CD19 targeted CAR-T therapy versus chemotherapy in re-induction treatment of refractory/relapsed acute lymphoblastic leukemia: results of a case-controlled study

The Evolving Landscape of Flowcytometric Minimal Residual Disease Monitoring in B-Cell Precursor Acute Lymphoblastic Leukemia

Detection of minimal residual disease (MRD) is a major independent prognostic marker in the clinical management of pediatric and adult B-cell precursor Acute Lymphoblastic Leukemia (BCP-ALL), and risk stratification nowadays heavily relies on MRD diagnostics. MRD can be detected using flow cytometry based on aberrant expression of markers (antigens) during malignant B-cell maturation. Recent advances highlight the significance of novel markers (e.g., CD58, CD81, CD304, CD73, CD66c, and CD123), improving MRD identification. Second and next-generation flow cytometry, such as the EuroFlow consortium's eight-color protocol, can achieve sensitivities down to 10-5 (comparable with the PCR-based method) if sufficient cells are acquired. The introduction of targeted therapies (especially those targeting CD19, such as blinatumomab or CAR-T19) introduces several challenges for flow cytometric MRD analysis, such as the occurrence of CD19-negative relapses. Therefore, innovative flow cytometry panels, including alternative B-cell markers (e.g., CD22 and CD24), have been designed. (Semi-)automated MRD assessment, employing machine learning algorithms and clustering tools, shows promise but does not yet allow robust and sensitive automated analysis of MRD. Future directions involve integrating artificial intelligence, further automation, and exploring multicolor spectral flow cytometry to standardize MRD assessment and enhance diagnostic and prognostic robustness of MRD diagnostics in BCP-ALL.

Comparing the efficacy of salvage regimens for relapsed/refractory B-cell acute lymphoblastic leukaemia: a systematic review and network meta-analysis

The complete remission (CR) rate and overall survival (OS) of relapsed/refractory (R/R) B-cell acute lymphoblastic leukaemia (B-ALL) are not satisfactory. The available salvage regimens include standard chemotherapy, inotuzumab ozogamicin, blinatumomab and cluster of differentiation (CD)19 chimeric antigen receptor T cells (CAR T), and the NCCN guidelines recommend all of these therapies with no preference. Dual CD19/CD22 CAR T-cells have emerged as new treatments and have shown some efficacy, with high CR rates and preventing CD19-negative relapse. However, direct comparisons of the CR rate and long-term survival among the different salvage therapies are lacking. Databases including PubMed, Embase, Web of Science and Cochrane were searched from inception to January 31, 2022, for relevant studies. The outcomes of interest were complete remission/complete remission with incomplete haematologic recovery (CR/CRi) rates and 1-year overall survival (OS) rates. Odds ratios (ORs) were generated for binary outcomes, and the mean difference (MD) was generated for consecutive outcomes by network meta-analysis. CD19 CAR T-cells demonstrated a significantly better effect in improving the CR/CRi rate than blinatumomab (OR = 8.32, 95% CI: 1.18 to 58.44) and chemotherapy (OR = 16.4, 95% CI: 2.76 to 97.45). In terms of OS, CD19 CAR T-cells and dual CD19/CD22 CAR T-cells both had a higher 1-year OS rate than blinatumomab, inotuzumab ozogamicin and chemotherapy. There was no significant difference between CD19 CAR T-cells and dual CD19/CD22 CAR T-cells in terms of 1-year OS and CR/CRi rates. CD19 CAR T-cells are effective in inducing CR, and CD19 CAR T-cells and dual CD19/CD22 CAR T-cells show benefits for overall survival. More high-quality randomized controlled trials and longer follow-ups are needed to confirm and update the results of this analysis in the future.

[Targeted immunotherapy efficacy analysis in patients with relapsed/refractory B cell acute lymphocytic leukemia]

