Autologous T-cell Research Articles

An assessment model for the efficacy of autologous CD19 chimeric antigen receptor T-cell therapy and relapse or refractory diffuse large B-cell lymphoma risk.

An assessment model for the efficacy of autologous CD19 chimeric antigen receptor T-cell therapy and relapse or refractory diffuse large B-cell lymphoma risk.

Phase 1 Study of ROR1 Specific CAR T Cells in Advanced Hematopoietic and Epithelial Malignancies.

The receptor tyrosine kinase-like orphan receptor 1 (ROR1) is expressed in hematopoietic and epithelial cancers but has limited expression on normal adult tissues. This phase 1 study evaluated the safety of targeting ROR1 with autologous T-lymphocytes engineered to express a ROR1 chimeric antigen receptor (CAR). Secondary objectives evaluated persistence, trafficking, and antitumor activity of CAR T cells. Twenty-one patients with ROR1+ tumors received CAR T cells at one of four dose levels (DL): 3.3x105/1x106/3.3x106/1x107 cells/kg, administered after lymphodepletion with Cyclophosphamide/Fludarabine (Cy/Flu) or Oxaliplatin/Cyclophosphamide (Ox/Cy). Cohort A included patients with chronic lymphocytic leukemia (CLL, n=3); cohort B included patients with triple-negative breast cancer (TNBC, n=10) or non-small-cell lung cancer (NSCLC, n=8). A second infusion was administered to one patient in cohort A with residual CLL in the marrow and three patients in cohort B with stable disease after first infusion. Treatment was well tolerated apart from one dose limiting toxicity at DL4 in a patient with advanced NSCLC. Two of the three (67%) CLL patients showed robust CAR T expansion and a rapid antitumor response. In patients with NSCLC and TNBC, CAR T cells expanded to variable levels, infiltrated tumor poorly, and one of eighteen patients (5.5%) achieved partial response by RECIST 1.1. ROR1 CAR T cells were well tolerated in most patients. Antitumor activity was observed in CLL but was limited in TNBC and NSCLC. Immunogenicity of the CAR and lack of sustained tumor infiltration were identified as limitations.

In brief: Afamitresgene autoleucel (Tecelra) for synovial sarcoma.

Afamitresgene autoleucel (Tecelra – Adaptimmune), a melanoma-associated antigen A4 (MAGE-A4)-directed genetically modified autologous T-cell immunotherapy, has received accelerated approval from the FDA for one-time treatment of adults with unresectable or metastatic synovial sarcoma who received prior chemotherapy and are HLA-A*02:01P, -A*02:02P, -A*02:03P, or -A*02:06P positive and whose tumor expresses the MAGE-A4 antigen. It is the first gene therapy to be approved in the US for treatment of synovial sarcoma. Accelerated approval of the immunotherapy was based on the overall response rate and duration of response.

Revolutionizing CAR T-Cell Therapies: Innovations in Genetic Engineering and Manufacturing to Enhance Efficacy and Accessibility.

Chimeric antigen receptor (CAR) T-cell therapy has achieved notable success in treating hematological cancers but faces significant challenges in solid-tumor treatment and overall efficacy. Key limitations include T-cell exhaustion, tumor relapse, immunosuppressive tumor microenvironments (TME), immunogenicity, and antigen heterogeneity. To address these issues, various genetic engineering strategies have been proposed. Approaches such as overexpression of transcription factors or metabolic armoring and dynamic CAR regulation are being explored to improve CAR T-cell function and safety. Other efforts to improve CAR T-cell efficacy in solid tumors include targeting novel antigens or developing alternative strategies to address antigen diversity. Despite the promising preclinical results of these solutions, challenges remain in translating CAR T-cell therapies to the clinic to enable economically viable access to these transformative medicines. The efficiency and scalability of autologous CAR T-cell therapy production are hindered by traditional, manual processes which are costly, time-consuming, and prone to variability and contamination. These high-cost, time-intensive processes have complex quality-control requirements. Recent advancements suggest that smaller, decentralized solutions such as microbioreactors and automated point-of-care systems could improve production efficiency, reduce costs, and shorten manufacturing timelines, especially when coupled with innovative manufacturing methods such as transposons and lipid nanoparticles. Future advancements may include harmonized consumables and AI-enabled technologies, which promise to streamline manufacturing, reduce costs, and enhance production quality.

