Predictive model for CAR-T cell therapy success in patients with relapsed/refractory B-cell acute lymphoblastic leukaemia.

Chimeric antigen receptor T-cell (CAR-T) therapy has demonstrated remarkable efficacy in treating relapsed/refractory acute B-cell lymphoblastic leukaemia (R/R B-ALL). However, a subset of patients does not benefit from CAR-T therapy. Our study aims to identify predictive indicators and establish a model to evaluate the feasibility of CAR-T therapy. Fifty-five R/R B-ALL patients and 22 healthy donors were enrolled. Peripheral blood lymphocyte subsets were analysed using flow cytometry. Sensitivity, specificity, accuracy, positive and negative predictive values and receiver operating characteristic (ROC) areas under the curve (AUC) were determined to evaluate the predictive values of the indicators. We identified B lymphocyte, regulatory T cell (Treg) and peripheral blood minimal residual leukaemia cells (B-MRD) as indicators for predicting the success of CAR-T cell preparation with AUC 0.936, 0.857 and 0.914. Furthermore, a model based on CD3+ T count, CD4+ T/CD8+ T ratio, Treg and extramedullary diseases (EMD) was used to predict the response to CAR-T therapy with AUC of 0.938. Notably, a model based on CD4+ T/CD8+ T ratio, B, Treg and EMD were used in predicting the success of CAR-T therapy with AUC 0.966 [0.908-1.000], with specificity (92.59%) and sensitivity (91.67%). In the validated group, the predictive model predicted the success of CAR-T therapy with specificity (90.91%) and sensitivity (100%). We have identified several predictive indicators for CAR-T cell therapy success and a model has demonstrated robust predictive capacity for the success of CAR-T therapy. These results show great potential for guiding informed clinical decisions in the field of CAR-T cell therapy.

[Clinical efficacy and safety of blinatumomab bridging CAR-T cell therapy in the treatment of patients with adult acute B-cell lymphoblastic leukemia].

Objective: Exploring the efficacy and safety of bridging blinatumomab (BiTE) in combination with chimeric antigen receptor T (CAR-T) cell therapy for the treatment of adult patients with acute B-cell lymphoblastic leukemia (B-ALL) . Methods: Clinical data from 36 adult B-ALL patients treated at the First Affiliated Hospital of Suzhou University from August 2018 to May 2023 were retrospectively analyzed. A total of 36 cases were included: 18 men and 18 women. The median age was 43.5 years (21-72 years). Moreover, 21 cases of Philadelphia chromosome-positive acute lymphoblastic leukemia were reported, and 16 of these cases were relapsed or refractory. Eighteen patients underwent blinatumomab bridging followed by CAR-T cell therapy, and 18 patients received CAR-T cell therapy. This study analyzed the efficacy and safety of treatment in two groups of patients. Results: In the BiTE bridge-to-CAR-T group, 16 patients achieved complete remission (CR) after BiTE immunotherapy, with a CR rate of 88.9%. One month after bridging CAR-T therapy, bone marrow examination showed a CR rate of 100.0%, and the minimal residual disease (MRD) negativity rate was higher than the nonbridging therapy group (94.4% vs. 61.1%, Fisher, P=0.041). The incidence of cytokine release syndrome and other adverse reactions in the BiTE bridge-to-CAR-T group was lower than that in the nonbridging therapy group (11.1% vs. 50.0%, Fisher, P=0.027). The follow-up reveals that 13 patients continued to maintain MRD negativity, and five patients experienced relapse 8.40 months (2.57-10.20 months) after treatment. Two of five patients with relapse achieved CR after receiving the second CAR-T cell therapy. In the nonbridging therapy group, 10 patients maintained continuous MRD negativity, 7 experienced relapse, and 6 died. The 1 year overall survival rate in the BiTE bridge-to-CAR-T group was higher than that in the nonbridging therapy group, with a statistically significant difference at the 0.1 level (88.9%±10.5% vs. 66.7%±10.9%, P=0.091) . Conclusion: BiTE bridging CAR-T cell therapy demonstrates excellent efficacy in adult B-ALL treatment, with a low recent recurrence rate and ongoing assessment of long-term efficacy during follow-up.

