Optimizing therapy in the modern age: differences in length of maintenance therapy in acute lymphoblastic leukemia

Psychiatric disorders among survivors of childhood acute lymphoblastic leukemia in Denmark and Sweden

BACKGROUND

The diagnosis and treatment of childhood acute lymphoblastic leukemia (ALL) may impact mental health. We investigated the long-term risk of psychiatric disorders among survivors of ALL in a population-based cohort study.

METHODS

We identified patients diagnosed with ALL in Denmark and Sweden before age 20 during 1982-2008. Survivors of ALL (n = 2026), their siblings (n = 3027), and population comparison subjects (n = 9713) were followed for hospital contacts for psychiatric disorders from 5 years after ALL diagnosis (or corresponding index date) until 2017.

RESULTS

By age 30, the absolute risk of psychiatric hospital contacts was 19.9% (95% confidence interval [CI]: 17.9-22.1) for ALL survivors, 18.5% (95% CI: 16.9-20.2) for siblings, and 18.3% (95% CI: 17.3-19.2) for population comparison subjects. Overall, survivors were at higher risk of any psychiatric disorders than siblings (hazard ratio [HR] = 1.25; 95% CI: 1.04-1.50), and population comparison subjects (HR = 1.20; 95% CI: 1.06-1.35). The subgroup of survivors (n = 332) who received a hematopoietic stem cell transplantation (HSCT) and/or had a relapse were at highest risk of psychiatric disorders (HR = 2.07; 95% CI: 1.26-3.41 compared to siblings; HR = 1.67; 95% CI: 1.25-2.23 compared to population comparison subjects).

CONCLUSIONS

The overall absolute risk of psychiatric hospital contacts among ALL survivors was close to that in siblings and population comparison subjects. The modestly increased relative risk was mainly driven by the subgroup of survivors who received HSCT and/or had a relapse. Our findings are reassuring for the large subgroup of ALL survivors without HSCT or relapse, and provide novel insight on both absolute and relative risk of hospital contacts for psychiatric disorders.

Use of allopurinol to manage skewed 6-mercaptopurine metabolism in pediatric maintenance acute lymphoblastic leukemia treatment

BACKGROUND

6-mercaptopurine is a cornerstone of maintenance therapy for pediatric ALL. Response to 6MP is typically determined by the ANC. Therapeutic ANC range while receiving 6MP is between 500 and 1500/μL. In addition to desired myelosuppression, 6MP is associated with multiple adverse drug effects. Increased doses of 6MP can lead to therapeutic ANC values; however, patients may experience adverse effects before obtaining therapeutic myelosuppression, often deemed "skewed metabolism." Allopurinol may potentially correct skewed 6MP metabolism.

PROCEDURE

Pediatric patients with ALL with 6MMP and 6TGN metabolites drawn during maintenance therapy were analyzed for allopurinol use. The primary outcome evaluated the percentage of time spent in therapeutic ANC range before and after allopurinol initiation. In addition, the difference in 6MMP:6TGN ratios before and after allopurinol initiation, incidence of hepatotoxicity, and rates of relapse, were analyzed.

RESULTS

Ninety-five patients were included for analysis. Thirty-two (34%) patients received allopurinol. There were no significant differences in baseline demographics between the patients who received allopurinol and those who did not. When comparing ANC values pre- and post-allopurinol initiation, a statistically significant increase in the percentage of time spent in therapeutic range was observed (27% vs. 43%; p = .03). In addition, when comparing metabolite ratios pre- and post-allopurinol initiation, a statistically significant decrease in 6MMP:6TGN metabolite ratio values was observed (86.7 vs. 3.6; p < .0001).

CONCLUSIONS

Allopurinol significantly increased the percent time in therapeutic ANC range and can be safely utilized to significantly lower the ratio of 6MMP:6TGN metabolites, alleviating the undesirable side effects of 6MMP, and optimizing the anti-leukemic effects associated with 6TGN.

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.

Association of NUDT15 gene polymorphism with adverse reaction, treatment efficacy, and dose of 6-mercaptopurine in patients with acute lymphoblastic leukemia: a systematic review and meta-analysis

6-mercaptopurine (6-MP) serves as the backbone in the maintenance regimens of acute lymphoblastic leukemia (ALL). We aimed to evaluate the influence of NUDT15 gene polymorphism on the risk of myelosupression, hepatotoxicity and interruption of 6-MP, as well as treatment efficacy and dose of 6-MP in ALL patients. A total of 24 studies with 3,374 patients were included in this meta-analysis. We found 9-fold higher risk of 6-MP induced leukopenia (odds ratio [OR] =9.00, 95% confidence interval [CI]: 3.73-21.74) and 2.5-fold higher risk of 6-MP-induced neutropenia (OR=2.52, 95% CI: 1.72-3.69) for NUDT15 c.415C>T variant carriers in the dominant model. Moreover, we found that the dose intensity of 6-MP in ALL patients with one NUDT15 c.415C>T variant alleles (CT) was 19% less than that in wild-type patients (CC) (mean differences: 19.43%, 95% CI: -25.36 to -13.51). The tolerable dose intensity of 6-MP in NUDT15 c.415C>T homozygote variant (TT) and heterozygote variant (CT) carriers was 49% and 15% less than that in wild-type patients, respectively. The NUDT15 c.415C>T variant group (CT+TT) had seven times (OR=6.98, 95% CI: 2.83-17.22) higher risk of developing 6-MP intolerance than the CC group. However, NUDT15 c.415C>T polymorphism did not appear significantly associated with hepatotoxicity, treatment interruption or relapse incidence. We concluded that NUDT15 c.415C>T was a good predictor for 6-MP-induced myelosuppression in ALL patients. The dose intensity of 6-MP in ALL patients with NUDT15 c.415C>T variants was significantly lower than that in wild-type patients. This research provided a basis for further investigation into relations between NUDT15 gene and adverse reaction, treatment efficacy and dose intensity of 6-MP.

