Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for acute myeloid leukemia (AML). However, most patients experience relapse after allo-HSCT, with a poor prognosis, and treatment options are limited. The lack of an ideal targetable antigen is a major obstacle for treating patients with relapsed AML. CD38 is known to be expressed on most AML and myeloma cells, and its lack of expression on hematopoietic stem cells (HSCs) renders it a potential therapeutic target for relapsed AML. To investigate the clinical therapeutic efficacy and safety of CD38-targeted chimeric antigen receptor T (CAR-T-38) cells, we enrolled 6 AML patients who experienced relapse post-allo-HSCT (clinicaltrials.gov: NCT04351022). Prior to CAR-T-38 treatment, the blasts in the bone marrow of these patients exhibited a median of 95% (92–99%) CD38 positivity. Four weeks after the initial infusion of CAR-T-38 cells, four of six (66.7%) patients achieved complete remission (CR) or CR with incomplete count recovery (CRi); the median CR or CRi time was 191 (range 117–261) days. The cumulative relapse rate at 6 months was 50%. The median overall survival (OS) and leukemia-free survival (LFS) times were 7.9 and 6.4 months, respectively. One case relapsed 117 days after the first CAR-T-38 cell infusion, with remission achieved after the second CAR-T-38 cell infusion. All six patients experienced clinically manageable side effects. In addition, multiparameter flow cytometry (FCM) revealed that CAR-T-38 cells eliminated CD38 positive blasts without off-target effects on monocytes and lymphocytes. Although this prospective study has a limited number of cases and a relatively short follow-up time, our preliminary data highlight the clinical utility and safety of CAR-T-38 cell therapy in treating relapsed AML post-allo-HSCT.
Background: Multiple myeloma (MM) is an incurable plasma cell malignancies despite the advent of numerously new drugs. Survival was poor particularly for high risk patients such as R-ISS stage III. The preliminary data from our center showed that the median PFS after auto-HSCT was 24 months for patients with R-ISS III stage, while 17 months for patients that achieved PR or less after induction. Chimeric antigen receptor (CAR)-transduced T cells is a promising strategy for cancer immunotherapy. Our previous study showed good response for RRMM patients after CD19 and BCMA-specific CART therapy without severe CRS and other deadly side effects. To improve the survival of high risk patients, this study was designed to observe the safety and efficacy of combined infusion of CD19 and BCMA-specific CART cells after autologous transplantation (SZ-MM-CART02 study, NCT 03455972). Methods:18-65y NDMM in R-ISS stage III, or who only achieved PR or less after 4 cycles of PAD triplet induction were enrolled with serum creatinine (Cr) <2.0 mg/dL, and adequate hepatic, cardiac and pulmonary function. BCMA and CD19 expression on MM cells were analyzed by flow cytometry. Lymphocytes were collected from PBSCs and cultured with an anti-CD3 monoclonal antibody to activate T-cell proliferation. The cells were transduced with recombinant lentiviral verctors which respectively contained the anti-BCMA or anti-CD19 single chain variable fragment (scFv), the cytoplasmic portion of the OX40 and CD28 costimulatory moiety, and the CD3z T-cell activation domain. This is the new third generation CAR technique applied in clinic. BUCY were used as conditioning, followed by infusion of autologous stem cells. Median time to engraftment were 10 days for nutrophils. CART-19 (1×107/kg on d0) and CART-BCMA cells as split-dose (40% on d1 and 60% on d2) were infused derectly on d14 to d20 after autologous transplantation. Levels of CAR-transduced cells are measured by qPCR. The cytokine release syndrome (CRS) was graded according to the UPen cytokine release syndrome grading system. Neurotoxic side effects and other toxicities were assessed according to the CTCAE v 4.03. Plasma levels of IL-2, IL-4, IL-6, IL-10, TNF-alpha, IFN-gamma, and IL-17A proteins were determined with a cytokine kit. Imids alone were given as maintenance therapy. Responses were assessed by IMWG criteria. 10-color flow cytometry was used to monitor MRD regularly after CART treatment. The median of follow-up was 3 (2∼11) months. Results: To date, 9 patients have completed the CART cells infusion (cohort 1). All cases expressed BCMA >50% without CD19 expression on MM cells. CRS occurred in 9 patients (100%) grade1 or 2 associated with fever(n=9), fatigue (n=9), elevated IL-6 and CRP (n=9), elevated ALT (n=1, grade 1). Two patients needed to use low-dose vascular active drugs (pts 04 and 07). Other toxicities to date included coagulopathy (n=6, grade 1 for 4 pts and grade 2 for 2 pts), elevated troponin T (n=4, grade 1), and atrial flutter (n=1). There was no serious CRS or neurologic complications occurred in this group of patients. The ORR was 100% with all patients were monitored for a period of more than 2 months, which may be eventually further improved. There were 2 CR, 1 VGPR, 4 PR, 2 SD after induction; 3 CR, 2 VGPR, 4 PR after APBSCT; 3 CR, 6 VGPR after CART therapy. MRD negativity in BM increased from 37.5% after transplantation to 66.7% after CART therapy latest. Four patients (pts 02, 03, 06 and 07) obtained partial PR after transplantation, and got VGPR after CART cells infusion. We found dramatic in vivo CART expansion that median of peak value of CART copies was 1059.54 folds (ranged from 536.90 to 10997.93 folds) which was 100 folds to that with RRMM patients in our previous study. Conclusions: Tandom autologous transplantation and combined infusion of CART-19 and CART-BCMA cells could be another choice of consolidation treatment for high risk MM patients. Toxicities to date including CRS and organ function impairment seemed to be mild and reversable. It is worthy of further study to compare DFS, OS between single autologous transplantation and tandom transplantation with CART therapy. Immune environment in high risk patients with multiple myelomaI remodelled by auto-HSCT may contribute to more rapid expansion of CART cells than that in RRMM patients, suggesting that the extent of CART expansion depends more than tumor burden. Table Table. Disclosures No relevant conflicts of interest to declare.
