Chimeric Antigen Receptor-modified T-cell Research Articles

Cytomegalovirus (CMV) Reactivation and CMV-Specific Cell-Mediated Immunity After Chimeric Antigen Receptor T-Cell Therapy.

The epidemiology of cytomegalovirus (CMV) after chimeric antigen receptor-modified T-cell immunotherapy (CARTx) is poorly understood owing to a lack of routine surveillance. We prospectively enrolled 72 adult CMV-seropositive CD19-, CD20-, or BCMA-targeted CARTx recipients and tested plasma samples for CMV before and weekly up to 12 weeks after CARTx. We assessed CMV-specific cell-mediated immunity (CMV-CMI) before and 2 and 4 weeks after CARTx, using an interferon γ release assay to quantify T-cell responses to IE-1 and pp65. We tested pre-CARTx samples to calculate a risk score for cytopenias and infection (CAR-HEMATOTOX). We used Cox regression to evaluate CMV risk factors and evaluated the predictive performance of CMV-CMI for CMV reactivation in receiver operator characteristic curves. CMV was detected in 1 patient (1.4%) before and in 18 (25%) after CARTx, for a cumulative incidence of 27% (95% confidence interval, 16.8-38.2). The median CMV viral load (interquartile range) was 127 (interquartile range, 61-276) IU/mL, with no end-organ disease observed; 5 patients received preemptive therapy based on clinical results. CMV-CMI values reached a nadir 2 weeks after infusion and recovered to baseline levels by week 4. In adjusted models, BCMA-CARTx (vs CD19/CD20) and corticosteroid use for >3 days were significantly associated with CMV reactivation, and possible associations were detected for lower week 2 CMV-CMI and more prior antitumor regimens. The cumulative incidence of CMV reactivation almost doubled when stratified by BCMA-CARTx target and use of corticosteroids for >3 days (46% and 49%, respectively). CMV testing could be considered between 2 and 6 weeks in high-risk CARTx recipients.

4SCAR2.0 therapy for the management of post-transplantation relapse of B-cell acute lymphoblastic leukemia

IntroductionAllogeneic hematopoietic stem cell transplantation (allo-HCT) is a standard treatment for relapsed/refractory B-cell acute lymphoblastic leukemia (r/r B-ALL). However, about 30-40% of patients still relapse after HCT. Chimeric antigen receptor-modified T-cell (CAR-T) therapy has been proven effective in the treatment of relapsed or refractory B-ALL.Patients and methodsWe report a cohort of 30 B-ALL patients, who relapsed after HCT and were enrolled in the 4SCAR2.0 study, receiving CD19 CAR-Ts alone (20 patients), or two types of CAR-Ts targeting CD19, CD22, CD38 or CD123 antigens (10 patients), depending on the tumor antigen expression profile. These patients had extramedullary (EM) relapse or bone marrow (BM) relapse, or both. Based on the GVHD history, donor chimerism, and the available T-cell source, 25 patients received allogeneic donor CAR-Ts, and 5 patients received autologous CAR-T treatment. ResultsAll 20 patients receiving a single CD19 CAR-T infusion achieved a minimal residual disease (MRD) remission within 60 days. The remaining 10 patients, due to low CD19 antigen expression profile, received 2 CAR-T products given on the same day, and 9 of 10 achieved complete remission (CR) and one had disease progression within 60 days. After CAR-T infusion, no cytokine release syndrome (CRS) was observed in 14 patients, and 16 patients experienced grade 1 CRS, and there was no neurotoxicity. Seventeen of the 30 patients who achieved remission (57%) remained in continuous remission following CAR-T treatment with a median follow-up period of 2 years and a median duration of remission of 12 months (range: 2.8 months - 67 months). Twelve out of 29 patients (41%) who achieved remission, subsequently relapsed at a median of 6.3 months (range: 2.8 months - 22.3 months) after CAR-T treatment. In summary, 29 patients (97%) achieved MRD negative remission within 60 days of therapy with a single or double CAR-T infusion, and seven patients remained in durable remission (7/30, 23%) after more than 2 years of follow-up. DiscussionThe tumor antigen profile-guided precision 4SCAR2.0 regimen for the treatment of r/r B-ALL after allo-HCT was highly effective with low toxicity. This approach warrants extended follow-up and further studies. Clinical trial registrationClinicalTrials.gov, identifier NCT03125577.

