CD19 CAR Research Articles

Point of care CD19 chimeric antigen receptor (CAR) T-cells for relapsed/refractory acute myeloid leukemia (AML) with aberrant CD19 antigen expression

Relapsed/refractory (r/r) acute myeloid leukemia (AML) is associated with poor prognosis. CD19 is a B-cell marker, is aberrantly expressed in AML, mostly with t(8; 21)(q22; q22.1). Here we report the results of a phase 2 study giving point of care produced CD19 CAR T- cells for r/r AML with aberrant expression of CD19 (NCT04257175). Lymphodepletion included fludarabine and cyclophosphamide The response was evaluated by bone marrow (BM) aspiration on day 28. Six patients (5 adults and 1 child) were included. Median number of previous chemotherapy lines was 4 (range, 3–8) and four patients received CAR T-cells 8–18 months post allogeneic hematopoietic stem cell transplantation (allo-HSCT). Cytokine release syndrome (CRS) of any grade occurred in all patients, and 1 patient had grade 3 CRS. Immune effector cell-associated neurotoxicity syndrome (ICANS) occurred in 2 patients at low grades. Tocilizumab was administered to 2 patients and corticosteroids to 3 patients. Four patients achieved a complete remission (CR), while 2/6 progressed (PD). Three patients (2 with CR and 1 with PD) underwent allo-HSCT (it was the second transplant in 2) 2–5 months post CAR T-cells infusion. The median duration of response in patients achieving CR was 8.5 (range; 3–14) months. However, all patients eventually died within 5 (1–18) months.In conclusion, CD19 CAR T- cell treatment for AML is feasible and safe. However, the response is short and should be followed by allo-HSCT. Hopefully, future long term results will be improved by combining the CAR T- cell therapy with the emerging novel effective anti-leukemic compounds.

A New Chimeric Antibody against the HIV-1 Fusion Inhibitory Peptide MT-C34 with a High Affinity and Fc-Mediated Cellular Cytotoxicity.

Peptides from heptad repeat (HR1 and HR2) regions of gp41 are effective inhibitors of HIV-1 entry that block the fusion of viral and cellular membranes, but the generation of antibodies highly specific for these peptides is challenging. We have previously described a mouse hybridoma that recognizes MT-C34-related peptides derived from HR2. It was used for the selection of HIV-1-resistant CD4 lymphocytes engineered to express the MT-C34 peptide via a CRISPR/Cas9-mediated knock-in into the CXCR4 locus. In this study, we cloned variable domains of this antibody and generated a recombinant chimeric antibody (chAb) by combining it with the constant regions of the humanized antibody Trastuzumab. The new chAb displayed a high specificity and two-fold higher level of affinity than the parental mouse monoclonal antibody. In addition, chAb mediated up to 27-43% of the antibody-dependent cellular cytotoxicity towards cells expressing MT-C34 on their surface. The anti-MT-C34 chAb can be easily generated using plasmids available for the research community and can serve as a valuable tool for the detection, purification, and even subsequent elimination of HIV-1-resistant CD4 cells or CAR cells engineered to fight HIV-1 infection.

Fate induction in CD8 CAR T cells through asymmetric cell division

Early expansion and long-term persistence predict efficacy of chimeric antigen receptor T cells (CARTs)1–7, but mechanisms governing effector versus memory CART differentiation and whether asymmetric cell division induces differential fates in human CARTs remain unclear. Here we show that target-induced proximity labelling enables isolation of first-division proximal-daughter and distal-daughter CD8 CARTs that asymmetrically distribute their surface proteome and transcriptome, resulting in divergent fates. Target-engaged CARs remain on proximal daughters, which inherit a surface proteome resembling activated-undivided CARTs, whereas the endogenous T cell receptor and CD8 enrich on distal daughters, whose surface proteome resembles resting CARTs, correlating with glycolytic and oxidative metabolism, respectively. Despite memory-precursor phenotype and in vivo longevity, distal daughters demonstrate transient potent cytolytic activity similar to proximal daughters, uncovering an effector-like state in distal daughters destined to become memory CARTs. Both partitioning of pre-existing transcripts and changes in RNA velocity contribute to asymmetry of fate-determining factors, resulting in diametrically opposed transcriptional trajectories. Independent of naive, memory or effector surface immunophenotype, proximal-daughter CARTs use core sets of transcription factors known to support proliferation and effector function. Conversely, transcription factors enriched in distal daughters restrain differentiation and promote longevity, evidenced by diminished long-term in vivo persistence and function of distal-daughter CARTs after IKZF1 disruption. These studies establish asymmetric cell division as a framework for understanding mechanisms of CART differentiation and improving therapeutic outcomes.