Chimeric Antigen Receptor T Cells Targeting CD19 and GCC in Metastatic Colorectal Cancer

Chimeric antigen receptor (CAR) T-cell therapy (CART) has transformed the treatment landscape of hematologic cancer, but has negligible effects for adult solid cancers. In this trial, an autologous CAR T-cell product demonstrated antitumor activity in heavily pretreated patients with metastatic colorectal cancer (mCRC). To evaluate the safety and efficacy of guanylate cyclase-C (GCC19) CART in participants with metastatic colorectal cancer (mCRC). This single-arm, nonrandomized, phase 1 trial was conducted at the First Hospital of Jilin University from December 3, 2020, to April 13, 2022. Data analysis was conducted from May 2022 to April 2024. Adults with relapsed and refractory mCRC expressing GCC were treated with GCC19CART, a mixture of autologous CAR T cells transduced with lentiviral vectors expressing genes that encode either CD-19 CAR or GCC CAR. Safety and tolerability of CAR T-cell therapy targeting GCC in patients with mCRC without therapeutic options is capable of conferring a reasonable likeliness of clinical benefit. Other outcomes included objective response rate, progression-free survival, overall survival, and immune activation. Of 15 patients 9 (60%) were women, and the median (range) age was 44 (33-61) years. Treatment with GCC19CART was associated with the development of cytokine release syndrome and diarrhea in most patients, all of which were self-limited and manageable. The objective response rate was 40%, with a partial response in 2 of 8 and 4 of 7 patients treated with either 1 × 106 cells/kg or 2 × 106 cells/kg. Median overall survival was 22.8 months (95% CI, 13.4-26.1) at data cutoff; the median progress-free survival was 6.0 months in the high dose level group (95% CI, 3.0 to not available). The results of this nonrandomized clinical trial suggest that GCC19CART was safe and tolerable in heavily pretreated patients with mCRC and is the first CAR T-cell therapy known to produce objective clinical activity in refractory cancer. Given the paucity of effective therapeutics developed for colorectal cancer in recent decades, the observation that CD-19 CART target engagement can robustly induce GCC19CART target engagement sufficient to produce objective activity may serve as a foundation to develop effective cellular therapy in mCRC and other solid cancers. Chinese Clinical Trial Registry: ChiCTR2000040645.

Immunoproteasome activation expands the MHC class I immunopeptidome, unmasks neoantigens and enhances T-cell antimyeloma activity.

Proteasomes generate antigenic peptides that are presented on the tumor surface to cytotoxic T-lymphocytes (CTLs). Immunoproteasomes are highly-specialized proteasome variants that are expressed at higher levels in antigen-presenting cells and contain replacements of the three constitutive proteasome catalytic subunits to generate peptides with a hydrophobic C-terminus that fit within the groove of MHC class I (MHC-I) molecules. A hallmark of cancer is the ability to evade immunosurveillance by disrupting the antigen presentation machinery and downregulating MHC-I antigen presentation. High-throughput screening was performed to identify Compound A, a novel molecule that selectively increased immunoproteasome activity and expanded the number and diversity of MHC-I-bound peptides presented on multiple myeloma (MM) cells. Compound A increased the presentation of individual MHC-I-bound peptides >100-fold and unmasked tumor-specific neoantigens on myeloma cells. Global proteomic integral stability assays determined that Compound A binds the proteasome structural subunit PSMA1 and promotes association of the proteasome activator PA28α/β (PSME1/PSME2) with immunoproteasomes. CRISPR/Cas9 silencing of PSMA1, PSME1, or PSME2 as well as treatment with immunoproteasome-specific suicide inhibitors abolished the effects of Compound A on antigen presentation. Treatment of MM cell lines and patient bone marrow-derived CD138+ cells with Compound A increased the antimyeloma activity of allogenic and autologous T-cells. Compound A was well-tolerated in vivo and co-treatment with allogeneic T-cells reduced the growth of myeloma xenotransplants in NSG mice. Taken together, our results demonstrate the paradigm-shifting impact of immunoproteasome activators to diversify the antigenic landscape, expand the immunopeptidome, potentiate T-cell-directed therapy, and reveal actionable neoantigens for personalized T-cell immunotherapy.

State of the Art on CAR T-Cell Therapies for Onco-Haematological Disorders and Other Conditions

The use of chimeric antigen receptors (CAR T-cells) for the treatment of patients with malignant haematological diseases has become a well-established application for conditions such as refractory or relapsed B-cell acute lymphoblastic leukaemia (B-ALL), B-cell lymphomas (BCL), and multiple myeloma (MM). Nearly 35,000 patients have received autologous CAR T-cells for the treatment of these conditions only in the USA. Since their approval by the Food and Drug Administration (FDA) in 2017, over 1200 clinical trials have been initiated globally and there are at least 10 different CAR T-cells with approval by different regulatory agencies around the globe. In the USA, the FDA has approved six commercial CAR T-cells that are widely distributed worldwide. At the time of writing, several clinical trials have been performed in patients with solid tumours such as glioblastoma, renal and pancreatic cancer, as well as in patients with autoimmune conditions such as systemic lupus erythematosus (SLE), idiopathic inflammatory myositis (IIM), and systemic sclerosis (SS). There are also several studies showing the potential benefit of CAR T-cells for other non-malignant diseases such as asthma and even fungal infections. In this review, without pretending to cover all current areas of treatments with CAR T-cells, we offer a brief summary of some of the most relevant aspects of the use of CAR T-cells for some of these conditions.