Bispecific T-cell engagers in childhood B-acute lymphoblastic leukemia.

Immunotherapy has revolutionized treatment for a wide variety of cancers yet its use has been relatively limited in childhood malignancies. With the introduction of bispecific T-cell engagers (BiTE®) and chimeric antigen T-cell receptor technologies, previously refractory patients have attained remission, including molecularly negative states of disease, thus providing the possibility of long-term cure. Blinatumomab is a widely available CD3-CD19 BiTE that has dramatically changed the landscape of therapy for some children with precursor-B acute lymphoblastic leukemias (B-ALL) and lymphoblastic lymphomas. Challenges remain with using BiTE in a broader population although the appeal of now-confirmed reduced toxicity and deeper molecular remissions suggests that this approach will be an essential part of future treatment of childhood B-ALL. Herein, we review some of the pertinent literature covering clinical trials with blinatumomab and address future approaches and combination trials including BiTE.

Allogeneic chimeric antigen receptor T cells for children with relapsed/refractory B-cell precursor acute lymphoblastic leukemia.

Chimeric antigen receptor (CAR) T-cell therapy has emerged as a breakthrough cancer therapy over the past decade. Remarkable outcomes in B-cell lymphoproliferative disorders and multiple myeloma have been reported in both pivotal trials and real-word studies. Traditionally, the use of a patient's own (autologous) T cells to manufacture CAR products has been the standard practice. Nevertheless, this approach has some drawbacks, including manufacturing delays, dependence on the functional fitness of the patient's T cells, which can be compromised by both the disease and prior therapies, and contamination of the product with blasts. A promising alternative is offered by the development of allogeneic CAR-cell products. This approach has the potential to yield more efficient drug products and enables the use of effector cells with negligible alloreactive potential and a significant CAR-independent antitumor activity through their innate receptors (i.e., natural killer cells, γδ T cells and cytokine induced killer cells). In addition, recent advances in genome editing tools offer the potential to overcome the primary challenges associated with allogeneic CAR T-cell products, namely graft-versus-host disease and host allo-rejection, generating universal, off-the-shelf products. In this review, we summarize the current pre-clinical and clinical approaches based on allogeneic CAR T cells, as well as on alternative effector cells, which represent exciting opportunities for multivalent approaches and optimized antitumor activity.

DNT cells mediate resistance to CAR-T cells therapy in a pediatric patient with relapsed and refractory B-ALL.

Chimeric antigen receptor T (CAR-T) cells therapy is a milestone achievement in the immunotherapy of relapsed and refractory (R/R) B cell acute lymphoblastic leukemia (B-ALL). However, some patients treated with CAR-T cells do not achieve complete remission, the mechanisms of which have not been elucidated. In the present study, we report a 9-year-old pediatric patient with refractory B-ALL received a triple infusion of autologous CD19 CAR-T cells therapy after the second relapse. CAR-T cells expanded in the peripheral blood and bone marrow. However, the patient did not achieve complete remission, indicating a lack of response to CAR-T cells therapy. Analysis of etiological factors revealed that the number of CD4 and CD8 double-negative T (DNT) cells was significantly upregulated in the peripheral blood, bone marrow, and autologous CAR-T cells products. In conclusiont, these findings indicate that DNT cells mediated resistance to CAR-T cells therapy in this pediatric patient with R/R B-ALL.

Comprehensive analysis of the efficacy and safety of CAR T-cell therapy in patients with relapsed or refractory B-cell acute lymphoblastic leukaemia: a systematic review and meta-analysis.