Objective: Comparison of conventional chemotherapy and immunotargeted therapy efficacy in patients with relapsed/refractory (R/R) acute B cell leukemia (B-ALL) . Methods: The clinical data of 212 patients with R/R B-ALL in the Affiliaed Cancer Hospital of Zhengzhou University from January 2008 to July 2020 were analyzed retrospectively to compare the response rate and survival time difference between conventional chemotherapy and immunotargeted therapies (antiCD19 CAR-T and CD3CD19 bi-specific antibody blinatumomab) , and to explore the related factors affecting prognosis. Results: The CR rate of patients with R/R B-ALL treated with anti-CD19 CAR-T cells was 80.4% , patients treated with blinatumomab was 62.5% , and patients treated with chemotherapy was 38.6% . There was significant difference in the CR rate among the three therapies (P<0.001) . CAR-T cells 1-year OS rate was 41.5% , which was significantly higher than that of the chemotherapy group (10.3% ) (P<0.001) . The 1-year PFS rate of CAR-T cells (30.1% ) was also significantly higher than that of the chemotherapy group (9.7% ) (P<0.001) . The median OS of patients with bridging allo-HSCT after CR treatment by CAR-T cells was 18.5 months, which was higher than that of patients without allo-HSCT (8 months) (P=0.027) . The median PFS of patients with allo-HSCT was 17 months, which was higher than that of patients without allo-HSCT (4 months) (P=0.001) . The 1-year OS rate of patients treated with blinatumomab was 14.3% , which was higher than that of the chemotherapy group (10.3% ) (P=0.018) . The 1-year PFS rate (14.6% ) was also higher than that of the chemotherapy group (9.7% ) (P=0.046) . The median OS and median PFS of patients with bridging allo-HSCT were 13 and 11 months, respectively, which was higher than that of patients without allo-HSCT (9.5 and 6 months) . The cytokine release syndrome (CRS) incidence in patients with R/R B-ALL treated with anti-CAR-T cells was 89.8% . Grades 3-4, grade 2, and grade 1 CRS were experienced by 30.2% , 11.3% and 58.5% patients, respectively. Only three patients (37.5% ) with blinatumomab developed CRS, all of which were grade 1. Conclusion: The response rate and survival rate of patients with R/R B-ALL treated with CD19 CAR-T cells and blinatumomab were significantly better than those treated with conventional chemotherapy.

Cytokine Release Syndrome after Chimeric Antigen Receptor Transduced T-Cell Therapy in Cancers: A Systematic Review

Patients with refractory or relapsed malignant disorders are in desperate condition, with few therapeutic options left, if any. Chimeric antigen receptor (CAR) transduced T-cell transplantation is a novel approach that has shown promising results as well as serious adverse events. This study aimed to systematically review the current data on the cytokine release syndrome (CRS) as a major side effect of CAR therapy. A systematic literature review was conducted to find reports of CAR T-cell therapy in the context of cancer patients and to extract reports of severe CRS. The factors that could significantly affect the incidence of CRS were investigated. Mortality rates were also compared regarding the occurrence of CRS. The incidence of severe CRS was 9.4% (95% confidence interval: 8.3-10.5) in the reviewed studies. Younger and older patients (vs. adults), higher doses of CAR T-cell infusions, lymphodepletion (LD) before CAR T-cell infusions, specific LD regimens, the source of allogeneic cells for the construction of CAR, chronic lymphocytic leukemia as the tumor type (vs. lymphoma), and CD28 as costimulatory domain in the structure of CAR were significantly associated with CRS events. Patients experiencing severe CRS had a significantly higher mortality rate within 2 and 3 months after transplantation. In conclusion, this study found many factors that could predict severe CRS and future clinical trials could reveal the relevance of appropriate interventions to the incidence and outcomes of CRS in cancer patients undergoing CAR T-cell transduced infusions.

Progress on CAR-T cell therapy for hematological malignancies

Chimeric antigen receptor (CAR) T cell therapy is an effective treatment for hematological malignancies, which have experienced the development of CD19 CAR-T cells for B lymphoblastic leukemia and lymphoma, B cell maturation antigen (BCMA) CAR-T cells for multiple myeloid, and more recently, the development of CD7 CAR-T cells for T cell malignancies. There are more obstacles for myeloid malignancies compared to other hematological malignancies in this field, thus concerning researches are in more diverse ways. In order to obtain more effective clinical CAR-T cells with lower side effects, scientists have developed multi-target CAR-T cells, universal CAR-T cells, as well as CAR-T cells, CAR-NK cells, CAR-iMac cells derived from induced pluripotent stem cells (iPSC) by genetic engineering. Chinese scientists have made significant contribution to the invention and manufacture of origin CAR-T cells and the establishment of an intact clinical research system. This review introduces the latest progress involving CAR-T cell therapy for hematological malignancies including B lymphoblastic malignancies, T lymphoblastic malignancies and myeloid malignancies, and also discuss the future developments including multi-target, universal and iPSC-derived CAR-related cell therapy.

Treatment-Related Adverse Events of Chimeric Antigen Receptor T-Cell (CAR T) in Clinical Trials: A Systematic Review and Meta-Analysis

Simple Summary

Successful treatment of hematological malignancies with chimeric antigen receptors T (CAR-T) cells has led to much enthusiasm for the wide clinical usage and development of novel CAR-T therapies. However, it also challenges physicians and investigators to recognize and deal with treatment-associated toxicities. We conducted a systematic review and meta-analysis from 84 eligible study and a total of 2592 patients to identify the comprehensive incidences and severity of CRS and neurological symptoms (NS) as well as the potential differences in AEs across a variety of cancer types, CAR-T targets, and other factors, thereby offering a significant implication on its future application and research.

