Children's Oncology Group AALL0434: A Phase III Randomized Clinical Trial Testing Nelarabine in Newly Diagnosed T-Cell Acute Lymphoblastic Leukemia

Determinants of survival after first relapse of acute lymphoblastic leukemia: a Children's Oncology Group study

Limited prognostic factors have been associated with overall survival (OS) post-relapse in childhood Acute Lymphoblastic Leukemia (ALL). Patients enrolled on 12 Children's Oncology Group frontline ALL trials (1996-2014) were analyzed to assess for additional prognostic factors associated with OS post-relapse. Among 16,115 patients, 2053 (12.7%) relapsed. Relapse rates were similar for B-ALL (12.5%) and T-ALL (11.2%) while higher for infants (34.2%). Approximately 50% of B-ALL relapses occurred late (≥36 months) and 72.5% involved the marrow. Conversely, 64.8% of T-ALL relapses occurred early (<18 months) and 47.1% involved the central nervous system. The 5-year OS post-relapse for the entire cohort was 48.9 ± 1.2%; B-ALL:52.5 ± 1.3%, T-ALL:35.5 ± 3.3%, and infant ALL:21.5 ± 3.9%. OS varied by early, intermediate and late time-to-relapse; 25.8 ± 2.4%, 49.5 ± 2.2%, and 66.4 ± 1.8% respectively for B-ALL and 29.8 ± 3.9%, 33.3 ± 7.6%, 58 ± 9.8% for T-ALL. Patients with ETV6::RUNX1 or Trisomy 4 + 10 had median time-to-relapse of 43 months and higher OS post-relapse 74.4 ± 3.1% and 70.2 ± 3.6%, respectively. Patients with hypodiploidy, KMT2A-rearrangement, and TCF3::PBX1 had short median time-to-relapse (12.5-18 months) and poor OS post-relapse (14.2 ± 6.1%, 31.9 ± 7.7%, 36.8 ± 6.6%). Site-of-relapse varied by cytogenetic subtype. This large dataset provided the opportunity to identify risk factors for OS post-relapse to inform trial design and highlight populations with dismal outcomes post-relapse.

Incidence and Clinical Presentation of Severe Neurotoxicity from Nelarabine in Patients with T-Cell Acute Lymphoblastic Leukemia

BACKGROUND

Nelarabine is a purine analog with demonstrated efficacy in the treatment of T-cell Lymphoblastic Leukemia and Lymphoma (T-ALL/LBL). Despite its efficacy and excellent blood-brain barrier penetration, it has a significant side effect profile which is namely concerning for neurotoxicity. Reported neurotoxicity has varied from mild peripheral neuropathy to debilitating grade 4 neurologic complications including Guillain-Barre like syndrome and myelopathy.

PATIENTS AND METHODS

We conducted a single centered, retrospective case series to study patients who developed severe neurotoxicity after receiving nelarabine as part of T-ALL treatment. One hundred thirty-five patients were identified. Thirteen patients were reviewed for severe neurotoxicity (defined as ≥grade 3), and of those five patients were deemed to have neurotoxicity secondary to nelarabine exposure.

RESULTS

Five patients (4%) developed severe neurotoxicity as manifested by Guillain-Barre like syndrome or myelopathy within a timeframe of eight to fifty-eight days from last nelarabine dose. Upon diagnosis, patients received formal neurologic evaluation by our neuro-oncology specialists including imaging, cerebrospinal fluid testing, and electromyography. Patients were treated with IVIG, and steroids upon diagnosis, but the majority of neuro-deficits were irreversible.

CONCLUSION

Our study shows that nelarabine is generally well-tolerated, and the incidence of severe neurotoxicity is rare. Given the potential risk of severe neurotoxicity, we propose capped dose of nelarabine 1000 mg/day, neurological assessment before subsequent dosing, and avoidance of simultaneous IT therapy during nelarabine administration.

Cost-utility of nelarabine for the first-line treatment of newly diagnosed pediatric T-cell acute lymphoblastic leukemia in Canada

BACKGROUND

The Children's Oncology Group (COG)-AALL0434 trial investigated the addition of nelarabine to the augmented Berlin-Frankfurt-Münster (aBFM) protocol in patients (1.0-30.99 years) with newly diagnosed T-cell acute lymphoblastic leukemia (T-ALL). Despite demonstrating superior outcomes, nelarabine is not currently funded by many health systems, in part due to a lack of cost-effectiveness data. We estimated the cost-utility of nelarabine for this indication from a Canadian public healthcare payer perspective.

METHODS

We developed a microsimulation model that followed hypothetical patients with newly diagnosed T-ALL from post-induction therapy to death. Three health states were modeled: relapse-free, post-relapse, and death. Efficacy was estimated using AALL0434 and retrospective data from Ontario, Canada. Costs were obtained from Canadian sources. Utility estimates and long-term mortality risks were sourced from literature. Total healthcare costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) were reported. Probabilistic and scenario analyses were conducted.

RESULTS

Incorporating nelarabine in the aBFM protocol increased costs by $51,670 Canadian dollars per patient, but resulted in 1.97 more QALYs and an ICER of $26,184/QALY. Most of the identified cost and benefit were accrued within the AALL0434 trial period (first 11 years post diagnosis) and while patients were in the relapse-free health state. Across multiple scenarios, the ICER was stable under an assumed $50,000/QALY threshold.

CONCLUSION

Incorporating nelarabine into aBFM was cost-effective across different scenarios and assumptions. These results support its funding by public and private payers.

Novel prognostic factors and therapeutic advances in adult acute lymphoblastic leukemia

The prognosis of adult patients with acute lymphoblastic leukemia (ALL) has improved in the last decades. This has been due to the sum of several factors including more precise recognition of the ALL subtypes, refinement of the assessment of prognostic factors, improvement in pediatric-inspired chemotherapy regimens and especially to the incorporation of novel targeted and immune therapeutics, as well as engineered cellular therapies, among others. These therapies were initially developed for relapsed or refractory patients but are now being incorporated into frontline treatment and represent a major step forward in ALL therapy. This review focuses on the recent advances in ALL characterization and especially on the treatment of ALL in adults.

[Prognostic factors in children with acute T-lymphoblastic leukemia: a single-center clinical study of the CCCG-ALL-2015 protocol]

OBJECTIVES

To explore the clinical characteristics of children with acute T-lymphoblastic leukemia (T-ALL) and analyze their relationship with prognosis.

METHODS

A retrospective analysis was conducted on the clinical data and follow-up results of 50 children with T-ALL who were treated using the CCCG-ALL-2015 protocol at the Department of Hematology and Oncology, Children's Hospital of Nanjing Medical University from November 2015 to December 2019. Kaplan-Meier survival analysis and Cox regression analysis were employed to identify factors affecting prognosis.

RESULTS

Among the 50 T-ALL patients, there were 7 cases of relapse. There was no statistically significant difference in the baseline clinical data between the relapse group and the non-relapse group (P>0.05). However, the positive rate of minimal residual disease (MRD) (≥0.01%) on day 46 after induction remission therapy in the relapse group was significantly higher than that in the non-relapse group (P=0.037). The 5-year overall survival rate for the 50 patients was (87±5)%, and the 5-year event-free survival rate was (86±5)%. Multivariate Cox regression analysis indicated that the MRD level on day 46 after induction remission therapy was an independent prognostic factor (HR=0.104, 95%CI: 0.015-0.740, P=0.024).

CONCLUSIONS

MRD is of significant importance for the prognosis of T-ALL children. Personalized treatment should be provided based on MRD levels to prevent relapse and improve prognosis in these patients.

