to FBS-expanded CAR-Vδ2 T cells. HPL-expanded CAR-Vδ2 T cells showed enhanced in vivo anti-tumor activity with longer T-cell persistence compared with FBS counterparts, with 4-1BB costimulated CAR showing the greatest activity. Mechanistically, HPL-expanded CAR Vδ2 T cells exhibited reduced apoptosis and senescence transcriptional pathways compared to FBS-expanded CAR-Vδ2 T cells and increased telomerase activity. CONCLUSIONS: This study supports enhancement of therapeutic potency of CAR-Vδ2 T cells through a manufacturing improvement.

A robust quality infrastructure is key to safe and effective delivery of immune effector cells: how FACT-finding can help.

ABSTRACT: Immune effector cells (IECs) include a broad range of immune cells capable of modulating several disease states, including malignant and nonmalignant conditions. The growth in the use of IECs as both investigational and commercially available products requires medical institutions to develop workflows/processes to safely implement and deliver transformative therapy. Adding to the complexity of this therapy are the variety of targets, diseases, sources, and unique toxicities that a patient experiences following IEC therapy. For over 25 years, the Foundation for the Accreditation of Cellular Therapy (FACT) has established a standard for the use of cellular therapy, initially with hematopoietic cell transplantation (HCT), and more recently, with the development of standards to encompass IEC products such as chimeric antigen receptor (CAR)-T cells. To date, IEC therapy has challenged the bandwidth and infrastructure of the institutions offering this therapy. To address these challenges, FACT has established a programmatic framework to improve the delivery of IEC therapy. In this study, we outline the current state of IEC program development, accreditation, and solutions to the challenges that programs face as they expand their application to novel IEC therapy.

Blinatumomab Therapy Is Associated with Favorable Outcomes after Allogeneic Hematopoietic Cell Transplantation in Pediatric Patients with B Cell Acute Lymphoblastic Leukemia.

Blinatumomab, a bispecific T cell engager that binds CD19 in leukemic cells and CD3 in cytotoxic T cells and leads to leukemic blast lysis, is often used in pediatric patients with relapsed/refractory (R/R) B cell acute lymphoblastic leukemia (B-ALL) prior to allogeneic hematopoietic cell transplantation (allo-HCT). Concerns about the potential risk of blinatumomab-related immune-mediated toxicities after allo-HCT have not been adequately addressed. These include graft-versus-host disease (GVHD), delayed engraftment, and graft failure or rejection. Pediatric-specific data reporting post-HCT outcomes of patients treated with blinatumomab are scarce and limited to small cohorts. We sought to investigate the clinical outcomes of pediatric patients with R/R B-ALL who received blinatumomab therapy pre-HCT, focusing on overall survival (OS), leukemia-free survival (LFS), cumulative incidence of relapse (CIR), and nonrelapse mortality (NRM), as well as the incidence of immune-mediated post-HCT complications including GVHD, delayed neutrophil or platelet engraftment, graft failure, and graft rejection. We also investigated blinatumomab's effects on B cell reconstitution based on achievement of i.v. immunoglobulin (IVIG) independence post-HCT. This single-center, retrospective study included patients with B-ALL receiving blinatumomab therapy before undergoing allo-HCT, with transplantation performed between 2016 and 2021 at our institution. Patients receiving blinatumomab for relapse after allo-HCT were excluded. Patients receiving chemotherapy alone before allo-HCT during the same period composed the control group. Seventy-two patients were included, 31 of whom received blinatumomab before allo-HCT. Survival estimates were obtained using the Kaplan-Meier method, and the log-rank test was used to analyze differences between groups. Categorical variables were compared between groups using the chi-square test or Fisher exact test, and continuous variables were compared using the Wilcoxon rank-sum test. Cumulative incidences were estimated using the competing risks method, and Gray's test was used to analyze differences between groups. A Cox proportional hazards regression model was used for univariate and multivariable analyses for OS. Landmark analysis was performed at the set time points of 30 days and 100 days post-allo-HCT. Most patients in the study cohort had high-risk relapsed B-ALL. Blinatumomab therapy induced minimal residual disease (MRD)-negative remissions in all patients, whereas 5 patients (12.2%) receiving chemotherapy alone had persistent MRD pre-allo-HCT. Time from the start of therapy to the date of allo-HCT was shorter for patients who received blinatumomab compared with those who received chemotherapy (P < .0001). Blinatumomab therapy was associated with greater LFS compared to chemotherapy alone (P = .049), but when limited to 1 year, LFS was not significantly different from control (P = .066). There appeared to be higher OS, lower CIR, and lower NRM in patients receiving blinatumomab compared to the control group; however, the differences were not significant. None of the variables assessed in multivariable analysis was associated with differences in OS. When compared to the controls, blinatumomab therapy did not result in a higher incidence of acute or chronic GVHD, delayed neutrophil or platelet engraftment, or graft failure or rejection. The time to IVIG infusion independence post-allo-HCT was similar in the 2 groups. This study supports the use of blinatumomab salvage therapy for R/R B-ALL before allo-HCT given its efficacy in inducing MRD-negative remissions and optimizing LFS, as well as its lack of association with an increased incidence of post-allo-HCT adverse immune-mediated toxicities. Larger, prospective studies are needed to confirm these findings and to investigate blinatumomab's effects in long-term post-allo-HCT events.

