Chimeric Antigen Receptor-modified T Therapy Research Articles

The Impact of Chimeric Antigen Receptor T Cell Quality to Clinical Safety and Efficacy in Non-Hodgkin Lymphomas

Background: Immunotherapy has become increasingly important in modern cancer treatments. It has become evident that chimeric antigen receptor-modified T (CAR-T) cells may be a promising treatment for hematological malignancies. Malignancies affecting B cells have been successfully treated using CAR-T cell therapies. Many studies have explored the influence of various factors on the efficacy and survival of CAR-T therapy from different aspects, including the patient's disease state, general condition, tumor burden, and even the dose of CAR-T cells infused. Few researchers have explored the effect of CAR-T cell quality on disease treatment impact on remission, survival, and prognosis. This study combines the essential condition of patients and quality data of CAR-T cells, such as transduction efficiency, killing efficiency, and the ratio of CD4+ and CD8+ subsets, to analyze CAR-T's safety and clinical efficacy in the treatment of non-Hodgkin's lymphoma in our center. Methods: This was a retrospective, single-center, investigator-initiated study. A total of 179 patients with NHL were included. Patients' baseline data were obtained from electronic medical records and telephone follow-ups. Laboratories provided data on the quality of patients' CAR-T cells. We conducted a multivariate analysis to determine the independent factors that influence treatment response and patient prognosis. Results: In our study, the median age of 179 NHL patients was 52 (range 17-78) years, and 51 (28.5%) were ≥60 years old. Before CAR-T treatment, 22 (12.3%) patients remained in complete remission (CR), and 83 (46.4%) patients were in progressive disease (PD). Among the available data, 105 (61.4%) patients had CAR-T cell killing efficiency (KE) <30%, while 66 (38.6%) patients had killing efficiency (KE) ≥30%. There were 101 (58%) patients with CAR-T cell transduction efficiency (TE) <40% and 73 (42%) with transduction efficiency (TE) ≥40%, respectively. CD4+/CD8+ ratio of CAR-T cells <1 in 32 (18.4%) patients and CD4+/CD8+ ratio of CAR-T cells ≥1 in 142 (81.6%) patients. Overall, the median event-free survival (PFS) was 10.6 months (95% CI: 4.064-17.136months), and the median overall survival has not yet been reached. The 6-month OS was 80.2%, and the 1-year OS was 70.6%. 2-year 0S is about 59.8%. In addition, we divided patients into different subgroups according to the TE and KE of CAR-T cells, and the results of multivariate logistic regression analysis were as follows. The subgroup with TE<40% had a higher complete remission rate than the subgroup with TE≥40%. And the subgroup with KE≥30% had a higher rate of complete remission than the subgroup with KE<30%, with p-values equal to 0.007 and 0.022, respectively. There was statistical significance, so TE and KE independently influenced efficacy factors. Multivariate cox regression analysis showed that the subgroup of CAR-T CD4+/CD8+<1 had better overall survival than CAR-T CD4+/CD8+≥1, p=0.039 (95% CI: 0.114-0.947). Therefore, the ratio of CAR-T CD4+/CD8+ was an independent factor for OS, while the subgroups of transduction efficiency and killing efficiency did not show statistical significance. Conclusion: In general, CAR-T therapy has shown significant efficacy in NHL, and the quality of CAR-T cells plays a vital role in treatment. Screening suitable CAR-T cells in future treatment will Make the treatment effect more satisfactory. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Chimeric Antigen Receptor T Cell Targeting to CD19 and CD22 Combined with Anti-PD-1 Antibody Induce High Response in Patients with Relapsed or Refractory B-Cell Non-Hodgkin Lymphoma