Treatment of Pediatric Acute Lymphoblastic Leukemia: A Historical Perspective

Acute lymphoblastic leukemia (ALL) is the most common disease in pediatric oncology. The history of developmental therapeutics for ALL began in the 1960s with the repetition of "unreliable" medical interventions against this lethal disease. By the 1990s, the development of multi-agent chemotherapy and various types of supportive care rendered ALL treatable. Highly sophisticated, molecular, diagnostic techniques have enabled highly accurate prediction of the relapse risk, and the application of risk-adapted treatments has increased the survival rate in the standard-risk group to nearly 100% in most European nations and North America. Incorporation of state-of-the-art, molecularly targeted agents and novel treatments, including cell and immunotherapy, is further improving outcomes even in the high-risk group. On the other hand, the financial burden of treating children with ALL has increased, imperiling the availability of these diagnostic and treatment strategies to patients in low- and middle-income countries (LMICs). The fundamental treatment strategy, consisting of corticosteroid and classical cytotoxic therapy, has achieved fairly good outcomes and should be feasible in LMICs as well. The present review will discuss the history of developmental therapeutics for childhood ALL in various countries through an extensive literature review with the aim of proposing a model for a treatment backbone for pediatric ALL. The discussion will hopefully benefit LMICs and be useful as a base for future clinical trials of novel treatments.

Maintenance Treatment in Acute Lymphoblastic Leukemia: A Clinical Primer

Cure rates in pediatric acute lymphoblastic leukemia (ALL) currently approach 90% in the developed world. Treatment involves 6-8 mo of intensive multi-drug chemotherapy followed by 24 mo of maintenance treatment (ALL-MT). The cornerstone of ALL-MT is the daily administration of oral 6-mercaptopurine (6MP), a purine analogue. 6MP is combined with weekly oral methotrexate (MTX), an antifolate drug, to augment therapeutic activity. Some protocols include additional chemotherapy drugs (such as vincristine and corticosteroids) during MT. The objective of ALL-MT is to ensure uninterrupted treatment at the highest tolerated doses of 6MP and MTX. This requires periodic adjustments of 6MP and MTX doses throughout treatment. Tolerance is determined through regular clinical assessments and careful monitoring of blood counts. Tolerated drug doses vary widely among patients, influenced by genetic and non-genetic factors, and require individualized dosing. Suboptimal treatment intensity in ALL-MT is associated with inferior outcomes and results from failure to treat at highest tolerated drug doses and/or interruptions in treatment due to non-adherence or toxicity. Management of MT thus requires close supervision to ensure treatment adherence, periodic drug dose modifications, and treatment to tolerance, while minimizing treatment interruptions due to toxicity. The review highlights these challenges and discusses approaches and strategies for the management of MT, focusing on the Indian context.

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.

Innovations in Cancer Treatment of Children

Pediatric cancer outcomes have significantly improved, and yet this success is not spread equally across cancer types or patients. Disparities data in pediatric oncology highlight needed improvements in access to care, including clinical trials and advanced testing for all patients. For cancers such as brain tumors and sarcomas, continued advancement in understanding the biology of tumor heterogeneity is an essential step toward finding new therapeutic combinations to improve outcomes. Pediatric cancer survivors need access to emerging technologies aimed at reducing or better managing toxicities from therapy. With advances in treatment and survival, pediatric oncology patients continue to need longitudinal, multidisciplinary subspecialty care. Refining the communication between pediatric oncologists, primary pediatricians, survivorship clinics, and adult primary care is key in ensuring the best lifelong care of pediatric cancer survivors. In this State-of-The-Art review, we discuss 5 major domains in pediatric oncology: reducing toxicity, cancer biology, novel therapies, detection and monitoring, and access to care, to highlight recent advances and areas for continued improvement.

Clinical characteristics and risk factors of acute lymphoblastic leukemia in children with severe infection during maintenance treatment

BACKGROUND

Infection is the most common adverse event of acute lymphoblastic leukemia (ALL) treatment and is also one of the main causes of death.

METHODS

To investigate the clinical characteristics and risk factors of severe infections during the maintenance phase of ALL treatment, we conducted a retrospective study.

RESULTS

A total of 181 children were eligible and 46 patients (25.4%) suffered from 51 events of severe infection, most of which occurred in the first half year of the maintenance phase (52.9%). The most common infection was pulmonary infection (86.3%) followed by bloodstream infection (19.6%). The main symptoms of ALL patients with pulmonary infection were fever, cough, and shortness of breath. The main manifestations of computer tomography (CT) were ground glass shadow (56.8%), consolidation shadow (27.3%), and streak shadow (25%). Multivariate binary logistic regression analysis showed that agranulocytosis, agranulocytosis ≥7 days, anemia, and low globulin level were independent risk factors for severe infection during the maintenance phase (all p < 0.05).

CONCLUSIONS

Taken together, blood routine examinations and protein levels should be monitored regularly for ALL patients in the maintenance phase, especially in the first 6 months. For ALL patients with risk factors, preventive anti-infective or supportive therapies can be given as appropriate to reduce the occurrence of severe infections.

Improved Outcome for ALL by Prolonging Therapy for IKZF1 Deletion and Decreasing Therapy for Other Risk Groups

PURPOSE

The ALL10 protocol improved outcomes for children with ALL by stratifying and adapting therapy into three minimal residual disease-defined risk groups: standard risk, medium risk (MR), and high risk. IKZF1-deleted (IKZF1del) ALL in the largest MR group still showed poor outcome, in line with protocols worldwide, accounting for a high number of overall relapses. ALL10 showed high toxicity in Down syndrome (DS) and excellent outcome in ETV6::RUNX1 ALL. Poor prednisone responders (PPRs) were treated as high risk in ALL10. In ALL11, we prolonged therapy for IKZF1del from 2 to 3 years. We reduced therapy for DS by omitting anthracyclines completely, for ETV6::RUNX1 in intensification, and for PPR by treatment as MR.

METHODS

Eight hundred nineteen patients with ALL (age, 1-18 years) were enrolled on ALL11 and stratified as in ALL10. Results were compared with those in ALL10.

RESULTS

The five-year overall survival (OS), event-free survival (EFS), cumulative risk of relapse (CIR), and death in complete remission on ALL11 were 94.2% (SE, 0.9%), 89.0% (1.2), 8.2% (1.1), and 2.3% (0.6), respectively. Prolonged maintenance for IKZF1del MR improved 5-year CIR by 2.2-fold (10.8% v 23.4%; P = .035) and EFS (87.1% v 72.3%; P = .019). Landmark analysis at 2 years from diagnosis showed a 2.9-fold reduction of CIR (25.6%-8.8%; P = .008) and EFS improvement (74.4%-91.2%; P = .007). Reduced therapy did not abrogate 5-year outcome for ETV6::RUNX1 (EFS, 98.3%; OS, 99.4%), DS (EFS, 87.0%; OS, 87.0%), and PPR (EFS, 81.1%; OS, 94.9%).