Incipient clonal hematopoiesis is accelerated following CD30.CAR-T therapy.

Chimeric antigen receptor (CAR) T-cells are an emerging therapy for refractory lymphomas. Clonal hematopoiesis (CH), the preferential outgrowth of mutated bone marrow progenitors, is enriched in lymphoma patients receiving CAR-T cells. CAR-T therapy requires conditioning chemotherapy and often induces systemic inflammatory reactions, both of which have been shown to promote expansion of CH clones. Thus, we hypothesized that pre-existing CH clones could expand during CAR-T cell treatment. We measured CH at 154 timepoints longitudinally sampled from 26 patients receiving CD30.CAR-T therapy for CD30+ lymphomas on an investigational protocol (NCT02917083). Pre-treatment CH was present in 54% of individuals and did not correlate with survival outcomes or inflammatory toxicities. Longitudinal tracking of single clones in individual patients revealed distinct clone growth dynamics. Initially small clones, defined as VAF <1%, expanded following CAR-T administration, compared with relatively muted expansions of larger clones (3.37-fold vs. 1.20-fold, P = 0.0014). Matched clones were present at low magnitude in the infused CD30.CAR-T product for all CH cases but did not affect the product's immunophenotype or transduction efficiency. As cellular immunotherapies expand to become frontline treatments for hematological malignancies, our data indicates CAR-T recipients could be enriched for CH, and further longitudinal studies centered on CH complications in this population are warranted.

Antitumor efficacy and safety of unedited autologous CD5.CAR T cells in relapsed/refractory mature T-cell lymphomas.

ABSTRACT: Despite newer targeted therapies, patients with primary refractory or relapsed (r/r) T-cell lymphoma have a poor prognosis. The development of chimeric antigen receptor (CAR) T-cell platforms to treat T-cell malignancies often requires additional gene modifications to overcome fratricide because of shared T-cell antigens on normal and malignant T cells. We developed a CD5-directed CAR that produces minimal fratricide by downmodulating CD5 protein levels in transduced T cells while retaining strong cytotoxicity against CD5+ malignant cells. In our first-in-human phase 1 study (NCT0308190), second-generation autologous CD5.CAR T cells were manufactured from patients with r/r T-cell malignancies. Here, we report safety and efficacy data from a cohort of patients with mature T-cell lymphoma (TCL). Among the 17 patients with TCL enrolled, CD5 CAR T cells were successfully manufactured for 13 out of 14 attempted lines (93%) and administered to 9 (69%) patients. The overall response rate (complete remission or partial response) was 44%, with complete responses observed in 2 patients. The most common grade 3 or higher adverse events were cytopenias. No grade 3 or higher cytokine release syndrome or neurologic events occurred. Two patients died during the immediate toxicity evaluation period due to rapidly progressive disease. These results demonstrated that CD5.CAR T cells are safe and can induce clinical responses in patients with r/r CD5-expressing TCLs without eliminating endogenous T cells or increasing infectious complications. More patients and longer follow-up are needed for validation. This trial was registered at www.clinicaltrials.gov as #NCT0308190.

Moving CAR-Ts to the outpatient clinic.