Combination of Pirtobrutinib and Lentiviral Transduced Bispecific Anti-CD20/CD19 (LV20 .19) CAR T-Cell Therapy to Improve Outcomes in Patients With Relapsed/Refractory Lymphoma

Combination of Pirtobrutinib and Lentiviral Transduced Bispecific Anti-CD20/CD19 (LV20 .19) CAR T-Cell Therapy to Improve Outcomes in Patients With Relapsed/Refractory Lymphoma

ABCL-720 Combination of Pirtobrutinib and Lentiviral Transduced Bispecific Anti-CD20/CD19 (LV20.19) CAR T-Cell Therapy to Improve Outcomes in Patients With Relapsed/Refractory Lymphoma

ABCL-720 Combination of Pirtobrutinib and Lentiviral Transduced Bispecific Anti-CD20/CD19 (LV20.19) CAR T-Cell Therapy to Improve Outcomes in Patients With Relapsed/Refractory Lymphoma

CD22 CAR T-cell therapy: new hope for patients with large B-cell lymphoma

CD22 CAR T-cell therapy: new hope for patients with large B-cell lymphoma

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.

Comparison of seven CD19 CAR designs in engineering NK cells for enhancing anti-tumour activity.

Chimeric antigen receptor-natural killer (CAR-NK) cell therapy is emerging as a promising cancer treatment, with notable safety and source diversity benefits over CAR-T cells. This study focused on optimizing CAR constructs for NK cells to maximize their therapeutic potential. We designed seven CD19 CAR constructs and expressed them in NK cells using a retroviral system, assessing their tumour-killing efficacy and persistence. Results showed all constructs enhanced tumour-killing and prolonged survival in tumour-bearing mice. In particular, CAR1 (CD8 TMD-CD3ζ SD)-NK cells showed superior efficacy in treating tumour-bearing animals and exhibited enhanced persistence when combined with OX40 co-stimulatory domain. Of note, CAR1-NK cells were most effective at lower effector-to-target ratios, while CAR4 (CD8 TMD-OX40 CD- FcεRIγ SD) compromised NK cell expansion ability. Superior survival rates were noted in mice treated with CAR1-, CAR2 (CD8 TMD- FcεRIγ SD)-, CAR3 (CD8 TMD-OX40 CD- CD3ζ SD)- and CAR4-NK cells over those treated with CAR5 (CD28 TMD- FcεRIγ SD)-, CAR6 (CD8 TMD-4-1BB CD-CD3ζ 1-ITAM SD)- and CAR7 (CD8 TMD-OX40 CD-CD3ζ 1-ITAM SD)-NK cells, with CAR5-NK cells showing the weakest anti-tumour activity. Increased expression of exhaustion markers, especially in CAR7-NK cells, suggests that combining CAR-NK cells with immune checkpoint inhibitors might improve anti-tumour outcomes. These findings provide crucial insights for developing CAR-NK cell products for clinical applications.

Clonal Hematopoiesis is Associated With Severe Cytokine Release Syndrome in Patients Treated With Chimeric Antigen Receptor T-Cell (CART) Therapy