Biologic and Clinical Analysis of Childhood Gamma Delta T-ALL Identifies LMO2/STAG2 Rearrangements as Extremely High Risk

Acute lymphoblastic leukemia expressing the gamma delta T-cell receptor (γδ T-ALL) is a poorly understood disease. We studied 200 children with γδ T-ALL from 13 clinical study groups to understand the clinical and genetic features of this disease. We found age and genetic drivers were significantly associated with outcome. γδ T-ALL diagnosed in children under 3 years of age was extremely high-risk and enriched for genetic alterations that result in both LMO2 activation and STAG2 inactivation. Mechanistically, using patient samples and isogenic cell lines, we show that inactivation of STAG2 profoundly perturbs chromatin organization by altering enhancer-promoter looping, resulting in deregulation of gene expression associated with T-cell differentiation. High-throughput drug screening identified a vulnerability in DNA repair pathways arising from STAG2 inactivation, which can be targeted by poly(ADP-ribose) polymerase inhibition. These data provide a diagnostic framework for classification and risk stratification of pediatric γδ T-ALL. Significance: Patients with acute lymphoblastic leukemia expressing the gamma delta T-cell receptor under 3 years old or measurable residual disease ≥1% at end of induction showed dismal outcomes and should be classified as having high-risk disease. The STAG2/LMO2 subtype was enriched in this very young age group. STAG2 inactivation may perturb chromatin conformation and cell differentiation and confer vulnerability to poly(ADP-ribose) polymerase inhibition.

Longitudinal follow up of a phase 2 trial of venetoclax added to hyper-CVAD, nelarabine and pegylated asparaginase in patients with T-cell acute lymphoblastic leukemia and lymphoma

Optimal frontline use of active agents in T-cell acute lymphoblastic leukemia/lymphoma (T-ALL/LBL) is prudent to improve outcomes. We report the long-term follow-up of the phase 2 trial of HyperCVAD with nelarabine and pegylated asparaginase (Original cohort). In the latest protocol iteration venetoclax was added to the induction/consolidation regimen (Venetoclax cohort). Eligible patients were adults with untreated T-ALL/LBL or after minimal therapy and with adequate organ function. Primary endpoint of this analysis was improvement in 2-year progression free survival (PFS) and overall survival (OS) with venetoclax. From Aug 2007 to Dec 2024, 145 patients, at a median age of 35.4 years, were treated; 46 (33.8%) were in the venetoclax cohort. At median follow-up (mFU) of 62.4 months, 5-year PFS, duration of response (DOR), and OS were 63.7%, 72.0% and 66.2% respectively. In the venetoclax cohort (mFU 24.4 months) 2-year PFS (87.9% versus 64.1%, p = 0.03) and 2-year DOR (93.6% versus 69.2%, p = 0.005) were superior to the original cohort (mFU 89.4 months) and 2-year OS appeared better (87.8% versus 73.9%, p = 0.16). Febrile neutropenia was the most common serious adverse event, seen in 60% patients. The addition of venetoclax to HyperCVAD-nelarabine-pegylated asparaginase was tolerable and led to improvement in DOR and PFS.

Prediction of Response to FDA-Approved Targeted Therapy and Immunotherapy in Acute Lymphoblastic Leukemia (ALL)

OPINION STATEMENT

Acute lymphoblastic leukemia (ALL) represents the predominant cancer in pediatric populations, though its occurrence in adults is relatively rare. Pre-treatment risk stratification is crucial for predicting prognosis. Important factors for assessment include patient age, white blood cell (WBC) count at diagnosis, extramedullary involvement, immunophenotype, and cytogenetic aberrations. Minimal residual disease (MRD), primarily assessed by flow cytometry following remission, plays a substantial role in guiding management plans. Over the past decade, significant advancements in ALL outcomes have been witnessed. Conventional chemotherapy has remarkably reduced mortality rates; however, its intensive nature raises safety concerns and has led to the emergence of treatment-resistant cases with recurrence of relapses. Consequently, The U.S. Food and Drug Administration (FDA) has approved several novel treatments for relapsed/refractory ALL due to their demonstrated efficacy, as indicated by improved complete remission and survival rates. These treatments include tyrosine kinase inhibitors (TKIs), the anti-CD19 monoclonal antibody blinatumomab, anti-CD22 inotuzumab ozogamicin, anti-CD20 rituximab, and chimeric antigen receptor (CAR) T-cell therapy. Identifying the variables that influence treatment decisions is a pressing necessity for tailoring therapy based on heterogeneous patient characteristics. Key predictive factors identified in various observational studies and clinical trials include prelymphodepletion disease burden, complex genetic abnormalities, and MRD. Furthermore, the development of serious adverse events following treatment could be anticipated through predictive models, allowing for appropriate prophylactic measures to be considered. The ultimate aim is to incorporate the concept of precision medicine in the field of ALL through valid prediction platform to facilitate the selection of the most suitable treatment approach.

Predicting relapse in acute lymphoblastic leukemia

Outcomes in adult and pediatric patients with acute lymphoblastic leukemia (ALL) have improved over successive generations due to rigorously conducted clinical trials and incorporation of novel therapeutic agents. Despite these advances, approximately 20% of high-risk pediatric patients and 50% of adults with ALL will fail to achieve long-term remission with frontline chemotherapy protocols, mostly due to relapse. The ability to predict which patients with ALL are more likely to relapse allows for early intensification of therapy and/or incorporation of novel immunotherapies with the goal of relapse prevention. In this review, we outline the most robust clinical predictors of relapse in ALL with a focus on measurable residual disease (MRD) and genomics. We also discuss application of these prognostic tools in different clinical settings including frontline treatment, pre-/post-allogeneic stem cell transplant, and pre-/post-Chimeric Antigen Receptor T-cell therapy.

Impact of Genetic Ancestry on T-cell Acute Lymphoblastic Leukemia Outcomes

The influence of genetic ancestry on biology, survival outcomes, and risk stratification in T-cell Acute Lymphoblastic Leukemia (T-ALL) has not been explored. Genetic ancestry was genomically-derived from DNA-based single nucleotide polymorphisms in children and young adults with T-ALL treated on Children's Oncology Group trial AALL0434. We determined associations of genetic ancestry, leukemia genomics and survival outcomes; co-primary outcomes were genomic subtype, pathway alteration, overall survival (OS), and event-free survival (EFS). Among 1309 patients, T-ALL molecular subtypes varied significantly by genetic ancestry, including increased frequency of genomically defined ETP-like, MLLT10, and BCL11B-activated subtypes in patients of African ancestry. In multivariable Cox models adjusting for high-risk subtype and pathways, patients of Admixed American ancestry had superior 5-year EFS/OS compared with European; EFS/OS for patients of African and European ancestry were similar. The prognostic value of five commonly altered T-ALL genes varied by ancestry - including NOTCH1 , which was associated with superior OS for patients of European and Admixed American ancestry but non-prognostic among patients of African ancestry. Furthermore, a published five-gene risk classifier accurately risk stratified patients of European ancestry, but misclassified patients of African ancestry. We developed a penalized Cox model which successfully risk stratified patients across ancestries. Overall, 80% of patients had a genomic alteration in at least one gene with differential prognostic impact by genetic ancestry. T-ALL genomics and prognostic associations of genomic alterations vary by genetic ancestry. These data demonstrate the importance of incorporating genetic ancestry into analyses of tumor biology for risk classification algorithms.

Identification of hub modules and therapeutic targets associated with CD8+T-cells in HF and their pan-cancer analysis

Heart failure (HF) is a terminal condition of multiple cardiovascular disorders. Cancer is a deadly disease worldwide. The relationship between HF and cancer remains poorly understood. The Gene Expression Omnibus database was used to download the RNA sequencing data of 356 patients with hypertrophic cardiomyopathy-induced HF and non-HF. A co-expression network was established through the weighted correlation network analysis (WGCNA) to identify hub genes of HF and cancer. Cox risk analysis was performed to predict the prognostic risks of HF hub genes in pan-cancer. HF was linked to immune response pathway by the analysis of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). A positive correlation was observed between the expression levels of 4 hub genes and the infiltration of CD8+T-cells in pan-cancer. 4 hub genes were identified as beneficial prognostic factors in several cancers. Western blotting and real-time polymerase chain reaction validated the high expression of GZMM, NKG7, and ZAP70 in both mice and patients with HF compared to control groups. Our study highlights the shared immune pathogenesis of HF and cancer and provides valuable insights for developing novel therapeutic strategies, offering new opportunities for improving the management and treatment outcomes of both HF and cancer.