As centres obtain more experience with commercial CARs, there has been increasing interest in trying to move as much as the procedure as possible to the outpatient clinic to reduce costs, maximize reimbursement and increase patient satisfaction. The report by Ly et al. details how their centre implemented outpatient CAR therapy and were able to reduce admission time without affecting outcomes. Commentary on: Ly et al. Outpatient CD19-directed CAR T-cell therapy is feasible in patients of all ages. Br J Haematol 2023;203:688-692.

Naive T cells inhibit the outgrowth of intractable antigen-activated memory T cells: implications for T-cell immunotherapy.

BACKGROUND: The wider application of T cells targeting viral tumor-antigens via their native receptors is hampered by the failure to expand potent tumor-specific T cells from patients. Here, we examine reasons for and solutions to this failure, taking as our model the preparation of Epstein-Barr virus (EBV)-specific T cells (EBVSTs) for the treatment of EBV-positive lymphoma. EBVSTs could not be manufactured from almost one-third of patients, either because they failed to expand, or they expanded, but lacked EBV specificity. We identified an underlying cause of this problem and established a clinically feasible approach to overcome it. METHODS: CD45RO+CD45RA- memory compartment residing antigen-specific T cells were enriched by depleting CD45RA positive (+) peripheral blood mononuclear cells (PBMCs) that include naïve T cells, among other subsets, prior to EBV antigen stimulation. We then compared the phenotype, specificity, function and T-cell receptor (TCR) Vß repertoire of EBVSTs expanded from unfractionated whole (W)-PBMCs and CD45RA-depleted (RAD)-PBMCs on day 16. To identify the CD45RA component that inhibited EBVST outgrowth, isolated CD45RA+ subsets were added back to RAD-PBMCs followed by expansion and characterization. The in vivo potency of W-EBVSTs and RAD-EBVSTs was compared in a murine xenograft model of autologous EBV+ lymphoma. RESULTS: Depletion of CD45RA+ PBMCs before antigen stimulation increased EBVST expansion, antigen-specificity and potency in vitro and in vivo. TCR sequencing revealed a selective outgrowth in RAD-EBVSTs of clonotypes that expanded poorly in W-EBVSTs. Inhibition of antigen-stimulated T cells by CD45RA+ PBMCs could be reproduced only by the naïve T-cell fraction, while CD45RA+ regulatory T cells, natural killer cells, stem cell memory and effector memory subsets lacked inhibitory activity. Crucially, CD45RA depletion of PBMCs from patients with lymphoma enabled the outgrowth of EBVSTs that failed to expand from W-PBMCs. This enhanced specificity extended to T cells specific for other viruses. CONCLUSION: Our findings suggest that naïve T cells inhibit the outgrowth of antigen-stimulated memory T cells, highlighting the profound effects of intra-T-cell subset interactions. Having overcome our inability to generate EBVSTs from many patients with lymphoma, we have introduced CD45RA depletion into three clinical trials: NCT01555892 and NCT04288726 using autologous and allogeneic EBVSTs to treat lymphoma and NCT04013802 using multivirus-specific T cells to treat viral infections after hematopoietic stem cell transplantation.

Ultralow-dose binary oncolytic/helper-dependent adenovirus promotes antitumor activity in preclinical and clinical studies.

We show that a binary oncolytic/helper-dependent adenovirus (CAdVEC) that both lyses tumor cells and locally expresses the proinflammatory cytokine IL-12 and PD-L1 blocking antibody has potent antitumor activity in humanized mouse models. On the basis of these preclinical studies, we treated four patients with a single intratumoral injection of an ultralow dose of CAdVEC (NCT03740256), representing a dose of oncolytic adenovirus more than 100-fold lower than used in previous trials. While CAdVEC caused no significant toxicities, it repolarized the tumor microenvironment with increased infiltration of CD8 T cells. A single administration of CAdVEC was associated with both locoregional and abscopal effects on metastases and, in combination with systemic administration of immune checkpoint antibodies, induced sustained antitumor responses, including one complete and two partial responses. Hence, in both preclinical and clinical studies, CAdVEC is safe and even at extremely low doses is sufficiently potent to induce significant tumor control through oncolysis and immune repolarization.

Posoleucel, an Allogeneic, Off-the-Shelf Multivirus-Specific T-Cell Therapy, for the Treatment of Refractory Viral Infections in the Post-HCT Setting.