CONCLUSION

Children with IKZF1del ALL seem to benefit from prolonged maintenance therapy. Chemotherapy was successfully reduced for patients with ETV6::RUNX1, DS, and PPR ALL. It has to be noted that these results were obtained in a nonrandomized study using a historical control group.

Impaired neurocognitive functioning 3 months following diagnosis of high-risk acute lymphoblastic leukemia: A report from the Children's Oncology Group

PURPOSE

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer diagnosis. Cognitive late effects develop in 20%-40% of ALL survivors, but the course of declines is unclear. The aim of this paper is to characterize cognitive functioning, and its association with patient-reported outcomes, early in treatment.

PATIENTS AND METHODS

A total of 483 children with high-risk ALL, aged 6-12 years at diagnosis, consented to the neurocognitive study embedded in a prospective therapeutic trial, Children's Oncology Group (COG) AALL1131. A computerized neurocognitive battery (Cogstate) was administered 3 months post diagnosis assessing reaction time, visual attention, working memory, visual learning, and executive functioning. Parent-reported executive functioning and patient-reported physical symptoms were also collected.

RESULTS

Data from 390 participants (mean age at diagnosis = 9.2 years, 55.4% male) were obtained. Relatively few patients reported pain (16.0%) or nausea (22.6%), but a majority (68.5%) reported feeling at least some fatigue at testing. Mean Cogstate Z-scores were within normal limits across tasks; however, rates of impairment (Z-scores ≤ -1.5) for reaction time, working memory, visual learning, and visual attention were all higher than expected compared to the standardization sample. Patients reporting fatigue were significantly more likely to have impaired reaction time and visual attention compared to those reporting no fatigue.

CONCLUSION

Findings support feasibility of computerized cognitive assessments and suggest higher-than-expected rates of impaired cognitive performance early during treatment for pediatric ALL, notably within 3 months of diagnosis, suggesting intervention efforts may be indicated. These results also highlight acute factors that may impact reliability of "baseline" assessments conducted soon after diagnosis.

Incidence and determinants of hematotoxicity in acute lymphoblastic leukemia children who received 6-mercaptopurine based maintenance therapy in Addis Ababa, Ethiopia

INTRODUCTION

The maintenance phase of acute lymphoblastic leukemia treatment is the final and longest stage of treatment, mainly focused on antimetabolite therapy. This phase is essential to eliminate residual leukemic clones and prevent relapse. However, dose-limiting hematotoxicity is a major problem during this phase resulting in dose reduction or treatment discontinuation.

OBJECTIVE

In this cohort study, the clinical features and risk factors of hematological toxicity during the maintenance phase of treatment were analyzed in pediatric patients from Ethiopia.

METHODS

A total of 160 patients from Tikur Anbessa specialized hospital were included in the study of which 142 had sufficient data available for analysis. Patient characteristics as well as information about the care-givers, sides-effects as reported by the care-givers and clinical factors were collected. Bivariable followed by multivariable analysis was performed to investigate which factors were associated with hematological toxicity during the maintenance phase.

RESULTS

During the first six months of maintenance phase treatment grade 4 neutropenia was detected in 52.8% of the patients. The risk of developing grade 4 neutropenia was increased by about two fold in children with the age of 6 years and less compared to those with the age of more than 6 years. Similarly, the rate of developing grade 4 neutropenia among children with less than 4,500 maintenance day 1 white blood cell counts was significantly higher than that of children with normal maintenance day 1 white blood cell counts (AHR 2.477, 95% CI = 1.461-4.200, p = 0.001).

CONCLUSION

In conclusion, child's age and day 1 maintenance white blood cell/absolute neutrophil counts significantly affected the occurrence of grade 4 hematotoxicity. Close monitoring for white blood cell and absolute neutrophil counts during maintenance phase treatment is recommended for early diagnosis of hematotoxicity.

Chemo-free maintenance therapy in adult T-cell acute lymphoblastic leukemia: A case report and literature review

Maintenance therapy in adult T-cell acute lymphoblastic leukemia (T-ALL) is the longest phase but with limited option. The classic drugs used in the maintenance phase such as 6-mercaptopurine, methotrexate, corticosteroid and vincristine have potentially serious toxicities. Optimizing therapy in the modern age, chemo-free maintenance therapy regimens for patients with T-ALL may dramatically improve the maintenance therapeutic landscape. We report here the combination of Anti-programmed cell death protein 1 antibody and histone deacetylase inhibitor as chemo-free maintenance treatment in a T-ALL patient with literature review, thus providing a unique perspective in addition to valuable information which may inform novel therapeutic approaches.

EBV-driven lymphoid neoplasms associated with pediatric ALL maintenance therapy

The development of a second malignancy after the diagnosis of childhood acute lymphoblastic leukemia (ALL) is a rare event. Certain second malignancies have been linked with specific elements of leukemia therapy, yet the etiology of most second neoplasms remains obscure and their optimal management strategies are unclear. This is a first comprehensive report of non-Hodgkin lymphomas (NHLs) following pediatric ALL therapy, excluding stem-cell transplantation. We analyzed data of patients who developed NHL following ALL diagnosis and were enrolled in 12 collaborative pediatric ALL trials between 1980-2018. Eighty-five patients developed NHL, with mature B-cell lymphoproliferations as the dominant subtype (56 of 85 cases). Forty-six of these 56 cases (82%) occurred during or within 6 months of maintenance therapy. The majority exhibited histopathological characteristics associated with immunodeficiency (65%), predominantly evidence of Epstein-Barr virus-driven lymphoproliferation. We investigated 66 cases of post-ALL immunodeficiency-associated lymphoid neoplasms, 52 from our study and 14 additional cases from a literature search. With a median follow-up of 4.9 years, the 5-year overall survival for the 66 patients with immunodeficiency-associated lymphoid neoplasms was 67.4% (95% confidence interval [CI], 56-81). Five-year cumulative risks of lymphoid neoplasm- and leukemia-related mortality were 20% (95% CI, 10.2-30) and 12.4% (95% CI, 2.7-22), respectively. Concurrent hemophagocytic lymphohistiocytosis was associated with increased mortality (hazard ratio, 7.32; 95% CI, 1.62-32.98; P = .01). A large proportion of post-ALL lymphoid neoplasms are associated with an immunodeficient state, likely precipitated by ALL maintenance therapy. Awareness of this underrecognized entity and pertinent diagnostic tests are crucial for early diagnosis and optimal therapy.