Treatment of Relapsed Acute Lymphocytic Leukemia in Adult Patients

OPINION STATEMENT

For adult patients diagnosed with relapsed B cell-ALL (B-ALL), there have been significant improvements in available treatment options following the FDA approval of novel cellular and immunotherapy approaches - blinatumomab, chimeric antigen receptor (CAR) T therapy, and inotuzumab. For the last several years, research has focused on gaining a better understanding of the effects of specific disease and patient characteristics on long-term outcomes with each of the FDA-approved agents. In combination with the better prevention and management of unique, treatment-specific toxicities, providers can now select the best available treatment option for each individual patient diagnosed with relapsed, adult B-ALL needing therapy. This has allowed more patients to proceed to consolidative hematopoietic stem cell transplant (HSCT), and long-term data has even brought into question the need for HSCT for long-term durable remission for all patients. However, with the adoption of blinatumomab, CAR T therapy, and inotuzumab in front-line treatment regimens, it remains unclear what effects this will have on patients with relapsed B-ALL following exposure to these novel cellular and immunotherapy therapies. Unlike B-ALL, similar advances have unfortunately not yet been realized in T cell-ALL (T-ALL). Currently, new therapeutic approaches are underway to utilize similar targeting strategies that have been successful in B-ALL - monoclonal antibodies, bispecific T-cell engagers (BiTE), and CAR T therapy. Like B-ALL, the only existing approved therapy for relapsed T-ALL, nelarabine, is now used in the upfront treatment setting potentially limiting its utility in relapsed disease. Over the next several years, the hope is for patients diagnosed with T-ALL to experience the drastic improvement in outcomes as has been seen for patients diagnosed with B-ALL over the last decade.

Diagnostic and treatment strategies for pediatric acute lymphoblastic leukemia in low- and middle-income countries

The survival rate of children and adolescents with acute lymphoblastic leukemia (ALL), the most common pediatric cancer, has improved significantly in high-income countries (HICs), serving as an excellent example of how humans can overcome catastrophic diseases. However, the outcomes in children with ALL in low- and middle-income countries (LMICs), where approximately 80% of the global population live, are suboptimal because of limited access to diagnostic procedures, chemotherapeutic agents, supportive care, and financial assistance. Although the implementation of therapeutic strategies in resource-limited countries could theoretically follow the same path of improvement as modeled in HICs, intensification of chemotherapy may simply result in increased toxicities. With the advent of genetic diagnosis, molecular targeted therapy, and immunotherapy, the management of ALL is changing dramatically in HICs. Multidisciplinary collaborations between institutions in LMICs and HICs will provide access to strategies that are suitable for institutions in LMICs, enabling them to minimize toxicities while improving outcomes. This article summarizes important aspects of the diagnosis and treatment of pediatric ALL that were mostly developed in HICs but that can be realistically implemented by institutions in countries with limited resources through resource-adapted multidisciplinary collaborations.

The genomic basis of childhood T-lineage acute lymphoblastic leukaemia

T-lineage acute lymphoblastic leukaemia (T-ALL) is a high-risk tumour1 that has eluded comprehensive genomic characterization, which is partly due to the high frequency of noncoding genomic alterations that result in oncogene deregulation2,3. Here we report an integrated analysis of genome and transcriptome sequencing of tumour and remission samples from more than 1,300 uniformly treated children with T-ALL, coupled with epigenomic and single-cell analyses of malignant and normal T cell precursors. This approach identified 15 subtypes with distinct genomic drivers, gene expression patterns, developmental states and outcomes. Analyses of chromatin topology revealed multiple mechanisms of enhancer deregulation that involve enhancers and genes in a subtype-specific manner, thereby demonstrating widespread involvement of the noncoding genome. We show that the immunophenotypically described, high-risk entity of early T cell precursor ALL is superseded by a broader category of 'early T cell precursor-like' leukaemia. This category has a variable immunophenotype and diverse genomic alterations of a core set of genes that encode regulators of hematopoietic stem cell development. Using multivariable outcome models, we show that genetic subtypes, driver and concomitant genetic alterations independently predict treatment failure and survival. These findings provide a roadmap for the classification, risk stratification and mechanistic understanding of this disease.

lncRNA signature mediates mitochondrial permeability transition-driven necrosis in regulating the tumor immune microenvironment of cervical cancer

Mitochondrial permeability transition (MPT)-driven necrosis (MPTDN) was a regulated variant of cell death triggered by specific stimuli. It played a crucial role in the development of organisms and the pathogenesis of diseases, and may provide new strategies for treating various diseases. However, there was limited research on the mechanisms of MPTDN in cervical cancer (CESC) at present. In this study, Weighted Gene Co-expression Network Analysis (WGCNA) was performed on differentially expressed genes in CESC. The module MEyellow, which showed the highest correlation with the phenotype, was selected for in-depth analysis. It was found that the genes in the MEyellow module may be associated with the tumor immune microenvironment (TIME). Through COX univariate regression and LASSO regression analysis, 6 key genes were identified. These genes were further investigated from multiple perspectives, including their independent diagnostic value, prognostic value, specific regulatory mechanisms in the tumor immune microenvironment, drug sensitivity analysis, and somatic mutation analysis. This study provided a comprehensive exploration of the mechanisms of action of these 6 key genes in CESC patients. And qRT-PCR validation was also conducted. Through COX univariate regression and LASSO coefficient screening of the MEyellow module, 6 key genes were identified: CHRM3-AS2, AC096734.1, BISPR, LINC02446, LINC00944, and DGUOK-AS1. Evaluation of the independent diagnostic value of these 6 key genes revealed that they can serve as independent diagnostic biomarkers. Through correlation analysis among these 6 genes, a potential regulatory mechanism among them was identified. Therefore, a risk prognostic model was established based on the collective action of these 6 genes, and the model showed good performance in predicting the survival period of CESC patients. By studying the relationship between these 6 key genes and the tumor microenvironment of CESC patients from multiple angles, it was found that these 6 genes are key regulatory factors in the tumor immune microenvironment of CESC patients. Additionally, 16 drugs that are associated with these 6 key genes were identified, and 8 small molecule drugs were predicted based on the lncRNA-mRNA network. The 6 key genes can serve as independent biomarkers for diagnosis, and the Risk score of these genes when acting together can be used as an indicator for predicting the clinical survival period of CESC patients. Additionally, these 6 key genes were closely related to the tumor immune microenvironment of CESC patients and were the important regulatory factors in the tumor immune microenvironment of CESC patients.

Advances in the treatment of Philadelphia chromosome negative acute lymphoblastic leukemia

There have been major paradigm shifts in the treatment of Philadelphia chromosome negative (Ph-) acute lymphoblastic leukemia (ALL) in the last decade with the introduction of new immunotherapies and targeted agents, adoption of pediatric-type chemotherapy protocols in younger adults as well as chemotherapy light approaches in older adults and the incorporation of measurable residual disease (MRD) testing to inform clinical decision making. With this, treatment outcomes in adult Ph- ALL have improved across all age groups. However, a subset of patients will still develop relapsed disease, which can be challenging to treat and associated with poor outcomes. Here we review the treatment of Ph- ALL in both younger and older adults, including the latest advancements and future directions.

Screening and interventional strategies for the late effects and toxicities of hematological malignancy treatments in pediatric survivors

INTRODUCTION

Advancements in pediatric cancer treatment have increased patient survival rates; however, childhood cancer survivors may face long-term health challenges due to treatment-related effects on organs. Regular post-treatment surveillance and early intervention are crucial for improving the survivors' quality of life and long-term health outcomes. The present paper highlights the significance of late effects in childhood cancer survivors, particularly those with hematologic malignancies, stressing the importance of a vigilant follow-up approach to ensure better overall well-being.

AREAS COVERED

This article provides an overview of the treatment history of childhood leukemia and lymphoma as well as outlines the emerging late effects of treatments. We discuss the various types of these complications and their corresponding risk factors.