BACKGROUND: Relapse/refractory B-cell acute lymphoblastic leukaemia (r/r B-ALL) represents paediatric cancer with a challenging prognosis. CAR T-cell treatment, considered an advanced treatment, remains controversial due to high relapse rates and adverse events. This study assessed the efficacy and safety of CAR T-cell therapy for r/r B-ALL. METHODS: The literature search was performed on four databases. Efficacy parameters included minimal residual disease negative complete remission (MRD-CR) and relapse rate (RR). Safety parameters constituted cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). RESULTS: Anti-CD22 showed superior efficacy with the highest MRD-CR event rate and lowest RR, compared to anti-CD19. Combining CAR T-cell therapy with haploidentical stem cell transplantation improved RR. Safety-wise, bispecific anti-CD19/22 had the lowest CRS rate, and anti-CD22 showed the fewest ICANS. Analysis of the costimulatory receptors showed that adding CD28ζ to anti-CD19 CAR T-cell demonstrated superior efficacy in reducing relapses with favorable safety profiles. CONCLUSION: Choosing a more efficacious and safer CAR T-cell treatment is crucial for improving overall survival in acute leukaemia. Beyond the promising anti-CD22 CAR T-cell, exploring costimulatory domains and new CD targets could enhance treatment effectiveness for r/r B-ALL.

Unraveling resistance mechanisms in anti-CD19 chimeric antigen receptor-T therapy for B-ALL: a novel in vitro model and insights into target antigen dynamics.

BACKGROUND: Cellular immunotherapy, represented by the chimeric antigen receptor T cell (CAR-T), has exhibited high response rates, durable remission, and safety in vitro and in clinical trials. Unfortunately, anti-CD19 CAR-T (CART-19) treatment alone is prone to relapse and has a particularly poor prognosis in relapsed/refractory (r/r) B-ALL patients. To date, addressing or reducing relapse remains one of the research priorities to achieve broad clinical application. METHODS: We manufactured second generation CART-19 cells and validated their efficacy and safety in vitro and in vivo. Through co-culture of Nalm-6 cells with short-term cultured CART-19 cells, CD19-negative Nalm-6 cells were detected by flow cytometry, and further investigation of the relapsed cells and their resistance mechanisms was evaluated in vitro. RESULTS: In this study, we demonstrated that CART-19 cells had enhanced and specific antileukemic activities, and the survival of B-ALL mouse models after CART-19 treatment was significantly prolonged. We then shortened the culture time and applied the serum-free culture to expand CAR-T cells, followed by co-culturing CART-19 cells with Nalm-6 cells. Surprisingly, we observed the proliferation of CD19-negative Nalm-6 cells around 28 days. Identification of potential resistance mechanisms showed that the relapsed cells express truncated CD19 proteins with decreased levels and, more importantly, CAR expression was detected on the relapsed cell surface, which may ultimately keep them antigen-negative. Furthermore, it was validated that CART-22 and tandem CART-22/19 cells could effectively kill the relapsed cells, but neither could completely eradicate them. CONCLUSIONS: We successfully generated CART-19 cells and obtained a CD19-negative refractory relapsed B-ALL cell line, providing new insights into the underlying mechanisms of resistance and a new in vitro model for the treatment of r/r B-ALL patients with low antigen density.

CAR-T Therapy Followed by Hematopoietic Stem Cell Transplantation Can Improve Survival in Children Relapsed/Refractory Philadelphia Chromosome-positive B-cell Acute Lymphoblastic Leukemia.

BACKGROUND: Philadelphia chromosome (Ph)-positive B-cell acute lymphoblastic leukemia (ALL) has a high complete remission (CR) rate, but relapse and prolonged measurable residual disease remain serious problems. We sought to describe the CR rate measurable residual disease negative rate and address the results and safety of pediatric patients who underwent after receiving chimeric antigen receptor (CAR) specific for CD19 (CAR-19) followed by hematopoietic stem cell transplantation (HSCT) for the treatment of Ph-positive ALL. METHODS: A descriptive study was conducted at Peking University People's Hospital from September 2013 to January 2021. 13 patients with relapsed/refractory Ph-positive B-ALL who received CAR-T therapy followed by allo-HSCT were included. We concentrated on the overall patient survival and CR rate. RESULTS: The median time between CAR-T therapy and allo-HSCT was 58 days. Among all the patients, the CR rate was 100%, the flow cytometry negativity rate was 84.62%, and the BCR-ABL negativity rate was 53.85% at 1 month after CAR-T infusion. All the patients achieved a major molecular response in 6 months after HSCT. After a median follow-up of 45 months, the 3-year OS rate was 66.7%, and the 3-year DFS rate was 61.5%. The 3-year OS rate of patients with BCR-ABL-positive pre-HSCT was significantly lower than that in the BCR-ABL-negative group (40.0% vs. 85.7%, P =0.042). Also, the same trend was observed for the 3-year DFS rate but did not differ significantly (40.0% vs. 75.0%, P =0.233). CONCLUSIONS: CAR-T therapy followed by allo-HSCT can be a safe and effective treatment for Ph-positive B-ALL pediatric patients.