The Landscape of Secondary Genetic Rearrangements in Pediatric Patients with B-Cell Acute Lymphoblastic Leukemia with t(12;21)

The most frequent chromosomal rearrangement in childhood B-cell acute lymphoblastic leukemia (B-ALL) is translocation t(12;21)(p13;q22). It results in the fusion of the ETV6::RUNX1 gene, which is active in the regulation of multiple crucial cellular pathways. Recent studies hypothesize that many translocations are influenced by RAG-initiated deletions, as well as defects in the RAS and NRAS pathways. According to a "two-hit" model for the molecular pathogenesis of pediatric ETV6::RUNX1-positive B-ALL, the t(12;21) translocation requires leukemia-causing secondary mutations. Patients with ETV6::RUNX1 express up to 60 different aberrations, which highlights the heterogeneity of this B-ALL subtype and is reflected in differences in patient response to treatment and chances of relapse. Most studies of secondary genetic changes have concentrated on deletions of the normal, non-rearranged ETV6 allele. Other predominant structural changes included deletions of chromosomes 6q and 9p, loss of entire chromosomes X, 8, and 13, duplications of chromosome 4q, or trisomy of chromosomes 21 and 16, but the impact of these changes on overall survival remains unclarified. An equally genetically diverse group is the recently identified new B-ALL subtype ETV6::RUNX1-like ALL. In our review, we provide a comprehensive description of recurrent secondary mutations in pediatric B-ALL with t(12;21) to emphasize the value of investigating detailed molecular mechanisms in ETV6::RUNX1-positive B-ALL, both for our understanding of the etiology of the disease and for future clinical advances in patient treatment and management.

Allele-specific polymerase chain reaction can determine the diplotype of NUDT15 variants in patients with childhood acute lymphoblastic Leukemia

Mercaptopurine intolerance is an adverse effect of mercaptopurine administration in pediatric patients with acute lymphoblastic leukemia (ALL). NUDT15 variants have emerged as major determinants of mercaptopurine intolerance, especially in the Asian population. Two variants, c.55_56insGAGTCG in exon 1 and c.415C > T in exon 3, were commonly detected in the same allele, named NUDT15*1/*2. Although rare, compound heterozygous mutations also occur, with the two variants on different alleles (NUDT15*3/*6), which may confer tolerance to considerably lesser mercaptopurine dosage. Sanger sequencing or pyrosequencing can determine the NUDT15 variants but not the phase. Here, we designed an allele-specific PCR (AS-PCR) with locked nucleic acid-modified primers. A cohort of 63 patients harboring heterozygous c.55_56insGAGTCG and c.415C > T NUDT15 variations was selected for haplotyping using AS-PCR. Of the 63 patients, 60 harbored the NUDT15*1/*2 variant and three harbored compound heterozygous mutations, including two NUDT15*3/*6 and one NUDT15*2/*7 variants. These findings suggest that AS-PCR can determine NUDT15 diplotype and identify patients with compound heterozygous NUDT15 variants, which may enable precise genetic diagnosis of NUDT15. Nevertheless, a larger clinical trial is required to understand the clinical significance of NUDT15*3/*6 in pediatric patients with ALL because of its low incidence rate and challenges in detecting this variant.

Adherence to Oral Chemotherapy in Acute Lymphoblastic Leukemia during Maintenance Therapy in Children, Adolescents, and Young Adults: A Systematic Review

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children and young adults. Treatment is long and involves 2-3 years of a prolonged maintenance phase composed of oral chemotherapies. Adherence to these medications is critical to achieving good outcomes. However, adherence is difficult to determine, as there is currently no consensus on measures of adherence or criteria to determine nonadherence. Furthermore, there have been few studies in pediatric B-ALL describing factors associated with nonadherence. Thus, we performed a systematic review of literature on oral chemotherapy adherence during maintenance therapy in ALL following PRISMA guidelines. Published studies demonstrated various objective and subjective methods of assessing adherence without generalizable definitions of nonadherence. However, the results of these studies suggested that nonadherence to oral maintenance chemotherapy was associated with increased risk of relapse. Future studies of B-ALL therapy should utilize a uniform assessment of adherence and definitions of nonadherence to better determine the impact of nonadherence on B-ALL outcomes and identify predictors of nonadherence that could yield targets for adherence improving interventions.

Prediction of chemotherapy-related complications in pediatric oncology patients: artificial intelligence and machine learning implementations

Although the overall incidence of pediatric oncological diseases tends to increase over the years, it is among the rare diseases of the pediatric population. The diagnosis, treatment, and healthcare management of this group of diseases are important. Prevention of treatment-related complications is vital for patients, particularly in the pediatric population. Nowadays, the use of artificial intelligence and machine learning technologies in the management of oncological diseases is becoming increasingly important. With the advancement of software technologies, improvements have been made in the early diagnosis of risk groups in oncological diseases, in radiology, pathology, and imaging technologies, in cancer staging and management. In addition, these technologies can be used to predict the outcome in chemotherapy treatment of oncological diseases. In this context, this study identifies artificial intelligence and machine learning methods used in the prediction of complications due to chemotherapeutic agents used in childhood cancer treatment. For this purpose, the concepts of artificial intelligence and machine learning are explained in this review. A general framework for the use of machine learning in healthcare and pediatric oncology has been drawn and examples of studies conducted on this topic in pediatric oncology have been given. IMPACT: Artificial intelligence and machine learning are advanced tools that can be used to predict chemotherapy-related complications. Algorithms can assist clinicians' decision-making processes in the management of complications. Although studies are using these methods, there is a need to increase the number of studies on artificial intelligence applications in pediatric clinics.

Association of Inherited Genetic Factors With Drug-Induced Hepatic Damage Among Children With Acute Lymphoblastic Leukemia

Importance

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. Hepatotoxic effects, including hyperbilirubinemia and elevated alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, are common during all phases of therapy and are linked to several chemotherapeutic agents, including asparaginase, mercaptopurine, and methotrexate.

Objective

To determine which genetic variants were associated with hyperbilirubinemia and elevated ALT and AST levels in children, adolescents, and young adults treated for ALL.

Design, Setting, and Participants

This retrospective analysis of a multiethnic genome-wide association study was conducted between January 1, 2019, and April 15, 2022, including patients treated as part of Children's Oncology Group (COG) trials with centers in the United States, Canada, and Australia, which accrued data from December 29, 2003, to January 21, 2011 (AALL0232), and from January 22, 2007, to July 24, 2014 (AALL0434). Germline genotypes were interrogated using genome-wide arrays and imputed using a National Institutes of Health TOPMed Imputation server. Mixed-effects logistic regressions were used to account for multiple episodes for an individual patient. Genotype × treatment phase interaction was tested to uncover phase-specific genetic risk factors.