Response to Mosunetuzumab in Patients with B-Cell Lymphomas Relapsed or Refractory after CAR-T Cell Therapy Is Associated with Changes in Lymphocyte Counts

Introduction: Mosunetuzumab is a CD20/CD3 bispecific antibody that redirects endogenous T cells to kill malignant B cells by concomitantly binding to CD3 on T cells and CD20 on B cells. A multicenter phase I/II study evaluating mosunetuzumab in relapsed/refractory (r/r) non-Hodgkin lymphomas, including patients r/r after chimeric antigen receptor-modified T-cell therapies (CAR-T), was the basis for FDA approval for mosunetuzumab in follicular lymphoma (NCT02500407; Budde et al. Lancet Oncol 2022). We retrospectively assessed the impact of mosunetuzumab on lymphocyte counts and CAR T cells in responding and non-responding patients. Methods: Samples were collected prospectively from participants enrolled on NCT02500407 and exploratory post hoc analyses were performed on a subset of patients who had received prior CAR-T. P-values unadjusted for multiple comparisons are reported. We examined changes in absolute lymphocyte counts (ALC) and CAR-T transgene levels, as well as CD4 counts and CD8 counts, at baseline (C1D1) and prior to cycle 2 day 1 (C2D1) of mosunetuzumab. We also examined length of time from CAR-T to mosunetuzumab. CAR transgene levels were assessed by quantitative PCR. Results: 30 patients had cycle 1 day 1 (C1D1) and C2D1 paired samples available for analysis. 27 patients had large B-cell lymphoma (90%) and 3 patients had low-grade follicular lymphoma (10%). The doses of mosunetuzumab received ranged from 6mg - 60mg IV or 1.6mg - 20mg SC. The median time from CAR-T infusion to mosunetuzumab was 161 days (range: 35-1071); 40% of patients (12/30) received mosunetuzumab within 100 days of CAR-T, 43% of patients (13/30) received mosunetuzumab > 100-days to 1 year after CAR-T, and 17% (5/30) of patients received mosunetuzumab > 1 year after CAR-T infusion. We found that patients who responded to mosunetuzumab had a longer time from CAR-T infusion than non-responders (mean 342 days [range: 98-587] vs 110 days [range: 70-150], respectively, p = 0.02). Although there was no difference in baseline ALC, we found that responding patients had higher ALCs on C2D1 (p=0.005). For 15 patients with available T-cell subsets, CD4 counts were higher on C2D1 for responders (p=0.05). We also investigated changes in CAR transgene levels. 14/20 patients who received commercially available standard of care CAR-T products had detectable CAR transgene levels vs only 1/10 patients who received an investigational CAR-T due to assay limitations. Thus, we examined changes in CAR transgene levels in those patients who had received commercially available standard of care CAR-T (n=20). No difference was observed between responders and non-responders in CAR transgene copy numbers at baseline; however, on C2D1 after one cycle of mosunetuzumab, non-responding patients had a trend toward decrease in CAR transgene levels while responding patients had persistence or increase in CAR transgene levels (p=0.07). Conclusions: We observed higher peripheral blood lymphocytes after one cycle of mosunetuzumab in responding patients. Of interest, an increase in lymphocytes in responding patients had previously been described after blinatumomab (Klinger et al. Blood 2012). These findings may indicate a class effect of bispecific antibodies in general. We also found that patients who were r/r to CAR-T and responding to mosunetuzumab had a trend towards an increase in CAR transgene levels compared with patients not responding to mosunetuzumab. This suggests an interaction between CAR-T cells and bispecific antibodies. Finally, it is notable that post-CAR patients responding to mosunetuzumab had a longer time from CAR-T infusion, perhaps reflecting recovery from lymphodepletion. Further investigations are needed to understand the mechanism(s) behind these observations.