Abstract

Chimeric antigen receptors T (CAR-T) cell therapy of cancer is a rapidly evolving field. It has been shown to be remarkably effective in cases of hematological malignancies, and its approval by the FDA has significantly increased the enthusiasm for wide clinical usage and development of novel CAR-T therapies. However, it has also challenged physicians and investigators to recognize and deal with treatment-associated toxicities. A total of 2592 patients were included from 84 eligible studies that were systematically searched and reviewed from the databases of PubMed, de, the American Society of Hematology and the Cochrane Library. The meta-analysis and subgroup analysis by a Bayesian logistic regression model were used to evaluate the incidences of therapy-related toxicities such as cytokine release syndrome (CRS) and neurological symptoms (NS), and the differences between different targets and cancer types were analyzed. The pooled all-grade CRS rate and grade ≥ 3 CRS rate was 77% and 29%, respectively, with a significantly higher incidence in the hematologic malignancies (all-grade: 81%; grade ≥ 3: 29%) than in solid tumors (all-grade: 37%; grade ≥ 3: 19%). The pooled estimate NS rate from the individual studies were 40% for all-grade and 28% for grade ≥ 3. It was also higher in the hematologic subgroup than in the solid tumors group. The subgroup analysis by cancer type showed that higher incidences of grade ≥ 3 CRS were observed in anti-CD19 CAR-T therapy for ALL and NHL, anti-BCMA CAR-T for MM, and anti-CEA CAR-T for solid tumors, which were between 24–36%, while higher incidences of grade ≥ 3 NS were mainly observed in CD19-ALL/NHL (23–37%) and BCMA-MM (12%). Importantly, subgroup analysis on anti-CD19 CAR-T studies showed that young patients (vs. adult patients), allologous T cell origin (vs. autologous origin), gamma retrovirus vector, and higher doses of CAR-T cells were associated with high-grade CRS. On the other hand, the patients with NHL (vs ALL), administered with higher dose of CAR-T, and adult patients (vs. young patients) had an increased incidence of grade ≥ 3 NS events. This study offers a comprehensive summary of treatment-related toxicity and will guide future clinical trials and therapeutic designs investigating CAR T cell therapy.

Cytokine Release Syndrome Is an Independent Risk Factor Associated With Platelet Transfusion Refractoriness After CAR-T Therapy for Relapsed/Refractory Acute Lymphoblastic Leukemia

Background: Chimeric antigen receptor T cell (CAR-T) therapy is successful in improving treatment outcomes for relapsed/refractory acute lymphoblastic leukemia (R/R ALL). However, toxicities associated with CAR-T therapy are being increasingly identified. Pancytopenia is one of the most common complications after CAR-T therapy, and platelet transfusions are an essential part of its supportive care. Study Design and Methods: This study aimed to assess the effectiveness of platelet transfusions for R/R ALL patients at our single center and identify associated risk factors. Overall, 44 R/R ALL patients were enrolled in this study, of whom 26 received CAR-T therapy and 18 received salvage chemotherapy. Result: Patients in the CAR-T group had a higher incidence of platelet transfusion refractoriness (PTR) (15/26, 57.7%) than those in the chemotherapy group (3/18, 16.7%) (p = 0.007). For patients receiving CAR-T therapy, multivariate analysis showed that the grade of cytokine release syndrome (CRS) was the only independent risk factor associated with PTR (p = 0.007). Moreover, higher peak serum IL-6 and IFN-γ levels suggested a higher risk of PTR (p = 0.024 and 0.009, respectively). Patients with PTR received more platelet infusion doses than those without PTR (p = 0.0426). Patients with PTR had more grade 3-4 bleeding events than those without PTR (21.4 vs. 0%, p = 0.230), and the cumulative incidence of grade 3-4 bleeding event was different (p = 0.023). Conclusion: We found for the first time that PTR is associated with the CRS grade. Improved knowledge on the mechanisms of PTR after CAR-T therapy is needed to design a rational therapeutic strategy that aims to improve the efficiency of transfusions.

Graft-versus-host disease risk after chimeric antigen receptor T-cell therapy: the diametric opposition of T cells

Chimeric antigen receptor (CAR) T-cell therapy has brought a paradigm shift in the management of haematological malignancies and has opened novel avenues of investigational therapeutic strategies. Given these encouraging responses, it has become imperative to understand the full spectrum of biology and potential toxicities that can arise from these novel agents, as well as those under investigation. With the increasing use of CAR T-cell therapy for relapse following allogeneic haematopoietic cell transplantation (HCT) and the imminence of allogeneic CAR T cells, risks from T cell-based therapy, such as the previously well-recognised graft-versus-host disease (GVHD), have gained prominence and warrant explanation. In the present review, we discuss the risk of GVHD in the: (1) post-HCT setting using recipient or donor-derived CAR T cells, as well as (2) non-HCT setting using autologous, as well as allogeneic T-cell therapies. A better understanding of this risk is important to advance the field and ensure safe development and use of these agents in the clinic.