Exposures

Total duration of multiagent protocol chemotherapy ranging from 2.5 to 3.5 years.

Main Outcomes and Measures

The primary outcomes were National Cancer Institute Common Terminology Criteria for Adverse Events (version 4) hyperbilirubinemia of grade 3 or higher and elevated liver ALT and AST levels.

Results

A total of 3557 participants were included in the analysis (2179 [61.3%] male; median age, 11.1 [range, 1-30] years). Among 576 known variants associated with these liver function test results in the general population, UGT1A1 variant rs887829 and PNPLA3 variant rs738409 were associated with increased risk of hyperbilirubinemia (odds ratio [OR], 2.18 [95% CI, 1.89-2.53]; P = 6.7 × 10-27) and ALT and AST levels (OR, 1.27 [95% CI, 1.15-1.40]; P = 3.7 × 10-7), respectively, during treatment for ALL. Corresponding polygenic risk scores were associated with hepatotoxic effects across all therapy phases and were largely driven by UGT1A1 and PNPLA3 variants. Genome-wide association analysis revealed an age-specific variant near the CPT1A gene that was only associated with elevated ALT and AST levels among patients younger than 10 years (OR, 1.28 [95% CI, 1.18-1.39]; P = 8.7 × 10-10).

Conclusions and Relevance

These results suggest a strong genetic basis for interpatient variability in hyperbilirubinemia and aminotransferase level elevations during leukemia chemotherapy.

The effects of NUDT15 and TPMT variants on mercaptopurine treatment in Vietnamese pediatric acute lymphoblastic leukemia patients

6-mercaptopurine (6-MP) plays a critical role in the treatment of pediatric acute lymphoblastic leukemia (ALL). NUDT15 and TPMT gene variants have been strongly associated with myelotoxicity caused by using 6-MP. Therefore, the purpose of this study is to investigate the frequency of NUDT15 and TPMT polymorphisms, as well as the impact of NUDT15 variants on the use of 6-MP to treat pediatric ALL in Vietnam. Sanger sequencing was applied to detect NUDT15 and TPMT gene variants in 70 pediatric ALL patients. Duration of drug interruption, level of neutropenia, and 6-MP tolerance dose were recorded. NUDT15 variants were detected from 23 out of 70 (32.9%) patients. Three well-known haplotype variants were identified as NUDT15 *2 (p.V18_V19insGV and p.R139C), *3 (p.R139C), and *6 (p.V18_V19insGV); besides, a novel NUDT15 p.R11Q was not previously reported. The NUDT15 wild-type, heterozygous variant, and homozygous variant genotypes were 67.1%, 30.1%, and 2.8%, respectively. Two TPMT heterozygous polymorphisms were TPMT*3C and *6, accounted for 2.8%. Patients with intermediate and low activity NUDT15 were given the median 6-MP tolerance dose of 55.2 and 37.2 versus 69.5 mg/m²/day of patients with NUDT15 normal activity (p = 0.0001). Patients with homozygous variant diplotype were drastically sensitive to 6-MP, with an average dose intensity of 49.6%, compared to 73.6% and 92.7% of those with heterozygous and wild-type diplotype, respectively (p = 0.0001). Our results suggest that 6-MP dose adjustment should be based on NUDT15 variants in pediatric Vietnamese ALL patients.

Effect of CB2 Stimulation on Gene Expression in Pediatric B-Acute Lymphoblastic Leukemia: New Possible Targets

Acute lymphoblastic leukemia type B (B-ALL) is the most common kind of pediatric leukemia, characterized by the clonal proliferation of type B lymphoid stem cells. Important progress in ALL treatments led to improvements in long-term survival; nevertheless, many adverse long-term consequences still concern the medical community. Molecular and cellular target therapies, together with immunotherapy, are promising strategies to overcome these concerns. Cannabinoids, enzymes involved in their metabolism, and cannabinoid receptors type 1 (CB1) and type 2 (CB2) constitute the endocannabinoid system, involved in inflammation, immune response, and cancer. CB2 receptor stimulation exerts anti-proliferative and anti-invasive effects in many tumors. In this study, we evaluated the effects of CB2 stimulation on B-ALL cell lines, SUP-B15, by RNA sequencing, Western blotting, and ELISA. We observe a lower expression of CB2 in SUP-B15 cells compared to lymphocytes from healthy subjects, hypothesizing its involvement in B-ALL pathogenesis. CB2 stimulation reduces the expression of CD9, SEC61G, TBX21, and TMSB4X genes involved in tumor growth and progression, and also negatively affects downstream intracellular pathways. Our findings suggest an antitumor role of CB2 stimulation in B-ALL, and highlight a functional correlation between CB2 receptors and specific anti-tumoral pathways, even though further investigations are needed.

How essential are in-person clinic visits during maintenance treatment of children with acute lymphoblastic leukemia?

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. Treatment consists of an initial intensive phase of chemotherapy, followed by a prolonged period of maintenance chemotherapy intended to reduce the risk of relapse. During the COVID-19 pandemic, the need arose to identify and reduce non-essential hospital visits.

OBJECTIVE

We aimed to determine which proportion of in-person clinic visits during ALL maintenance therapy was associated with a change of management based on the results of the physical examination.

PATIENTS AND METHODS

Medical records of children receiving maintenance chemotherapy for B-precursor ALL between September 2019 and February 2020 were reviewed. Visits with a new finding on physical examination were divided into those where an in-person assessment was deemed essential versus not essential. Finally, we determined the proportion of essential in-person visits that resulted in a change of management.

RESULTS

A total of 240 maintenance visits by 75 children were analyzed. An abnormal finding on physical examination was noted during 20 visits (8.3%). Of those, 14 (5.8%) uncovered a new finding, six (2.5%) were classified as "in-person visit essential," and among those six visits, three (1.2%) resulted in a change of patient management (one for acute otitis media, one for wheezing, and one for limp).

CONCLUSION

Our findings support the evaluation of care delivery models other than in-person visits during ALL maintenance therapy. A prospective study is required to delineate criteria, benefits/risks, and families' perspectives associated with virtual care delivery and the optimal frequency of in-person visits.

