Chimeric Antigen Receptor-modified Research Articles

Advancements in cancer immunotherapies targeting CD20: from pioneering monoclonal antibodies to chimeric antigen receptor-modified T cells.

CD20 located predominantly on the B cells plays a crucial role in their development, differentiation, and activation, and serves as a key therapeutic target for the treatment of B-cell malignancies. The breakthrough of monoclonal antibodies directed against CD20, notably exemplified by rituximab, revolutionized the prognosis of B-cell malignancies. Rituximab, approved across various hematological malignancies, marked a paradigm shift in cancer treatment. In the current landscape, immunotherapies targeting CD20 continue to evolve rapidly. Beyond traditional mAbs, advancements include antibody-drug conjugates (ADCs), bispecific antibodies (BsAbs), and chimeric antigen receptor-modified (CAR) T cells. ADCs combine the precision of antibodies with the cytotoxic potential of drugs, presenting a promising avenue for enhanced therapeutic efficacy. BsAbs, particularly CD20xCD3 constructs, redirect cytotoxic T cells to eliminate cancer cells, thereby enhancing both precision and potency in their therapeutic action. CAR-T cells stand as a promising strategy for combatting hematological malignancies, representing one of the truly personalized therapeutic interventions. Many new therapies are currently being evaluated in clinical trials. This review serves as a comprehensive summary of CD20-targeted therapies, highlighting the progress and challenges that persist. Despite significant advancements, adverse events associated with these therapies and the development of resistance remain critical issues. Understanding and mitigating these challenges is paramount for the continued success of CD20-targeted immunotherapies.

CT radiomics can predict disease progression within 6 months after chimeric antigen receptor-modified T-cell therapy in relapsed/refractory B-cell non-Hodgkin's lymphoma patients

To predict progression within 6 months after chimeric antigen receptor-modified (CAR) T-cell therapy for relapsed/refractory (R/R) B-cell non-Hodgkin's lymphoma (B-NHL) patients by radiomic indexes derived from contrast-enhanced computed tomography (CECT) examinations. Seventy R/R B-NHL patients who underwent CECT before treatment with CAR T-cells were examined retrospectively. In total, 297 volumes of interest for lesions were segmented from CECT images. Patients without and with disease progression were assigned to groups 1 and 2, respectively. Radiomic and combined predictive models were constructed by three machine-learning algorithms using features from the training set, respectively. Furthermore, predictive models were constructed based on multi-lesion-based and largest-lesion-based radiomic features, respectively. In the test set, no marked differences were observed between the areas under the curves (AUCs) of the combined and radiomic models for all three machine-learning algorithms (all p>0.05). Differences in machine-learning algorithms did not significantly affect the predictive performances of the models. Radiomics and combined models constructed with multi-lesion-based radiomic features showed better predictive performances than those applying largest-lesion-based radiomic features (all p<0.05 for comparisons between combined models). CECT-based radiomic features may be applied to predict disease progression in R/R B-NHL patients within 6 months after CAR T-cell treatment, and radiomic features from multiple lesions may have better predictive efficacy. Different machine-learning algorithms may not show significant differences in prediction performance.

Clinical characteristics and prognosis of 16 relapsed/refractory B-cell malignancy patients with CAR T-cell-related hyperferritinaemia.