The rapid evolution of cell‐based theranostics has attracted extensive attention due to their unique advantages in biomedical applications. However, the inherent functions of cells alone cannot meet the needs of malignant tumor treatment. Thus endowing original cells with new characteristics to generate multifunctional living cells may hold a tremendous promise. Here, the nanoengineering method is used to combine customized liposomes with neutrophils, generating oxygen‐carrying sonosensitizer cells with acoustic functions, which are called Acouscyte/O2, for the visual diagnosis and treatment of cancer. Specifically, oxygen‐carried perfluorocarbon and temoporfin are encapsulated into cRGD peptide modified multilayer liposomes (C‐ML/HPT/O2), which are then loaded into live neutrophils to obtain Acouscyte/O2. Acouscyte/O2 can not only carry a large amount of oxygen but also exhibits the ability of long circulation, inflammation‐triggered recruitment, and decomposition. Importantly, Acouscyte/O2 can be selectively accumulated in tumors, effectively enhancing tumor oxygen levels, and triggering anticancer sonodynamics in response to ultrasound stimulation, leading to complete obliteration of tumors and efficient extension of the survival time of tumor‐bearing mice with minimal systemic adverse effects. Meanwhile, the tumors can be monitored in real time by temoporfin‐mediated fluorescence imaging and perfluorocarbon (PFC)‐microbubble‐enhanced ultrasound imaging. Therefore, the nanoengineered neutrophils, i.e., Acouscyte/O2, are a new type of multifunctional cellular drug, which provides a new platform for the diagnosis and sonodynamic therapy of solid malignant tumors.
The low rate of durable response against relapsed and/or refractory multiple myeloma (RRMM) in recent studies indicates that chimeric antigen receptor T‐cell (CART) treatment is yet to be optimized. This study aims to investigate the safety and efficacy of sequential infusion of CD19‐CART and B‐cell maturation antigen (BCMA)‐CARTs for RRMM with a similar 3 + 3 dose escalation combined with a toxicity sentinel design. We enrolled 10 patients, among whom 7 received autologous infusion and 3 received allogeneic infusion. The median follow‐up time was 20 months. The most common grade 3/4 treatment‐emergent toxicities were hematological toxicities. Cytokine‐release syndrome (CRS) adverse reactions were grade 1/2 in 9 out of 10 subjects. No dose‐limited toxicity (DLT) was observed for BCMA‐CAR‐positive T cells ≤5 × 10 7 /kg), while two patients with dose‐levels of 5–6.5 × 10 7 /kg experienced DLTs. The overall response rate was 90% (five partial responses and four stringent complete responses). Three out of four patients with stringent complete responses to autologous CART had progression‐free survival for over 2 years. The three patients with allogeneic CART experienced disease progression within 2 months. These results evidence the sequential infusion's preliminarily tolerability and efficacy in RRMM, and present a simple and safe design applicable for the establishment of multiple CART therapy.
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. Methods Supernatants from cocultures of regular CART-19 cells and B lymphoma cells were added to monocytes in vitro, and the IL-6 levels in monocyte supernatants were measured 24 h later. IL-6 expression was knocked down in regular CART-19 cells by adding a short hairpin RNA (shRNA) (termed ssCART-19) expression cassette specific for IL-6 to the conventional CAR vector. Transduction efficiency and cell proliferation were measured by flow cytometry, and cytotoxicity was measured by evaluating the release of lactate dehydrogenase into the medium. Gene expression was assessed by qRT-PCR and RNA sequencing. A xenograft leukemia mouse model was established by injecting NOD/SCID/γc-/- mice with luciferase-expressing B lymphoma cells, and then the animals were treated with regular CART-19 cells or ssCART-19. Tumor growth was assessed by bioluminescence imaging. Results Both recombinant IL-6 and CART-19 derived IL-6 significantly triggered IL-6 release by monocytes. IL-6 knockdown in ssCART-19 cells dramatically reduced IL-6 release from monocytes in vitro stduy. In vivo study further demonstrated that the mice bearing Raji cells treated with ssCART-19 cells showed significant lower IL-6 levels in serum than those treated with regular CART-19 cells, but comparable anti-tumor efficacy between the animal groups. Conclusion CAR T-derived IL-6 is one of the most important initiators to amplify release of IL-6 from monocytes that further drive sCRS development. IL-6 knockdown in ssCART-19 cells by shRNA technology provide a promising strategy to improve the safety of CAR T cell therapy.
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