Autologous CD7 CAR-T cells generated without T cell pre-selection in pediatric patients with relapsed/refractory T-ALL: A phase I trial

Chimeric antigen receptor (CAR) T-cell therapy showed preliminary activity in patients with refractory or relapsed T-cell acute lymphoblastic leukemia (r/r T-ALL). However, many obstacles remain, including manufacturing difficulties and risk of infections. This phase I study (NCT04840875) evaluated autologous CD7 CAR T cells manufactured without pre-selection of healthy T cells in r/r T-ALL. Thirty patients (29 children and one adult) with a median of two lines of prior therapy but without detectable peripheral leukemia were enrolled. Excluding three cases of manufacturing failures, a total of 27 (90%) patients received infusions after products were confirmed free of leukemia contamination, including 16 (59%) meeting planned target doses. Common adverse events within 30 days included grade 3-4 cytopenias (100%), grade 1-2 (70%) and 3-4 (7%; including one dose-limiting toxicity) cytokine release syndrome, grade 1 neurotoxicity (7%), grade 2 infection (4%), and grade 2 graft-versus-host disease (4%). Two patients developed grade 2 infections after day 30. At day 30, 96% responded and 85% achieved CR or CRi. 74% underwent transplantation. Twelve-month progression-free survival with and without censoring transplantation was 22% (95%CI 4-100) and 57% (41-81), respectively. These results support that autologous CD7 CAR T-cell therapy without T-cell pre-selection is feasible in patients with r/r T-ALL.

The Current Landscape of Secondary Malignancies after CAR T-Cell Therapies: How Could Malignancies Be Prevented?

Chimeric antigen receptor (CAR) T-cell therapies have revolutionised the field of haematological malignancies by achieving impressive remission rates in patients with highly refractory haematological malignancies, improving overall survival. To date, six commercial anti-CD19 and anti-BCMA CAR T-cell products have been approved by the Food and Drug Administration (FDA) for the treatment of relapsed/refractory B-cell haematological malignancies and multiple myeloma. The indications for CAR T-cell therapies are gradually expanding, with these therapies being investigated in a variety of diseases, including non-malignant ones. Despite the great success, there are several challenges surrounding CAR T-cell therapies, such as non-durable responses and high-grade toxicities. In addition, a new safety concern was added by the FDA on 28 November 2023 following reports of T-cell malignancies in patients previously treated with either anti-CD19 or anti-BCMA autologous CAR T-cell therapies both in clinical trials and in the real-world setting. Since then, several reports have been published presenting the incidence and analysing the risks of other secondary malignancies after CAR T-cell therapies. In this opinion article, the current landscape of secondary malignancies after CAR T-cell therapies is presented, along with a proposed strategy for future research aiming at potentially diminishing or abrogating the risk of developing secondary malignancies after CAR T-cell therapies.

Advancements in Personalized CAR-T Therapy: Comprehensive Overview of Biomarkers and Therapeutic Targets in Hematological Malignancies.

Chimeric antigen receptor T-cell (CAR-T) therapy is a novel anticancer therapy using autologous or allogeneic T-cells. To date, six CAR-T therapies for specific B-cell acute lymphoblastic leukemia (B-ALL), non-Hodgkin lymphomas (NHL), and multiple myeloma (MM) have been approved by the Food and Drug Administration (FDA). Significant barriers to the effectiveness of CAR-T therapy include cytokine release syndrome (CRS), neurotoxicity in the case of Allogeneic Stem Cell Transplantation (Allo-SCT) graft-versus-host-disease (GVHD), antigen escape, modest antitumor activity, restricted trafficking, limited persistence, the immunosuppressive microenvironment, and senescence and exhaustion of CAR-Ts. Furthermore, cancer drug resistance remains a major problem in clinical practice. CAR-T therapy, in combination with checkpoint blockades and bispecific T-cell engagers (BiTEs) or other drugs, appears to be an appealing anticancer strategy. Many of these agents have shown impressive results, combining efficacy with tolerability. Biomarkers like extracellular vesicles (EVs), cell-free DNA (cfDNA), circulating tumor (ctDNA) and miRNAs may play an important role in toxicity, relapse assessment, and efficacy prediction, and can be implicated in clinical applications of CAR-T therapy and in establishing safe and efficacious personalized medicine. However, further research is required to fully comprehend the particular side effects of immunomodulation, to ascertain the best order and combination of this medication with conventional chemotherapy and targeted therapies, and to find reliable predictive biomarkers.