With the success of chimeric antigen receptor-modified (CAR) T-cell therapy for relapsed/refractory (r/r) B-cell malignancies, severe complications after CAR T-cell infusion have emerged as nonnegligible prognosis-related factors. However, the prognosis of patients with CAR T-cell-related hyperferritinaemia (HFA) is unclear. We report the efficacy and safety of CAR T-cell therapy in 16 r/r B-cell malignancy patients with CAR T-cell-related HFA. The rates of serum ferritin levels above 10,000 ng/ml during CAR T-cell therapy were 6.2% and 14.3% in B-cell non-Hodgkin’s lymphoma (B-NHL) and acute B lymphocyte leukemia (B-ALL), respectively. These patients were characterized by an extremely high tumor burden and a high rate of extranodal involvement. In lymphoma, the complete remission (CR) rate was 37.5% (3/8), which was lower than that in the control group with the lowest value of ferritin (CR was 87.5% (7/8), P=0.0406), and it could also be seen that the OS of the control group (1-year OS rate 100%) had a better trend than HFA group (1-year OS rate 50%). In the B-ALL patients, the OS of the control group (1-year OS rate 100%) was higher than HFA group (1-year OS rate 45%, P=0.0189), although there was no significant difference in CR rate. High-grade CRS (≥3) occurred in 56.25% of the patients, and the mortality rate was 56.25%, which was significantly higher than control group (12.5% and 12.5%, P=0.009). The peak serum ferritin level in the patients who died of CRS was significantly higher than others (P=0.0168). Regardless of whether the CAR T-related MAS diagnostic criteria were met, there was no significant difference in ORR and OS in HFA group, however patients with MAS showed a higher rate of high-grade CRS. Interestingly, in our study, glucocorticoid intervention in HFA group showed little impact on expansion of CAR-T cells, whether compared with control group or compared within HFA group by dividing patients into high and low dosage subgroups based on the median dose of glucocorticoid. High mortality was observed in patients with CAR T-cell-related HFA. Early glucocorticoid intervention might be worth trying to improve the safety of CAR T therapy in these patients.

Common Trajectories of Highly Effective CD19-Specific CAR T Cells Identified by Endogenous T-cell Receptor Lineages.

Utilizing clonal trajectories to define transcriptional potential, we find a unique signature of CAR T-cell effector precursors present in preinfusion cell products. Functional assessment of cells with this signature indicated early effector potential and resistance to exhaustion, consistent with postinfusion cellular patterns observed in patients. This article is highlighted in the In This Issue feature, p. 2007.

Chimeric Antigen Receptor-Modified T Cell Immunotherapy for Relapsed and Refractory Adult Burkitt Lymphoma.

Patients with Burkitt lymphoma who are refractory to initial therapy or who relapse after undergoing intensive chemotherapy and autologous stem cell transplantation (ASCT) usually have a poor prognosis. While there has been considerable progress in the use of chimeric antigen receptor-modified (CAR) T cell immunotherapy for the treatment of relapsed and refractory (r/r) malignancies, explicit data on adult patients with r/r Burkitt lymphoma are limited. We conducted two single-arm clinical trials to evaluate the clinical efficacy and toxicity of CD19/CD22 CAR T cell immunotherapy both alone (trial A) and in combination with ASCT (trial B) in adult patients with r/r Burkitt lymphoma. In total, 28 adult patients with r/r Burkitt lymphoma were enrolled [trial A (n = 15) and trial B (n = 13)]. The median doses of CD22 and CD19 CAR T cell infusions were 4.1 × 106/kg and 4.0 × 106/kg, respectively. Subsequently, after CAR T cell infusion, overall and complete responses were observed in 19 (67.9%) and 16 (57.1%) patients, respectively. The cumulative incidence rates of grade 2–4 cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome were 39.3% (11/28) and 10.7% (3/28), respectively. After a median follow-up duration of 12.5 months, 16 patients (5 in trial A and 11 in trial B) survived. Both the estimated 1-year progression-free and overall survival rates were 55.6%. Our preliminary results indicated that salvage therapy with CD19/CD22 CAR T cell infusion alone and that in combination with ASCT are effective in treating some adult patients with r/r Burkitt lymphoma.

Common trajectories of highly effective CD19-specific CAR T cells identified by endogenous T cell receptor lineages