EXPERT OPINION

Standardizing survivorship care in pediatric cancer aims to improve patient well-being by optimizing their health outcomes and quality of life. This involves early identification and intervention of late effects, requiring collaboration among specialists, nurses, and advocates, and emphasizing data sharing and international cooperation.

Acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) is a haematological malignancy characterized by the uncontrolled proliferation of immature lymphoid cells. Over past decades, significant progress has been made in understanding the biology of ALL, resulting in remarkable improvements in its diagnosis, treatment and monitoring. Since the advent of chemotherapy, ALL has been the platform to test for innovative approaches applicable to cancer in general. For example, the advent of omics medicine has led to a deeper understanding of the molecular and genetic features that underpin ALL. Innovations in genomic profiling techniques have identified specific genetic alterations and mutations that drive ALL, inspiring new therapies. Targeted agents, such as tyrosine kinase inhibitors and immunotherapies, have shown promising results in subgroups of patients while minimizing adverse effects. Furthermore, the development of chimeric antigen receptor T cell therapy represents a breakthrough in ALL treatment, resulting in remarkable responses and potential long-term remissions. Advances are not limited to treatment modalities alone. Measurable residual disease monitoring and ex vivo drug response profiling screening have provided earlier detection of disease relapse and identification of exceptional responders, enabling clinicians to adjust treatment strategies for individual patients. Decades of supportive and prophylactic care have improved the management of treatment-related complications, enhancing the quality of life for patients with ALL.

Preclinical testing of CT1113, a novel USP28 inhibitor, for the treatment of T-cell acute lymphoblastic leukaemia

T-cell acute lymphoblastic leukaemia (T-ALL) is a highly aggressive and heterogeneous lymphoid malignancy with poor prognosis in adult patients. Aberrant activation of the NOTCH1 signalling pathway is involved in the pathogenesis of over 60% of T-ALL cases. Ubiquitin-specific protease 28 (USP28) is a deubiquitinase known to regulate the stability of NOTCH1. Here, we report that genetic depletion of USP28 or using CT1113, a potent small molecule targeting USP28, can strongly destabilize NOTCH1 and inhibit the growth of T-ALL cells. Moreover, we show that USP28 also regulates the stability of sterol regulatory element binding protein 1 (SREBP1), which has been reported to mediate increased lipogenesis in tumour cells. As the most critical transcription factor involved in regulating lipogenesis, SREBP1 plays an important role in the metabolism of T-ALL. Therefore, USP28 may be a potential therapeutic target, and CT1113 may be a promising novel drug for T-ALL with or without mutant NOTCH1.

Differential impact of asparaginase discontinuation on outcomes of children with T-cell acute lymphoblastic leukemia and T-cell lymphoblastic lymphoma

BACKGROUND

Asparaginase is essential for treating T-cell acute lymphoblastic leukemia (T-ALL). Despite the ongoing debate on whether T-ALL and T-cell lymphoblastic lymphoma (T-LBL) are the same disease entity or two distinct diseases, patients with T-LBL often receive the same or similar treatment protocols as those with T-ALL.

METHODS

The outcomes of patients with or without L-asparaginase discontinuation were retrospectively analyzed among four national protocols: Japan Association of Childhood Leukemia Study (JACLS) ALL-02 and ALL-97 for T-ALL and Japanese Pediatric Leukemia/Lymphoma Study Group ALB-NHL03 and JACLS NHL-98 for T-LBL. The hazard ratio (HR) was calculated with the Cox regression model by considering L-asparaginase discontinuation as a time-dependent variable.

RESULTS

In total, 199 patients with T-ALL, and 133 patients with T-LBL were included. L-asparaginase discontinuation compromised event-free survival (EFS) of T-ALL patients (ALL-02: HR 3.32, 95% confidence interval [CI] 1.40-7.90; ALL-97: HR 3.39, 95%CI 1.19-9.67). Conversely, EFS compromise was not detected among T-LBL patients (ALB-NHL03: HR 1.39, 95%CI 0.41-4.68; NHL-98: HR 0.92, 95%CI 0.11-7.60).

CONCLUSION

The effects of L-asparaginase discontinuation differed between T-ALL and T-LBL. We assume that the differential impact results from (1) the inherent differential response to L-asparaginase between them and/or (2) a less stringent assessment of early treatment response in T-LBL than in T-ALL. Given the poor salvage rate of refractory or relapsed T-ALL and T-LBL, optimization of the frontline therapy is critical, and the current study provides a new suggestion for further treatment modifications. However, larger studies in contemporary intensified treatment protocols are required.

Methylation of PLK-1 Potentially Drives Bendamustine Resistance in Leukemia Cells

BACKGROUND

Drug resistance remains a significant impediment in leukemia treatment. While Bendamustine hydrochloride (BH) stands out as a promising therapeutic agent for non-Hodgkin's lymphoma and mantle cell lymphoma, the mechanisms of resistance to BH are not yet fully understood. Our study focuses on elucidating the mechanisms behind bendamustine resistance in leukemia cells, with a specific emphasis on epigenetics.

METHODS

Bendamustine-resistant cells were cultivated from human B cell lymphoblastic leukemia cell lines through systematic and sustained exposure to bendamustine, using the limiting dilution method. Gene expression was assessed via real-time polymerase chain reaction, while the expression of the multidrug resistance protein 1 (MDR1) was evaluated using flow cytometry.

RESULTS

Bendamustine-resistant leukemia cells exhibited a decreased RNA expression level for Polo-like kinase-1 (PLK-1). Notably, after treatment with the demethylating agent 5-aza-2'-deoxycytidine, PLK-1 gene expression surged significantly, enhancing bendamustine's cytotoxicity in the resistant leukemia cells. However, MDR1 expression, as determined by flow cytometry, remained consistent between parental and bendamustine-resistant leukemia cells.

CONCLUSIONS

Our findings indicate that the methylation of the PLK-1 gene plays a pivotal role in modulating PLK-1 expression and is central to the development of bendamustine resistance in leukemia cells.

Management of ALL in adults: 2024 ELN recommendations from a European expert panel

ABSTRACT

Experts from the European Leukemia Net (ELN) working group for adult acute lymphoblastic leukemia have identified an unmet need for guidance regarding management of adult acute lymphoblastic leukemia (ALL) from diagnosis to aftercare. The group has previously summarized their recommendations regarding diagnostic approaches, prognostic factors, and assessment of ALL. The current recommendation summarizes clinical management. It covers treatment approaches, including the use of new immunotherapies, application of minimal residual disease for treatment decisions, management of specific subgroups, and challenging treatment situations as well as late effects and supportive care. The recommendation provides guidance for physicians caring for adult patients with ALL which has to be complemented by regional expertise preferably provided by national academic study groups.

T-Cell Acute Lymphoblastic Leukemia/Lymphoma (T-ALL) With Negative Screening Immaturity Markers and Gamma-Delta Receptor Expression

T-cell acute lymphoblastic leukemia/lymphoma (T-ALL) is characterized by the combination of T-cell lineage and the presence of immaturity marker(s). Sometimes, the most common immaturity markers for initial flow cytometry screening in T-ALL may be negative, which can be a diagnostic pitfall. When a lack of common first-line immaturity markers is encountered in combination with gamma/delta T-cell receptor expression, a misdiagnosis of mature gamma-delta T-cell leukemia/lymphoma could be rendered. Here, we discuss two T-ALL cases with the absence of common flow cytometry immaturity markers and positive gamma/delta receptor expression.

Durable responses in acute lymphoblastic leukaemia with the use of FLT3 and IDH inhibitors

Data regarding the use of FMS-like tyrosine kinase 3 (FLT3) and isocitrate dehydrogenase 1/2 (IDH1/2) inhibitors in acute lymphoblastic leukaemia (ALL) are lacking. We identified 14 patients with FLT3- or IDH1/2-mutated ALL. Three early T-cell precursor-ALL patients received FLT3 or IDH2 inhibitors. Patient 1 maintains a complete remission (CR) with enasidenib after intolerance to chemotherapy. Patient 2 maintained a CR for 27 months after treatment with enasidenib for relapsed disease. Patient 3 was treated with venetoclax and gilteritinib at the time of relapse and maintained a CR with gilteritinib for 8 months. These cases suggest that FLT3 and IDH inhibitors could represent a viable therapeutic option for ALL patients with these mutations.

