Minimal residual disease (MRD) monitoring is currently performed in T-ALL patients to evaluate treatment response and define risk stratification. Patients with good prognosis have undetectable MRD levels after treatment, while persistent MRD defines high relapse-risk patients. The standardized flow cytometry assay detects MRD reliably in bone marrow or peripheral blood at levels ≥0.01% mononuclear cells. More sensitive MRD assay detecting specific clonal T cell receptors (TCR) by next-generation sequencing (NGS) can reliably detect blasts at levels ≤10-6 cells. Given the high sensitivity, NGS-MRD approach improves distinction between deeply negative and very low positive cases. Recent studies also demonstrate that NGS-MRD assessment of the bone marrow with undetectable blast cells is a strong predictive factor, indicating patients with possible long-term response after CAR-T cell therapy.~Acute lymphoblastic leukemia (ALL) is hematological malignancy with the highest incidence in children and adolescents. After standardized treatment, the survival rate is relatively high. ALL is divided into two types: B cells and T cells, the latter accounting for about 15% of childhood leukemias and about 25% of adult leukemias. Compared with children and adolescents with B-lineage ALL (B-ALL), T-ALL is extremely aggressive, and patients are prone to early disease recurrence, and in the event of recurrence, event-free survival (EFS) and overall survival (OS) are lower, at less than 25%, even with more intensive treatment, which might require further combination therapy to enhance anti-tumor immunity and eradicate all malignant cells. Therefore, this protocol includes multi-target CAR-T cell infusions followed by antigen-specific cytotoxic T lymphocyte (CTL)-based immunotherapy, which is based on T cells reacting with specific T-ALL tumor antigens and immune-modified dendritic cells (DCvac) fused with T leukemic cells as DC vaccines. In addition to the significant success of CAR-T cell therapy, various clinical studies also reported the importance and potential benefits of using tumor-specific T cells in different types of cancer. Moreover, DC-based vaccines as another agent of immunotherapy have proven to prevent or delay relapse in leukemia patients achieving remission. In this study, we combine those strategies to augment anti-tumor immunity in patients and expect undetectable NGS-MRD, a long-lasting remission to prevent disease recurrence.~We propose a novel protocol which combines multi-CAR-T cell therapy, engineered immune effector CTLs and DCvac against T-ALL. The aim of this study is to evaluate the feasibility, safety, and efficacy of the NGS-MRD analysis-based combinational immunotherapy.
The purpose of this study is to determine the feasibility, safety, and efficacy of a combination therapy in the treatment of T-cell acute lymphoblastic leukemia (T-ALL): multi-antigen-targeted chimeric antigen receptor T cells (CAR-T) followed by engineered immune effector cytotoxic T cells (CTLs) and immune modified dendritic cell vaccine (DCvac). This approach is aimed to achieve NGS MRD negativity in T-ALL patients, which can identify a very low risk of relapse and define patients with possible long-term remission without further treatment.