Abstract Current chimeric antigen receptor-modified (CAR) T cell therapy products are evaluated in bulk, without assessment of the possible heterogeneity in effector potential between cells. Conceivably, only a subset of the pre-infusion product differentiates into optimal effectors. We generated a comprehensive single-cell gene expression and T cell receptor (TCR) sequencing dataset using both pre- and post-infusion CD19-CAR T cells from peripheral blood and bone marrow of pediatric patients with B cell acute lymphoblastic leukemia (B-ALL). We identified potent effector post-infusion cells with identical TCRs to a subset of pre-infusion CAR T cells. Effector precursor CAR T cells exhibited a unique transcriptional profile compared to other pre-infusion cells, and the number of effector precursor cells infused correlated with peak CAR T cell expansion. Additionally, we identified an unexpected cell surface phenotype (TIGIT+, CD62Llo, CD27−), conventionally associated with inhibiting effective T cell responses, that we used to successfully enrich for subsequent effector potential. Collectively, these results demonstrate that highly diverse effector potentials are present among cells in pre-infusion cell products, which can be exploited for diagnostic and therapeutic applications. Furthermore, we provide an integrative experimental and analytical framework for elucidating the biological mechanisms underlying effector development in other CAR T cell therapy products. This work was supported by the National Institutes of Health (NIH)/National Cancer Institute grant P30CA021765, NIH grants U01AI150747 and R01AI136514 (PGT), the American Society of Transplantation and Cellular Therapy (AT), the American Society of Hematology (AT), the Key for a Cure Foundation (PGT), the Mark Foundation ASPIRE Award (PGT), and the American Lebanese Syrian Associated Charities (SG, PGT). Part of the laboratory studies were performed by the Center for Translational Immunology and Immunotherapy (CeTI2), which is supported by SJCRH. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

Gp350-anchored extracellular vesicles: promising vehicles for delivering therapeutic drugs of B cell malignancies

Although chimeric antigen receptor-modified (CAR) T cell therapy has been successfully applied in the treatment of acute B lymphocytic leukemia, its effect on Burkitt lymphoma (BL) and chronic B lymphocytic leukemia (B-CLL) is unsatisfactory. Moreover, fatal side effects greatly impede CAR T cell application. Extracellular vesicles (EVs) are excellent carriers of therapeutic agents. Nevertheless, EVs mainly accumulate in the liver when administered without modification. As an envelope glycoprotein of Epstein–Barr viruses, gp350 can efficiently bind CD21 on B cells. Here, gp350 was directly anchored onto red blood cell EVs (RBC-EVs) via its transmembrane region combined with low-voltage electroporation. The results showed that gp350 could anchor to RBC-EVs with high efficiency and that the resulting gp350-anchored RBC-EVs (RBC-EVs/gp350Etp) exhibited increased targeting to CD21+ BL and B-CLL relative to RBC-EVs. After the loading of doxorubicin or fludarabine, RBC-EVs/gp350Etp had powerful cytotoxicity and therapeutic efficacy on CD21+ BL or B-CLL, respectively. Moreover, RBC-EVs/gp350Etp loaded with a drug did not exhibit any apparent systemic toxicity and specifically induced the apoptosis of tumor B cells but not normal B cells. Therefore, our findings indicate that drug-loaded RBC-EVs/gp350Etp may be adopted in the treatment of CD21+ B cell malignancies.

CD19 or CD20 CAR T Cell Therapy Demonstrates Durable Antitumor Efficacy in Patients with Central Nervous System Lymphoma.

Patients with central nervous system (CNS) lymphomas have a poor prognosis. Chimeric antigen receptor-modified (CAR) T cells have shown remarkable efficacy for B-cell non-Hodgkin's lymphoma. However, few studies have reported the effects of CAR T cells in the treatment of CNS lymphoma, and the duration of remission is short. In this study, seven CNS lymphoma patients (six patients with secondary CNS lymphomas and one patient with primary CNS lymphoma) were treated with CD19 or CD20 CAR T cell therapy, and the clinical efficacy and toxicity profiles were evaluated. All patients responded to CAR T cell therapy. Four patients achieved complete remission (CR), while three demonstrated partial remission. We also found that either CD19 or CD20 CAR T cells could be detected in the cerebrospinal fluid of four patients. The median progression-free survival and median overall survival were not assessed. The median duration of CR was 22.4 months. Five patients (5/7) in this cohort received combination therapy (bridging with autologous hematopoietic stem cell transplantation and programmed death-1 inhibitor for maintenance treatment) and three (3/7) received CAR T cell therapy as soon as possible after the relapse of CNS lymphoma. This could help explain why these patients achieved long-term remission. After a median follow-up of 10.4 months, three patients demonstrated disease progression, and the antigen loss of CD20 was confirmed as the reason for relapse in one patient. The results of this study suggest that CD19 or CD20 CAR T cells are effective against CNS lymphoma. This research was registered at http://www.chictr.org.cn (No. ChiCTR2000036350).