Human plasma cells engineered to secrete bispecifics drive effective in vivo leukemia killing

Bispecific antibodies are an important tool for the management and treatment of acute leukemias. As a next step toward clinical translation of engineered plasma cells, we describe approaches for secretion of bispecific antibodies by human plasma cells. We show that human plasma cells expressing either fragment crystallizable domain-deficient anti-CD19×anti-CD3 (blinatumomab) or anti-CD33×anti-CD3 bispecific antibodies mediate Tcell activation and direct Tcell killing of B acute lymphoblastic leukemia or acute myeloid leukemia cell lines invitro. We demonstrate that knockout of the self-expressed antigen, CD19, boosts anti-CD19-bispecific secretion by plasma cells and prevents self-targeting. Plasma cells secreting anti-CD19-bispecific antibodies elicited invivo control of acute lymphoblastic leukemia patient-derived xenografts in immunodeficient mice co-engrafted with autologous Tcells. In these studies, we found that leukemic control elicited by engineered plasma cells was similar to CD19-targeted chimeric antigen receptor-expressing Tcells. Finally, the steady-state concentration of anti-CD19 bispecifics in serum 1month after cell delivery and tumor eradication was comparable with that observed in patients treated with a steady-state infusion of blinatumomab. These findings support further development of ePCs for use as a durable delivery system for the treatment of acute leukemias, and potentially other cancers.

Analysis of polyfunctionality for enhanced BAFF-R CAR T-cell therapy for hematologic malignancies

AbstractChimeric antigen receptor (CAR) T-cell therapy has emerged as a promising immunotherapeutic strategy for eradicating human cancers. Their therapeutic success and durability of clinical responses hinges, in large part, on their functional capacity, including the ability of these engineered cells to simultaneously expand and persist after infusion into patients. CD19 CAR T-cell polyfunctionality, assessing the simultaneous functions of cytokine production, proliferation, and cytotoxicity has been reported to correlate with clinical outcomes. Assay optimization is potentially limited by the heterogeneous nature of CAR T-cell infusion products and target specificity. We optimized a single-cell platform for polyfunctionality using CAR T-cell products manufactured from healthy donors, engineered against a novel target, B-cell–activating factor receptor (BAFF-R) and validated the protocol using CD19 CAR T cells. We observed distinct qualitative differences between BAFF-R and CD19 CAR T cells relative to the proportions of stimulatory vs effector cytokines, based on target antigen density, and, generally, CD19 CAR T cells exhibited lower indices of polyfunctionality. Finally, we applied our assay to the autologous BAFF-R CAR T-cell product generated from the first patient with non-Hodgkin lymphoma treated in an ongoing clinical trial who had progressed after prior CD19 CAR T-cell therapy. We observed robust indicators of polyfunctionality, which correlated with successful CAR T-cell expansion after infusion and achievement of durable complete remission ongoing after 18 months. The precise identification of factors determining the role of BAFF-R CAR T-cell fitness in toxicity and clinical outcome will require the application of this robust assay in the analysis of additional treated patients. This trial was registered at www.ClinicalTrials.gov as #NCT05370430.

DIPG-47. SEQUENTIAL INTRAVENOUS AND INTRACEREBROVENTRICULAR GD2-CAR T-CELL THERAPY FOR H3K27M-MUTATED DIFFUSE MIDLINE GLIOMAS