Maintenance therapy for acute lymphoblastic leukemia: basic science and clinical translations

Maintenance therapy (MT) with oral methotrexate (MTX) and 6-mercaptopurine (6-MP) is essential for the cure of acute lymphoblastic leukemia (ALL). MTX and 6-MP interfere with nucleotide synthesis and salvage pathways. The primary cytotoxic mechanism involves the incorporation of thioguanine nucleotides (TGNs) into DNA (as DNA-TG), which may be enhanced by the inhibition of de novo purine synthesis by other MTX/6-MP metabolites. Co-medication during MT is common. Although Pneumocystis jirovecii prophylaxis appears safe, the benefit of glucocorticosteroid/vincristine pulses in improving survival and of allopurinol to moderate 6-MP pharmacokinetics remains uncertain. Numerous genetic polymorphisms influence the pharmacology, efficacy, and toxicity (mainly myelosuppression and hepatotoxicity) of MTX and thiopurines. Thiopurine S-methyltransferase (encoded by TPMT) decreases TGNs but increases methylated 6-MP metabolites (MeMPs); similarly, nudix hydrolase 15 (encoded by NUDT15) also decreases TGNs available for DNA incorporation. Loss-of-function variants in both genes are currently used to guide MT, but do not fully explain the inter-patient variability in thiopurine toxicity. Because of the large inter-individual variations in MTX/6-MP bioavailability and metabolism, dose adjustments are traditionally guided by the degree of myelosuppression, but this does not accurately reflect treatment intensity. DNA-TG is a common downstream metabolite of MTX/6-MP combination chemotherapy, and a higher level of DNA-TG has been associated with a lower relapse hazard, leading to the development of the Thiopurine Enhanced ALL Maintenance (TEAM) strategy-the addition of low-dose (2.5-12.5 mg/m²/day) 6-thioguanine to the 6-MP/MTX backbone-that is currently being tested in a randomized ALLTogether1 trial (EudraCT: 2018-001795-38). Mutations in the thiopurine and MTX metabolism pathways, and in the mismatch repair genes have been identified in early ALL relapses, providing valuable insights to assist the development of strategies to detect imminent relapse, to facilitate relapse salvage therapy, and even to bring about changes in frontline ALL therapy to mitigate this relapse risk.

Sex-based disparities in outcome in pediatric acute lymphoblastic leukemia: a Children's Oncology Group report

BACKGROUND

Boys with acute lymphoblastic leukemia (ALL) have historically experienced inferior survival compared to girls. This study determined whether sex-based disparities persist with contemporary therapy and whether patterns of treatment failure vary by sex.

METHODS

Patients 1 to 30.99 years old were enrolled on frontline Children's Oncology Group trials between 2004 and 2014. Boys received an additional year of maintenance therapy. Sex-based differences in the distribution of various prognosticators, event-free survival (EFS) and overall survival (OS), and subcategories of relapse by site were explored.

RESULTS

A total of 8202 (54.4% male) B-cell ALL (B-ALL) and 1562 (74.3% male) T-cell ALL (T-ALL) patients were included. There was no sex-based difference in central nervous system (CNS) status. Boys experienced inferior 5-year EFS and OS (EFS, 84.6% ± 0.5% vs 86.0% ± 0.6%, P = .009; OS, 91.3% ± 0.4% vs 92.5% ± 0.4%, P = .02). This was attributable to boys with B-ALL, who experienced inferior EFS (hazard ratio [HR], 1.2; 95% confidence interval [95% CI], 1.1-1.3; P = .004) and OS (HR, 1.2; 95% CI, 1.0-1.4; P = .046) after adjustment for prognosticators. Inferior B-ALL outcomes in boys were attributable to more relapses (5-year cumulative incidence 11.2% ± 0.5% vs 9.6% ± 0.5%; P = .001), particularly involving the CNS (4.2% ± 0.3% vs 2.5% ± 0.3%; P < .0001). There was no difference in isolated bone marrow relapses (5.4% ± 0.4% vs 6.2% ± 0.4%; P = .49). There were no sex-based differences in EFS or OS in T-ALL.

CONCLUSIONS

Sex-based disparities in ALL persist, attributable to increased CNS relapses in boys with B-ALL. Studies of potential mechanisms are warranted. Improved strategies to identify and modify treatment for patients at highest risk of CNS relapse may have particular benefit for boys.

Cognitive impairment persists at least 1 year after juvenile rats are treated with methotrexate

Methotrexate (MTX) is widely employed for children with cancer, but is also associated with persistent cognitive deficits among survivors. The present study investigated the mechanisms behind long-term cognitive dysfunction after juvenile animals are treated with MTX. Male and female Long-Evans rats were treated with a combination of 6 systemic doses (0.5 mg/kg/dose intraperitoneally) and 4 intrathecal doses (1 mg/kg) beginning at post-natal age 3 weeks, a schedule designed to mimic repeated exposure given to children with leukemia. Behavioral testing was conducted at 60-61 weeks of age, followed by analysis of brain histolopathology. This MTX regimen had no acute toxicity and no effect on growth. The spatial memory and visual memory deficits observed at 13 and 17 weeks of age persisted 1 year after MTX exposure in both females and males. Significantly decreased cell proliferation and increased hippocampal microglial activation were observed in MTX-treated females when compared to the controls, with a similar trend in the male groups. In addition, MTX treatment significantly increased the number of TUNEL positive cells in the periventricular area. Our study demonstrates that a clinically relevant regimen of systemic and intrathecal MTX induces persistent deficits in cognition, lasting approximately 1 year after the last injection. The mechanisms behind MTX-induced deficits are likely multifactorial, including suppression of neurogenesis, microglial activation, and increased brain cell apoptosis. Our study suggests female and male animals differ in susceptibility to MTX-induced neurotoxicity and provides insights for developing therapeutic approaches to prevent treatment related cognitive impairment among children with ALL.

Excess morbidity and mortality among survivors of childhood acute lymphoblastic leukaemia: 25 years of follow-up from the United Kingdom Childhood Cancer Study (UKCCS) population-based matched cohort

OBJECTIVES

To examine morbidity and mortality among teenagers and young adults (TYAs) previously diagnosed with acute lymphoblastic leukaemia (ALL) in childhood, and compare to the general TYA population.

DESIGN

National population-based sex-matched and age-matched case-control study converted into a matched cohort, with follow-up linkage to administrative healthcare databases.

SETTING

The study population comprised all children (0-14 years) registered for primary care with the National Health Service (NHS) in England 1992-1996.

PARTICIPANTS

1082 5-year survivors of ALL diagnosed<15 years of age (1992-1996) and 2018 unaffected individuals; followed up to 15 March 2020.

MAIN OUTCOME MEASURES

Associations with hospital activity, cancer and mortality were assessed using incidence rate ratios (IRR) and differences.