Among patients receiving CD19 or B-cell maturation antigen (BCMA) CAR T therapy, inflammation pre- and post-CAR T infusion is implicated in the development of toxicities including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and likely contributes to prolonged cytopenias. Clonal hematopoiesis (CH), the clonal expansion of hematopoietic stem cells harboring somatic mutations, has been associated with inflammasome upregulation. Herein, we examined the prevalence of pre-CAR T CH in a predominantly transplant-naïve cohort of recipients with non-Hodgkin lymphoma (NHL) or multiple myeloma (MM), and assessed the relationship between the presence of CH mutations and CAR T-related outcomes including CRS, ICANS, prolonged cytopenia, progression-free survival (PFS), and overall survival (OS). This study included 62 patients with NHL or MM who underwent CD19 or BCMA CAR T therapy from 2017 to 2022 at City of Hope and had available pre-CAR T cryopreserved peripheral blood mononuclear cells (PBMCs). DNA was isolated with QIAamp DNA Mini Kit (Qiagen) from PBMC samples (94% collected <30d of CART infusion), on which we performed targeted exome sequencing (108 pre-defined gene panel with 1000x sequencing depth) to determine the presence of CH (variant allele frequency [VAF] ≥2%). Multivariable logistic regression was used to examine the association between CH and absolute neutrophil count (ANC) recovery at day +30 and +60, maximum grade CRS and ICANS, grade <2 versus 2+, and OS and PFS at 1y. Covariates considered were age at CART, baseline ANC, sex, race, CAR-HEMATOTOX, LDH, bridging therapy (Y/N), and number of prior lines of therapy. Fifteen (24%) patients had at least one pathogenic CH mutation; 2 (13%) had ≥2 CH mutations concurrently. DMT3A mutations were the most common; 29% of mutations had VAFs >10%. Patients with CH were significantly more likely to develop grade ≥2 CRS (60% versus 28%, p = .03) compared to those without CH (odds ratio [OR] 3.9, 95% CI 1.2-13.2; p = .027). Accounting for baseline ANC (which was higher among the CH cohort and associated with delayed ANC recovery, p = .02) patients with CH did not have a significantly different rate of delayed ANC recovery compared to those without CH (adjusted OR 0.37, 95% CI 0.09-1.5; p = .17). There was no association between CH and ICANS, nor with 1y PFS or OS. CH was frequent (24%) in this cohort of CAR T recipients and was associated with a higher risk of development of grade ≥2 CRS after CAR T. Additional validation studies are currently underway, which may set the stage for consideration of pre-CAR T CH as a biomarker for risk stratification towards more proactive CRS prophylaxis. Translational studies could aim to prove a direct relationship between CH-mutated myeloid cells and CRS.

Combination of pirtobrutinib and lentiviral transduced bispecific anti-CD20/CD19 (LV20.19) CAR T-cell therapy to improve outcomes in patients with relapsed/refractory lymphoma.

7043 Background: Combination trials of BTK inhibitors (BTKi) with CAR-T have suggested potential synergistic benefit by improving CAR-T immunophenotype and clinical outcomes but are limited by increased toxicity. We report immunophenotype, cytokine profile, and patient outcomes with the new non-covalent BTKi, pirtobrutinib (pirto) when given prior to LV20.19 CAR-T and compare the final CAR product to pts who did not receive pirtobrutinib prior to CAR. Methods: Pts received LV20.19 CAR-T as part of a phase 1/2 trial (NCT04186520). Only pts who received pirto £4 weeks prior to apheresis were included. To determine the impact of pirto on LV20.19 CAR-T, we calculated both polyfunctionality (PFA) and polyfunctional strength index (PSI) for each product using the Isoplexis. Descriptive statistics, t-tests and Kaplan-Meier method were used as appropriate. Results: 11 pts received pirto prior to LV20.19 CAR-T (Table). Median age was 65 (50-80) yrs and median prior lines of therapy were 4 (2-8). There were 4 MCL pts, 5 Richter’s (RT)/CLL, 1 MZL and 1 DLBCL. Median duration of pirto was 4 (1-20) mo. Pts were on pirto for a median of 12 (1-22) days prior to apheresis. All except 1 pts received target CAR-T dose. The day 28 ORR was 82% (CR=7, PR=2). After a median follow up of 13 mo, 3 pts died (PD, Covid, Guillain Barre). The median PFS and OS were both 30.8 mo while the 1-year PFS and OS rates were 9 and 15 mo respectively. 9 pts had CRS and 2 had ICANS, all grades 1-2, while 4 had IEC-HS. One pt had afib recurrence and 1 pt had CMV viremia within 30 days of CAR-T. Among the pts with immunophenotypic data (n=10), there were no differences in naïve or more differentiated T-cell percentages in apheresis and final CAR-T products when compared to pts who did not receive pirto before LV20.19 CAR-T (n=57). Although not statistically significant, both PFA (CD4=61.8 vs 59, CD8= 49.8 vs 46.9) and PSI (CD4= 1752 vs 1608, CD8=1299 vs 1079) were higher with pirto pre-treated pts, suggesting a potential trend towards improved CAR-T functionality. Conclusions: These data represent the largest experience of pirto prior to CAR-T apheresis and demonstrate that pirto can be safely used as a bridge to LV20.19 CAR-T without negatively impacting their immunophenotype and potentially improving functionality. These data support our planned phase 1 clinical trial to assess the safety of pirto as bridging and maintenance therapy with LV20.19 CAR-T (NCT05990465). [Table: see text]

Early prediction of severe ICANS after standard-of-care CD19 CAR T-cell therapy using gradient-boosted classification trees.

