Few studies have described chimeric antigen receptor-modified T cell (CAR-T) therapy for central nervous system (CNS) B-cell acute lymphocytic leukemia (B-ALL) patients due to life-threatening CAR-T-related encephalopathy (CRES) safety issues. In this study, CAR-Ts targeting CD19 with short hairpin RNA (shRNA)-IL-6 gene silencing technology (ssCART-19s) were prepared. We conducted a phase 1 clinical trial (ClinicalTrials.gov number, NCT03064269). Three patients with relapsed CNS B-ALL were enrolled, conditioned with the fludarabine and cyclophosphamide for lymphocyte depletion and infused with ssCART-19s for three consecutive days. Clinical symptoms and laboratory examinations were monitored. After ssCART-19 treatment, three patients' symptoms resolved almost entirely. Brain leukemic infiltration reduced significantly based on magnetic resonance imaging (MRI), and there were no leukemic blasts in cerebrospinal fluid (CSF), which was confirmed by cytological and molecular examinations. Additionally, increases in the levels of cytokines and immune cells were observed in the CSF of all patients. Only grade 1 cytokine release syndrome (CRS) manifesting as fever was noted in patients. In conclusion, CAR-Ts with shRNA-IL-6 gene knockdown migrated into the CNS, eradicated leukemic cells and elevated cytokines in CSF with mild, acceptable side effects.
Clinical tracking of chimeric antigen receptor (CAR) T cells in vivo by positron emission tomography (PET) imaging is an area of intense interest. But the long-lived positron emitter-labeled CAR T cells stay in the liver and spleen for days or even weeks. Thus, the excessive absorbed effective dose becomes a major biosafety issue leading it difficult for clinical translation. In this study we used 68Ga, a commercially available short-lived positron emitter, to label CAR T cells for noninvasive cell tracking in vivo. CAR T cells could be tracked in vivo by 68Ga-PET imaging for at least 6 h. We showed a significant correlation between the distribution of 89Zr and 68Ga-labeled CAR T cells in the same tissues (lungs, liver, and spleen). The distribution and homing behavior of CAR T cells at the early period is highly correlated with the long-term fate of CAR T cells in vivo. And the effective absorbed dose of 68Ga-labeled CAR T cells is only one twenty-fourth of 89Zr-labeled CAR T cells, which was safe for clinical translation. We conclude the feasibility of 68Ga instead of 89Zr directly labeling CAR T cells for noninvasive tracking of the cells in vivo at an early stage based on PET imaging. This method provides a potential solution to the emerging need for safe and practical PET tracer for cell tracking clinically.
Background: Mixed phenotype acute leukemia (MPAL) is a rare leukemia and is regarded as a high-risk entity with a poor prognosis. Induction therapy of an acute lymphoblastic leukemia type or hybrid regimen and hematopoietic stem cell transplantation has been recommended for MPAL. However, the optimal therapies for relapsed or refractory MPAL remain unclear, especially for relapse after stem cell transplantation. Donor-derived chimeric antigen receptor T (CAR-T) cell therapy may be a promising therapeutic option for patients with MPAL who express target antigens and have relapsed after stem cell transplantation. However, recurrence remains a challenge, and reinfusion of CAR-T cells is not always effective. An infusion of secondary donor-derived humanized CD19-modified CAR-T cells may be effective in inducing remission.
Keywords: Philadelphia chromosome; allogeneic haematopoietic stem cell transplantation; chimeric antigen receptor; minimal residual disease; mixed phenotype acute leukaemia.
Relapsed/refractory Philadelphia chromosome-positive acute lymphoblastic leukemia (r/r Ph+ ALL) has an extremely poor prognosis. Chimeric antigen receptor T-cell (CART) therapy has acquired unprecedented efficacy in B-cell malignancies, but its role in the long-term survival of r/r Ph+ ALL patients is unclear. We analyzed the effect of CART on 56 adults with r/r Ph+ ALL who accepted split doses of humanized CD19-targeted CART after lymphodepleting chemotherapy. 51/56 (91.1%) achieved complete remission (CR) or CR with inadequate count recovery (CRi), including 38 patients with negative minimal residual disease (MRD) tested by bone marrow BCR-ABL1 copies. Subsequently, 30/51 CR/CRi patients accepted consolidative allogeneic haematopoietic stem cell transplantation (alloHSCT). Their outcomes were compared with those of 21/51 contemporaneous patients without alloHSCT. The 2-year overall survival (OS) and leukemia-free survival (LFS) of CR/CRi patients with alloHSCT were significantly superior to those without alloHSCT (58.9%, CI 49.8-68.0% vs. 22.7%, CI 12.7-32.7%, p = 0.005; 53.2%, CI 43.6-62.8% vs. 18.8%, CI 9.2-28.4%, p = 0.000, respectively). Multivariate analysis revealed that alloHSCT and MRD-negative post-CART were the independent prognostic factors for OS and LFS. CART therapy is highly effective for r/r Ph+ ALL patients, and consolidative alloHSCT could prolong their OS and LFS.