Promises and challenges of a decentralized CAR T-cell manufacturing model

Autologous chimeric antigen receptor-modified T-cell (CAR T) products have demonstrated un-precedent efficacy in treating many relapsed/refractory B-cell and plasma cell malignancies, leading to multiple commercial products now in routine clinical use. These positive responses to CAR T therapy have spurred biotech and big pharma companies to evaluate innovative production methods to increase patient access while maintaining adequate quality control and profitability. Autologous cellular therapies are, by definition, manufactured as single patient batches, and demand has soared for manufacturing facilities compliant with current Good Manufacturing Practice (cGMP) regulations. The use of a centralized production model is straining finite resources even in developed countries in North America and the European Union, and patient access is not feasible for most of the developing world. The idea of having a more uniform availability of these cell therapy products promoted the concept of point-of-care (POC) manufacturing or decentralized in-house production. While this strategy can potentially decrease the cost of manufacturing, the challenge comes in maintaining the same quality as currently available centrally manufactured products due to the lack of standardized manufacturing techniques amongst institutions. However, academic medical institutions and biotech companies alike have forged ahead innovating and adopting new technologies to launch clinical trials of CAR T products produced exclusively in-house. Here we discuss POC production of CAR T products.

Co-infusion of CAR T cells with aAPCs expressing chemokines and costimulatory ligands enhances the anti-tumor efficacy in mice

Chimeric antigen receptor-modified T (CAR-T) cell therapy has shown curable efficacy for treating hematological malignancies, while in solid tumors, the immunosuppressive microenvironment causes poor activation, expansion and survival of CAR-T cells, accounting mainly for the unsatisfactory efficacy. The artificial antigen-presenting cells (aAPCs) have been used for ex vivo expansion and manufacturing of CAR-T cells. Here, we constructed a K562 cell-based aAPCs expressing human epithelial cell adhesion molecule (EpCAM), chemokines (CCL19 and CCL21) and co-stimulatory molecular ligands (CD80 and 4-1BBL). Our data demonstrated that the novel aAPCs enhanced the expansion, and increased the immune memory phenotype and cytotoxicity of CAR-T cells recognizing EpCAM, in vitro. Of note, co-infusion CAR-T and aAPC enhances the infiltration of CAR-T cells in solid tumors, which has certain potential for the treatment of solid tumors Moreover, IL-2-9-21, a cytokine cocktail, prevents CAR-T cells from entering the state of exhaustion prematurely after continuous antigen engagement and boosts the anti-tumor activity of CAR-T cells co-infused with aAPCs. These data provide a new strategy to enhance the therapeutic potential of CAR-T cell therapy for the treatment of solid tumors.

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.

Immune-based therapies in diffuse large B-cell lymphoma

ABSTRACT Introduction Diffuse large B-cell lymphoma (DLBCL) is an aggressive and clinically heterogeneous malignancy originating from B-cells with up to 40% of patients experiencing primary refractory disease or relapse after first-line treatment. However, the past 5 years have seen a flurry of new drug approvals for DLBCL anchored upon new immune therapies, including chimeric antigen receptor (CAR) T-cells and antibody-based therapies. Areas covered This article summarizes recent advances in the treatment of DLBCL, including in the first line and relapsed and refractory setting (second-line and beyond). A literature search was conducted for publications relevant to the immunotherapeutic approach to DLBCL from 2000 through March 2023 within PubMed and articles were reviewed. The search terms were immunotherapy, monoclonal antibodies, chimeric antigen receptor modified T-cell (CAR-T), and classification of DLBCL. Relevant clinical trials and pre-clinical studies exploring the strengths and weaknesses of current immune therapies against DLBCL were chosen. We additionally explored how intrinsic differences amongst DLBCL subtype biology and endogenous host immune recruitment contribute to variable therapeutic efficacy. Expert Opinion Future treatments will minimize chemotherapy exposure and be chosen by underlying tumor biology, paving the way for the promise of chemotherapeutic free regimens and improved outcomes for poor-risk subgroups.

Utilizing induced neural stem cell-based delivery of a cytokine cocktail to enhance chimeric antigen receptor-modified T-cell therapy for brain cancer.