Bartonella henselae Infection and Lymphadenopathy in a Patient With T Cell Acute Lymphoblastic Leukemia

Patients undergoing therapy for T cell acute lymphoblastic leukemia are at risk of infections during their treatment course. Cat scratch disease caused by Bartonella hensalae can masquerade as leukemic relapse and cause systemic infection. Obtaining a thorough exposure history may aid clinicians in making the diagnosis.

SOHO State of the Art Updates and Next Questions | Approach to Older Adults With Phildadelphia-Chromosome Negative Acute Lymphoblastic Leukemia

Philadelphia-chromosome-negative (Ph-neg) acute lymphoblastic leukemia (ALL) has historically been associated with poor outcomes in older patients due to adverse disease biology, as well as inferior tolerance of conventional chemotherapy. Fortunately, novel therapies, including inotuzumab ozogamicin, blinatumomab, and venetoclax, are now being incorporated into first-line therapy to improve efficacy and decrease toxicity of initial therapy. Inotuzumab ozogamicin, alone or in combination with low intensity chemotherapy, appears to be best suited for the induction phase of treatment due to efficacy in the setting of high tumor burden. In contrast, blinatumomab may be best suited for consolidation due to superior efficacy in setting of morphologic remission, with or without measurable residual disease (MRD). Venetoclax is being investigated in combination with chemotherapy and can be used for treatment of older adults with both B-cell and T-cell ALL. Ongoing trials incorporating inotuzumab, blinatumomab, and venetoclax demonstrate high rates of MRD-negative complete remissions with low early mortality. Long-term outcomes have been less favorable so far, with several trials reporting nonrelapse mortality during subsequent treatment. Unanswered questions remain regarding the optimal treatment of older adults with Ph-neg ALL, including central nervous system (CNS) prophylaxis, the most appropriate consolidation to minimize toxicity without compromising efficacy, and the role of transplant and cellular therapy. T-cell ALL remains an area of unmet need and effort is required to ensure that therapeutic advances benefit all populations equitably. In this manuscript, we review current data and ongoing trials regarding the treatment of older adults with Ph-neg ALL and define topics for further research.

Nelarabine-containing salvage therapy and conditioning regimen in transplants for pediatric T-cell acute lymphoblastic leukemia and lymphoma

Therapy for relapsed or refractory (r/r) T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL) in children is challenging, and new treatment methods are needed. We retrospectively analyzed eight patients with r/r T-ALL (five patients) and T-LBL (three patients) who were treated with nelarabine (NEL) plus etoposide, cyclophosphamide, and intrathecal therapy, administered 3 days apart. Five patients achieved a complete response, and the other three achieved a partial response (PR). All patients underwent hematopoietic stem cell transplantation (HSCT) after two cycles of treatment, except for one patient who received one cycle. Three patients who had previously received HSCT were treated with reduced-intensity conditioning regimens, including fludarabine, melphalan, and NEL; one survived for over 5 years after the second HSCT. Grade 2 neuropathy occurred in one patient, but other severe toxicities commonly associated with NEL were not observed during NEL administration in combination with chemotherapy. The 2-year overall survival and event-free survival rates were 60.0% and 36.5%, respectively. The addition of NEL to reinduction chemotherapy was useful in achieving remission and did not lead to excessive toxicity. In addition, a conditioning regimen, including NEL, appeared to be effective in patients who had previously undergone HSCT.

Future of Treatment of Adolescents and Young Adults With ALL: A Vision for Collaboration and Equity

Over the past several decades, survival of children with ALL has improved dramatically with treatment regimens refined through cooperative group trials. Despite aggressive treatment and iterative therapy changes for adolescents and young adults (AYAs), improvement has not been as promising. Comparisons between pediatric and adult clinical trials have consistently demonstrated superior outcomes for AYAs treated on pediatric ALL protocols, leading to the implementation of pediatric-inspired ALL protocols by several groups worldwide and/or expansion of the age limit of pediatric trials to include the full spectrum of the AYA population. Despite these efforts, AYAs in both pediatric and adult settings continue to have inferior survival compared with younger children with ALL. Real-world data suggest that uptake of pediatric-style treatment is variable, and even with identical pediatric-style treatment, AYAs still fare worse than younger children. As we enter an era of immunotherapy and precision medicine for newly diagnosed ALL, now is an opportune time to consider how best to approach future therapy for AYA patients. Comparisons of pediatric and adult treatment approaches and subanalyses of AYA patients will help guide harmonization of treatment. The focus of the next stage of ALL therapy for AYA should not only involve novel treatment approaches but also standardization and optimization of supportive care measures, psychosocial support, adherence interventions, oncofertility treatment, and survivorship care. All these efforts should simultaneously work to address health disparities to ensure that a future of improved outcomes is experienced equitably for all AYA patients.

Dose-Related Effect of Chemotherapy on Bone Mineral Density Among Pediatric Acute Lymphoblastic Leukemia Survivors

OBJECTIVES

Reduced bone mineral density (BMD) can negatively affect lifelong skeletal health by -increasing the risk for developing osteopenia and osteoporosis. This study evaluated the relationship between BMD and cumulative doses of intravenous (IV) methotrexate (MTX) and glucocorticoids in pediatric acute lymphoblastic leukemia (ALL) survivors. The association between BMD and vitamin D concentrations measured at the time of entry into the long-term follow-up program was also assessed.

METHODS

This retrospective study included pediatric ALL survivors who had received a dual-energy X-ray absorptiometry (DXA) scan after the end of therapy (EOT) or within the 6 months prior to the EOT. Low/-intermediate and high cumulative IV MTX doses were defined as doses less than 20,000 mg/m2 and -greater than or equal to 20,000 mg/m2, respectively. Descriptive statistics, Student t test, and linear -regression were used to analyze the data.

RESULTS

A total of 62 patients, with 34 patients in the low/intermediate and 28 patients in the high -cumulative IV MTX dose groups, were analyzed. The median time from EOT to DXA scan was 2.3 years. The mean DXA lumbar spine z score was significantly lower in the high cumulative IV MTX dose group -compared with the low/intermediate dose group (-0.86 vs -0.14; p = 0.008). Cumulative glucocorticoid doses and vitamin D concentrations were not associated with BMD.

CONCLUSIONS

Pediatric patients who had received cumulative IV MTX doses of greater than or equal to 20,000 mg/m2 during their ALL treatment had lower BMD than those who had received lower cumulative doses.

Treatment outcomes of childhood PICALM::MLLT10 acute leukaemias

The prognostic impact of PICALM::MLLT10 status in childhood leukaemia is not well described. Ten International Berlin Frankfurt Münster-affiliated study groups and the Children's Oncology Group collaborated in this multicentre retrospective study. The presence of the PICALM::MLLT10 fusion gene was confirmed by fluorescence in situ hybridization and/or RNA sequencing at participating sites. Ninety-eight children met the study criteria. T-cell acute lymphoblastic leukaemia (T-ALL) and acute myeloid leukaemia (AML) predominated 55 (56%) and 39 (40%) patients, respectively. Most patients received a chemotherapy regimen per their disease phenotype: 58% received an ALL regimen, 40% an AML regimen and 1% a hybrid regimen. Outcomes for children with PICALM::MLLT10 ALL were reasonable: 5-year event-free survival (EFS) 67% and 5-year overall survival (OS) 76%, but children with PICALM::MLLT10 AML had poor outcomes: 5-year EFS 22% and 5-year OS 26%. Haematopoietic stem cell transplant (HSCT) did not result in a significant improvement in outcomes for PICALM::MLLT10 AML: 5-year EFS 20% for those who received HSCT versus 23% for those who did not (p = 0.6) and 5-year OS 37% versus 36% (p = 0.7). In summary, this study confirms that PICALM::MLLT10 AML is associated with a dismal prognosis and patients cannot be salvaged with HSCT; exploration of novel therapeutic options is warranted.