7034 Background: Severe immune effector cell-associated neurotoxicity syndrome (ICANS) has arisen as a major complication leading to morbidity, mortality, and increased resource utilization. There is an urgent need to accurately predict the development of severe ICANS after CAR T-cell therapy. Here, we demonstrate the high performance of the XGBoost (“eXtreme Gradient Boosting”) machine learning algorithm in predicting the development of severe ICANS using commonly available laboratory and vital sign data from patients with B-cell lymphomas undergoing standard-of-care CD19 CAR T-cell therapy. Methods: We included patients who received axicabtagene ciloleucel (axi-cel) or brexucabtagene autoleucel (brexu-cel) per standard of care. ICANS was graded by CTCAE 4.03 criteria (pre-12/2018) or ASTCT Consensus Grading System (post-1/2019). Predictions were generated using XGBoost, a widely used supervised machine learning algorithm that trains ensembles of decision trees to learn iteratively from prior trees and allows for very flexible modeling (e.g. non-linear effects, complex high-order interaction effects). K-fold cross-validation was used to assess calibration and overfitting. Variables assessed included age, ferritin, CRP, LDH, IL-6, fibrinogen, platelet count, and temperature at pre-infusion, day 0, and day +3 post-infusion timepoints. Results: A total of 175 patients were included with 39 receiving brexu-cel (22%) and 136 receiving axi-cel (78%). Grade ≥3 ICANS occurred in 40 patients (23.3%). XGBoost modeling of factors demonstrated that serum ferritin level on day +3 was the most important variable predictive of grade ≥3 ICANS (accuracy gain: 0.28). Other influential factors included day 0 and +3 platelet count, patient age, day +3 IL-6 level, day 0 fibrinogen level, and day 0 and +3 CRP level, in descending order of importance. The XGBoost model maintained high discrimination (ability to distinguish high-risk from low-risk patients; mean AUROC 0.74, sensitivity 0.95, specificity 0.90). Longitudinal LOESS smoothing confirmed associations between severe ICANS and elevation in serum ferritin at day 0 (OR 3.01, 95% CI 1.41 – 6.73, p = 0.005) and day +3 (OR 5.50, 95% CI 2.31-14.5, p &lt;0.001). Conclusions: A supervised machine learning model using XGBoost incorporating age, temperature and commonly accessible laboratory data including ferritin, CRP, LDH, IL-6, fibrinogen, and platelet count predicted severe ICANS prior to the development of symptoms with high discrimination (AUROC 0.74) in patients undergoing standard of care CAR T-cell therapy. This allows for the early identification of patients at highest risk for developing severe ICANS who may benefit from prophylactic interventions. Once externally validated, we plan to develop a user-friendly web application to generate individualized predictions from our model.

Predictors of severe hematotoxicity after CAR T-cell therapy.