Chimeric antigen receptor (CAR)-modified T-cell therapy has shown enormous clinical promise against blood cancers, yet efficacy against solid tumors remains a challenge. Here, we investigated the potential of a new combination cell therapy, where tumor-homing induced neural stem cells (iNSCs) are used to enhance CAR-T-cell therapy and achieve efficacious suppression of brain tumors. Using in vitro and in vivo migration assays, we found iNSC-secreted RANTES/IL-15 increased CAR-T-cell migration sixfold and expansion threefold, resulting in greater antitumor activity in a glioblastoma (GBM) tumor model. Furthermore, multimodal imaging showed iNSC delivery of RANTES/IL-15 in combination with intravenous administration of CAR-T cells reduced established orthotopic GBM xenografts 2538-fold within the first week, followed by durable tumor remission through 60 days post-treatment. By contrast, CAR-T-cell therapy alone only partially controlled tumor growth, with a median survival of only 19 days. Together, these studies demonstrate the potential of combined cell therapy platforms to improve the efficacy of CAR-T-cell therapy for brain tumors.

Clinical status, drug resistance, and countermeasures of CAR-T cell cancer immunotherapy

The field of adoptive immune cell therapy, known as CAR-T cells (chimeric antigen receptor-modified T-cells), has advanced significantly in recent years. However, the drug resistance of CAR-T therapy limits the further development of this technology, and a large proportion of tumor patients have drug resistance or cancer recurrence. Immune evasion due to drug resistance may be caused by CAR-T cell dysfunction, the effects of the tumor microenvironment, or drug-resistant tumor cells. The clinical status of CAR-T is reviewed here, along with the intrinsic mechanisms by which tumor cells resist CAR-T therapy and potential development options to address CAR-T resistance..

A guide to the collection of T-cells by apheresis for ATMP manufacturing-recommendations of the GoCART coalition apheresis working group.

Autologous chimeric antigen receptor-modified T-cells (CAR-T) provide meaningful benefit for otherwise refractory malignancies. As clinical indications for CAR-T cells are expanding, hospitals hitherto not active in the field of immune effector cell therapy will need to build capacity and expertise. The GoCART Coalition seeks to disseminate knowledge and skills to facilitate the introduction of CAR-T cells and to standardize management and documentation of CAR-T cell recipients, in order to optimize outcomes and to be able to benchmark clinical results against other centers. Apheresis generates the starting material for CAR-T cell manufacturing. This guide provides some initial suggestions for patient's apheresis readiness and performance to collect starting material and should thus facilitate the implementation of a CAR-T-starting material apheresis facility. It cannot replace, of course, the extensive training needed to perform qualitative apheresis collections in compliance with national and international regulations and assess their cellular composition and biological safety.

IL13Rα2-targeted third-generation CAR-T cells with CD28 transmembrane domain mediate the best anti-glioblastoma efficacy.

Chimeric antigen receptor (CAR)-modified T (CAR-T) cell therapy has been proven to be a powerful tool for the treatment of cancer, however, the limits are obvious, especially for solid tumors. Therefore, constantly optimizing the structure of CAR to improve its therapeutic effect is necessary. In this study, we generated three different third-generation CARs targeting IL13Rα2, with the same scFv, but different transmembrane domains (TMDs) from CD4, CD8 or CD28 (IL13-CD4TM-28.BB.ζ, IL13-CD8TM-28.BB.ζ and IL13-CD28TM-28.BB.ζ). CARs were transduced into primary T cells using retroviruses. The anti-GBM efficacy of CAR-T cells was monitored by flow cytometry and real-time cell analysis (RTCA) in vitro and examined in two xenograft mouse models. The differentially expressed genes related to different anti-GBM activity were screened by high throughput RNA sequencing. We observed that T cells transduced with these three CARs have similar anti-tumor activity when co-cultured with U373 cells which expressed higher IL13Rα2 but exhibited different anti-tumor activity when co-cultured with U251 cells that expressed lower IL13Rα2. All the three groups of CAR-T cells can be activated by U373 cells, but only IL13-CD28TM-28.BB.ζ CAR-T cells could be activated and expressed increased IFN-γ after co-culturing with U251 cells. IL13-CD28TM-28.BB.ζ CAR-T cells exhibited the best anti-tumor activity in xenograft mouse models which can infiltrate into the tumors. The superior anti-tumor efficacy of IL13-CD28TM-28.BB.ζ CAR-T cells was partially owing to differentially expressed extracellular assembly, extracellular matrix, cell migration and adhesion-related genes which contribute to the lower activation threshold, increased cell proliferation, and elevated migration capacity.