Objective: Despite the remarkable success of chimeric antigen receptor modified T (CAR-T) cell therapy for refractory or relapsed B cell non-Hodgkin lymphoma (R/R B-NHL), high rates of treatment failure and relapse after CAR-T cell therapy are considerable obstacles to overcome. Preclinical models have demonstrated that anti-PD-1 antibody is an attractive option following CAR-T therapy to reverse T cell exhaustion. Thus, we investigated their combination in R/R B-NHL.Methods: We performed a prospective, single-arm study of CAR-T cell combined with anti-PD-1 antibody treatment in R/R B-NHL (NCT04539444). Anti-PD-1 antibody was administrated on day 1 after patients received sequential infusion of anti-CD19 and anti-CD22 second-generation CAR-T cells, and the efficacy and safety of the combination treatment were evaluated.Results: From August 1, 2020 to June 30, 2021, a total of 11 patients were enrolled and completed at least 3 months follow-up. The median follow-up time is 5.8 months. Overall response was achieved in 9 of 11 patients (81.8%), and the complete response (CR) was achieved in 8 of 11 patients (72.7%). All 8 patients achieving CR still sustained remission at the last follow-up. The progression-free survival (PFS) and overall survival (OS) rates at 6 months were 80.8% and 100.0%, respectively. Cytokine release syndrome (CRS) occurred in only 4 patients (all were grade 1), and no neurotoxicity were observed.Conclusion: This study suggests that CAR-T cells combined with anti-PD-1 antibody elicit a safe and durable response in R/R B-NHL.Keywords: chimeric antigen receptor modified T cell, anti-PD-1 antibody, CD19/CD22, refractory or relapsed B cell non-Hodgkin lymphoma DisclosuresNo relevant conflicts of interest to declare. OffLabel Disclosure:We use the T cells were transduced with a lentivirus encoding the CD19-4-1BB-CD3 z and CD22-4-1BB-CD3 ztransgene to produce CAR-T cells. The main purpose of our study is to improve the response rate in patients with R/R B-NHL.

Cardiac Toxicity Associated with Cancer Immunotherapy and Biological Drugs.

Simple SummaryImmunotherapy is increasingly being used to treat solid tumors and lymphoproliferative diseases. The main classes of drugs are: HER-2-targeted therapies, CTLA-blockers, PD/PDL-1 inhibitors, CAR-T therapy. All these drugs are associated with meaningful cardiac toxicity, ranging from a transient decline of left ventricular function with complete reversibility to myocarditis with a high fatality rate.Cancer immunotherapy significantly contributed to an improvement in the prognosis of cancer patients. Immunotherapy, including human epidermal growth factor receptor 2 (HER2)-targeted therapies, immune checkpoint inhibitors (ICI), and chimeric antigen receptor-modified T (CAR-T), share the characteristic to exploit the capabilities of the immune system to kill cancerous cells. Trastuzumab is a monoclonal antibody against HER2 that prevents HER2-mediated signaling; it is administered mainly in HER2-positive cancers, such as breast, colorectal, biliary tract, and non-small-cell lung cancers. Immune checkpoint inhibitors (ICI) inhibit the binding of CTLA-4 or PD-1 to PDL-1, allowing T cells to kill cancerous cells. ICI can be used in melanomas, non-small-cell lung cancer, urothelial, and head and neck cancer. There are two main types of T-cell transfer therapy: tumor-infiltrating lymphocytes (or TIL) therapy and chimeric antigen receptor-modified T (CAR-T) cell therapy, mainly applied for B-cell lymphoma and leukemia and mantle-cell lymphoma. HER2-targeted therapies, mainly trastuzumab, are associated with left ventricular dysfunction, usually reversible and rarely life-threatening. PD/PDL-1 inhibitors can cause myocarditis, rare but potentially fulminant and associated with a high fatality rate. CAR-T therapy is associated with several cardiac toxic effects, mainly in the context of a systemic adverse effect, the cytokines release syndrome.

A phase I clinical trial of PSMA-directed/TGFβ-insensitive CAR-T cells in metastatic castration-resistant prostate cancer.