Abstract BACKGROUND H3K27M-mutant diffuse midline gliomas (DMGs) express uniformly high levels of the GD2 disialoganglioside. In preclinical models, chimeric antigen receptor modified T-cells (CAR T-cells) targeting GD2 robustly regressed orthotopically xenografted DMGs. METHODS This Phase I trial (NCT04196413) administered one IV dose of autologous T-cells transduced with a GD2-CAR retroviral vector to patients with H3K27M-mutant pontine (DIPG) or spinal (sDMG) diffuse midline gliomas at two dose levels (DL1=1e6 GD2-CAR T-cells/kg; DL2=3e6 GD2-CAR T-cells/kg) following standard lymphodepleting (LD) chemotherapy. Patients with clinical or imaging benefit following IV infusion were eligible for subsequent intracerebroventricular (ICV) GD2-CAR T-cell infusions (10-30e6 GD2-CAR T-cells). Primary objectives were to determine feasibility of manufacturing, assess tolerability of IV GD2-CAR T-cells in patients with DIPG and sDMG, and identify a maximally tolerated dose of IV GD2-CAR T-cells following lymphodepleting chemotherapy. Secondary objectives included preliminary assessments of benefit. Here we report the final results of Arm A. RESULTS Thirteen patients enrolled and 11 received one IV GD2-CAR T infusion on study [n=3 DL1(3 DIPG); n=8 DL2(6 DIPG/2 sDMG). GD2-CAR T-cells were successfully manufactured for each patient. After IV infusion, no dose-limiting toxicities (DLTs) occurred on DL1, but three patients experienced DLT on DL2 due to grade 4 cytokine release syndrome (CRS). Nine patients received ICV infusions, which were not associated with DLTs. All patients exhibited tumor inflammation-associated neurotoxicity (TIAN). Four patients demonstrated major volumetric reductions of 52%, 54%, 91% and 100%. One patient exhibited a complete response durable for >30 months since therapy began. Eight patients demonstrated neurological benefit based upon a protocol-directed Clinical Improvement Score. CONCLUSIONS Sequential IV followed by ICV GD2-CAR T-cells infusions induced tumor regressions and neurological improvements. DL1 was established as the maximally tolerated IV GD2-CAR T-cell dose. Neurotoxicity was safely managed with intensive monitoring and close adherence to a management algorithm.

Stromal cells engineered to express T cell factors induce robust CLL cell proliferation in vitro and in PDX co-transplantations allowing the identification of RAF inhibitors as anti-proliferative drugs

Several in vitro models have been developed to mimic chronic lymphocytic leukemia (CLL) proliferation in immune niches; however, they typically do not induce robust proliferation. We prepared a novel model based on mimicking T-cell signals in vitro and in patient-derived xenografts (PDXs). Six supportive cell lines were prepared by engineering HS5 stromal cells with stable expression of human CD40L, IL4, IL21, and their combinations. Co-culture with HS5 expressing CD40L and IL4 in combination led to mild CLL cell proliferation (median 7% at day 7), while the HS5 expressing CD40L, IL4, and IL21 led to unprecedented proliferation rate (median 44%). The co-cultures mimicked the gene expression fingerprint of lymph node CLL cells (MYC, NFκB, and E2F signatures) and revealed novel vulnerabilities in CLL-T-cell-induced proliferation. Drug testing in co-cultures revealed for the first time that pan-RAF inhibitors fully block CLL proliferation. The co-culture model can be downscaled to five microliter volume for large drug screening purposes or upscaled to CLL PDXs by HS5-CD40L-IL4 ± IL21 co-transplantation. Co-transplanting NSG mice with purified CLL cells and HS5-CD40L-IL4 or HS5-CD40L-IL4-IL21 cells on collagen-based scaffold led to 47% or 82% engraftment efficacy, respectively, with ~20% of PDXs being clonally related to CLL, potentially overcoming the need to co-transplant autologous T-cells in PDXs.

Late Treatment With Autologous Expanded Regulatory T-cell Therapy After Alemtuzumab Induction Is Safe and Facilitates Immunosuppression Minimization in Living Donor Renal Transplantation.

The TWO Study (Transplantation Without Overimmunosuppression) aimed to investigate a novel approach to regulatory T-cell (Treg) therapy in renal transplant patients, using a delayed infusion protocol at 6 mo posttransplant to promote a Treg-skewed lymphocyte repopulation after alemtuzumab induction. We hypothesized that this would allow safe weaning of immunosuppression to tacrolimus alone. The COVID-19 pandemic led to the suspension of alemtuzumab use, and therefore, we report the unique cohort of 7 patients who underwent the original randomized controlled trial protocol. This study presents a unique insight into Treg therapy combined with alemtuzumab and is therefore an important proof of concept for studies in other diseases that are considering lymphodepletion. Living donor kidney transplant recipients were randomized to receive autologous polyclonal Treg at week 26 posttransplantation, coupled with weaning doses of tacrolimus, (Treg therapy arm) or standard immunosuppression alone (tacrolimus and mycophenolate mofetil). Primary outcomes were patient survival and rejection-free survival. Successful cell manufacturing and cryopreservation until the 6-mo infusion were achieved. Patient and transplant survival was 100%. Acute rejection-free survival was 100% in the Treg-treated group at 18 mo after transplantation. Although alemtuzumab caused a profound depletion of all lymphocytes, including Treg, after cell therapy infusion, there was a transient increase in peripheral Treg numbers. The study establishes that delayed autologous Treg therapy is both feasible and safe, even 12 mo after cell production. The findings present a new treatment protocol for Treg therapy, potentially expanding its applications to other indications.