CD19 CAR-T cell treatment conferred sustained remission in B-ALL patients with minimal residual disease

The persistence or recurrence of minimal residual disease (MRD) after chemotherapy predicts relapse of B-cell acute lymphoblastic leukemia (B-ALL). CD19-directed chimeric antigen receptor T (CD19 CAR-T) cells have shown promising responses in B-ALL. However, their role in chemotherapy-refractory MRD-positive B-ALL remains unclear. Here we aimed to assess the effectiveness and safety of CD19 CAR-T cells in MRD-positive B-ALL patients. From January 2018, a total of 14 MRD-positive B-ALL patients received one or more infusions of autogenous CD19 CAR-T cells. Among them, 12 patients achieved MRD-negative remission after one cycle of CAR-T infusion. At a median follow-up time of 647 days (range 172–945 days), the 2-year event-free survival rate in MRD-positive patients was 61.2% ± 14.0% and the 2-year overall survival was 78.6 ± 11.0%, which were significantly higher than patients with active disease (blasts ≥ 5% or with extramedullary disease). Moreover, patients with MRD had a lower grade of cytokine release syndrome (CRS) than patients with active disease. However, the peak expansion of CAR-T cells in MRD positive patients showed no statistical difference compared to patients with active disease. Five patients received two or more CAR-T cell infusions and these patients showed a decreased peak expansion of CAR-T cell in subsequent infusions. In conclusion, pre-emptive CD19 CAR-T cell treatment is an effective and safe approach and may confer sustained remission in B-ALL patients with chemotherapy-refractory MRD. The trials were registered at www.chictr.org.cn as ChiCTR-ONN-16009862 (November 14, 2016) and ChiCTR1800015164 (March 11, 2018).

Biomarkers for Chimeric Antigen Receptor T Cell Therapy in Acute Lymphoblastic Leukemia: Prospects for Personalized Management and Prognostic Prediction

Chimeric antigen receptor (CAR) T cell therapy represents a breakthrough in immunotherapy with the potential of ushering in a new era in cancer treatment. Remarkable therapeutic response and complete remission of this innovative management have been observed in patients with relapse/refractory acute lymphoblastic leukemia. With CAR-T cell therapy becoming widely used both in multicenter clinical trials and as a commercial treatment, therapeutic efficacy monitoring and management of toxicities will be indispensable for ensuring safety and improving overall survival. Biomarkers can act not only as effective indicators reflecting patients' baseline characteristics, CAR-T cell potency, and the immune microenvironment, but can also assess side effects during treatment. In this review, we will elaborate on a series of biomarkers associated with therapeutic response as well as treatment-related toxicities, and present their current condition and latent value with respect to the clinical utility. The combination of biomarker research and CAR-T cell therapy will contribute to establishing a safer and more powerful monitoring system and prolonging the event-free survival of patients.

The incidence of cytokine release syndrome and neurotoxicity of CD19 chimeric antigen receptor-T cell therapy in the patient with acute lymphoblastic leukemia and lymphoma

Our objective was to summarize the side effect of chimeric antigen receptor (CAR)-T cell therapy in patients with acute lymphocytic leukemia (ALL) and lymphoma. Two independent reviewers extracted relevant data. A total of 35 hematologic malignancy studies with CD19 CAR-T cell were included (1412 participants). Severe cytokine release syndrome (sCRS) proportion was experienced by 18.5% (95% confidence interval [CI], 0.128-0.259; P = 0.000) of 982 patients with the National Cancer Institute/Lee/common terminology criteria for adverse events grading system. The pooled neurotoxicity proportion was 21.7% (95% CI, 0.167-0.287; P = 0.000) of 747 patients with the same grading system. For all of the 25 clinical trials with the same grading system, subgroup analysis was performed. Based on the different disease type, a pooled prevalence of 35.7% was observed with event rate (ER) of 0.358 (95% CI, 0.289-0.434; P = 0.000) for ALL in 12 clinical trials. For lymphoma, a pooled prevalence of 13% was observed with ER of 0.073 (95% CI, 0.028-0.179; P = 0.000) in eight clinical trials. It was demonstrated that the patients who were older than 18 years of age have the lower sCRS incidence of 16.1% (95% CI, 0.110-0.250; P = 0.000) compared with 28.6% of the remaining population who were younger than 18 years of age (95% CI, 0.117-0.462: P = 0.023) in our analysis. Based on the different co-stimulatory domain, the sCRS of 16.5% was observed with ER of 0.175 (95% CI, 0.090-0.312; P = 0.000) for 4-1BB. The sCRS of 22.2% was observed with ER of 0.193 (95% CI, 0.107-0.322; P = 0.000) for CD28. For both the CD28 and 4-1BB, the sCRS of 17.3% was observed with ER of 0.170 (95% CI, 0.067-0.369; P = 0.003). Sub-analysis sCRS of the impact with cell dose and specific disease indication were also demonstrated. Limitations include heterogeneity of study populations, as well as high risk of bias of included studies. These results are helpful for physicians, patients and the other stakeholders to understand the adverse events and to further promote the improvement of CAR-T cell therapy in the future.