NCMP-20. PRE-INFUSION NEUROFILAMENT LIGHT CHAIN (NFL) LEVELS PREDICT THE DEVELOPMENT OF IMMUNE EFFECTOR CELL-ASSOCIATED NEUROTOXICITY SYNDROME (ICANS) – A MULTICENTER RETROSPECTIVE STUDY

Abstract BACKGROUND Neurological side effects after chimeric antigen receptor-modified (CAR) T cell therapy, termed immune effector cell-associated neurotoxicity syndrome (ICANS), are common and potentially devastating. We previously demonstrated that pre-infusion plasma neurofilament light chain (NfL), a well-established marker of neurodegeneration, may predict subsequent development of ICANS in a small, single-center cohort. This larger, retrospective multicenter study compares pre-infusion NfL to known post-infusion risk factors for developing ICANs including white blood cell (WBC) count, platelet count, C-reactive protein (CRP), fibrinogen, and ferritin levels. METHODS Inclusion criteria included available pre-infusion (up to 4 weeks prior to lymphodepletion) plasma from patients treated with a CAR T cell therapy (n = 30, 36% with ICANS, ASTCT consensus ICANS grade range 1-4). Exclusion criteria included confounding diagnoses known to elevate NfL levels (dementia, multiple sclerosis, recent stroke). Plasma NfL was assayed using a Simoa HD-1/HD-X kit (QuanterixTM). Post-infusion Day 3 or Day 5 WBC, Platelet, CRP, fibrinogen, and ferritin were obtained from the medical record. Group comparisons were done using log-rank tests with a Bonferroni-derived significance threshold, followed by receiver operating characteristic (ROC) curve classification. RESULTS Prior to infusion, individuals who ultimately developed ICANS had elevations in NfL ([87.6 v 29.4 pg/ml], p = 0.00004) with excellent classification (AUC 0.96), sensitivity (0.91) and specificity (0.95). Among known post-infusion risk factors, only post-infusion Day 3 ferritin (p = 0.004) and Day 5 ferritin (p = 0.003) differed between groups. Classification was inferior for both time points (Day 3 AUC = 0.87, specificity 0.71; Day 5 AUC 0.87, specificity 0.86). CONCLUSION Pre-infusion plasma NfL levels are a robust early marker for the development of ICANS that exceeds known post-infusion markers. Our findings suggest the risk of developing ICANS reflects pre-existing host-factors. Foreknowledge of ICANS development of may permit early, aggressive (preemptive or prophylaxis) ICANS-directed therapies, improving patient outcomes.

NCMP-24. PRE-INFUSION NEUROFILAMENT LIGHT CHAIN (NFL) LEVELS PREDICT THE DEVELOPMENT OF IMMUNE EFFECTOR CELL-ASSOCIATED NEUROTOXICITY SYNDROME (ICANS)

Abstract Neurological side effects after chimeric antigen receptor-modified (CAR) T cell therapy are common and potentially devastating. Termed immune effector cell-associated neurotoxicity syndrome (ICANS), symptoms range from mild encephalopathy to diffuse cerebral edema. No predictive biomarkers exist to identify individuals at risk for developing ICANS. Serum neurofilament light chain (NfL) is a well-established marker of neural injury known to dynamically change in neuro-inflammatory disorders (e.g. multiple sclerosis). We hypothesized individuals undergoing CAR T cell therapy who ultimately developed ICANS would have early and sustained elevations in serum NfL. We performed a retrospective analysis of serum samples from 11 individuals treated with tisagenlecleucel or axicabtagene ciloleucel (mean age 61.3, 18% female, 27% ICANS, all with peak severity score 3). Most individuals had a longitudinal sampling at baseline, pre-infusion, post-transfusion day (PTD) 1, PTD 3, PTD 7, PTD 14, and PTD 30. Serum NfL were assayed using a Simoa HD-1/HD-X kit (QuanterixTM). We found that individuals who developed ICANS had early and sustained elevations in serum NfL levels at baseline (p = 0.0075), pre-infusion (p = 0.0172), and PTD 3 (p = 0.0026) and PTD 30 (p = 0.0066). All group comparisons survived multiple comparison testing using false-discovery rate (FDR). Receiver operating characteristic (ROC) curve classification by logistic regression of serum NfL revealed an area under the curve (AUC) of 1.0 with a cut-off of 44 pg/mL. No correlation was observed between NfL levels and age, sex, or history of central nervous system involvement of the underlying malignancy. In summary, we found serum NfL levels are a robust, early marker for the development of ICANS. Our findings suggest the risk of developing ICANS reflects pre-transfusion host-factors, permitting the screening well in advance of drug administration.