Telemedicine With Wearable Technologies in Patients Undergoing Hematopoietic Cell Transplantation and Chimeric Antigen Receptor T-Cell Therapy (TEL-HEMATO Study): Prospective Noninterventional Single-Center Study.

Patients with hematological malignancies receiving hematopoietic cell transplantation (HCT) or chimeric antigen receptor (CAR) T-cell therapy are at risk of developing serious clinical complications after discharge. The aim of the TEL-HEMATO study was to improve our telehealth platform for the follow-up of patients undergoing HCT or CAR T-cell therapy during the first 3 months after discharge with the addition of wearable devices. Eleven patients who received autologous (n=2) or allogeneic (n=5) HCT or CAR T-cell therapy (n=4) for hematological malignancies were screened from November 2022 to July 2023. Two patients discontinued the study after enrollment. The telehealth platform consisted of the daily collection of vital signs, physical symptoms, and quality of life assessment up to 3 months after hospital discharge. Each patient received a clinically validated smartwatch (ScanWatch) and a digital thermometer, and a dedicated smartphone app was used to collect these data. Daily revision of the data was performed through a web-based platform by a hematologist or a nurse specialized in HCT and CAR T-cell therapy. Vital signs measured through ScanWatch were successfully collected with medium/high adherence: heart rate was recorded in 8/9 (89%) patients, oxygen saturation and daily steps were recorded in 9/9 (100%) patients, and sleeping hours were recorded in 7/9 (78%) patients. However, temperature recorded manually by the patients was associated with lower compliance, which was recorded in 5/9 (55%) patients. Overall, 5/9 (55%) patients reported clinical symptoms in the app. Quality of life assessment was completed by 8/9 (89%) patients at study enrollment, which decreased to 3/9 (33%) at the end of the third month. Usability was considered acceptable through ratings provided on the System Usability Scale. However, technological issues were reported by the patients. While the addition of wearable devices to a telehealth clinical platform could have potentially synergic benefits for HCT and CAR T-cell therapy patient monitoring, noncomplete automation of the platform and the absence of a dedicated telemedicine team still represent major limitations to be overcome. This is especially true in our real-life setting where the target population generally comprises patients of older age with a low digital education level.

Phase 2 open label, multicenter study evaluating CRG-022, a CD22-directed autologous CAR T-cell therapy, in patients (pts) with relapsed/refractory (R/R) large B-cell lymphoma (LBCL) after CD19-directed CAR T-cell therapy.

TPS7085 Background: Autologous (auto) CD19-directed CAR T-cell therapy can induce long-term remissions for pts with R/R LBCL but approximately 60% will experience disease progression resulting in poor outcomes (Neelapu, 2023; Zurko, 2023). CRG-022 is a novel CAR T-cell product targeting CD22, a common B-cell antigen widely expressed in LBCL. Key features of CRG-022 include a fully human scFv derived from the m971 monoclonal antibody and 4-1BB/CD3z intracellular signaling domains (Singh, 2021). This CD22 CAR construct was developed at the National Cancer Institute and was investigated in phase (ph) 1 studies of pediatric/young adult pts with R/R CD22+ malignancies (Shah, 2020; NCT02315612) and at Stanford University in adults with R/R LBCL (Baird, 2021; NCT04088890) primarily in pts who received prior CD19-directed CAR-T therapy. The Stanford ph 1b study reported an overall response rate (ORR) and complete response rates of 66% and 52%, respectively in 29 pts treated at the recommended Phase 2 dose (RP2D) of 1x106 CAR+ T cells/kg (Frank, 2023). After a median follow-up of 27.3 months, the median overall survival had not been reached at the RP2D (Su, 2023). At the RP2D, no grade >3 cytokine release syndrome (CRS), immune-effector cell associated neurotoxicity syndrome (ICANS), or immune effector cell associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS) occurred; two pts (7%) developed grade 2 IEC-HS (Su, 2023; Srinagesh, 2023). Based on these notable results, this potentially pivotal ph 2 trial has been initiated. Methods: This Phase 2 study will evaluate the safety/efficacy of CRG-022 at 1x106 CAR+ T cells/kg in pts with R/R LBCL whose disease has progressed after CD19-directed CAR T-cell therapy. The primary endpoint is ORR according to Lugano response criteria (Cheson, 2014) by blinded independent review. Adverse events (AEs) are graded per CTCAE v5 except with CRS, ICANS, and IEC-HS graded per ASTCT guidelines. Pts with diffuse large B-cell lymphoma (DLBCL), high grade B-cell lymphoma, DLBCL transformed from follicular or marginal zone lymphoma, follicular large B-cell lymphoma (FLBL)/FL Grade 3B, and primary mediastinal B-cell lymphoma are eligible. Other eligibility criteria include adequate hematologic and organ function, and no prior allogeneic stem cell transplant. Pts with prior treatment to both a CD19-directed auto CAR-T and a bispecific T-cell engaging antibody are also eligible within a separate cohort. Lymphodepletion with fludarabine 30 mg/m2/day and cyclophosphamide 500 mg/m2/day for 3 days will be administered ahead of a single infusion of CRG-022. The study is designed to enroll approximately 123 pts. Study enrollment commenced in the US in August 2023, with 9 pt infused as of 08 JAN 2024. Clinical trial information: NCT05972720 .