Successful treatment of acute B lymphoblastic leukemia relapse in the skin and testicle by anti-CD19 CAR-T with IL-6 knocking down: a case report

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.

Case presentation

Here we reported a single case of a patient with relapsed B-ALL in skin and testicle who was successfully treated by the shRNA-IL6-modified anti-CD19 CAR-T(ssCAR-T-19) therapy. A 29-year-old man with relapsed B-ALL in skin and testicle was enrolled in clinal trial involving the shRNA-IL6-modified anti-CD19 CAR-T(ssCAR-T-19) therapy (ClinicalTrials.gov number, NCT03919240). The patient had toxicity consistent with the grade 1 cytokine release syndrome.

Conclusions

ssCART-19 therapy may be used to effectively eliminate infiltrating leukemia cells in the skin and testicle with mild toxicity, which could be a much safer approach to bridge allo-HSCT, thus further improving the patient’s outcome.

Trial registration

ClinicalTrials.gov number, NCT03919240, Registered 18 April 2019, retrospectively registered.

Treatment response, survival, safety, and predictive factors to chimeric antigen receptor T cell therapy in Chinese relapsed or refractory B cell acute lymphoblast leukemia patients

This study aimed to evaluate treatment response, survival, safety profiles, and predictive factors to chimeric antigen receptor T cell (CAR-T) therapy in Chinese patients with relapsed or refractory B cell acute lymphoblast leukemia (R/R B-ALL). 39R/R B-ALL patients who underwent CAR-T therapy were included. Baseline data were collected from patients’ electronic medical records. Patients’ peripheral bloods, bone marrow aspirates, and biopsies were obtained for routine examination, and treatment response and survival profiles as well as adverse events were evaluated. The rates of complete remission (CR), CR with minimal residual disease (MRD) negative/positive, and bridging to hematopoietic stem-cell transplantation (HSCT) were 92.3%, 76.9%, 15.4%, and 43.6%, respectively. The median event-free survival (EFS) was 11.6 months (95% confidence interval (CI): 4.0–19.2 months) and median overall survival (OS) was 14.0 months (95% CI: 10.9–17.1 months). Bridging to HSCT independently predicted better EFS and OS, while high bone marrow blasts level independently predicted worse EFS. The incidence of cytokine release syndrome (CRS) was 97.4%, and refractory disease as well as decreased white blood cell independently predicted higher risk of severe CRS. Other common adverse events included hematologic toxicities (grade I: 5.1%, grade II: 7.7%, grade III: 17.9%, grade IV: 69.2%), neurotoxicity (28.2%), infection (38.5%), and admission for intensive care unit (10.3%). In conclusion, CAR-T therapy presents with promising treatment response, survival and safety profiles, and higher disease burden predicts worse survival as well as increased risk of severe CRS in Chinese R/R B-ALL patients.

[Safety and efficacy of patients with refractory B-lymphoblastic leukemia treated with anti-CD19 CAR-T cell bridging to allogeneic hematopoietic stem cell transplantation]