Background: T cells expressing a chimeric antigen receptor (CAR) engineered to target CD19 can treat leukemia effectively but also increase the risk of complications such as cytokine release syndrome (CRS) and CAR T cell related encephalopathy (CRES) driven by interleukin-6 (IL-6). Here, we investigated whether IL-6 knockdown in CART-19 cells can reduce IL-6 secretion from monocytes, which may reduce the risk of adverse events.
Background: Treatment with chimeric antigen receptor (CAR)-engineered T cells directed against the B-cell maturation antigen (BCMA) promoted transient recovery from multiple myeloma (MM). However, the absence of this antigen on immature plasma cells may limit the efficacy of this modality and facilitate relapse. The purpose of this study is to characterize a novel CAR that includes both a single-chain variable fragment (scFv)-BCMA and an scFv-CD19 in tandem orientation (tan-CAR) in an attempt to target both BCMA and CD19 expression on MM cells.
Background: Extramedullary relapse is an important cause of treatment failure among patients with acute lymphoblastic leukemia (ALL). This type of relapse is commonly observed in the central nervous system, while it is rare in the testicles and skin. Chimeric antigen receptor-modified T cell (CAR-T) therapy targeting CD19 has shown to be a beneficial treatment approach for relapsed/refractory B cell acute lymphoblasticleukemia (r/r B-ALL). Yet, few studies have reported data regarding the treatment of extramedullary B-ALL relapse, especially both in skin and testicle, with CAR-T therapy.
Pediatric Philadelphia chromosome-like (Ph-like) acute B-lymphoblastic leukemia (B-ALL), a high-risk subset of B-ALL characterized by a gene expression proﬁle similar to that of Ph-positive ALL, has extremely poor outcome after a relapse following autologous chimeric antigen receptor (CAR)-T and haploidentical (haplo) hematopoietic stem cell transplantation(HSCT)therapy. with very limited treatment options. Donor-derived CAR T-cell therapy, the most vital advanced anticancer technology, may be a promising salvage strategy for patients with Ph-like B-ALL. Here, we presented a relapsed and refractory case of a child with Ph-like B-ALL after autologous anti-CD19 CAR T-cell therapy followed by haplo-HSCT. She successfully achieved the fourth complete remission (CR4) and maintained CR for five months after the sequential infusion of donor-derived anti-CD22 and anti-CD19 CAR T cells, with mild CRS side effects and no obvious graft-versus-host disease. A donor-derived anti-CD22 and -CD19 CAR T-cell therapy combined with a sequential infusion strategy may provide a promising alternative treatment strategy as effective and safe salvage therapy for children with recurrent and refractory Ph-like B-ALL after autologous CD19-directed CAR T-cell therapy followed by haplo-HSCT.
Effective treatments for relapsed Ph+ALL with T315I mutation are few; CD19 CAR T-cell therapy are a potential therapy for this condition. We reported 7 patients with relapsed Ph+ALL with T315I mutation, who were treated pre- or post-allo-HSCT with CD19-specific CAR T-cells. Of the 7 cases, 6 were in CR or CRp within 1 month after the first infusion of CAR T-cells. MRD revealed a rapid decline in 6 patients. BCR/ABL fusion transcripts were negative in 4/5 cases (not performed in 2). Three patients maintained remission without evidence of MRD by QPCR until the final follow-up, of which 2 received anti-CD19 CAR T-cells and ponatinib at the same time. Our study confirmed the efficacy of anti-CD19 CAR T-cell therapy in treatment of relapsed Ph+ALL with T315I mutation pre- or post-allo-HSCT and the concurrent applicability of this therapy with ponatinib.
This study aimed to assess the effectiveness of inhibiting cholesterol acyltransferase 1 (ACAT-1) in chimeric antigen receptor T (CAR-T) cells on potentiating the antitumor response against mesothelin (MSLN)-expressing pancreatic carcinoma (PC) cells. We engineered ACAT-1-inhibited CAR-T cells (CAR-T-1847 and CAR-T-1848) using the targeting MSLN CAR lentiviral vector and small interfering RNA (siRNA) targeting the conserved region of the ACAT-1 gene, and characterized the efficacy of these modified CAR-T cells in terms of the cytotoxicity and cytokine release of both MSLN-positive and MSLN-negative PC cells using in vitro methods and in vivo mouse xenografts. The ACAT-1-inhibited CAR-T-1847 and CAR-T-1848 cells showed a higher cytotoxicity at effector-to-target cell (E:T) ratios of 8:1 and 10:1, respectively, and induced a higher secretion of proinflammatory cytokines interleukin-2 (IL-2) and interferon-gamma (IFNγ) in vitro. In addition, bioluminescence imaging of tumor xenografts of ACAT-1-inhibited targeting MSLN CAR-T cells in MSLN-positive PC mice in vivo showed significant tumor regression, which is consistent with the in vitro observations. Our findings demonstrate a novel immunotherapeutic strategy involving the transplantation of ACAT-1-inhibited targeting MSLN CAR-T cells and the feasibility of enhancing the antitumor potency of CAR-T through the novel strategy.