Anti CD19/22 Cocktail CAR T-Cell Therapy Can Improve the Outcomes of Patients with TP53-Mutated Relapsed/Refractory B-Cell Lymphoma

Mutations of the Tp53 gene occur in a subset of patients with refractory/relapse B-cell lymphoma and confer an exceedingly adverse prognosis. Chimeric antigen receptor-modified (CAR) T-cell immunotherapy represents a novel promising treatment and has achieved impressive anti-tumor responses in patients with refractory or relapsed B cell malignancies. Whether CAR T cell therapy can improve the outcomes of refractory/relapse B-cell lymphoma with Tp53 mutations or high-risk functional classification of Tp53 mutations has not been fully investigated yet. In phase 2 trial, we evaluated the anti-CAR 19/22 cocktail therapy in patients with relapsed or refractory B-cell lymphoma with Tp53 mutations. The primary endpoint was the percentage of patients with an objective response (complete and partial response). The high-risk Tp53 mutations were defined as missense mutations, 'disruptive' mutations and the 'high-risk group of evolutionary action (EAp53) score. The outcome impact of CAR T cell therapy on high-risk Tp53 mutations were also assessed. Between September 2016 to January 2020, a total of 30 patients [median age, 44.0 years (range: 28.0 to 61.0)] were enrolled. The primary efficacy analysis showed that 76.7 % (95%CI: 61% to 93%) patients have best objective response(Figure 1A), while 60.0 % (95%CI: 41% to 79%) patients at month three maintained the objective response(Figure 1B). At a median follow-up of 7.95 months (range: 1.13 to 42.76), the 12-months progression-free survival and overall survival rate were 43.33% and 45.33% respectively(Figure 1C-D). The therapy led to similar serious and life-threatening toxic effects with those reported with other CAR T-cell therapies. For all 30 enrolled patients, total 32 Tp53 Mutations were detected in this cohort including 23 missense, 4 splice site mutations, 4 insertions, 2 deletions and 1 nonsense mutation. Two Tp53 mutations were found in 2 patients. 21 patients were assessed with Tp53 FISH and 14 patients (66.66%) had 17p-. There is no difference on ORR,OS and PFS in patients based on three different Tp53-specific scoring systems. The ORR at three months predicts the long-term survival of this group of patients (Figure 1E-F). CAR19/22 T-cell cocktail therapy can improve the outcome of r/r B-cell lymphoma with high-risk of functional classification of Tp53 mutation. The patients who achieved overall response at month three can greatly benefit from CAR19/22 T-cell cocktail therapy with long-term favorable outcome. Trial registration: ChiCTR-OPN-16008526. Key words: B cell lymphoma; CAR T-cell therapy; Tp53 mutation; outcome Figure 1 Disclosures No relevant conflicts of interest to declare.

EGLIF-CAR-T Cells Secreting PD-1 Blocking Antibodies Significantly Mediate the Elimination of Gastric Cancer.

ObjectiveTo investigate the anti-tumor effects of programmed cell death protein 1 (PD-1) scFv-secreting EGFR-chimeric antigen receptor-modified (CAR)-T cells against gastric cancer.MethodsSecond-generation EGFR-CAR-T cells and fourth-generation PD-1 scFv-secreting EGFR-CAR-T cells were engineered. The anti-tumor activities of chimeric antigen receptor-modified (CAR)-T cells were analyzed in vitro by long-term co-culture with gastric cancer cells. The tumor scavenging capacity in vivo was evaluated in xenograft and PDX mouse models.ResultsEGFR-CAR-T cells secreting PD-1 scFv showed enhanced long-term tumor cell killing capacity in vitro. These cells also showed significant anti-tumor effect in the subcutaneous xenograft model of gastric cancer as well as in the PDX model, and autocrine PD-1 antibody secretion significantly increased tumor infiltration of the CAR-T cells.ConclusionEGFR-CAR-T cells secreting PD-1 scFv are highly effective against gastric cancer and offer new insights into anti-cancer immunotherapy.