RESULTS

Mortality in the 5-year ALL survivor cohort was 20 times higher than in the comparison cohort (rate ratio 21.3, 95% CI 11.2 to 45.6), and cancer incidence 10 times higher (IRR 9.9 95% CI 4.1 to 29.1). Hospital activity was increased for many clinical specialties, the strongest associations being for endocrinology; outpatient IRR 36.7, 95% CI 17.3 to 93.4 and inpatient 19.7, 95% CI 7.9 to 63.2 for males, and 11.0, 95% CI 6.2 to 21.1 and 6.2 95% CI 3.1 to 13.5, respectively, for females. Notable excesses were also evident for cardiology, neurology, ophthalmology, respiratory medicine and general medicine. Males were also more likely to attend gastroenterology; ear, nose and throat; urology; and dermatology, while females were more likely to be seen in plastic surgery and less likely in midwifery.

CONCLUSIONS

Adding to excess risks of death and cancer, survivors of childhood ALL experience excess outpatient and inpatient activity across their TYA years, which is not related to routine follow-up monitoring. Involving most clinical specialties, associations are striking, showing no signs of diminishing over time. Recognising that all survivors are potentially at risk of late treatment-associated effects, our findings underscore the need to take prior ALL diagnosis into account when interpreting seemingly unrelated symptoms later in life.

Intensive chemotherapy perturbs heart rate variability in children with cancer

OBJECTIVES

In children, cancer chemotherapy may impair the functioning of the cardiac autonomic nervous system. Moreover, it is not known whether there are any differences between intensive and maintenance phases of chemotherapy. Therefore, the aim of the current study was to assess autonomic nervous system activity using heart rate variability, in children receiving intensive or maintenance cancer chemotherapy.

METHODS

For that purpose, children who were healthy (healthy control, n = 30), receiving intensive chemotherapy (chemotherapy, n = 30), and receiving maintenance chemotherapy (maintenance, n = 25) were included in the study. Autonomic nervous system activity was measured by means of heart rate variability. Electrocardiogram recordings were used to calculate time- and frequency-domain heart rate variability parameters.

RESULTS

Time-domain parameters such as standard deviation of NN intervals and frequency-domain parameters such as total power were lower during the intensive chemotherapy but not during maintenance phase (standard deviation of NN intervals: 50±5, 33±3, and 48±3 ms, and total power: 2613±504, 1379±296 and 2295±264 ms², respectively for healthy control, chemotherapy and maintenance groups, P<0.001 for both standard deviation of NN intervals and total power).

DISCUSSION

The present results indicate that intensive chemotherapy perturbs the function of heart rate variability in children, with recovery during the maintenance phase. This suggests that intensive chemotherapy is likely to affect the autonomic nervous system but this effect does not appear to be permanent.

Curing the Curable: Managing Low-Risk Acute Lymphoblastic Leukemia in Resource Limited Countries

Although childhood acute lymphoblastic leukemia (ALL) is curable, global disparities in treatment outcomes remain. To reduce these global disparities in low-middle income countries (LMIC), a paradigm shift is needed: start with curing low-risk ALL. Low-risk ALL, which accounts for >50% of patients, can be cured with low-toxicity therapies already defined by collaborative studies. We reviewed the components of these low-toxicity regimens in recent clinical trials for low-risk ALL and suggest how they can be adopted in LMIC. In treating childhood ALL, the key is risk stratification, which can be resource stratified. NCI standard-risk criteria (age 1–10 years, WBC < 50,000/uL) is simple yet highly effective. Other favorable features such as ETV6-RUNX1, hyperdiploidy, early peripheral blood and bone marrow responses, and simplified flow MRD at the end of induction can be added depending on resources. With limited supportive care in LMIC, more critical than relapse is treatment-related morbidity and mortality. Less intensive induction allows early marrow recovery, reducing the need for intensive supportive care. Other key elements in low-toxicity protocol designs include: induction steroid type; high-dose versus low-dose escalating methotrexate; judicious use of anthracyclines; and steroid pulses during maintenance. In summary, the first effective step in curing ALL in LMIC is to focus on curing low-risk ALL with less intensive therapy and less toxicity.

NUDT15 polymorphism and NT5C2 and PRPS1 mutations influence thiopurine sensitivity in acute lymphoblastic leukaemia cells

In chemotherapy for childhood acute lymphoblastic leukaemia (ALL), maintenance therapy consisting of oral daily mercaptopurine and weekly methotrexate is important. NUDT15 variant genotype is reportedly highly associated with severe myelosuppression during maintenance therapy, particularly in Asian and Hispanic populations. It has also been demonstrated that acquired somatic mutations of the NT5C2 and PRPS1 genes, which are involved in thiopurine metabolism, are detectable in a portion of relapsed childhood ALL. To directly confirm the significance of the NUDT15 variant genotype and NT5C2 and PRPS1 mutations in thiopurine sensitivity of leukaemia cells in the intrinsic genes, we investigated 84 B‐cell precursor‐ALL (BCP‐ALL) cell lines. Three and 14 cell lines had homozygous and heterozygous variant diplotypes of the NUDT15 gene, respectively, while 4 and 2 cell lines that were exclusively established from the samples at relapse had the NT5C2 and PRPS1 mutations, respectively. Both NUDT15 variant genotype and NT5C2 and PRPS1 mutations were significantly associated with DNA‐incorporated thioguanine levels after exposure to thioguanine at therapeutic concentration. Considering the continuous exposure during the maintenance therapy, we evaluated in vitro mercaptopurine sensitivity after 7‐day exposure. Mercaptopurine concentrations lethal to 50% of the leukaemia cells were comparable to therapeutic serum concentration of mercaptopurine. Both NUDT15 variant genotype and NT5C2 and PRPS1 mutations were significantly associated with mercaptopurine sensitivity in 83 BCP‐ALL and 23 T‐ALL cell lines. The present study provides direct evidence to support the general principle showing that both inherited genotype and somatically acquired mutation are crucially implicated in the drug sensitivity of leukaemia cells.