Anti-CD 19 CAR-T Cell Therapy with Tisagenlecleucel for Ritcher Syndrome

About 2-10 percent of patients with chronic lymphocytic leukemia (CLL) will transform into an aggressive large cell lymphoma, called Ritcher syndrome (RS). The transformation is to DLBCL in 90-95% of cases and Hodgkin lymphoma in the remaining 5-10%. Current treatment strategies that typically mirror DLBCL have not significantly improved the historically dismal outcomes of RS. Chimeric antigen receptor-modified T (CAR-T) cells have revolutionized the treatment of B-cell malignancies and are currently approved for relapsed/refractory DLBCL. The impact of CAR-T cell therapy in the management of RS is limited by the small number of affected patients and published reports. We report the outcomes in 2 patients with RS treated with tisagenlecleucel (Tisa-cel) at our institution. Patient 1. This is a 75-year-old lady diagnosed with CLL at the age of 64, Rai stage 1, trisomy 12, mutated IGVH. She was on observation until she became symptomatic 5 yrs. after diagnosis and had a biopsy which showed CLL with RS, fluorescent in-situ hybridization (FISH) negative for C-MYC, BCL2 and BCL6. She was treated with RCHOP x 6 cycles with complete remission (CR) on PET. She received high dose chemotherapy with R-BEAM followed by autologous stem cell transplant, followed by 4 cycles of maintenance brentuximab given every 3 weeks for her CD30 positive large B cell lymphoma. About 5 yrs. later, surveillance PET showed hypermetabolic cervical lymph nodes and excisional biopsies showed CLL and DLBCL, non-germinal center type, concerning for relapsed RS. She was referred to us for CAR-T cell therapy evaluation. Bone marrow biopsy was negative for marrow involvement, minimal residual disease (MRD) by ClonoSEO was positive. She received lymphodepleting chemotherapy with fludarabine and cyclophosphamide followed by CAR-T cell infusion with tisa-cel 5x10^8 anti CD19 CAR-T cells on 4/18/22. Treatment was complicated by grade 1-2 cytokine release syndrome (CRS) (treated with tocilizumab and dexamethasone) requiring brief hospitalization. Day 90 PET showed CMR and bone marrow biopsy was negative for disease, MRD negative. She continues to be in CR 100 days post CAR-T cell therapy. Patient 2. A 63 years-old lady originally diagnosed with CLL in 2016 at the age of 57, with 17p deletion, 13q deletion and IgHV unmutated. She was started on ibrutinib shortly after due to a short lymphocyte doubling time. Three years later (in 2020), she developed worsening lymphadenopathy while on ibrutinib, underwent excisional biopsy and this showed RS with TP53 mutation, 17p deletion, gain of 13q, BCL2 positive. Venetoclax was added to ibrutinib and later, 2 cycles of Obinutuzumab were also given. Subsequent PET 7 months after showed disease progression with a lugano score of 5. She received 6 cycles of RCHOP in addition to venetoclax/ibrutinib but end of treatment PET showed disease progression. She was then referred to us for CAR-T cell evaluation. She received lymphodepleting chemotherapy with fludarabine and cyclophosphamide followed by CAR-T cell infusion with tis-cel 3.7 x 10^8 cells anti CD19 CAR-T cells on 6/7/21. This was complicated by grade 2 CRS that was treated with tocilizumab. Day 30 PET showed PR. Ibrutinib was resumed and the patient received radiation to right cervical lymph nodes. Day 100 PET reaffirmed PR and she subsequently underwent FluCyTBI RIC followed by haploidentical alloSCT from her daughter on 09/29/21. On day 180 post-transplant, the patient remained in CR by PET and bone marrow biopsy. She continues to be in CR now 1 year since her CAR-T cell infusion. Conclusion CAR-T cell therapy with Tisagenlecleucel shows promising activity in patients with RS. It is an evolving treatment strategy and more follow up is needed to assess the durability of the responses observed in these patients.