Long-term follow-up of ARI0002h (cesnicabtagene autoleucel), an academic point-of-care B-cell maturation antigen (BCMA)-directed chimeric antigen receptor (CAR) T-cell strategy: Activity and safety after fractionated initial therapy and booster dose in 60 patients with relapsed/refractory multiple myeloma (RRMM).

7544 Background: The activity and safety ofARI0002h, an academic autologous CAR T-cell product with a humanized single chain variable fragment targeting BCMA has been reported in a pilot multicenter clinical trial (CARTBCMA-HCB-01) treating 30 patients (pts) with RRMM (NCT04309981) (Oliver-Caldés, Lancet Onc 2023). Here, we describe results of the final cohort of 60 pts with longer follow-up. Methods: Patients aged 18-75 years old with RRMM were eligible if they had measurable disease, were refractory to the last line of treatment and received ≥2 prior regimens, including a proteasome inhibitor, an immunomodulatory drug and an anti-CD38 antibody. The target dose (3x106/kg CAR+cells) was administered in a fractionated manner (10%/30%/60%). A second dose of up to 3x106 CAR+ cells/kg was planned at least 3 months after the first dose in pts with any kind of response and no limiting side effects. Primary endpoints were overall response rate (ORR) within the first 3 months and rate of cytokine release syndrome (CRS) and/or neurotoxicity in the first 30 days. Bone marrow minimal residual disease (MRD) was analyzed by next-generation flow at a sensitivity of 10-6. Results: As of December 18th 2023, 72 pts with RRMM were screened, 69 underwent apheresis and 61 received LD, with 60 pts finally receiving ARI0002h. The ORR in the first 3 months was 95% (≥ very good partial response (VGPR) in 77%). Median time to first response was one month. Responses deepened over time, achieving 58% complete response (CR) (55% stringent CR). MRD-negative rates on evaluable samples on days 28 and 100 were 98% and 96%, respectively. With a median follow-up of 24 months (95%CI 9.8-39.9), estimated median progression-free survival (PFS) was 20 months (95% CI 13.2-26.8). Median overall survival (OS) was not reached with OS rate at 24 months of 63%. CRS was observed in 90% with 5% grades ≥ 3. Median time to CRS was 7 days (1-14) with a median duration of 4.5 days. Mild acute neurotoxicity was reported in only 2 pts (3%) with no late neurologic events. 6 pts (10%) developed a macrophage activation syndrome (4 grades 1-2, 1 grade 3, 1 grade 5). Seven patients (11.7%) developed second primary malignancies after ARI0002h infusion, including 3 skin cancers (one in situ melanoma), 3 solid tumors and one acute myeloid leukemia. 80% (44 out of 5) eligible pts had already received the booster dose, with no relevant toxicities. Median time after first infusion was 4.4 months. Response was evaluable in 42 pts; 45% (n=19) were already in sCR, 29% (n=12) maintained the response and 26% (n=11) improved the response. Conclusions: Results from 60 pts and a longer follow-up confirm the safety profile and the deep and durable responses obtained after ARI0002h infusion. Clinical trial information: NCT04309981 .

Open-label, phase 1, multicenter study to evaluate the safety and preliminary anti-tumor activity of NT-175 in human leukocyte antigen-a*02:01-positive adult subjects with unresectable, advanced and/or metastatic solid tumors that are positive for the TP53 R175H mutation.