Objective: To investigate the efficacy and side effects of anti-CD19 CAR-T cell bridging to allogeneic hematopoietic stem cell transplantation (allo-HSCT) regimen for refractory B-lymphoblastic leukemia. Methods: 10 patients with refractory B-lymphoblastic leukemia with minimal residual disease (MRD) negative after anti-CD19 CAR-T cell treatment, then bridging to allo-HSCT from November 2017 to March 2019 in the Affiliated Cancer Hospital of Zhengzhou University were retrospectively analyzed. Results: ①Among 10 patients, 5 were males and 5 females, with a median age of 23.6 (10-31) years. 9 patients were diagnosed refractory acute lymphoblastic leukemia and the other one was chronic lymphoblastic leukemia. 10 patients reached MRD negative 30 days after anti-CD19 CAR-T cell. ②The donors were identical sibling (2 cases) and haploidentical family member (8 cases) . The median time from MRD negative after CAR-T treatment to transplantation were 32.5 (20-60) days. ③10 patients obtained complete haploidentical engraftment. The median time of neutrophil implantation was 15 (15-21) days, and 19 (17-30) days of platelet implantation. ④ After conditioning, no hepatic venoocclusive disease and hemorrhagic cystitis occurred. One patient had leakage syndrome and got improved after intervention such as limited water entry, albumin supplementation and diuresis. 8 (80%) patients had fever, 2 cases experienced acute graft-versus-host disease (GVHD) grade Ⅱ, 1 case with aGVHD grade Ⅲ. Among 9 survivals, localized chronic GVHD occurred in 8 patients. ⑤The median follow-up was 262 (150-540) days and the estimated 1-years overall survivaln (OS) and disease free survival (DFS) were (90.0±1.0) % and (85.7±1.3) %, respectively. Conclusion: Anti-CD19 CAR-T cell bridging to allo-HSCT regimen is a feasible choice with favorable outcome for refractory B-lymphoblastic leukemia.

Preclinical safety evaluation of chimeric antigen receptor-modified T cells against CD19 in NSG mice

Background

With the increase of chimeric antigen receptor-modified T (CAR-T) cell therapy, serious complications initiated by CAR-T cells have garnered wide attention. We have previously developed a 4-1BB/CD3-ζ-costimulated CAR-T cells against CD19 (CART19) for adult acute lymphoblastic leukemia (ALL). In this study, a preclinical safety assessment of CART19 was performed on NSG mice, to evaluate the preclinical toxicity along with its efficacy and tissue distribution.

Methods

A total of 120 NSG mice were used for a combined pharmacodynamics and toxicity study for 56 days. Ninety-six mice of which were single dosed with Raji-Luc (5×10⁵ per animal, i.p.) and different concentrations of CART19 (0.2×10⁷, 0.6×10⁷ and 1.8×10⁷ per animal, i.v.), while the rest were assigned to the Untreated group. Optical intensity of Raji-Luc in mice, clinical symptoms, body mass, hematological analysis, humanized cytokine, lymphocyte subset counting, necropsy and histopathological examinations were performed. In addition, a single dose of 0.6×10⁷ CART19 was intravenously administered to 48 NSG mice, and the distribution of CART19 in different tissues was analyzed using quantitative PCR.

Results

CART19 is widely distributed in organs well-perfused with blood, including the lungs, blood, bone marrow, liver and spleen. Significant proliferation of CART19 was also found in the blood by through recognition using humanized CD3⁺ for T lymphocytes. The survival rate and leukemia related clinical symptoms in mice administered CART19 were markedly ameliorated, and the proliferation of Raji cells in mice was effectively inhibited. However, CART19 had no obvious effects on either the mean body mass or the blood cell counts, and no cytokine release syndrome and graft versus host disease were observed.

Conclusions

NSG mice given CART19 treatment demonstrated a longer survival period without significant immunotoxicity, suggesting encouraging clinical prospects for CART19 in patients with R/R ALL. Our study shed light on evaluation and supervision strategies for CAR-T products for the treatment of hematological diseases or leukemia.

Role of CAR-T cell therapy in B-cell acute lymphoblastic leukemia

Chimeric antigen receptor (CAR) T cells are genetically engineered cells containing fusion proteins combining an extracellular epitope-specific binding domain, a transmembrane and signaling domains of the T cell receptor. The CD19-CAR T cell product tisagenlecleucel has been approved by the US Food and Drug Administration and the European Medicines Agency for therapy of children and young adults under 25 years with relapsed/refractory B‑cell acute lymphoblastic leukemia (ALL) due to a high overall response rate of 81% at 3 months after therapy. The rates of event-free and overall survival were 50 and 76% at 12 months. Despite the high initial response rate with CD19-CAR‑T cells in B‑ALL, relapses occur in a significant fraction of patients. Current strategies to improve CAR‑T cell efficacy focus on improved persistence of CAR‑T cells in vivo, use of multispecific CARs to overcome immune escape and new CAR designs. The approved CAR‑T cell products are from autologous T cells generated on a custom-made basis with an inherent risk of production failure. For large scale clinical applications, universal CAR‑T cells serving as “off-the-shelf” agents would be of advantage. During recent years CAR‑T cells have been frequently used for bridging to allogeneic hematopoietic stem cell transplantation (HSCT) in patients with relapsed/refractory B‑ALL since we currently are not able to distinguish those CAR‑T cell induced CRs that will persist without further therapy from those that are likely to be short-lived. CAR‑T cells are clearly of benefit for treatment following relapse after allogeneic HSCT. Future improvements in CAR‑T cell constructs may allow longer term remissions without additional HSCT.