Bispecific Antibodies: A New Era of Treatment for Multiple Myeloma.

Despite the introduction of novel agents such as proteasome inhibitors, immunomodulatory drugs, and autologous stem cell transplant, multiple myeloma (MM) largely remains an incurable disease. In recent years, monoclonal antibody-based treatment strategies have been developed to target specific surface antigens on MM cells. Treatment with bispecific antibodies (bsAbs) is an immunotherapeutic strategy that leads to an enhanced interaction between MM cells and immune effector cells, e.g., T-cells and natural killer cells. With the immune synapse built by bsAbs, the elimination of MM cells can be facilitated. To date, bsAbs have demonstrated encouraging results in preclinical studies, and clinical trials evaluating bsAbs in patients with MM are ongoing. Early clinical data show the promising efficacy of bsAbs in relapsed/refractory MM. Together with chimeric antigen receptor-modified (CAR)-T-cells, bsAbs represent a new dimension of precision medicine. In this review, we provide an overview of rationale, current clinical development, resistance mechanisms, and future directions of bsAbs in MM.

CAR T-Cell Therapy for B-Cell non-Hodgkin Lymphoma and Chronic Lymphocytic Leukemia: Clinical Trials and Real-World Experiences.

Chimeric antigen receptor-modified (CAR) T cells targeting CD19 have revolutionized the treatment of relapsed or refractory aggressive B-cell lymphomas, and their use has increased the cure rate for these cancers from 10 to 40%. Two second-generation anti-CD19 CAR T-cell products, axicabtagene ciloleucel and tisagenlecleucel, have been approved for use in patients, and the approval of a third product, lisocabtagene maraleucel, is expected in 2020. The commercial availability of the first two products has facilitated the development of real-world experience in treating relapsed or refractory aggressive B-cell lymphomas, shed light on anti-CD19 CAR T-cell products' feasibility in trial-ineligible patients, and raised the need for strategies to mitigate the adverse effects associated with anti-CD19 CAR T-cell therapy, such as cytokine release syndrome, neurotoxicity, and cytopenia. In addition, promising clinical data supporting the use of anti-CD19 CAR T-cell therapy in patients with indolent B-cell lymphomas or chronic lymphocytic leukemia have recently become available, breaking the paradigm that these conditions are not curable. Multiple clinical CAR T-cell therapy-based trials are ongoing. These include studies comparing CAR T-cell therapy to autologous stem cell transplantation or investigating their use at earlier stages of disease, novel combinations, and novel constructs. Here we provide a thorough review on the use of the anti-CD19 CAR T-cell products axicabtagene ciloleucel, tisagenlecleucel and lisocabtagene maraleucel in patients with indolent or aggressive B-cell lymphoma or with chronic lymphocytic leukemia, and present novel CAR T cell-based approaches currently under investigation in these disease settings.

High Cytotoxic Efficiency of Lentivirally and Alpharetrovirally Engineered CD19-Specific Chimeric Antigen Receptor Natural Killer Cells Against Acute Lymphoblastic Leukemia.