TCRαß-depleted hematopoietic stem cell transplant and third-party CD45RA+ depleted adoptive cell therapy for treatment of post-transplant parvovirus B19 aplastic crisis.

This is a case report of a 6-year-old girl with relapsed B cell acute lymphoblastic leukemia in which adoptive cell therapy was applied successfully to treat refractory human parvovirus (HPV) B19 infection. Allogenic chimeric antigen receptor (CAR) T-cell therapy (bispecific CD19/CD22) was bridged to hematopoietic stem cell transplantation (HSCT) using a haploidentical paternal donor. However, HPV B19 DNAemia progressed and transfusion-related graft versus host disease occurred. After finding a third-party related donor with a better HLA match, haploidentical HPV B19-seropositive CD45RA+ depleted cells (16.5 × 106/kg) were administered and paternal TCRαß+ depleted stem cell were retransplanted. The HPV B19 DNAemia became negative within 1 week and the reticulocyte, neutrophil, hemoglobin, and platelet counts gradually normalized. The patient remained stable during the 1-year outpatient follow-up period. Thus, our case report highlights that persistent B19 infection can lead to pancytopenia, aplastic crisis, and graft rejection and TCRαß+ depleted haplo-HSCT is an effective means of hematopoiesis recovery. CD45RO memory T-cell therapy is the key to treating and preventing the development of refractory severe HPV B19 infection.

Plasma microbial cell-free DNA following chimeric antigen receptor T cell therapy in pediatric patients with relapsed/refractory leukemia.

Chimeric antigen receptor (CAR) T cell therapy is a promising treatment for pediatric patients with relapsed or refractory B cell acute lymphoblastic leukemia (R/R B ALL). Cytokine release syndrome (CRS) is a common toxicity after CAR T cell therapy and fever is often the first symptom. Differentiating CRS from infection after CAR T cell therapy can be challenging. Plasma microbial cell free DNA (mcfDNA) is a novel diagnostic tool which allows for qualitative and quantitative assessment of over 1000 organisms. This pilot study sought to characterize mcfDNA results in pediatric patients with R/R B ALL in the first 2 months after CAR T cell therapy.

Allogeneic CD19/CD22 CAR T-Cell Therapy for B-Cell Acute Lymphoblastic Leukemia.

This case series reports durable remissions in 2 patients with relapsed/refractory B-cell acute lymphoblastic leukemia treated with allogeneic bispecific CD19/CD22-targeting chimeric antigen receptor T cells.

CXCR6 defines therapeutic subtypes of CD4+ cytotoxic T cell lineage for adoptive cell transfer therapy in pediatric B cell acute lymphoblastic leukemia.

The potential of cytotoxic CD4+ T cells and tissue resident memory T cells (Trm) in achieving adult leukemia remission have been highlighted [1,2]. We hypothesized that CXCR6 could serve as a marker for cytotoxic CD4+ Trm cells in the bone marrow (BM) of pediatric B-ALL patients. Flow cytometry (FCM) and published single cell RNA sequencing (scRNA-seq) datasets were employed to characterize CXCR6+CD4+ T cells in the BM and peripheral blood (PB) of pediatric B-ALL patients and healthy donors. FCM, scRNA-seq and co-culture were utilized to explore the cytotoxicity of CXCR6+CD4+ T cells in vitro based on in vitro induction of CXCR6+CD4+ T cells using tumor antigens and peripheral blood mononuclear cells (PBMCs). The ssGSEA based on the cell markers identified according to the in vivo scRNA-seq data, the TARGET-ALL-P2 datasets, and integrated machine learning algorithm were employed to figure out the key cells with prognostic values, followed by simulation of adoptive cell transfer therapy (ACT). Integrated machine learning identified the high-risk cells for disease free survival, and overall survival, while simulation of ACT therapy using CXCR6+CD4+T cells indicated that CXCR6+CD4+ T cells could remodel the bone marrow microenvironments towards anti-tumor. Based on the expression of genes involved in formation of resident memory T cells, CXCR6 is not a marker of resident memory CD4+T cells but defines therapeutic subtypes of CD4+ cytotoxic T cell lineage for pediatric B-ALL.