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

CD22-Targeted CAR-Modified T-Cells Safely Induce Remissions in Children and Young Adults with Relapsed, CD19-Negative B-ALL after Treatment with CD19-Targeted CAR T-Cells

Introduction: Children and young adults with B-lymphoblastic leukemia (B-ALL) who relapse with CD19 antigen loss after CD19-targeted CAR T-cell therapy have a dismal prognosis, with a median overall survival of 9.7 months. Novel immunotherapies are urgently needed for this population. CD22 can serve as a potential alternative target. In our initial pilot trial of CD22-targeted/4-1BB CAR T cells, clinical activity was unexpectedly poor. Based on additional preclinical work demonstrating that shorter scFv linkers improve T-cell effector function, a novel CD22/4-1BB CAR construct with a short scFv linker (CART22-65s) was developed and investigated in a phase 1 study (NCT02650414). Methods: After fludarabine/cyclophosphamide lymphodepletion, patients (pts) were infused with CART22-65s using a 3-day fractionated dosing scheme with the 2nd/3rd doses held for early signs of cytokine release syndrome (CRS). The primary endpoint was safety. Key secondary endpoints were feasibility, efficacy, and CAR T cell expansion and persistence. Results: Nineteen pts were enrolled and had a product successfully manufactured. Of 17 pts infused (median age, 16 years; range 3-28 years), all had CD19-negative, relapsed disease after prior CD19-directed therapy (CART19, n=16; blinatumomab, n=1); 8 had prior inotuzumab; 9 had prior stem cell transplant (SCT); and 3 had multiple prior SCTs. Median bone marrow blasts immediately pre-infusion was 31% (range, 0-99%); 8 patients had >75% blasts. The median cell dose infused was 4x106 CART22-65s cells/kg (range, 0.8 to 10 x 106). In vivo cellular kinetics by qPCR demonstrated robust initial CAR T cell proliferation peaking at a median of 20 days post-infusion, and persistence that correlated with clinical response (Figure A). At day 28, 13/17 (77%) pts achieved a complete remission (CR) of which 10 (77%) had undetectable minimal residual disease (uMRD) by flow cytometry. One additional pt cleared MRD at month 2 without intervention. Notably, 4/5 (80%) pts refractory to prior inotuzumab achieved a CR with CART22-65s. Of 11 pts with a best response of uMRD CR, 5 proceeded to consolidative SCT, including 3 with prior SCT: 2 remain in CR post-SCT, 2 are in CR after a brief course of alternative therapy for emergence of MRD, and 1 had a CD22+ relapse post-SCT. Of 6 pts with uMRD CR who did not proceed to SCT (5 had a prior SCT), 5 experienced relapsed disease with a range of CD22 expression and 1 remains in CR 30 months after infusion with ongoing CAR T persistence. Of 2 pts with MRD+ CR (1 CD22+, 1 CD22-), both progressed to morphologic relapse; one received alternative therapy prior to progression. Of 4 pts with non-response, all died of disease within 9 months. Thus, with a median follow-up of 29 months, median relapse-free, event-free, and overall survival were 5.3 (95% CI, 1.9-NR), 5.8 (95% CI, 2.1-NR), and 16.5 (95% CI, 9.3-NR) months, respectively (Figure B). In addition, 2 patients received CART22-65s retreatment for CD22+ relapsed disease after initial infusion. Both engrafted, but only 1 achieved uMRD CR. CRS was observed in 15 pts (grade 1, n=10; grade 2, n=5), and mild neurotoxicity in 6 pts (grade 1, n=5; grade 2, n=1). In the retreatment setting, 1 pt developed grade 3 CRS, which resolved, and grade 3 encephalopathy/hypotonia, but died of progressive disease prior to resolution. Autopsy findings were consistent with leukomyelopathy of the spinal cord, which was inconclusive in its relation to CART22-65s. Other SAEs included: (1) platelet refractoriness and recurrent, severe inflammatory reactions to platelet transfusions in 1 pt that improved with corticosteroids and anakinra; and (2) delayed hemophagocytic lymphohistiocytosis in 1 pt after CART22-65s retreatment that resolved without intervention. Conclusion: CART22-65s induced remissions in 77% of children and young adults with highly refractory, CD19-negative B-ALL, including in 4/5 pts refractory to prior CD22-directed therapy. Manufacturing was successful, and the overall toxicity profile was favorable even in pts with high disease burden. Several uncommon toxicities were observed, but the only grade 3 CRS and neurotoxicity events occurred in the retreatment setting. Our observation of high initial response rates, but later recurrences, highlights the need to use CART22-65s as part of combination therapy. These promising preliminary data provide support for a combined CD19/22 approach using the CART22-65s construct. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

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.