Autologous chimeric antigen receptor-modified (CAR) T cells with specificity for CD19 showed potent antitumor efficacy in clinical trials against relapsed and refractory B-cell acute lymphoblastic leukemia (B-ALL). Contrary to T cells, natural killer (NK) cells kill their targets in a non-antigen-specific manner and do not carry the risk of inducing graft vs. host disease (GvHD), allowing application of donor-derived cells in an allogenic setting. Hence, unlike autologous CAR-T cells, therapeutic CD19-CAR-NK cells can be generated as an off-the-shelf product from healthy donors. Nevertheless, genetic engineering of peripheral blood (PB) derived NK cells remains challenging and optimized protocols are needed. In our study, we aimed to optimize the generation of CD19-CAR-NK cells by retroviral transduction to improve the high antileukemic capacity of NK cells. We compared two different retroviral vector platforms, the lentiviral and alpharetroviral, both in combination with two different transduction enhancers (Retronectin and Vectofusin-1). We further explored different NK cell isolation techniques (NK cell enrichment and CD3/CD19 depletion) to identify the most efficacious methods for genetic engineering of NK cells. Our results demonstrated that transduction of NK cells with RD114-TR pseudotyped retroviral vectors, in combination with Vectofusin-1 was the most efficient method to generate CD19-CAR-NK cells. Retronectin was potent in enhancing lentiviral/VSV-G gene delivery to NK cells but not alpharetroviral/RD114-TR. Furthermore, the Vectofusin-based transduction of NK cells with CD19-CARs delivered by alpharetroviral/RD114-TR and lentiviral/RD114-TR vectors outperformed lentiviral/VSV-G vectors. The final generated CD19-CAR-NK cells displayed superior cytotoxic activity against CD19-expressing target cells when compared to non-transduced NK cells achieving up to 90% specific killing activity. In summary, our findings present the use of RD114-TR pseudotyped retroviral particles in combination with Vectofusin-1 as a successful strategy to genetically modify PB-derived NK cells to achieve highly cytotoxic CD19-CAR-NK cells at high yield.

CR4 RESOURCE UTILIZATION WITHIN 30 DAYS OF CAR T CELLS FOR HEMATOLOGIC MALIGNANCIES

To characterize institutional resources for 30 days after chimeric antigen receptor-modified (CAR) T cells administration. Adult patients treated on selected investigator-initiated clinical trials of CAR T cell therapy at Memorial Sloan Kettering Cancer Center were identified from the institutional database. Utilization data was collected from day -7 through day 30 from CAR T cell infusion. Descriptive statistics were used to analyze the data. Patients with B-cell acute lymphoblastic leukemia (ALL, 56, 53%), chronic lymphocytic leukemia (CLL, 37, 35%), and multiple myeloma (MM, 13, 12%) received CAR T cells from 6/2007 to 4/2018 on 4 clinical trials. The median age was 53 yrs (range 22-77) with 35% female. The median length of stay for the admission during which CAR T cells was given was 23 days (range 4 -38), with 41% in the intensive care unit (ICU) for at least 1 day, with a range of 1-28 days. A total of 40,327 laboratory panels and 955 radiology studies occurred. Seventeen percent of the labs were complete blood counts, basic or comprehensive metabolic panels, or liver function tests. Among the radiology studies, 25% were CT scans, 10% MRIs, 4% PET scans, 6% ultrasounds, and 56% x-rays, with differences in patterns of use by disease type. 20,367 medications were given with 102/106 pts receiving chemotherapy. All patients received some antibiotics. 25 doses of tocilizumab were given to 20 patients (19%), with 25% of ALL pts receiving a dose. Pressors were given to 20% of patients and growth factors to 57%. Identifying the resources needed for CAR T cell therapy will allow for better resource allocation. Improvement and standardization CAR T cell-related toxicity management may permit safer delivery of this therapy and reduce costs per patient. Comparison with alternative resource intense therapies is warranted.

Donor-Derived CD19-Targeted T Cell Infusion Eliminates B Cell Acute Lymphoblastic Leukemia Minimal Residual Disease with No Response to Donor Lymphocytes after Allogeneic Hematopoietic Stem Cell Transplantation