Breast Relapse of Pediatric B-Cell Acute Lymphoblastic Leukemia After CAR-T Therapy Detected by 18F-FDG PET/CT.

BACKGROUND: B-cell acute lymphoblastic leukemia (B-ALL) is the most common childhood malignancy. Medullary and extramedullary disease relapse is a well-known occurrence in B-ALL pediatric patients treated with standard chemo-immunotherapy and, more recently, with chimeric antigen receptor (CAR)-T cell therapy. 18F-Fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) emerges as a sensitive imaging tool for detecting disease relapse at extra-medullary sites, with only limited literature evidence in the CAR-T therapy setting. CASE REPORT: In a 12-year-old female treated with CAR-T therapy for B-ALL relapse, 18F-FDG PET/CT scan performed for surveillance, after disease remission, detected a solitary and clinically occult relapse in the breast parenchyma that was histologically confirmed. CONCLUSION: At our knowledge, this is the first report about a pediatric B-ALL patient with a solitary and occult breast relapse after CAR-T therapy, early discovered by 18F-FDG PET/CT during disease monitoring.

Donor matters: Donor selection impact on hematopoietic stem cell transplantation outcomes in Hispanic patients with B-cell acute lymphocytic leukemia: Insights from a myeloablative HSCT study.

BACKGROUND: Hematopoietic stem cell transplantation (HSCT) is a pivotal treatment for high-risk acute lymphocytic leukemia (ALL), although limited by suitable human leukocyte antigen (HLA)-matched sibling donors (MSD). This study evaluates the impact of donor selection on outcomes in post-HSCT Hispanic B-cell ALL patients. METHODOLOGY: This single-center retrospective study evaluates outcomes in 88 adult Hispanic B-cell ALL patients who underwent haploidentical, MSD, or MUD myeloablative HSCT between 2013 and 2023. RESULTS: Compared to Haploidentical transplants, MSD exhibited worse cumulative incidence of relapse (CIR) (HR = 3.39; P = 0.014) and disease-free survival (DFS) (HR = 2.44; P = 0.048) whereas MUD outcomes did not differ. This effect persisted even when controlling for pre-HSCT stage and Minimal residual disease (MRD) status. In addition, Ph-like was a significant predictor of worse DFS (HR = 3.60; P=0.014) and CIR (HR = 2.97; P=0.035) on multivariate analysis. Older donor age correlated with worse GVHD-free, relapse-free survival (GRFS) in haploidentical transplants (HR = 1.05; P=0.036). CONCLUSION: Our data highlights improved outcomes with younger, haploidentical donors among Hispanic B-cell ALL patients undergoing myeloablative HSCT. This underscores the importance of donor selection in optimizing outcomes for ALL patients.

Real world outcome of B ALL with t (1; 19) (q23; p13)/TCF3::PBX1 in adolescents and adults treated with intensive regimes.

Significant heterogeneity has been reported in outcome of Acute lymphoblastic leukemia with t(1;19)(q23;p13)/TCF3::PBX1 in adolescents and adults leading to a lack of consensus on precise risk stratification. We evaluated clinical outcome of 17 adult ALL cases (≥15 years) with this genotype treated on intensive regimes.13/17 received COG0232 and 4/17 cases received UK-ALL protocol. All achieved CR (100%) with above treatment. End of induction MRD was evaluated in 14/17 cases of which 11 (78.5%) achieved MRD negativity. Total nine patients relapsed (7 marrows, 2 CNS). Overall survival at 2 years was 53.3%. The 2 year estimated PFS was 42.9%. The 2 years CIR was 54.2%. Adults with this genotype perform poorly despite early favorable response. Incorporation of novel immunotherapies and prompt HSCT should be strongly considered with this genotype. Targeted NGS panels for additional genetic aberrations can further help in risk stratifying and guiding therapy for this genotype.