Project description:CD19-targeted chimeric antigen receptor T (CAR T) cell therapy is a promising option to treat relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL). However, the majority of CAR T-treated patients will eventually progress and require salvage treatment, for which there is no current standard. In this study, we analyzed data from 6 patients with R/R DLBCL who experienced progression following CD19-CAR T therapy, and then received CD19-specific CAR T cells that express a PD-1/CD28 chimeric switch-receptor (CD19-PD-1/CD28-CAR T) as salvage therapy at our institution. After the second infusion of CAR T cells, 3 of 6 patients achieved complete remissions and the duration of the response of responsive patients ranged from 8 to 25 months. One patient showed a stable disease. In contrast, 2/6 patients died on 60 days because of progression disease. Importantly, no severe neurologic toxicity or cytokine release syndrome was observed. These data suggest that CD19-PD-1/CD28-CAR-T cells, a novel anti-CD19 CAR-T cell therapy, elicit a potent and durable anticancer response, and can be used in the post-CD19-CAR T failure setting.
Project description:Chimeric antigen receptor (CAR) T cells targeting CD19 mediate potent effects in relapsed and/or refractory pre-B cell acute lymphoblastic leukemia (B-ALL), but antigen loss is a frequent cause of resistance to CD19-targeted immunotherapy. CD22 is also expressed in most cases of B-ALL and is usually retained following CD19 loss. We report results from a phase 1 trial testing a new CD22-targeted CAR (CD22-CAR) in 21 children and adults, including 17 who were previously treated with CD19-directed immunotherapy. Dose-dependent antileukemic activity was observed, with complete remission obtained in 73% (11/15) of patients receiving ≥1 × 106 CD22-CAR T cells per kg body weight, including 5 of 5 patients with CD19dim or CD19- B-ALL. Median remission duration was 6 months. Relapses were associated with diminished CD22 site density that likely permitted CD22+ cell escape from killing by CD22-CAR T cells. These results are the first to establish the clinical activity of a CD22-CAR in B-ALL, including leukemia resistant to anti-CD19 immunotherapy, demonstrating potency against B-ALL comparable to that of CD19-CAR at biologically active doses. Our results also highlight the critical role played by antigen density in regulating CAR function.
Project description:Our study provides compelling support to an effective CAR-T cell anti-aging intervention using NMN, a key NAD+ intermediate. We found the clinical potential of NMN for CAR-T cell immunotherapy for human cancers, attributed to their central memory phenotype. The cells are more viable, proliferative, and long-lived in vivo. Furthermore, these CAR-T cells exerted great antitumor efficacy against tumors in human xenograft mouse models. Detailed molecular mechanisms responsible for the pleiotropic effects of NMN need to be investigated further. So RNA-seq was used to analyze the different gene expression of these CAR-T cells.
Project description:B cell aplasia caused by "on-target off-tumor" toxicity is one of the clinical side effects during CD19-targeted chimeric antigen receptor (CAR) T (CD19-CAR-T) cells treatment for B cell malignancies. Persistent B cell aplasia was observed in all patients with sustained remission, which increased the patients' risk of infection. Some patients even died due to infection. To overcome this challenge, the concept of incorporating an inhibitory CAR (iCAR) into CAR-T cells was introduced to constrain the T cells response once an "on-target off-tumor" event occurred. In this study, we engineered a novel KIR/PD-1-based inhibitory CAR (iKP CAR) by fusing the extracellular domain of killer cell immunoglobulin-like receptors (KIR) 2DL2 (KIR2DL2) and the intracellular domain of PD-1. We also confirmed that iKP CAR could inhibit the CD19 CAR activation signal via the PD-1 domain and CD19-CAR-T cells bearing an iKP CAR (iKP-19-CAR-T) exerted robust cytotoxicity in vitro and antitumor activity in the xenograft model of CD19+HLA-C1- Burkitt's lymphoma parallel to CD19-CAR-T cells, whilst sparing CD19+HLA-C1+ healthy human B cells both in vitro and in the xenograft model. Meanwhile, iKP-19-CAR-T cells exhibited more naïve, less exhausted phenotypes and preserved a higher proportion of central memory T cells (TCM). Our data demonstrates that the KIR/PD-1-based inhibitory CAR can be a promising strategy for preventing B cell aplasia induced by CD19-CAR-T cell therapy.
Project description:B-cell malignancies routinely express surface antigens CD19 and CD22. Immunotoxins against both antigens have been evaluated, and the immunotoxins targeting CD22 are more active. To understand this disparity in cytotoxicity and guide the screening of therapeutic targets, we compared two immunotoxins, FMC63(Fv)-PE38-targeting CD19 and RFB4(Fv)-PE38 (BL22)-targeting CD22. Six lymphoma cell lines have 4- to 9-fold more binding sites per cell for CD19 than for CD22, but BL22 is 4- to 140-fold more active than FMC63(Fv)-PE38, although they have a similar cell binding affinity (Kd, approximately 7 nmol/L). In 1 hour, large amounts of BL22 are internalized (2- to 3-fold more than the number of CD22 molecules on the cell surface), whereas only 5.2% to 16.6% of surface-bound FMC63(Fv)-PE38 is internalized. The intracellular reservoir of CD22 decreases greatly after immunotoxin internalization, indicating that it contributes to the uptake of BL22. Treatment of cells with cycloheximide does not reduce the internalization of BL22. Both internalized immunotoxins are located in the same vesicles. Our results show that the rapid internalization of large amounts of BL22 bound to CD22 makes CD22 a better therapeutic target than CD19 for immunotoxins and probably for other immunoconjugates that act inside cells.