125 Background: Prostate specific membrane antigen (PSMA) is a highly expressed tumor-associated antigen potentially amenable to chimeric antigen receptor-modified T (CAR-T) cell therapy for castration-resistant prostate cancer (CRPC). However, a primary challenge to the success of CAR-T therapy in CRPC is the immunosuppressive microenvironment, characterized by high levels of TGFβ. The immunosuppressive functions of TGFβ can be inhibited in T cells using a dominant negative TGFβ receptor (TGFβRdn), thereby enhancing antitumor immunity. Methods: We conducted a first-in-human phase 1 clinical trial to evaluate the feasibility, safety and preliminary efficacy of PSMA-directed/TGFβ-insensitive CAR-T cells (CART-PSMA-TGFβRdn) in patients with metastatic CRPC (NCT03089203). In a 3+3 dose-escalation design, patients received a single dose of 1-3 x 107/m2 (Cohort 1) or 1-3 x 108/m2 (Cohort 2) CART-PSMA-TGFβRdn cells without lymphodepleting (LD) chemotherapy. In Cohort 3, one patient received 1-3 x 108/m2 CART-PSMA-TGFβRdn cells following a LD chemotherapy regimen of cyclophosphamide and fludarabine (Cy/Flu). In Cohort -3, three patients received 1-3 x 107/m2 CART-PSMA-TGFβRdn cells following Cy/Flu. Patients underwent metastatic tumor biopsies at baseline and on day 10 following treatment. Quantitative PCR of CART-PSMA-TGFβRdn DNA was performed at serial timepoints to evaluate for CAR-T expansion and persistence in peripheral blood and trafficking to target tissues. Multiplex cytokine analysis assessed CART-PSMA-TGFβRdn bioactivity. Results: Ten patients received CART-PSMA-TGFβRdn therapy across dose-level cohorts. All CART-PSMA-TGFβRdn infusion products met target transduction efficiency. Evaluation of CAR-T cellular kinetics demonstrated dose-dependent peripheral blood T cell expansion, as well as tumor tissue trafficking in post-treatment tumor biopsies. At Cohort 2 and above, 5 of 7 treated patients developed grade ≥2 cytokine release syndrome (CRS). Marked increases in inflammatory cytokines (IL-6, IL-15, IL-2, IFNγ) correlated with high-grade CRS events. One grade 5 adverse event (sepsis) occurred in Cohort 3. PSA decline was observed in 6 of 10 patients (median decline -33.2%, range -11.6% to -98.3%), and PSA30 response occurred in 4 of 10 patients (including one patient achieving PSA &lt; 0.1 ng/mL). Conclusions: Adoptive cellular therapy with CART-PSMA-TGFβRdn is safe and feasible in patients with metastatic CRPC. A dose-dependent and lymphodepletion chemotherapy-dependent relationship was observed with CART-PSMA-TGFβRdn cell expansion, cytokine expression, CRS, and anti-tumor effect. Correlative cell trafficking and paired tumor Nanostring analyses will be presented. Future clinical investigations seek to enhance anti-tumor efficacy, while optimizing the therapeutic window. Clinical trial information: NCT03089203.

Efficacy and Safety of CAR-Modified T Cell Therapy in Patients with Relapsed or Refractory Multiple Myeloma: A Meta-Analysis of Prospective Clinical Trials.

Background: In recent years, chimeric antigen receptor-modified T (CAR-T) cell therapy for B-cell leukemia and lymphoma has shown high clinical efficacy. Similar CAR-T clinical trials have also been carried out in patients with refractory/relapsed multiple myeloma (RRMM). However, no systematic review has evaluated the efficacy and safety of CAR-T cell therapy in RRMM. The purpose of this study was to fill this literature gap. Methods: Eligible studies were searched in PUBMED, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), CNKI, and WanFang from data inception to December 2019. For efficacy assessment, the overall response rate (ORR), minimal residual disease (MRD) negativity rate, strict complete response (sCR), complete response (CR), very good partial response (VGPR), and partial response (PR) were calculated. The incidence of any grade cytokine release syndrome (CRS) and grade ≥3 adverse events (AEs) were calculated for safety analysis. The effect estimates were then pooled using an inverse variance method. Results: Overall, 27 studies involving 497 patients were included in this meta-analysis. The pooled ORR and MRD negativity rate were 89% (95% Cl: 83–94%) and 81% (95% Cl: 67–91%), respectively. The pooled sCR, CR, VGPR, and PR were 14% (95% Cl: 5–27%), 13% (95% Cl: 4–26%), 23% (95% Cl: 14–33%), and 15% (95% Cl: 10–21%), respectively. Subgroup analyses of ORR by age, proportion of previous autologous stem cell transplantation (ASCT), and target selection of CAR-T cells revealed that age ≤ 55 years (≤55 years vs. > 55 years, p = 0.0081), prior ASCT ≤70% (≤70% vs. > 70%, p = 0.035), and bispecific CAR-T cells (dual B-cell maturation antigen (BCMA)/BCMA + CD19 vs specific BCMA, p = 0.0329) associated with higher ORR in patients. Subgroup analyses of remission depth by target selection suggested that more patients achieved a better response than VGPR with dual BCMA/BCMA + CD19 CAR-T cells compared to specific BCMA targeting (p = 0.0061). In terms of safety, the pooled incidence of any grade and grade ≥ 3 CRS was 76% (95% CL: 63–87%) and 11% (95% CL: 6–17%). The most common grade ≥ 3 AEs were hematologic toxic effects. Conclusion: In heavily treated patients, CAR-T therapy associates with promising responses and tolerable AEs, as well as CRS in RRMM. However, additional information regarding the durability of CAR-T cell therapy, as well as further randomized controlled trials, is needed.