7024 Background: The EHA/EBMT immune effector cell-associated hematotoxicity (ICAHT) grading system characterizes hematotoxicity after CAR T-cell therapy based on depth and duration of neutropenia (Rejeski et al, Blood, 2023). We evaluated pre- and post-infusion factors associated with grade 3-4 ICAHT and developed a predictive model in 602 patients with hematologic malignancies undergoing CAR T-cell therapy at Fred Hutch Cancer Center. Methods: Grading of early hematotoxicity (day-0-30 after CAR T-cell cell infusion) was automated using the heatwaveR package. Associations with 50 patient, disease-related, and laboratory factors, and grade 3-4 ICAHT were modeled using univariate and multivariable logistic regression. Results: The most common disease types were aggressive non-Hodgkin lymphoma (NHL; n = 293; 49%), indolent NHL (n = 150; 25%), and acute lymphoblastic leukemia (ALL; n = 94; 16%). The most common CAR T-cell products were the investigational CD19 CAR T-cell product JCAR014 (n = 197; 33%), axicabtagene ciloleucel (n = 129; 21%), and lisocabtagene maraleucel (n = 73; 12%). Incidences of early ICAHT grades 1, 2, 3, and 4 were 319 (53%), 96 (16%), 60 (10%), and 35 (6%) patients, respectively. Baseline patient factors associated with grade 3-4 ICAHT included ALL (reference: aggressive NHL, OR = 4.18, 95% CI, 2.41-7.26, p &lt; 0.001) , Hispanic or Latino ethnicity (OR = 2.17, 95% CI, 1.07-4.20, p = 0.025), and lower age (OR = 1.03, 95% CI, 1.02-1.05, p &lt; 0.001). Pre-lymphodepletion (LD) laboratory factors associated with grade 3-4 ICAHT in univariate analyses included lower ANC (OR = 6.67 per log10 cells/μL, 95% CI, 4.0-11.1, p &lt; 0.001), LDH (OR = 8.70per log10U/L, 95% CI, 4.03-19.4, p &lt; 0.001), CRP (OR = 3.18 per log10mg/L, 95% CI, 2.06-5.07, p &lt; 0.001), and ferritin (OR = 6.07 per log10mg/L, 95% CI, 3.65-10.6, p &lt; 0.001). Peak CRP (OR = 15.6, 95% CI, 7.27-36.4, p &lt; 0.001), peak ferritin (OR = 7.41, 95% CI, 5.02-11.3, p &lt; 0.001), peak CRS grade (OR = 2.01, 95% CI, 1.59-2.56, p &lt; 0.001), and peak ICANS grade (OR = 1.51, 95% CI, 1.29-1.77, p &lt; 0.001) after CAR T-cell infusion were also strongly associated with grade 3-4 ICAHT. A multivariable model using restricted cubic splines and including disease type, pre-LD ANC, pre-LD LDH, peak CRP, peak ferritin, and CRS grade demonstrated high discrimination to predict grade 3-4 ICAHT (C-index = 0.89). Internal validation using bootstrapping showed near-perfect calibration without overfitting. Sensitivity and specificity based on the Youden criteria was 74% and 90%, respectively. The sensitivity and specificity of the CAR-HEMATOTOX score in predicting grade 3-4 ICAHT was 93% and 30%, respectively. Conclusions: We identified pre- and post-infusion predictors of grade 3-4 ICAHT and internally validated a multivariable logistic regression model including disease-type, pre-LD ANC, pre-LD LDH, peak CRP, peak ferritin, and CRS grade. We plan to further evaluate our model in an external cohort.

PMB-CT01 (BAFFR-CAR T cell) therapy to examine preliminary safety and clinical responses in patients with B-cell malignancies who are ineligible for or failed CD19-directed therapy, including CD19-negative disease.

6534 Background: CD19-targeted therapies have shown remarkable efficacy in patients with B-cell malignancies. However, relapse with CD19 loss as a mechanism of tumor escape is common and represents a serious challenge. Patients who are ineligible for or have failed prior CD19-directed therapy have limited salvage options and a very poor prognosis. The B-cell activating factor receptor (BAFF-R) is functionally expressed in B-cell acute lymphoblastic leukemia (B-ALL) and non-Hodgkin lymphomas (NHL), including in patients with CD19-negative relapse (Qin et al., Sci Transl Med. 2019). As a critical regulator of B-cell function and survival, BAFF-R may be less prone to downregulation by tumors as a mechanism of antigen escape. Methods: We are conducting two phase 1 clinical trials of BAFFR-CAR T cells in patients with relapsed/refractory (r/r) B-ALL (NCT04690595) and NHL (NCT05370430). Primary endpoints are dose limiting toxicities (DLTs) and all other toxicities. Secondary endpoints include response rate, minimal residual disease (MRD) negative rate, PFS and OS. Response is evaluated using European LeukemiaNet criteria for B-ALL and Lugano 2014 for NHL. Results: As of Feb. 1st, 2024, 1 B-ALL and 3 NHL patients have completed treatment and post-treatment evaluations. Each received 50M BAFFR CAR T cells (starting dose level in both trials). The B-ALL patient had CD19/CD20/CD22-negative disease, and had received prior blinatumomab. NHL patients #1 and #2 both had CD19-expressing mantle cell lymphoma (MCL) and had received prior CD19 CAR T cells. Patient #2 had also received a CD3/CD20 bispecific antibody. NHL patient #3 had CD19/CD20-negative T cell/histiocyte-rich large B-cell lymphoma (THRBCL) and had not received prior CD19 CAR T cells. There were no DLTs, all patients had Gr. 1 cytokine release syndrome, and 2/3 NHL patients had Gr. 1 immune effector cell-associated neurotoxicity syndrome. Robust CAR T cell expansion was seen in all patients with a peak on days 12-14 post-infusion. The B-ALL and the 2 MCL patients reached MRD-negative complete response (CR) at 1 month post-treatment. The THRBCL patient had partial response (PR) at 1 month that converted to CR at 3 months. The B-ALL patient successfully transitioned to allogeneic HCT while in CR at 3 months post-infusion. Responses are ongoing in all NHL patients at 14, 10, and 8 months for patients #1, #2 and #3, respectively. Additional patients have been enrolled at the next dose level (200M CAR T cells). Results for these patients will be presented at the meeting. Conclusions: With a 100% CR rate at 3 months in the first 4 patients and durable responses at dose level 1, BAFFR-CAR T cells are a promising therapeutic option for patients with r/r B-cell malignancies who are ineligible or failed prior CD19-targeted therapy, including with CD19 antigen loss. Clinical trial information: NCT04690595 , NCT05370430 .