Relapsed/Refractory T- Acute Lymphoblastic Leukemia - Current Options and Future Directions

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. The T-cell subtype (T-ALL) accounts for 10-15% of pediatric ALL cases and has been historically associated with outcomes inferior to those of B-cell ALL (B-ALL). The prognosis of T-ALL has significantly improved with contemporary intensive pediatric regimens. However, most children with relapsed T-ALL have dismal outcomes and fewer therapeutic salvage options than those available for B-ALL. After demonstrating efficacy in relapsed T-ALL, nelarabine is being increasingly incorporated into frontline T-ALL regimens. The development of genomic sequencing has led to the identification of new T-ALL subgroups and potential targeted therapeutic approaches which could improve patients' outcomes and reduce the toxicity associated with current therapy. Immunotherapy and cellular therapy regimens are also under early investigation in T-cell malignancies. This review outlines the clinical and biological characteristics of T-ALL and provides an overview of novel treatment options for refractory and relapsed T-ALL.

Novel therapies for pediatric acute lymphoblastic leukemia

PURPOSE OF REVIEW

This review summarizes the current novel therapy landscape in pediatric acute lymphoblastic leukemia (ALL), with a focus on key clinical trials which will shape the future direction of care for these children.

RECENT FINDINGS

Recent landmark immunotherapy trials in B-ALL have demonstrated significant benefit for children, adolescents, and young adults with relapsed/refractory high-risk leukemia. Due to these successes, current trials are asking the question as to whether immunotherapy can be successfully incorporated upfront. Additionally, therapies targeting novel antigens or molecular pathways are being developed, providing new options for children previously thought to have incurable leukemia.

SUMMARY

As survival for ALL has relatively plateaued with maximizing intensity through conventional chemotherapy, continued preclinical and clinical study of novel immunotherapeutic and targeted agents is crucial to further improve outcomes in childhood leukemia.

Nelarabine: when and how to use in the treatment of T-cell acute lymphoblastic leukemia

ABSTRACT

T-cell acute lymphoblastic leukemia or lymphoblastic lymphoma (T-ALL/LBL) is a rare hematologic malignancy most commonly affecting adolescent and young adult males. Outcomes are dismal for patients who relapse, thus, improvement in treatment is needed. Nelarabine, a prodrug of the deoxyguanosine analog 9-β-arabinofuranosylguanine, is uniquely toxic to T lymphoblasts, compared with B lymphoblasts and normal lymphocytes, and has been developed for the treatment of T-ALL/LBL. Based on phase 1 and 2 trials in children and adults, single-agent nelarabine is approved for treatment of patients with relapsed or refractory T-ALL/LBL, with the major adverse effect being central and peripheral neurotoxicity. Since its approval in 2005, nelarabine has been studied in combination with other chemotherapy agents for relapsed disease and is also being studied as a component of initial treatment in pediatric and adult patients. Here, we review current data on nelarabine and present our approach to the use of nelarabine in the treatment of patients with T-ALL/LBL.

Diagnostic and therapeutic advances in adults with acute lymphoblastic leukemia in the era of gene analysis and targeted immunotherapy

Acute lymphoblastic leukemia (ALL) is one of the most rapidly changing hematological malignancies with advanced understanding of the genetic landscape, detection methods of minimal residual disease (MRD), and the development of immunotherapeutic agents with good clinical outcomes. The annual incidence of adult ALL in Korea is 300-350 patients per year. The WHO classification of ALL was revised in 2022 to reflect the molecular cytogenetic features and suggest new adverse- risk subgroups, such as Ph-like ALL and ETP-ALL. We continue to use traditional adverse-risk features and cytogenetics, with MRD-directed post-remission therapy including allogeneic hematopoietic cell transplantation. However, with the introduction of novel agents, such as ponatinib, blinatumomab, and inotuzumab ozogamicin incorporated into frontline therapy, good MRD responses have been achieved, and overall survival outcomes are improving. Accordingly, some clinical trials have suggested a possible era of chemotherapy-free or transplantation-free approaches in the near future. Nevertheless, relapse of refractory ALL still occurs, and some poor ALL subtypes, such as Ph-like ALL and ETP-ALL, are unsolved problems for which novel agents and treatment strategies are needed. In this review, we summarize the currently applied diagnostic and therapeutic practices in the era of advanced genetic analysis and targeted immunotherapies in United States and Europe and introduce real-world Korean data.

Targeting Histone 3 Variants Epigenetic Landscape and Inhibitory Immune Checkpoints: An Option for Paediatric Brain Tumours Therapy

Despite little progress in survival rates with regular therapies, which do not provide complete care for curing pediatric brain tumors (PBTs), there is an urgent need for novel strategies to overcome the toxic effects of conventional therapies to treat PBTs. The co-inhibitory immune checkpoint molecules, e.g., CTLA-4, PD-1/PD-L1, etc., and epigenetic alterations in histone variants, e.g., H3K27me3 that help in immune evasion at tumor microenvironment have not gained much attention in PBTs treatment. However, key epigenetic mechanistic alterations, such as acetylation, methylation, phosphorylation, sumoylation, poly (ADP)-ribosylation, and ubiquitination in histone protein, are greatly acknowledged. The crucial checkpoints in pediatric brain tumors are cytotoxic T lymphocyte antigen-4 (CTLA-4), programmed cell death protein-1 (PD-1) and programmed death-ligand 1 (PDL1), OX-2 membrane glycoprotein (CD200), and indoleamine 2,3-dioxygenase (IDO). This review covers the state of knowledge on the role of multiple co-inhibitory immunological checkpoint proteins and histone epigenetic alterations in different cancers. We further discuss the processes behind these checkpoints, cell signalling, the current scenario of clinical and preclinical research and potential futuristic opportunities for immunotherapies in the treatment of pediatric brain tumors. Conclusively, this article further discusses the possibilities of these interventions to be used for better therapy options.

Acute Lymphoblastic Leukemia with Central Nervous System Involvement-Challenges in Management

The survival of patients with acute lymphoblastic leukemia (ALL) has dramatically improved during the last six decades. This improvement is secondary to improved diagnostics, risk stratification of treatment by biological features and response to treatment, improved supportive care, and the introduction of new treatment modalities such as immunotherapy and molecular targeted therapy. However, many questions remain concerning the involvement of the central nervous system (CNS) in leukemia, including ones pertaining to the risk factors for CNS involvement and relapse, the optimal treatment strategy to prevent relapse, and the role of newer therapies. This review discusses these questions by addressing the diagnosis of CNS leukemia, the current clinical trial data for treatment regimens with CNS activity, and issues specific to treatment in low- and middle-income countries (LMICs).

Advancing Diagnostics and Therapy to Reach Universal Cure in Childhood ALL

Systemic combination chemotherapy and intrathecal chemotherapy markedly increased the survival rate of children with ALL. In the past two decades, the use of minimal (measurable) residual disease (MRD) measurements early in therapy improved risk group stratification with subsequent treatment intensifications for patients at high risk of relapse, and enabled a reduction of treatment for low-risk patients. The recent development of more sensitive MRD technologies may further affect risk stratification. Molecular genetic profiling has led to the discovery of many new subtypes and their driver genetic alterations. This increased our understanding of the biological basis of ALL, improved risk classification, and enabled implementation of precision medicine. In the past decade, immunotherapies, including bispecific antibodies, antibody-drug conjugates, and cellular therapies directed against surface proteins, led to more effective and less toxic therapies, replacing intensive chemotherapy courses and allogeneic stem-cell transplantation in patients with relapsed and refractory ALL, and are now being tested in newly diagnosed patients. It has taken 50-60 years to increase the cure rate in childhood ALL from 0% to 90% by stepwise improvements in chemotherapy. This review provides an overview of how the developments over the past 10-15 years mentioned above have significantly changed the diagnostic and treatment approach in ALL, and discusses how the integrated use of molecular and immunotherapeutic insights will very likely direct efforts to cure those children with ALL who are not cured today, and improve the quality of life for survivors who should have decades of life ahead. Future efforts must focus on making effective, yet very expensive, new technologies and therapies available to children with ALL worldwide.