ABCL-101 Cost-Effectiveness of Polatuzumab Vedotin in Previously Untreated Diffuse Large B-Cell Lymphoma

Polatuzumab vedotin in combination with rituximab, cyclophosphamide, doxorubicin, and prednisone (Pola-R-CHP) significantly increased progression-free survival (PFS) (HR, 0.73; 95% CI: 0.57-0.95) vs rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) in the POLARIX clinical trial (NCT03274492). The objective of this analysis was to evaluate the cost-effectiveness of Pola-R-CHP vs R-CHOP in frontline diffuse large B-Cell lymphoma (DLBCL). In our cost-effectiveness model, we derived PFS, overall survival (OS), drug utilization, adverse events (AE), and subsequent treatment from POLARIX, including higher utilization of chimeric antigen receptor-modified T-cell therapy (CAR-T) and stem-cell transplantation in the R-CHOP arm compared with Pola-R-CHP arm. Costs included drug acquisition, AE management, routine medical care, subsequent treatments, end-of-life care, and work productivity. A scenario analysis was conducted to assess the future impact of increased second-line CAR-T utilization. We estimated the life years, quality-adjusted life years (QALY), cost impacts, and incremental cost-effectiveness ratio (ICER) of Pola-R-CHP vs R-CHOP. Probabilistic sensitivity analyses (PSA) were performed to assess the impact of uncertainty on cost per QALY-gained outcomes. The ICER of Pola-R-CHP vs R-CHOP was $80,920/QALY gained from a societal perspective and $96,014/QALY gained from a payer perspective. From a societal perspective, the total cost of Pola-R-CHP was $41,159 higher than R-CHOP, primarily due to higher drug costs ($125,623 vs $34,034, respectively). Drug cost offsets for Pola-R-CHP included subsequent treatment costs (-$42,269), routine care (-$1,195), end-of-life care (-$393), and work productivity (-$7,677). AE management costs were $1,069 higher with Pola-R-CHP vs. R-CHOP. Pola-R-CHP resulted in an increase of 0.50 life years and 0.51 QALYs vs R-CHOP. PSA results demonstrated that Pola-R-CHP was cost-effective in 63.0% of simulations at a willingness-to-pay of $150,000/QALY gained from a societal perspective, and 60.8% of simulations from a payer perspective. In the increased CAR-T use scenario, the ICER was $61,220/QALY gained. Pola-R-CHP was projected to be cost-effective vs R-CHOP in previously untreated DLBCL. Our economic model demonstrates an improvement in QALYs with Pola-R-CHP vs R-CHOP and savings in costs relating to DLBCL progression. These cost-effectiveness results reinforce the clinical findings from POLARIX suggesting that Pola-R-CHP should be considered as a frontline standard of care.

Comparison of Droplet Digital PCR and Metagenomic Next-Generation Sequencing Methods for the Detection of Human Herpesvirus 6B Infection Using Cell-Free DNA from Patients Receiving CAR-T and Hematopoietic Stem Cell Transplantation