PURPOSE: Viral infections are a major cause of morbidity and mortality following allogeneic hematopoietic cell transplantation (allo-HCT). In the absence of safe and effective antiviral treatments, virus-specific T cells have emerged as a promising therapeutic option. Posoleucel is a multivirus-specific T-cell therapy for off-the-shelf use against six viral infections that commonly occur in allo-HCT recipients: adenovirus, BK virus (BKV), cytomegalovirus, Epstein-Barr virus, human herpes virus-6, and JC virus. PATIENTS AND METHODS: We conducted an open-label, phase II trial to determine the feasibility and safety of posoleucel in allo-HCT recipients infected with one or more of these viruses. Infections were either unresponsive to or patients were unable to tolerate standard antiviral therapies. Fifty-eight adult and pediatric patients were enrolled and treated. RESULTS: Posoleucel was well tolerated, with no cytokine release syndrome or other infusion-related toxicities; two patients (3.4%) developed Grade 2 and one patient (1.7%) Grade 3 GvHD during the trial. The overall response rate 6 weeks after the first posoleucel infusion was 95%, with a median plasma viral load reduction of 97%. Of the 12 patients who had two or more target viral infections identified at study entry, 10 (83%) had a clinical response for all evaluable viruses. Of the 23 patients treated for refractory BKV-associated hemorrhagic cystitis, 74% had resolution of symptoms and macroscopic hematuria by 6 weeks post-infusion. CONCLUSIONS: In this open-label trial, treatment of refractory viral infections/disease in allo-HCT recipients with posoleucel was feasible, safe, and effective.

Paving the Road for Chimeric Antigen Receptor T Cells: American Society for Transplantation and Cellular Therapy 80/20 Task Force Consensus on Challenges and Solutions to Improving Efficiency of Clinical Center Certification and Maintenance of Operations for Commercially Approved Immune Effector Cell Therapies.

As the number and type of regulatory authority-approved cellular therapies grow, clinical treatment centers face a heavy burden of duplicative documentation around initial qualification, ongoing auditing, and reporting, with overlapping requirements from each manufacturer to ensure safe use of their specific product, which in the United States are stipulated under individual Food and Drug Administration (FDA) Biologic License Applications. The American Society for Transplantation and Cellular Therapy (ASTCT) convened the 80/20 Task Force to consider challenges and potential solutions to these issues. The Task Force proposed that 80% of manufacturers' requirements for onboarding and ongoing operations of commercially available products could be standardized and streamlined. Task Force members interviewed dozens of stakeholders, including clinicians at large academic medical centers already using commercial and investigational immune effector cell (IEC) products, regulators, members of accrediting bodies and professional cellular therapy societies, and manufacturers of IEC therapies for oncologic indications. In November 2021, the Task Force organized and led virtual discussions in a public forum and at a private ASTCT 80/20 Workshop at the online AcCELLerate Forum, a cellular-therapy stakeholders' meeting organized by the ASTCT, National Marrow Donor Program (NMDP), and Center for International Blood and Marrow Transplant Research (CIBMTR). At the workshop, approximately 60 stakeholders worked to identify and prioritize common challenges in onboarding and maintenance of operations at clinical sites for commercial FDA-approved and future IEC therapies and ways to streamline the process. It was agreed that standardization would improve efficiency of onboarding, allowing more cost-effective, sustainable growth of approved IEC therapies at treatment centers, and facilitate wider access while maintaining safety and clinical success. This early but extensive survey of stakeholders resulted in 5 overarching suggestions for both established and emerging treatment centers: (1) eliminate duplication in accreditation and auditing of clinical sites; (2) define expectations for the education about and management of CAR-T therapy toxicities to potentially replace product-specific REMS programs; (3) streamline current REMS education, testing, and data reporting; (4) standardize information technology (IT) platforms supporting enrollment, clinical site-manufacturer communication, and logistics of maintaining chain of identity/chain of custody across multiple transportation steps; and (5) encourage the use of universal nomenclature by cell therapy manufacturers. Future discussions need to engage a broader range of stakeholders, including administrators, pharmacists, nurses, data coordinators, surgeons, pathologists, and those developing promising cellular therapies for solid tumors, as well as teams from smaller academic or community cancer center settings. Continued collaboration with stakeholders outside of clinical sites will include accrediting bodies/auditors, established and emerging cell therapy companies, software developers, professional societies, and the patients who receive these therapies. Active dialog with government regulators remains essential. Such joint efforts are critical as the number of IEC therapies for myriad oncologic and nononcologic indications grows.