[Ibrutinib combined with CAR-T cells in the treatment of del (17p) chronic lymphocytic leukemia with BCL-2 inhibitor resistance: a case report and literature review]

Objective: To improve the knowledge and experience of ibrutinib combined with CAR-T cells in the treatment of high-risk chronic lymphoblastic leukemia (CLL) patients or small lymphocytic lymphoma (SLL) with TP53 gene aberration. Methods: One case of del (17p) CLL patients with BCL-2 inhibitor resistance was treated with ibrutinib combined with CAR-T cells, successfully bridged to allogeneic hematopoietic stem cell transplantation (allo-HSCT) , and the relative literatures were reviewed. Results: The patient was a young female with superficial lymph node enlarging at the beginning of the onset. Lymph node biopsy was confirmed as small lymphocytic lymphoma (SLL) without del (17p) . The disease progressed rapidly to CLL/SLL with del (17p) and bone marrow hematopoietic failure 2 years later. Firstly, the patient was treated with BCL-2 inhibitor (Venetoclax) , and the enlarged lymph nodes shrank significantly 2 months later. After 3 months, the disease progressed rapidly. The spleen was enlarged to 16 cm below the ribs, the neck lymph nodes was rapidly enlarged, and the superior vena cava syndrome appeared, which were mainly attributed to venetoclax resistance; so BTK inhibitor (ibrutinib) was used continuously after venetoclax discontinuation. Partial remission (PR) was achieved without lymphocytosis after 2 months, then ibrutinib was combined with CAR-T cells targeting CD19 antigen. Grade 1 of cytokine release syndrome (CRS) appeared after CAR-T cells infusion, and the complete remission (CR) was achieved after 1 month both in bone marrow and peripheral blood, with minimal residual disease (MRD) negative, then bridging allo-HSCT after 2 months of combined therapy. Conclusion: CLL/SLL patients with TP53 aberration have poor prognosis because of rapid progression, drug resistance, etc. Ibrutinib combined with CAR-T cell therapy can quickly achieved complete remission.

Comparation of CART19 and autologous stem-cell transplantation for refractory/relapsed non-Hodgkin's lymphoma

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.

METHODS

We performed a prospective single-arm study of CAR-T therapy in 29 patients with R/R B-NHL and compared the outcomes with contemporaneous 27 patients who received ASCT. NHL was diagnosed by histopathological assessments, and the safety and efficacy were compared.

RESULTS

The CAR-T group exhibited better rates of CR (48.0% vs. 20.8%, P=0.046) and one-year OS (74.4% vs. 44.5%, P=0.044) compared with the ASCT group. Subpopulation analysis showed that patients with IPI scores ≥ 3 achieved significantly higher ORR and CR rates in the CAR-T group than in the ASCT group (ORR: 72.0% vs. 10.0%, P=0.002; CR: 38.9% vs 0% P=0.030, respectively). The most common severe adverse events in the CAR-T group were cytokine release syndrome, neurotoxicity and infection compared with cytopenia, gastrointestinal toxicity and infection in the ASCT group. Additionally, the incidence of non-hematologic severe adverse events (SAEs) was markedly lower in the CAR-T group than in the ASCT group (20.7% vs. 48.1% P=0.030).

CONCLUSION

CAR-T therapy exhibited superior clinical outcomes in safety and efficacy over ASCT in patients with R/R B-NHL, suggesting CAR-T may be a recommended alternative to ASCT.

Improving the safety of CAR-T cell therapy by controlling CRS-related coagulopathy

The CD19-targeted chimeric antigen receptor T cell (CAR-T) therapy has been widely proved effective on relapsed and refractory (r/r) B cell acute lymphoblastic leukemia (B-ALL). Meanwhile, CAR-T therapy-related toxicities, including cytokine release syndrome (CRS) and neurological toxicities, are drawing researchers' attention. In addition, our research team notices that coagulopathy and even disseminated intravascular coagulation (DIC) are common problems during CAR-T therapy. In our phase 1/2 clinical trial (NCT02965092), 53 r/r B-ALL patients underwent leukapheresis on day - 11 and received lymphodepleting chemotherapy on day - 7 to day - 5. Finally, they received split infusions of anti-CD19 CAR-T cells on day 0 to day 2. Plasma concentrations of tissue factor (TF) and platelet endothelial cell adhesion molecular-1 (PECAM-1) were also measured to identify the mechanism of coagulation disorders. The overall 1-month remission rate of the 53 patients was 88.7%. During the treatment course, 19 patients experienced grade 3-4 CRS, 8 patients developed grade 2-3 neurological toxicities. Beyond that, 30 patients (30/53, 56.6%) suffered from coagulation disorders, and half of them should be diagnosed as DIC. Benefiting from replacement and anticoagulant therapy, 14 patients successfully got out of the conditions of DIC. Remarkably, the severity of coagulopathy was positively correlated with CRS grade. What is more, plasma TF and PECAM-1 levels indicated that vascular endothelial factors played key roles in the process of CRS-related coagulopathy. To conclude, coagulation disorders frequently happen during CAR-T therapy. TF and PECAM-1 are of great importance in the etiology and pathogenesis of coagulation problems. Early and proper interventions targeted at CRS-related coagulopathy contribute a lot to the control of side effects in CAR-T therapy.