Preclinical Development of Anti-FLT3 CAR-T Therapy for the Treatment of Acute Myeloid Leukemia

FMS-like tyrosine kinase 3 (FLT3) is a class III transmembrane receptor tyrosine kinase involved in survival, proliferation, and differentiation of hematopoietic stem/progenitor cells. It is preferentially expressed on the leukemic cells of myeloid lineage including acute myeloid leukemia (AML) and is mutated in approximately one-third of patients with AML, resulting in constitutive signaling associated with poor disease prognosis. Although small molecule inhibitors targeting FLT3 have shown some success in clinical trials, they only work transiently while resistance develops in virtually all patients. The only proven curative treatment for the relapsed or refractory (R/R) AML is allogenic hematopoietic stem cell transplantation (HSCT) which requires highly toxic conditioning regimens often associated with fatal side effects. Thus, there still remains an urgent need for the development of safe yet effective new therapies for the treatment of AML. We developed a novel chimeric antigen receptor modified T (CAR-T) cell therapy targeting FLT3 to eliminate FLT3+ R/R AML leukemia via cytotoxic T lymphocytes (CTL)-mediated cytolysis. Since FLT3 is also expressed on hematopoietic stem cells (HSCs) as well as on early hematopoietic progenitors (HPs), we evaluated the conditioning efficacy of our anti-FLT3 CAR-T in addition to its anti-leukemic activity. We first discovered a novel mouse monoclonal antibody that binds to the extracellular domain of human FLT3 with high affinity (0.8 nM EC50 in FLT3+ leukemic cell line REH) while not competing with FLT3 ligand in order to achieve unobstructed and efficient binding to FLT3. We next generated humanized single-chain variable fragment (scFv) antibodies and characterized their binding affinities. The scFv clone that exhibited highest binding to FLT3 (3.42 nM EC50 in REH cells) was used to design a third generation CAR construct with CD28 and 4-1BB costimulatory and CD3ζ activation domains. T cells isolated from peripheral blood (PB) were transduced with a lentiviral vector encoding the FLT3-CAR. Transduced cells exhibited stable expression of CAR protein and expanded over 120-fold after 18 days in culture. We demonstrated high cytotoxicity of FLT3-CAR-T cells towards AML-derived cell lines in co-culture experiments, even at effector-to-target cells ratios as low as 1:10. In vivo functionality of FLT3-CART was determined by flow cytometry analysis of leukemia burden in the peripheral blood of mice engrafted with GFP+ MOLM-13 (FLT3+ AML cell line) and treated with two doses of 4x106 control or FLT3-CAR-T cells. Compared to control, the appearance of MOLM-13 cells in peripheral blood was significantly delayed in FLT3-CAR-T treated mice. AML progression in mice was also assessed by detection of physical symptoms such as cachexia and hind-leg paralysis in terminal stages. FLT3-CAR-T treatment extended the median survival to 47 days compared to 24 days in control. Moreover, to test if our CAR-T therapy can also efficiently eliminate FLT3+ HSCs and HPs, humanized mice generated by engrafting human cord blood CD34+ cells were injected with autologous control or FLT3-CAR-T cells. Analysis of bone marrow 18 days post treatment, showed that mice that received FLT3-CAR-T cells exhibited dramatically lower frequencies (by 57% in CD38+ and 86% in CD38-) of human CD34+ hematopoietic stem and progenitor cells than control mice, suggesting the potential of CAR-T therapy for HSCT conditioning. In conclusion, our CAR-T therapy shows robust cytolytic activity against FLT3+ cells, demonstrates high efficacy in eradicating FLT3+ R/R AML leukemia in vivo and enables bone marrow conditioning for potentially curative HSCTs by specifically targeting FLT3+ HSCs and early HPs. To prevent the potentially harmful side effects associated with CAR-T therapies, such as cytokine release syndrome and cytotoxicity towards newly transplanted HSCs post conditioning, we are currently testing FLT3-CAR-T cells equipped with inducible caspase9 or EGFRT expression based safety switch to specifically eliminate CAR-Ts by administering FDA-approved small molecules or biologics. Disclosures Shrestha: Hemogenyx Pharmaceuticals LLC: Current Employment. Liang:Hemogenyx Pharmaceuticals LLC: Current Employment. Sirochinsky:Hemogenyx Pharmaceuticals LLC: Current Employment. Ben Jehuda:Hemogenyx Pharmaceuticals LLC: Current Employment. Sandler:Hemogenyx Pharmaceuticals LLC: Current Employment, Current equity holder in publicly-traded company.