Prognostic significance of ETP phenotype and minimal residual disease in T-ALL: a Children's Oncology Group study

The early thymic precursor (ETP) immunophenotype was previously reported to confer poor outcome in T-cell acute lymphoblastic leukemia (T-ALL). Between 2009 and 2014, 1256 newly diagnosed children and young adults enrolled in Children's Oncology Group (COG) AALL0434 were assessed for ETP status and minimal residual disease (MRD) using flow cytometry at a central reference laboratory. The subject phenotypes were categorized as ETP (n = 145; 11.5%), near-ETP (n = 209; 16.7%), or non-ETP (n = 902; 71.8%). Despite higher rates of induction failure for ETP (6.2%) and near-ETP (6.2%) than non-ETP (1.2%; P < .0001), all 3 groups showed excellent 5-year event-free survival (EFS) and overall survival (OS): ETP (80.4% ± 3.9% and 86.8 ± 3.4%, respectively), near-ETP (81.1% ± 3.3% and 89.6% ± 2.6%, respectively), and non-ETP (85.3% ± 1.4% and 90.0% ± 1.2%, respectively; P = .1679 and P = .3297, respectively). There was no difference in EFS or OS for subjects with a day-29 MRD <0.01% vs 0.01% to 0.1%. However, day-29 MRD ≥0.1% was associated with inferior EFS and OS for patients with near-ETP and non-ETP, but not for those with ETP. For subjects with day-29 MRD ≥1%, end-consolidation MRD ≥0.01% was a striking predictor of inferior EFS (80.9% ± 4.1% vs 52.4% ± 8.1%, respectively; P = .0001). When considered as a single variable, subjects with all 3 T-ALL phenotypes had similar outcomes and subjects with persistent postinduction disease had inferior outcomes, regardless of their ETP phenotype. This clinical trial was registered at AALL0434 as #NCT00408005.

Acute lymphoblastic leukemia in young adults: which treatment?

Despite improvements in survival among pediatric patients with acute lymphoblastic leukemia (ALL), survival outcomes for adolescents and young adults (AYAs) with ALL have lagged. The reasons for the inferior outcomes among AYAs are multifactorial, each presenting unique challenges and requiring novel solutions. First, adverse disease biology is more common among AYAs with ALL. Ongoing trials are investigating novel approaches to treatment, such as incorporating JAK inhibitors for Philadelphia chromosome-like ALL, menin inhibitors for KMT2A-rearranged ALL, and BCL2/BCLXL inhibition for T-cell ALL. Poorer adherence to therapy also impedes improvements in survival outcomes for AYAs with ALL, but early data suggest that technology, both for monitoring and interventions, may be useful in increasing adherence among this population. Finally, better access to clinical trials and collaboration between pediatric and adult centers is critical in advancing the care of AYAs with ALL. Significant improvements have been made over the past decade, but recognizing, understanding, and addressing each of these unique challenges provides hope that the outcomes for AYAs will continue to improve even further.

Inhibition of Integrin αvβ3-FAK-MAPK signaling constrains the invasion of T-ALL cells

The role of adhesion receptor integrin αvβ3 in T-ALL was unclear. Firstly, we performed quantitative real-time PCR to assess medullary expression of integrin β3(ITGB3) in T-ALL patients and high ITGB3 expression was relevant with the central nervous system leukemia(CNSL) incidence. Decreasing of cell invasion was observed in Jurkat and Molt4 treated with integrin αvβ3 specific antibody and inhibitor as well as cells with ITGB3 interference. Further, phosphorylation of FAK, cRAF, MEK and ERK decreased in cells with integrin αvβ3 inhibition or interference. Invasion decreased in T-ALL cells treated with FAK and ERK inhibitors. In conclusion, inhibition of integrin αvβ3 signals significantly limits the cell invasion of T-ALL cells.

A Review of Acute Lymphocytic Leukemia (ALL) in the Pediatric Population: Evaluating Current Trends and Changes in Guidelines in the Past Decade

Acute lymphocytic leukemia (ALL) is a commonly diagnosed cancer in children. Despite technological advancements to improve treatment and survival rates, there has been a steady increase in the incidence of ALL and treatment failures. This paper discusses the pathogenic interaction between genetic and environmental factors leading to childhood ALL. It evaluates the current treatment guidelines and notable obstacles leading to resistance, relapse, and treatment toxicities. The review evaluates a 10-year trend in the management guidelines of pediatric ALL through a systematic literature review of records from 2012 to 2023. Findings show that improvement in the five-year survival rates, notwithstanding rates of relapse and incurable diseases, is still high. Furthermore, several risk factors, including an interplay between genetic and environmental factors, are largely contributory to the outcome of ALL treatments and its overall incidence. Moreover, huge financial costs have remained a significant challenge in outcomes. There remains a need to provide individualized treatment plans, shared decision-making, and goals of care as parts of the management guidelines for the best possible outcomes. We expect that future advancements will increase overall survival rates and disease-free years.

Developing Targeted Therapies for T Cell Acute Lymphoblastic Leukemia/Lymphoma

PURPOSE OF REVIEW

Largely, treatment advances in relapsed and/or refractory acute lymphoblastic leukemia (ALL) have been made in B cell disease leaving T cell ALL reliant upon high-intensity chemotherapy. Recent advances in the understanding of the biology of T-ALL and the improvement in immunotherapies have led to new therapeutic pathways to target and exploit. Here, we review the more promising pathways that are able to be targeted and other therapeutic possibilities for T-ALL.

RECENT FINDINGS

Preclinical models and early-phase clinical trials have shown promising results in some case in the treatment of T-ALL. Targeting many different pathways could lead to the next advancement in the treatment of relapsed and/or refractory disease. Recent advances in cellular therapies have also shown promise in this space. When reviewing the literature as a whole, targeting important pathways and antigens likely will lead to the next advancement in T-ALL survival since intensifying chemotherapy.

Comprehensive characterization of patient-derived xenograft models of pediatric leukemia

Patient-derived xenografts (PDX) remain valuable models for understanding the biology and for developing novel therapeutics. To expand current PDX models of childhood leukemia, we have developed new PDX models from Hispanic patients, a subgroup with a poorer overall outcome. Of 117 primary leukemia samples obtained, successful engraftment and serial passage in mice were achieved in 82 samples (70%). Hispanic patient samples engrafted at a rate (51/73, 70%) that was similar to non-Hispanic patient samples (31/45, 70%). With a new algorithm to remove mouse contamination in multi-omics datasets including methylation data, we found PDX models faithfully reflected somatic mutations, copy-number alterations, RNA expression, gene fusions, whole-genome methylation patterns, and immunophenotypes found in primary tumor (PT) samples in the first 50 reported here. This cohort of characterized PDX childhood leukemias represents a valuable resource in that germline DNA sequencing has allowed the unambiguous determination of somatic mutations in both PT and PDX.

Integration of Genomic Sequencing Drives Therapeutic Targeting of PDGFRA in T-Cell Acute Lymphoblastic Leukemia/Lymphoblastic Lymphoma

PURPOSE

Patients with relapsed or refractory T-cell acute lymphoblastic leukemia (T-ALL) or lymphoblastic lymphoma (T-LBL) have limited therapeutic options. Clinical use of genomic profiling provides an opportunity to identify targetable alterations to inform therapy.

EXPERIMENTAL DESIGN

We describe a cohort of 14 pediatric patients with relapsed or refractory T-ALL enrolled on the Leukemia Precision-based Therapy (LEAP) Consortium trial (NCT02670525) and a patient with T-LBL, discovering alterations in platelet-derived growth factor receptor-α (PDGFRA) in 3 of these patients. We identified a novel mutation in PDGFRA, p.D842N, and used an integrated structural modeling and molecular biology approach to characterize mutations at D842 to guide therapeutic targeting. We conducted a preclinical study of avapritinib in a mouse patient-derived xenograft (PDX) model of FIP1L1-PDGFRA and PDGFRA p.D842N leukemia.