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 &gt;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 .

PD-1-CD28-enhanced receptor and CD19 CAR-modified tumor-infiltrating T lymphocytes produce potential anti-tumor ability in solid tumors

The limited expansion ability and functional inactivation of T cells within the solid tumor microenvironment are major problems faced during in the application of using tumor-infiltrating lymphocytes (TILs) in vivo. We sought to determine whether TILs carrying a PD-1-CD28-enhanced receptor and CD19 CAR could overcome this limitation and mediate tumor regression. First, anti-tumor effects of PD-1-CD28-enhanced receptor or CD19 CAR modified NY-ESO-1-TCR-T cells to mimic the TILs function (hereafter “PD-1-CD28-TCR-T” or “CD19 CAR-TCR-T” cells, respectively) were tested using the NY-ESO-1 over-expressed tumor cell line in vitro and in a tumor-bearing model. Furthermore, the safety and anti-tumor ability of S-TILs (TILs modified through transduction with a plasmid encoding the PD-1-CD28-T2A-CD19 CAR) were evaluated in vivo. PD-1-CD28-TCR-T cells showed a formidable anti-tumor ability that was not subject to PD-1/PD-L1 signaling in vivo. CD19 CAR-TCR-T cells stimulated with CD19+ B cells exhibited powerful expansion and anti-tumor abilities both in vitro and in vivo. Three patients with refractory solid tumors received S-TILs infusion. No treatment-related mortality was observed, and none of the patients experienced serious side effects. One patient with melanoma achieved a partial response, and two patients with colon or kidney cancer achieved long-term stable disease following S-TILs therapy. To the best of our knowledge, this is the first study describing the safety and efficacy of the adoptive transfer of autologous S-TILs to control disease in patients with advanced cancers, suggesting that S-TILs may be a promising alternative therapy for cancer.

Chimeric antigen receptor T-cell infusion for large B-cell lymphoma in complete remission: a center for international blood and marrow transplant research analysis.

CD19 CAR T-cell (CAR-T) therapy is commonly administered to patients with relapsed or refractory large B-cell lymphomas (LBCL), but salvage or bridging therapy can sometimes lead to a complete response (CR) prior to infusion. Limited studies have assessed the outcomes of patients infused in CR. A total of 134 patients with LBCL in CR prior to CAR-T infusion were identified from the CIBMTR registry, with median prior lines of therapy of 3 (range 2-9). At two years post-infusion, the probability of progression-free survival was 43.5% (95% CI 34.4-52.8) and the probability of overall survival was 63.8% (95% CI 54.4-72.6). The cumulative incidence rates of non-relapse mortality and relapse/progression at two years were 9.2% (95% CI 4.5-15.4) and 47.3% (95% CI 38.2-56.6), respectively. The rate of grade 3 or higher cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were 2.2% and 8.2%, respectively. In summary, CAR-T in heavily pretreated patients with LBCL who are in CR following two or more lines of prior therapy demonstrate that a subset of patients may remain free of progression at two years. Additionally, the toxicity profile was impressive with very low rates of grade 3 CRS and ICANS.