e14514 Background: The TP53 tumor suppressor gene is the most commonly mutated gene across all cancer types, and TP53 R175H is the most common recurrent mutation across indications, identified in 6.7% of patients with breast cancer, 6% of patients withs colorectal cancer, and 4.2% of patients with pancreatic cancer. No therapy is approved for treatment directly targeting TP53 R175H. NT-175 is an armored autologous T-cell product expressing an HLA-A*02:01-restricted TCR recognizing TP53 R175H with disruption of the endogenous TCR and the transforming growth factor beta receptor type 2 (TGFBR2) genes. Methods: This first-in-human phase I, open label study will assess the safety and preliminary anti-tumor activity, identify the maximum tolerated dose (MTD), and evaluate the persistence, and functional capacity of NT-175 in subjects with advanced, recurrent unresectable/metastatic solid tumors refractory to treatment options. The study will enroll approximately 24 subjects harboring TP53 R175H and HLA-A*02:01. Enrolled patients will undergo leukapheresis from which CD4 and CD8 T cells will be enriched and activated ex vivo. The endogenous TCR α and β chain gene are knocked out utilizing clustered Regularly Interspaced Short Palindromic repeats (CRISPR-Cas9) and the TCR encoding an HLA-A*02:01-restricted TCR specific to the TP53 R175H mutation is inserted in the TCR α locus. Additionally, the T cells are edited to disrupt the gene encoding the TGFBR2 to reduce the immunosuppressive effect of TGF-β in the tumor microenvironment. Subjects will undergo lymphodepletion chemotherapy with fludarabine and cyclophosphamide followed by a single infusion of NT-175 and subcutaneous recombinant IL-2 administration for up to 8 days. Dose escalation will occur across 3 ascending dose levels following the BOIN design. Subjects will be monitored for dose-limiting toxicities for 28 days after NT-175 infusion. Tumor response will be assessed by RECISTv1.1 criteria. All subjects will be followed for up to 15 years. Primary endpoints include safety, dose limited toxicities, MTD determination, and recommended Phase II dose. Secondary endpoints include preliminary efficacy measures. Translational analysis will evaluate potential biomarkers for insights into mechanism of action, response prediction, or resistance mechanisms. The study was activated in March 2023 and is open to accrual; 5 patients have been enrolled as of 4 Jan 2024.

DUET-01: A first-in-human, phase 1/2 study of BOXR1030 in patients with advanced glypican-3-positive solid tumors.

TPS2681 Background: Glypican-3 (GPC3) is a membrane-bound heparin sulfate proteoglycan involved in cell proliferation that is overexpressed in several tumor types. BOXR1030 is an autologous T-cell therapy that co-expresses a chimeric antigen receptor (CAR) targeting GPC3 on tumor cells and glutamic-oxaloacetic transaminase 2 (GOT2), a mitochondrial enzyme that plays an important role in maintaining mitochondrial function and improving T-cell functionality in the solid tumor microenvironment. In non-clinical studies, BOXR1030 showed GPC3-specific cytotoxicity, proliferation and cytokine release only in the presence of GPC3+ cells. Methods: DUET-01 (NCT05120271) is an open-label, dose escalation and expansion clinical trial to determine a safe dose of BOXR1030 in patients with advanced GPC3-positive solid tumors. Dose escalation will be guided by the occurrence of dose-limiting toxicities (DLTs) within 28 days of dosing. The Bayesian logistic regression model will be used on the accumulated DLT data to estimate the maximum tolerated dose (MTD). The Dose Escalation Committee will select the recommended phase 2 dose (RP2D) to be used in the expansion phase cohort(s) (10-20 subjects each) based on data accumulated in the dose escalation cohorts. Eligible subjects will undergo leukapheresis to obtain T cells for BOXR1030 manufacturing and will receive 3 days of lymphodepleting chemotherapy with fludarabine and cyclophosphamide within 5 days prior to BOXR1030 administration. The starting dose is 0.3 × 106 BOXR1030 T cells/kg body weight. Antitumor activity will be assessed every 6 weeks after cell infusion per Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1 and RECIST for immune-based therapeutics (iRECIST). Six months after BOXR1030 administration, subjects will enter long-term follow-up for up to 15 years. Long-term follow-up assessments will focus on long-term safety and disease status. Main inclusion criteria are histologically confirmed advanced unresectable or metastatic hepatocellular carcinoma, squamous cell carcinoma of the lung, myxoid/round cell liposarcoma, or Merkel cell carcinoma; GPC3 overexpression by immunohistochemistry assay confirmed centrally on tumor specimen taken within 6 months prior to signing consent and after the initiation of the subject’s most recent systemic anticancer therapy; body weight of ≥ 50 kg (≥ 65 kg for dose level 1); and life expectancy > 16 weeks. The primary endpoints are the incidence of DLTs; determination of the MTD and RP2D; the type, frequency and severity of treatment-emergent adverse events; clinically significant abnormal safety laboratory findings and vital signs. Key secondary endpoints include efficacy parameters such as objective response rate, BOXR1030 T-cell expansion and persistence, and levels of inflammatory markers and cytokines. The first patient was treated with BOXR1030 in December 2022. Clinical trial information: NCT05120271 .