Chimeric antigen receptor T-cell (CAR-T) therapy demonstrates impressive efficacy in relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). However, CAR-T therapy-related severe cytokine release syndrome and neurological toxicity limit its clinical application in R/R DLBCL patients with high tumor burden. Here, we conducted a phase II clinical trial testing the efficacy and toxicities of CAR-T therapy in R/R non-Hodgkin lymphoma patients (NCT03196830). Among the enrolled patients, 10 R/R DLBCL patients with high tumor burden were analyzed. Before CAR-T therapy, 4 were treated with intensive combined chemotherapy (C-CAR-cohort), and 6 were exposed to radiotherapy (R-CAR-cohort). Patients in the R-CAR-T-cohort showed a higher overall response rate (100% vs. 25%, P=0.033) and less severe cytokine release syndrome (0% vs. 100%, P=0.0048) and neurotoxicity (0% vs. 75%, P=0.033) incidences than patients in the C-CAR-T-cohort. Furthermore, one case who responded to CAR-T therapy initially and who suffered a relapse shortly was exposed to radiation and achieved complete remission, with an increase in the number of CAR-T copies detected. This study demonstrates that radiotherapy is an optimal debulking regimen to managing R/R DLBCL patients before CAR-T therapy and a promising alternative salvage therapy for patients who suffer a relapse after CAR-T therapy by fuelling CAR-T copies.
Objective: To investigate the safety and efficacy of allogeneic CAR-T cells in the treatment of relapsed/refractory multiple myeloma (RRMM) . Methods: CAR-T cells were prepared from peripheral blood lymphocytes of HLA mismatch healthy donors. Median age was 55 (48-60) . Allogeneic cells were derived from 3 HLA haploidentical donors and 1 HLA completely mismatch unrelated donor. Four patients with RRMM were conditioned with FC regimen followed by CAR-T cell transfusion. They were infused into CART-19 (1×10(7)/kg on day 0) and (4.0-6.8) ×10(7)/kg CART-BCMA cells as split-dose infusions (40% on day 1 and 60% on day 2) . The adverse reactions and clinical efficacy were observed during follow-up after infusion, and the amplification and duration of CAR-T cells in vivo were monitored by PCR technique.
Background: Autologous stem-cell transplantation (ASCT) is the standard treatment for R/R B-NHL, while chimeric antigen receptor T (CAR-T) therapy targeting CD19 emerges as an alternative strategy. Here we report a comparative analysis of the two strategies in a single center.
Background: CD19-modified CAR-T cells greatly influence responses in patients with relapsed/refractory acute lymphoblastic leukemia (ALL). However, recurrence remains a challenge, and reinfusion of CAR-T cells is not always effective. Sequential infusion of humanized CD19-modified and CD22-modified CAR-T cells may overcome this issue and induce remission.
Chimeric antigen receptor-modified T cell (CART) therapy has been demonstrated to have significant effect on hematologic tumor in patients. However, many persistent obstacles and challenges still limit the application. It is known that CD8 T cells are a key component of antitumor immunity. An avasimibe-induced inhibition of cholesterol esterification has been shown to improve the antitumor response of CD8 T cells in mice. In this study, using human CD19-directed CART cells as effector cells and CD19-overexpressing K562 cells as target cells, we detected whether cholesterol acyltransferase inhibition by avasimibe can enhance the antitumor effect of human CART cells. After avasimibe treatment, the infection rate was dropped by up to 50% (P<0.05). The cytotoxic effect of CART cells was significantly increased than the control group in a dose-dependent manner. Moreover, the level of secreted interferon-γ increased in almost half of the cases (P<0.05); the ratio of CD8CD4 T cells was increased among the total T cells and the CART cells in some of cases (P<0.05). Our study suggests that inhibition of cholesterol acyltransferase can promote the antitumor effect of CART cells, and provides a new option for a combination therapy by regulating T-cell metabolism to enhance antitumor effects.
Currently, conventional therapies for acute myeloid leukemia (AML) have high failure and relapse rates. Thus, developing new strategies is crucial for improving the treatment of AML. With the clinical success of anti-CD19 chimeric antigen receptor (CAR) T cell therapies against B-lineage malignancies, many studies have attempted to translate the success of CAR T cell therapy to other malignancies, including AML. This review summarizes the current advances in CAR T cell therapy against AML, including preclinical studies and clinical trials, and discusses the potential AML-associated surface markers that could be used for further CAR technology. Finally, we describe strategies that might address the current issues of employing CAR T cell therapy in AML.