Selective CAR T cell-mediated B cell depletion suppresses IFN signature in SLE.

Applying advanced molecular profiling together with highly specific targeted therapies offers the possibility to better dissect the mechanisms underlying immune-mediated inflammatory diseases such as systemic lupus erythematosus (SLE) in humans. Here we apply a combination of single-cell RNA-Seq and T/B cell repertoire analysis to perform an in-depth characterization of molecular changes in the immune-signature upon CD19 CAR T cell-mediated depletion of B cells in patients with SLE. The resulting data sets not only confirm a selective CAR T cell-mediated reset of the B cell response but simultaneously reveal consequent changes in the transcriptional signature of monocyte and T cell subsets that respond with a profound reduction in type I IFN signaling. Our current data, thus, provide evidence for a causal relationship between the B cell response and the increased IFN signature observed in SLE and additionally demonstrate the usefulness of combining targeted therapies and analytic approaches to decipher molecular mechanisms of immune-mediated inflammatory diseases in humans.

Emerging Innate Immune Cells in Cancer Immunotherapy: Promises and Challenges.

Immune checkpoint inhibitor (ICI)-based therapy has made an unprecedented impact on survival benefit for a subset of cancer patients; however, only a subset of cancer patients is benefiting from ICI therapy if all cancer types are considered. With the advanced understanding of interactions of immune effector cell types and tumors, cell-based therapies are emerging as alternatives to patients who could not benefit from ICI therapy. Pioneering work of chimeric antigen receptor T (CAR-T) therapy for hematological malignancies has brought encouragement to a broad range of development for cellular-based cancer immunotherapy, both innate immune cell-based therapies and T-cell-based therapies. Innate immune cells are important cell types due to their rapid response, versatile function, superior safety profiles being demonstrated in early clinical development, and being able to utilize multiple allogeneic cell sources. Efforts on engineering innate immune cells and exploring their therapeutic potential are rapidly emerging. Some of the therapies, such as CD19 CAR natural killer (CAR-NK) cell-based therapy, have demonstrated comparable early efficacy with CD19 CAR-T cells. These studies underscore the significance of developing innate immune cells for cancer therapy. In this review, we focus on the current development of emerging NK cells, γδ T cells, and macrophages. We also present our views on potential challenges and perspectives to overcome these challenges.

T-cell recruiting immunotherapies in B-cell lymphoma - the future backbone for all therapy lines?

The introduction of immunologically targeted therapies has represented a significant advancement in the treatment of B-cell lymphomas, particularly aggressive B-cell lymphoma. CD19 CAR-T cells such as Axicabtagen-Ciloleucel (Axi-cel) and Lisocabtagen Maraleucel (Liso-cel) have been approved since 2022 and 2023, respectively, for second-line therapy of Diffuse Large B-Cell Lymphomas (DLBCL), when there is primary refractory disease or relapse within 12 months after the end of first-line therapy. These therapies result in a significant improvement in progression-free survival compared to the previous standard therapy (salvage chemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation). Especially in elderly patients or patients with underlying medical conditions, CAR-T cell therapies like Axi-cel and Liso-cel demonstrate acceptable tolerability and high efficacy.Furthermore, bispecific T-cell-engaging antibodies ("bispecifics") such as Glofitamab, Epcoritamab, and Mosunetuzumab also represent promising treatment options for patients with relapsed disease after failure of second- or later line therapy and show efficacy even in a subset of patients relapsing after CD19 CAR-T cells. However, randomized study results for these substances are not yet available. They are expected to be used in earlier lines of therapy in the future, especially in combination with standard chemotherapy regimens. Common side effects of bispecific antibody therapies are cytokine release syndrome (CRS) and immune-mediated cytopenias, whereas immune-cell associated neurotoxicity syndrome (ICANS) is relatively rare compared to CD19 CAR T cells. In summary, bispecifics represent a novel, highly effective immunotherapy for the treatment of lymphomas with a very favourable toxicity profile.

High efficacy of CD19 CAR T cells in patients with transformed Waldenström macroglobulinemia

AbstractHistologic transformation of Waldenström macroglobulinemia (HT-WM) carries a poor prognosis with standard treatments. Here, we report the first series of HT-WM treated with chimeric antigen receptor T cells showing a high efficacy and no unexpected toxicity.