Abstract Leukemia relapse is still the leading cause of treatment failure after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for B cell acute lymphoblastic leukemia (B-ALL). Relapsed patients with B-ALL after allo-HSCT have a very short median survival. Minimal residual disease (MRD) is predictive of forthcoming hematological relapse after hematopoietic stem cell transplantation (HSCT); furthermore, eliminating MRD effectively prevents relapse. Donor lymphoblastic infusion (DLI) is the main established approach to treat B-ALL with MRD after allo-HSCT. However, about one-third of patients with MRD are non-responsive to DLI and their prognosis worsens. Although donor-derived cluster of differentiation (CD)19-directed chimeric antigen receptor-modified (CAR) T cells (CART19s) can potentially cure leukemia, the efficiency and safety of infusions with these cells have not yet been investigated in patients with MRD after HSCT. Between September 2014 and February 2018, six patients each received one or more infusions of CART19s from HSCT donors. Five (83.33%) achieved MRD-negative remission, and one case was not responsive to the administration of CAR T cells. Three of the six patients are currently alive without leukemia. No patient developed acute graft-versus-host disease (aGVHD), and no patient died of cytokine release syndrome. Donor-derived CAR T cell infusions seem to be an effective and safe intervention for patients with MRD in B-ALL after allo-HSCT and for those who were not responsive to DLI.

Resource Utilization Early after Chimeric Antigen Receptor (CAR) T Cell Infusion for Hematologic Malignancies

Resource Utilization Early after Chimeric Antigen Receptor (CAR) T Cell Infusion for Hematologic Malignancies

Cytokine release syndrome and neurotoxicity after CD19 chimeric antigen receptor-modified (CAR-) T cell therapy.

Chimeric antigen receptor-modified (CAR)-T cells have demonstrated impressive results in the treatment of haematological malignancies. However, cytokine release syndrome (CRS) and neurotoxicity are common toxicities which are potentially life-threatening in severe cases. Risk factors for CRS and neurotoxicity identified so far include disease burden, lymphodepletion intensity and CAR-T cell dose administered. Risk-adapted dosing, with lower CAR-T cell doses administered to B-cell acute lymphoblastic leukaemia patients with high marrow blast counts, has been successful at decreasing severe CRS rates in this population. Intervention with therapies, such as tocilizumab and corticosteroids, have been effective at ameliorating toxicity, enabling CAR-T cells to be administered safely to many patients without significantly compromising efficacy. Deeper understanding of the pathophysiology of underlying CRS and neurotoxicity will enable the development of novel approaches to reduce toxicity and improve outcomes.

Pharmacologically upregulated carcinoembryonic antigen-expression enhances the cytolytic activity of genetically-modified chimeric antigen receptor NK-92MI against colorectal cancer cells

BackgroundThe natural killer cell line, NK-92MI, is cytotoxic against various types of cancer. The aim of this study was to develop chimeric antigen receptor-modified (CAR) NK-92MI cells targeting carcinoembryonic antigen-expressing (CEA) tumours and increase killing efficacy by pharmacologically modifying CEA-expression.ResultWe generated anti-CEA-CAR NK-92MI cells by retroviral vector transduction. This genetically-modified cell line recognised and lysed high CEA-expressing tumour cell lines (LS174T) at 47.54 ± 12.60% and moderate CEA-expressing tumour cell lines (WiDr) at 31.14 ± 16.92% at a 5:1 effector: target (E/T) ratio. The cell line did not lyse low CEA-expressing tumour cells (HCT116) as they did their parental cells (NK-92MI cells). The histone deacetylase-inhibitor (HDAC) sodium butyrate (NaB) and the methylation-inhibitor 5-azacytidine (5-AZA), as epigenetic modifiers, induced CEA-expression in HCT116 and WiDr cells. Although the IC50 of 5 fluorouracil (5-FU) increased, both cell lines showed collateral sensitivity to anti-CEA-CAR NK-92MI cells. The cytolytic function of anti-CEA-CAR NK-92MI cells was increased from 22.99 ± 2.04% of lysis background to 69.20 ± 11.92% after NaB treatment, and 69.70 ± 9.93% after 5-AZA treatment, at a 10:1 E/T ratio in HCT116 cells. The WiDr cells showed similar trend, from 22.99 ± 4.01% of lysis background to 70.69 ± 10.19% after NaB treatment, and 59.44 ± 10.92% after 5-AZA treatment, at a 10:1 E/T ratio.ConclusionsThis data indicates that the effector-ability of anti-CEA-CAR NK-92MI increased in a CEA-dependent manner. The combination of epigenetic-modifiers like HDAC-inhibitors, methylation-inhibitors, and adoptive-transfer of ex vivo-expanded allogeneic-NK cells may be clinically applicable to patients with in 5-FU resistant condition.