PurposeThe aim of this study was to examine and compare the differences between droplet digital PCR (ddPCR) and metagenomic next-generation sequencing (mNGS) in the detection of human herpesvirus 6B (HHV-6B). Long-term monitoring of HHV-6B viral load in patients receiving chimeric antigen receptor-modified T-cell (CAR-T) therapy and hematopoietic stem cell transplantation (HSCT) can be used to identify immune effector cell-associated neurotoxicity syndrome (ICANS) and guide drug therapy.MethodsTwenty-seven patients with suspected HHV-6B infection who had both mNGS and ddPCR test results were analyzed retrospectively, including 19 patients who received CAR T-cell therapy and 8 who received HSCT. The HHV-6B probe and primers were designed, and the performance of the ddPCR assay was evaluated. Subsequently, ddPCR was performed utilizing blood and urine. Data on clinical information and mNGS investigations were collected.ResultsThe ddPCR test results correlated significantly with the mNGS test results (P < 0.001, R2 = 0.672). Of the 27 time-paired samples, ddPCR showed positive HHV-6B detection in 20 samples, while mNGS alone showed positive HHV-6B detection in 12 samples. ddPCR detected additional HHV-6B infections in 8 samples that would have been missed if only mNGS were used. In addition, the first HHV-6B infection event was detected at a median of 14 days after CAR T-cell infusion (range, 8 to 19 days). Longitudinal monitoring of HHV-6B by ddPCR was performed to assess the effectiveness of antiviral therapy. The data showed that with antiviral treatment HHV-6B viral load gradually decreased.ConclusionOur results indicated that ddPCR improved the HHV-6B positive detection ratio and was an effective adjunct to mNGS methods. Furthermore, the longitudinal detection and quantification of HHV-6B viral load in patients undergoing CAR T-cell therapy and HSCT may serve as a guide for drug treatment.

EP08.01-099 Activity of aPD1-MSLN-CART Cells against Metastatic Lung Cancer in a Phase 1 Trial

Mesothelin (MSLN) has been found to be highly expressive in multiple solid tumors including lung cancer. We engineered autocrine PD-1 nano antibodies MSLN CAR-T cells (aPD1-MSLN-CART), targeting MSLN positive tumor cells by chimeric antigen receptor-modified T (CAR-T) cells as well as secretion of PD1 antibodies, playing dual antitumor immune mechanism.

The tumor microenvironment of hepatocellular carcinoma and its targeting strategy by CAR-T cell immunotherapy.

Hepatocellular carcinoma (HCC) is the major subtype of liver cancer, which ranks sixth in cancer incidence and third in mortality. Although great strides have been made in novel therapy for HCC, such as immunotherapy, the prognosis remains less than satisfactory. Increasing evidence demonstrates that the tumor immune microenvironment (TME) exerts a significant role in the evolution of HCC and has a non-negligible impact on the efficacy of HCC treatment. In the past two decades, the success in hematological malignancies made by chimeric antigen receptor-modified T (CAR-T) cell therapy leveraging it holds great promise for cancer treatment. However, in the face of a hostile TME in solid tumors like HCC, the efficacy of CAR-T cells will be greatly compromised. Here, we provide an overview of TME features in HCC, discuss recent advances and challenges of CAR-T immunotherapy in HCC.

Developing ROR1 Targeting CAR-T Cells against Solid Tumors in Preclinical Studies.

Simple SummaryA ROR1 CAR-T cells derived from scFv of Zilovertamab with short IgG4 hinge spacer region, holds the specific cytotoxicities against a broad range of ROR1+ solid tumors with no observed toxicity in vivo. Our results have provided preclinical evidence to further develop ROR1 CAR-T adoptive therapy against solid tumors in the clinical stage. Chimeric antigen receptor (CAR)-modified T-cells (CAR-T) have demonstrated promising clinical benefits against B-cell malignancies. Yet, its application for solid tumors is still facing challenges. Unlike haematological cancers, solid tumors often lack good targets, which are ideally expressed on the tumor cells, but not by the normal healthy cells. Fortunately, receptor tyrosine kinase-like orphan receptor 1 (ROR1) is among a few good cancer targets that is aberrantly expressed on various tumors but has a low expression on normal tissue, suggesting it as a good candidate for CAR-T therapy. Here, we constructed two ROR1 CARs with the same antigen recognition domain that was derived from Zilovertamab but differing in hinge regions. Both CARs target ROR1+ cancer cells specifically, but CAR with a shorter IgG4 hinge exhibits a higher surface expression and better in vitro functionality. We further tested the ROR1 CAR-T in three human solid tumor xenografted mouse models. Our ROR1 CAR-T cells controlled the solid tumor growth without causing any severe toxicity. Our results demonstrated that ROR1 CAR-T derived from Zilovertamab is efficacious and safe to suppress ROR1+ solid tumors in vitro and in vivo, providing a promising therapeutic option for future clinical application.