Effective Chimeric Antigen Receptor T Cell Therapy for Relapsed and Refractory Acute Lymphoblastic Leukemia in Children Can be Administered Safely Under the Real-Time Monitoring of Th1/Th2 Cytokine Patterns Measured By the Cytometric Bead Array Technology

Background and Objectives: Chimeric antigen receptor modified T (CAR-T) cell therapy has emerged as a promising strategy for the treatment of relapsed and refractory hematological malignancies recently. CD19 chimeric antigen receptor T (CD19CAR-T) cell therapy is a representative case showing promising results in treating relapsed and refractory B-lineage acute lymphoblastic leukemia (r/r B-ALL). However, challenges remain due to the concurrent severe side-effects such as cytokine release syndrome (CRS) or neurological toxicities which may cause death if they are not properly managed. So, how to safely use the CAR-T cell therapy in patients has drawn a lot of concern and attention worldwide. The objective of this study was to investigate the cytokine patterns to early identify and monitor the severe side-effects of cytokine release syndrome (CRS) and neurotoxicity caused by the therapy so that the therapy can be safely administered. Patients and Method: From December 2015 to March 2017, five patients with r/r B-ALL treated with CD19CAR-T cells were enrolled in this study. The Th1/Th2 cytokines including Interleukin (IL)-2, IL-4, IL6, IL-10, Tumor necrosis factor (TNF) and Interferon-gamma (IFN-γ ) in the serum and cerebral spinal fluid (CSF) were quickly measured by cytometric bead array (CBA) technology which allowed the result being available within 5 hours after the samples taken. The test were repeated more than once a day during the therapy. Results: 5 pediatric patients (2 boys and 3 girls) with r/r B-ALL aged 4 months -12 years old were treated by CD19CAR-T cell therapy. Four patients achieved complete remission (80% of CR rate) with minimal residual diseases (MRD) negative detected by flow cytometry within 2 weeks. One patient did not respond to the therapy due to the poor quality of his T cells. Five to 10 times of cytokine measurements were carried out for the five patients. Two types of cytokine patterns were identified: (1) very high levels of IL-6, IFN-γ with moderately elevated IL-10 indicated the CAR-T therapy effective pattern; (2) IL-6 slightly - severely elevated IL-6 level without concurrent elevation of IFN-γ represented a CAR-T cell therapy ineffective pattern but rather indicating a current infection. All the four responding patients presented the CAR-T therapy effective cytokine pattern, while the non-responding patient presented the CAR-T therapy ineffective cytokine pattern. We also analyzed the relationship between the cytokine levels and the severity of the side-effects and found that they were highly correlated. The cytokine levels in the CSF of two patients with seizure were also measured and we found that the elevation of the cytokine pattern in the CSF was paralleled to those in their serum but CNS-leukemia and CAR-T cells in their CSFs were not detected, indicating that the neurotoxicity concurrently presented in these two patients might be caused by the cytokines in the serum leaked into the CSF through the blood brain barrier. Extremely high level of cytokines occurred at 12 hours after CAR-T cell infusion in a patient was identified immediately and treated timely in onn-ICU setting to avoid the fatal consequence. Acute toxicities including fever, hypotension and other neurological toxicities occurred in responding patients within 2 weeks post infusion and managed properly with tocilizumab and/or steroids according to the “real-time” monitoring of this simple 6-Th1/Th2 cytokine patterns at the non-ICU setting. In conclusion, our study demonstrates that CD19CAR-T cell therapy can be administered safely for patients with relapsed and refractory leukemia under the “real-time” monitoring of a simple 6-cytokine pattern. DisclosuresNo relevant conflicts of interest to declare.

Progress of chimeric antigen receptor modified natural killer cells immunotherapy in hematological neoplasms

Chimeric antigen receptor modified T (CAR-T) cells have been a kind of promising immunotherapeutic strategy for the treatment of malignances, which could target the specific antigen and exert a specific cytotoxic effect by gene modification of T cells. There has been a great stride in B lymphocytic leukemia along with CAR-T therapy. As the essential effector cells of the innate immune system, natural killer (NK) cells play a critical role in host immunity against cancer and have a wide application prospect in the tumor immunotherapy. The potential of CAR modification in NK cells has also attracted much attention. A lot of remarkable results have been obtained in vitro experiments and animal model of CAR-NK targeting hematologic neoplasms. This paper reviews the progress of CAR-NK immunotherapy in hematological malignancies. Key words: Hematologic neoplasms; Chimeric antigen receptor; Killer cells, natural