Blinatumomab for Acute Lymphoblastic Leukemia Relapse after Allogeneic Hematopoietic Stem Cell Transplantation

Patients with relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) following allogeneic hematopoietic stem cell transplantation (alloHSCT) have a poor prognosis, and alternative therapies are needed for this patient population. Blinatumomab, a bispecific T cell engager immunotherapy, was evaluated in an open-label, single-arm, phase II study of adults with R/R Philadelphia chromosome-negative B cell precursor ALL and resulted in a rate of complete remission (CR) or CR with partial hematologic recovery of peripheral blood counts (CRh) of 43% within 2 treatment cycles. We conducted an exploratory analysis to determine the efficacy and safety of blinatumomab in 64 patients who had relapsed following alloHSCT before enrollment in the phase II study. Forty-five percent of the patients (29 of 64) achieved a CR/CRh within the first 2 cycles of treatment, 22 of whom had a minimal residual disease (MRD) response (including 19 with a complete MRD response). After 1 year and 3 years of follow-up, the median relapse-free survival was 7.4 months for patients who achieved CR/CRh in the first 2 cycles, and the median overall survival was 8.5 months; overall survival rate (Kaplan-Meier estimate) was 36% at 1 year and 18% at 3 years. Grade 3 and 4 adverse events were reported in 20 patients (31%) and 28 patients (44%), respectively, with grade 3 and 4 neurologic events in 8 and 2 patients, respectively, and grade 3 cytokine release syndrome in 2 patients. Eight patients had fatal adverse events, including 5 due to infections. Seven patients had grade ≤ 3 graft-versus-host disease during the study, none of which resulted in the discontinuation of blinatumomab or hospitalization. Our data suggest that blinatumomab is an effective salvage therapy in this patient population.

Targeting the A3 adenosine receptor to treat cytokine release syndrome in cancer immunotherapy

Cancer patients undergoing immunotherapy may develop cytokine release syndrome (CRS), an inflammatory cytokine storm condition, followed by neurotoxic manifestations and may be life-threatening. The current treatments for CRS successfully reduce the inflammatory response but may limit the anticancer effect of the given immunotherapy and fail to overcome the neurotoxic adverse events. Adenosine, a ubiquitous purine nucleoside, induces a plethora of effects in the body via its binding to four adenosine receptors A₁, A_2a, A_2b, and the A₃. Highly selective agonists to the A₃ adenosine receptor act as inhibitors of proinflammatory cytokines, possess robust anti-inflammatory and anticancer activity, and concomitantly, induce neuroprotective effects. Piclidenoson and namodenoson belong to this group of compounds, are effective upon oral administration, show an excellent safety profile in human clinical studies, and therefore, may be considered as drug candidates to treat CRS. In this article, the detailed anti-inflammatory characteristics of these compounds and the rationale to use them as drugs to combat CRS are described.

Chimeric Antigen Receptor T-cell (CAR T) Therapy for Hematologic and Solid Malignancies: Efficacy and Safety-A Systematic Review with Meta-Analysis

Chimeric antigen receptors T cells (CAR T) had been used for treating various tumor patients in clinic, and owned an incredible efficacy in part of malignancies. However, CAR T therapy remains controversial due to doubts about its efficacy and safety in the clinical treatment of various malignancies. A total of 997 tumor patients from 52 studies were included in this review. Eligible studies were searched and reviewed from the databases of PubMed, Web of Science, Wanfang and Clinicaltrials.gov. Then meta-analysis and subgroup analysis were used to investigate the overall response rate (ORR), complete response rate (CRR), common side effect rate (CSER) and relapse rate (RR) of CAR T therapy for patients in clinical researches, respectively. The results further confirmed that CAR T therapy had a higher response rate for hematologic malignancies. More importantly, CAR T therapy had a higher CSER in patients with hematologic malignancies, and it had a similar RR in patients with different malignancies. Cell cultured without the addition of IL-2 and total administration less than 10⁸ cells were recommended. This study offers a reference for future research regarding the application in solid and hematologic malignancies, side effects and relapse, and even the production processes of CAR T cells.