Chimeric antigen receptor T-cell therapy for T-cell acute lymphoblastic leukemia

Venetoclax-based low-intensity chemotherapy in the salvage treatment of relapsed/refractory T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is a very rare hematological malignancy with a poor prognosis. Conventional cytotoxic regimens have exhibited poor tolerance in clinical practice. Preclinical researches, sparse case reports, and small-scale single-arm studies showed that venetoclax-based salvage chemotherapy had a promising clinical efficacy. However, to date, no case-control studies or prospective trials in relapsed/refractory T-ALL have been conducted to compare venetoclax-based therapies with conventional cytotoxic chemotherapies, owing to the disease's rarity and the challenging treatment landscape. We conducted a retrospective case-cohort study comparing venetoclax-based low-intensity chemotherapy with conventional cytotoxic chemotherapies in the treatment of relapsed/refractory T-ALL. Our results indicated that venetoclax-based chemotherapy achieved comparable outcomes with heavily cytotoxic agents in complete remission rates (58.3% vs. 41.7%, P = 0.759), renal dysfunction (0% vs. 16.7%, P = 0.478), infections (50.0% vs. 75.0%, P = 0.400), and thrombocytopenia duration (17.0 vs. 14.5 days, P = 0.434) between the venetoclax and non-venetoclax cohorts. Additionally, venetoclax-treated patients experienced fewer non-hematological adverse events, such as elevated liver enzymes than conventional cytotoxic chemotherapies (0% vs. 41.6%, P = 0.014), which may be attributed to reduced use of intensive cytotoxic agents like pegylated asparaginase in the venetoclax cohort. Venetoclax-based low-intensity chemotherapy might have a relatively favorable safety profile and non-inferior efficacy compared to conventional cytotoxic regimens. Therefore, venetoclax-based low-intensity chemotherapy might become a potential treatment option, especially for frail patients or those with poor hepatic function who were unable to tolerate multiple cytotoxic therapies.

New models for the development of and access to CAR T-cell therapies for children and adolescents with cancer: an ACCELERATE multistakeholder analysis

Realising the potentially substantial benefits of chimeric antigen receptor (CAR) T-cell therapy for children with cancer is hindered by non-scientific barriers that are also relevant for other rare diseases. A solely commercial development model will not deliver optimally due to insufficient return on investment for pharmaceutical companies. Access to therapies is restricted for patients who might benefit and advancing innovation in the academic research setting is difficult. Challenges relating to CAR T-cell therapies in paediatric malignancies and how they might be addressed were discussed in a meeting convened by ACCELERATE-an international multistakeholder organisation aiming to advance the timely investigation of new anticancer drugs. New academic and biopharma hybrid development models could benefit rare populations and coordination of early development can promote synergy and avoid duplicative efforts. Following promising first-in-child trials, new models are needed to support pivotal trials, decentralised manufacturing, registration, and reduced costs. The European Medicines Agency and the US Food and Drug Administration encourage academic development and early discussions. A biotech company funded via a pooled investment vehicle could provide access to safe and effective products for children and adolescents with cancer through registration and reimbursement.

Anti-CD19 CAR T-cell therapy for primary and secondary CNS lymphomas

Central nervous system lymphomas (CNSL) are a heterogeneous group of generally aggressive tumors whose prognosis varies significantly, being more favorable in patients with primary disease and poorer in those with secondary lymphoma. Current treatments typically involve intensive chemotherapy followed by consolidation with autologous stem cell transplantation or whole-brain radiotherapy. However, if the disease relapses, there is no established standard of care. The recent approval of anti-CD19 chimeric antigen receptor (CAR) T-cell therapy for systemic B-cell lymphomas has shifted the treatment landscape for previously incurable patients. Even though this therapy was initially underexplored in the setting of CNSL due to safety and efficacy concerns, it could offer a new therapeutic avenue for these patients. In this review, we will provide a concise overview of the current treatment strategies for CNSL, highlighting their key limitations, including relapse rates and long-term toxicity. Following this, we will explore the most important studies and clinical trials on CNSL, focusing on recent advancements in anti-CD19 CAR T-cell therapy. This comprehensive analysis will offer insights into the successes and challenges of treating CNSL effectively.

Analysis of Antigen Expression in T-Cell Acute Lymphoblastic Leukemia by Multicolor Flow Cytometry: Implications for the Detection of Measurable Residual Disease

Multicolor flow cytometry (MFC) is a key method for assessing measurable residual disease (MRD) in acute lymphoblastic leukemia (ALL). However, very few approaches were developed for MRD in T-cell ALL (T-ALL). To identify MRD markers suitable for T-ALL, we analyzed the expression of CD2, CD3, CD4, CD5, CD7, CD8, CD10, CD34, CD45, CD48, CD56, CD99, and HLA-DR in T-ALL patients at diagnosis. The median fluorescence intensities (MFIs) of surface CD3, CD4, CD5, CD7, CD8, CD45, CD48, CD99, and CD16+CD56 were also evaluated at Day 15 and the end-of-induction (EOI). The MFC data from 198 pediatric T-ALL patients were analyzed retrospectively. At diagnosis, the most common antigens were identified, and the MFI of T-lineage antigens in blasts was compared to that in T lymphocytes. At follow-up, the MFIs of the proposed MRD markers were compared to those observed at diagnosis. The most common T-ALL antigens were CD7 (100.0%), intracellular CD3 (100.0%), CD45 (98.5%), and CD5 (90.9%). The MFIs of T-lineage antigens in blasts differed significantly from those in T lymphocytes. By the EOI, a substantial modulation of sCD3, CD4, CD5, CD7, CD8, and CD45 was observed. CD48 and CD99 were the most stable markers. The proposed MRD markers (sCD3, CD4, CD5, CD7, CD8, CD45, CD48, CD99, CD16+CD56) enabled MFC-MRD monitoring in virtually all T-ALL patients.

T-cell receptor architecture and clonal tiding provide insight into the transformation trajectory of peripheral T-cell lymphomas

While T-cell lymphomas are classified as mature neoplasms, emerging evidence indicates that malignant transformation may occur at an earlier stage of T-cell maturation. In this study, we determined clonal architecture in a broad range of T-cell lymphomas. Our multidimensional profiling indicates that many of these lymphomas do in fact emerge from an immature lymphoid T-cell precursor at a maturation stage prior to V(D)J rearrangement that undergoes branching evolution. Consequently, at single-cell resolution we observed considerable clonal tiding under selective therapeutic pressure. T-cell receptor next-generation sequencing suggested a highly biased usage of TRBV20-1 gene segments as part of multiple antigen receptor rearrangements per patient. The predominance of TRBV20-1 was found across all major T-cell lymphoma subtypes analyzed. This suggested that this particular V gene - independently of complementarity-determining region 3 configuration - may represent a driver of malignant transformation. Together, our data indicate that T-cell lymphomas are derived from immature lymphoid precursors and display considerable intratumoral heterogeneity that may provide the basis for relapse and resistance in these hard-to-treat cancers.