Project description:Anti-CD19 chimeric antigen receptor (CAR) T cell therapies can cause severe cytokine-release syndrome (CRS) and neurotoxicity, impeding their therapeutic application. Here we generated a new anti-CD19 CAR molecule (CD19-BBz(86)) derived from the CD19-BBz prototype bearing co-stimulatory 4-1BB and CD3? domains. We found that CD19-BBz(86) CAR T cells produced lower levels of cytokines, expressed higher levels of antiapoptotic molecules and proliferated more slowly than the prototype CD19-BBz CAR T cells, although they retained potent cytolytic activity. We performed a phase 1 trial of CD19-BBz(86) CAR T cell therapy in patients with B cell lymphoma (ClinicalTrials.gov identifier NCT02842138 ). Complete remission occurred in 6 of 11 patients (54.5%) who each received a dose of 2?×?108-4?×?108 CD19-BBz(86) CAR T cells. Notably, no neurological toxicity or CRS (greater than grade 1) occurred in any of the 25 patients treated. No significant elevation in serum cytokine levels after CAR T cell infusion was detected in the patients treated, including in those who achieved complete remission. CD19-BBz(86) CAR T cells persistently proliferated and differentiated into memory cells in vivo. Thus, therapy with the new CD19-BBz(86) CAR T cells produces a potent and durable antilymphoma response without causing neurotoxicity or severe CRS, representing a safe and potent anti-CD19 CAR T cell therapy.
Project description:The monoclonal antibodies (MAbs) HD37 and RFB4 bind to receptors on precursor B acute lymphoblastic leukemia (ALL) cells. These MAbs were tested alone and in combination with chemotherapy for their anti-leukemic activity. HD37 and not RFB4 increased the in vitro cytotoxicity of daunorubicin (DNR) and vincristine (VCR) in three Pre-B ALL cell lines. HD37 alone induced apoptosis in 30% of the cells versus 2% for RFB4. The treatment of SCID/ALL mice with either chemotherapy agent minimally prolonged their mean survival time (MST) versus controls but HD37 or RFB4 plus VCR significantly extended the MST. Forty percent of the mice treated with HD37 plus VCR survived. In conclusion, chemotherapy was made more effective when combined with HD37, and less so with RFB4.
Project description:CD19-directed chimeric antigen receptor-T (CAR-T) cells with a 4-1BB or CD28 co-stimulatory domain have shown impressive antitumor activity against relapsed or refractory B cell acute lymphoblastic leukemia (r/r B-ALL). However, a parallel comparison of their performances in r/r B-ALL therapy has not been sufficiently reported. Here, we manufactured 4-1BB- and CD28-based CD19 CAR-T cells using the same process technology and evaluated their efficacy and safety in r/r B-ALL therapy based on pre-clinical and exploratory clinical investigations. In B-ALL-bearing mice, a similar antitumor effect and CAR-T kinetics in peripheral blood were observed at the CAR-T dose of 1 × 107/mouse. However, when the dose was decreased to 1 × 106/mouse, 4-1BB CAR-T cells were more potent in eradicating tumor cells and showed longer persistence than CD28 CAR-T cells. Retrospective analysis of an exploratory clinical study that used 4-1BB- or CD28-based CAR-T cells to treat r/r B-ALL was performed. Compared with CD28 CAR-T cells, 4-1BB CAR-T cells resulted in higher antitumor efficacy and less severe adverse events. This study demonstrated that the performance of 4-1BB CAR-T cells was superior to that of CD28 CAR-T cells in suppressing CD19+ B-ALL, at least under our manufacturing process.
Project description:Clinical trials of chimeric antigen receptor (CAR) T cells in hematologic malignancy associate remissions with two profiles of CAR T cell proliferation kinetics, which differ based upon costimulatory domain. Additional T cell intrinsic factors that influence or predict clinical response remain unclear. To address this gap, we report the case of a 68-year-old woman with refractory/relapsed diffuse large B cell lymphoma (DLBCL), treated with tisagenlecleucel (anti-CD19), with a CD137 costimulatory domain (4-1BB) on an investigational new drug application (#16944). For two months post-infusion, the patient experienced dramatic regression of subcutaneous nodules of DLBCL. Unfortunately, her CAR T exhibited kinetics unassociated with remission, and she died of DLBCL-related sequelae. Serial phenotypic analysis of peripheral blood alongside sequencing of the ?-peptide variable region of the T cell receptor (TCR?) revealed distinct waves of oligoclonal T cell expansion with dynamic expression of immune checkpoint molecules. One week prior to CAR T cell contraction, T cell immunoglobulin mucin domain 3 (Tim-3) and programmed cell death protein 1 (PD-1) exhibited peak expressions on both the CD8 T cell (Tim-3 ? 50%; PD-1 ? 17%) and CAR T cell subsets (Tim-3 ? 78%; PD-1 ? 40%). These correlative observations draw attention to Tim-3 and PD-1 signaling pathways in context of CAR T cell exhaustion.