RESULTS

Two patients with T-ALL in the LEAP cohort (14%) had targetable genomic alterations affecting PDGFRA, a FIP1-like 1 protein/PDGFRA (FIP1L1-PDGFRA) fusion and a novel mutation in PDGFRA, p.D842N. The D842N mutation resulted in PDGFRA activation and sensitivity to tested PDGFRA inhibitors. In a T-ALL PDX model, avapritinib treatment led to decreased leukemia burden, significantly prolonged survival, and even cured a subset of mice. Avapritinib treatment was well tolerated and yielded clinical benefit in a patient with refractory T-ALL.

CONCLUSIONS

Refractory T-ALL has not been fully characterized. Alterations in PDGFRA or other targetable kinases may inform therapy for patients with refractory T-ALL who otherwise have limited treatment options. Clinical genomic profiling, in real time, is needed for fully informed therapeutic decision making.

Outcome for Children and Young Adults With T-Cell ALL and Induction Failure in Contemporary Trials

PURPOSE

Historically, patients with T-cell acute lymphoblastic leukemia (T-ALL) who fail to achieve remission at the end of induction (EOI) have had poor long-term survival. The goal of this study was to examine the efficacy of contemporary therapy, including allogeneic hematopoietic stem cell transplantation (HSCT) in first remission (CR1).

METHODS

Induction failure (IF) was defined as the persistence of at least 5% bone marrow (BM) lymphoblasts and/or extramedullary disease after 4-6 weeks of induction chemotherapy. Disease features and clinical outcomes were reported in 325 of 6,167 (5%) patients age 21 years and younger treated in 14 cooperative study groups between 2000 and 2018.

RESULTS

With a median follow-up period of 6.4 years (range, 0.3-17.9 years), the 10-year overall survival (OS) was 54.7% (SE = 2.9), which is significantly higher than the 27.6% (SE = 2.9) observed in the historical cohort from 1985 to 2000. There was no significant impact of sex, age, white blood cell count, central nervous system disease status, T-cell maturity, or BM disease burden at EOI on OS. Postinduction complete remission (CR) was achieved in 93% of patients with 10-year OS of 59.6% (SE = 3.1%) and disease-free survival (DFS) of 56.3% (SE = 3.1%). Among the patients who achieved CR, 72% underwent HSCT and their 10-year DFS (with a 190-day landmark) was significantly better than nontransplanted patients (63.8% [SE = 3.6] v 45.5% [SE = 7.1]; P = .005), with OS of 66.2% (SE = 3.6) versus 50.8% (SE = 6.8); P = .10, respectively.

CONCLUSION

Outcomes for patients age 21 years and younger with T-ALL and IF have improved in the contemporary treatment era with a DFS benefit among those undergoing HSCT in CR1. However, outcomes still lag considerably behind those who achieve remission at EOI, warranting investigation of new treatment approaches.

Biologic and clinical features of childhood gamma delta T-ALL: identification of STAG2/LMO2 γδ T-ALL as an extremely high risk leukemia in the very young

PURPOSE

Gamma delta T-cell receptor-positive acute lymphoblastic leukemia (γδ T-ALL) is a high-risk but poorly characterized disease.

METHODS

We studied clinical features of 200 pediatric γδ T-ALL, and compared the prognosis of 93 cases to 1,067 protocol-matched non-γδ T-ALL. Genomic features were defined by transcriptome and genome sequencing. Experimental modeling was used to examine the mechanistic impacts of genomic alterations. Therapeutic vulnerabilities were identified by high throughput drug screening of cell lines and xenografts.

RESULTS

γδ T-ALL in children under three was extremely high-risk with 5-year event-free survival (33% v. 70% [age 3-<10] and 73% [age ≥10], P =9.5 x 10 -5 ) and 5-year overall survival (49% v. 78% [age 3-<10] and 81% [age ≥10], P =0.002), differences not observed in non-γδ T-ALL. γδ T-ALL in this age group was enriched for genomic alterations activating LMO2 activation and inactivating STAG2 inactivation ( STAG2/LMO2 ). Mechanistically, we show that inactivation of STAG2 profoundly perturbs chromatin organization by altering enhancer-promoter looping resulting in deregulation of gene expression associated with T-cell differentiation. Drug screening showed resistance to prednisolone, consistent with clinical slow treatment response, but identified a vulnerability in DNA repair pathways arising from STAG2 inactivation, which was efficaciously targeted by Poly(ADP-ribose) polymerase (PARP) inhibition, with synergism with HDAC inhibitors. Ex-vivo drug screening on PDX cells validated the efficacy of PARP inhibitors as well as other potential targets including nelarabine.

CONCLUSION

γδ T-ALL in children under the age of three is extremely high-risk and enriched for STAG2/LMO2 ALL. STAG2 loss perturbs chromatin conformation and differentiation, and STAG2/LMO2 ALL is sensitive to PARP inhibition. These data provide a diagnostic and therapeutic framework for pediatric γδ T-ALL.

SUPPORT

The authors are supported by the American and Lebanese Syrian Associated Charities of St Jude Children's Research Hospital, NCI grants R35 CA197695, P50 CA021765 (C.G.M.), the Henry Schueler 41&9 Foundation (C.G.M.), and a St. Baldrick's Foundation Robert J. Arceci Innovation Award (C.G.M.), Gabriella Miller Kids First X01HD100702 (D.T.T and C.G.M.) and R03CA256550 (D.T.T. and C.G.M.), F32 5F32CA254140 (L.M.), and a Garwood Postdoctoral Fellowship of the Hematological Malignancies Program of the St Jude Children's Research Hospital Comprehensive Cancer Center (S.K.). This project was supported by the National Cancer Institute of the National Institutes of Health under the following award numbers: U10CA180820, UG1CA189859, U24CA114766, U10CA180899, U10CA180866 and U24CA196173.

DISCLAIMER

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The funding agencies were not directly involved in the design of the study, gathering, analysis and interpretation of the data, writing of the manuscript, or decision to submit the manuscript for publication.

Evaluating the efficacy and toxicity of dose adjusted pegylated L-asparaginase in combination with therapeutic drug monitoring

The incorporation of pediatric-inspired regimens in the adolescent-young-adult (AYA) and adult populations have resulted improved survival outcomes (Stock et al. Blood 133(14):1548-1559 2019; Dunsmore et al. J Clin Oncol 38(28):3282-3293 2020; DeAngelo et al. Leukemia 29(3):526-534 2015). Nonetheless incorporation of such regimens is limited by increased toxicity to asparaginase. Dosing strategies that reduce the weight-based dose of pegylated-L-asparaginase (PEG-asparaginase) utilizing activity monitoring have been shown to result in better tolerability of these regimens. The purpose of this study was to analyze the efficacy and safety of treating adults with Philadelphia chromosome negative (Ph-) ALL with pediatric-inspired regimens that incorporate PEG-asparaginase dose adjustments and asparaginase activity level monitoring. Patients aged 18-65 years initiated on pediatric-inspired regimens utilizing dose-reduced PEG-asparaginase with therapeutic drug monitoring-guided adjustments were included. The screening of 122 patients treated between 2015 and 2021 resulted in the inclusion of 54 patients. The median age of the cohort was 35 years (16-65 years), and median body mass index (BMI) was 30 kg/m2 (18.3-53.4 kg/m2). The 36-month survival estimate was 62.1% (95% CI 48.1-77.7%), and the median overall survival (OS) was 62.2 months (95% CI 35.1-89.3 months). In the AYA cohort, the 36-month survival was 71.2% (95% CI 55.8-91%) and the median overall survival was not reached. Survival was not significantly affected by immunophenotype or BMI. Discontinuation due to toxicity or hypersensitivity reactions was low at 11% and 9% respectively. The encouraging survival outcomes and favorable tolerability of this older population in the real-world setting support the use of individualized PEG-asparaginase dosing with PharmD-guided therapeutic drug monitoring.