Deubiquitinases in hematological malignancies

Deubiquitinases (DUBs) are enzymes that control the stability, interactions or localization of most cellular proteins by removing their ubiquitin modification. In recent years, some DUBs, such as USP7, USP9X and USP10, have been identified as promising therapeutic targets in hematological malignancies. Importantly, some potent inhibitors targeting the oncogenic DUBs have been developed, showing promising inhibitory efficacy in preclinical models, and some have even undergone clinical trials. Different DUBs perform distinct function in diverse hematological malignancies, such as oncogenic, tumor suppressor or context-dependent effects. Therefore, exploring the biological roles of DUBs and their downstream effectors will provide new insights and therapeutic targets for the occurrence and development of hematological malignancies. We summarize the DUBs involved in different categories of hematological malignancies including leukemia, multiple myeloma and lymphoma. We also present the recent development of DUB inhibitors and their applications in hematological malignancies. Together, we demonstrate DUBs as potential therapeutic drug targets in hematological malignancies.

Maintenance therapies in acute myeloid leukemia: the renaissance of an old therapeutic concept

PURPOSE OF REVIEW

Disease relapse remains the major cause of death in patients with acute myeloid leukemia (AML) and is driven by the persistence of leukemic cells following induction chemotherapy or allogeneic hematopoietic cell transplant (allo-HCT). Maintenance therapies to extend the duration of remission and to improve survival have been proposed for several years with mixed results but have experienced a renaissance recently.

RECENT FINDINGS

The oral hypomethylating agent CC-486 has been the first agent to show an overall survival (OS) benefit compared with observation in AML patients in remission following intensive chemotherapy who are not proceeding to allo-HCT. In the realm of postallo-HCT maintenance therapy, the FLT3 inhibitor sorafenib has yielded superior results in terms of OS and relapse-free survival in randomized trials compared with observation. Several open questions remain regarding patient selection, timing, duration and safety of maintenance therapies. Various targeted agents are currently tested in clinical trials and could potentially enable an even more individualized therapeutic approach.

SUMMARY

Maintenance therapies following intensive chemotherapy or allo-HCT offer a new therapeutic paradigm for an increasing number of AML patients and have been shown to result in an OS benefit in selected patients.

Testicular involvement of acute lymphoblastic leukemia in children and adolescents: Diagnosis, biology, and management

Acute lymphoblastic leukemia (ALL) in children and adolescents can involve the testes at diagnosis or upon relapse. The testes were long considered pharmacologic sanctuary sites, presumably because of the blood-testis barrier, which prevents the entry of large-molecular-weight compounds into the seminiferous tubule. Patients with testicular involvement were historically treated with testicular irradiation or orchiectomy. With the advent of contemporary intensive chemotherapy, including high-dose methotrexate, vincristine/glucocorticoid pulses, and cyclophosphamide, testicular leukemia present at diagnosis can be eradicated, with the risk of testicular relapse being 2% or lower. However, the management of testicular leukemia is not well described in the recent literature and remains relevant in low- and middle-income countries where testicular relapse is still experienced. Chemotherapy can effectively treat late, isolated testicular B-cell ALL relapses without the need for irradiation or orchiectomy in patients with an early response and thereby preserve testicular function. For refractory or early-relapse testicular leukemia, newer treatment approaches such as chimeric antigen receptor-modified T (CAR-T) cell therapy are under investigation. The control of testicular relapse with CAR-T cells and their penetration of the blood-testis barrier have been reported. The outcome of pediatric ALL has been improved remarkably by controlling the disease in the bone marrow, central nervous system, and testes, and such success should be extended globally. LAY SUMMARY: Acute lymphoblastic leukemia (ALL) in children and adolescents can involve the testes at diagnosis or upon relapse. Modern intensive chemotherapy has largely eradicated testicular relapse in high-income countries. Consequently, most current clinicians are not familiar with how to manage it if it does occur, and testicular relapse continues to be a significant problem in low- and middle-income countries that have not had access to modern intensive chemotherapy. The authors review the historical progress made in eradicating testicular ALL and use the lessons learned to make recommendations for treatment.

Expression of NK Cell Receptor Ligands on Leukemic Cells Is Associated with the Outcome of Childhood Acute Leukemia

Simple Summary

Natural killer cells (NK cells) of the innate immune system are suspected of playing an important role in eliminating residual leukemia cells during maintenance chemotherapy given to children with acute lymphoblastic leukemia for about two years. This study analyzes the expression of ligands for the receptors that regulate the function of NK cells on leukemic cells of more than one hundred children with acute lymphoid and myeloid leukemia. Our results show that the loss of expression of some molecules involved in the activation of NK cells is associated with poorer survival. In addition, a genetic combination of molecules that interact to regulate NK cell function seems to be associated with a higher relapse rate during/after chemotherapy and shorter patient survival. Children who carry this genetic combination are refractory to current chemotherapy treatments, and stem cell transplantation does not seem to contribute to their cure either, and therefore, they should be considered as candidates for alternative biological therapies that might offer better results.

Abstract

Acute leukemia is the most common malignancy in children. Most patients are cured, but refractory/relapsed AML and ALL are the first cause of death from malignancy in children. Maintenance chemotherapy in ALL has improved survival by inducing leukemic cell apoptosis, but immune surveillance effectors such as NK cells might also contribute. The outcome of B-ALL (n = 70), T-ALL (n = 16), and AML (n = 16) pediatric patients was evaluated according to leukemic cell expression of ligands for activating and inhibiting receptors that regulate NK cell functioning. Increased expression of ULBP-1, a ligand for NKG2D, but not that of CD112 or CD155, ligands for DNAM-1, was associated with poorer 5-year event-free survival (5y-EFS, 77.6% vs. 94.9%, p < 0.03). Reduced expression of HLA-C on leukemic cells in patients with the KIR2DL1/HLA-C*04 interaction was associated with a higher rate of relapse (17.6% vs. 4.4%, p = 0.035) and lower 5y-EFS (70.6% vs. 92.6%, p < 0.002). KIR2DL1/HLA-C*04 interaction was an independent predictive factor of events (HR = 4.795, p < 0.005) or death (HR = 6.731, p < 0.005) and might provide additional information to the current risk stratification. Children who carry the KIR2DL1/HLA-C*04 interaction were refractory to current chemotherapy treatments, including allogeneic stem cell transplantation; therefore, they should be considered as candidates for alternative biological therapies that might offer better results.

Health care utilisation and costs associated with different treatment protocols for newly diagnosed childhood acute lymphoblastic leukaemia: A population-based study in Ontario, Canada

BACKGROUND

Although different treatment protocols for childhood acute lymphoblastic leukaemia (ALL) all achieve high cure rates, their health care utilisation and costs have not been rigorously compared.

METHODS

Disease, treatment, and outcome data were chart abstracted for all children with ALL in Ontario, Canada, diagnosed 2002-2012. Linkage to population-based databases identified health care utilisation. Utilisation-associated costs were determined through validated algorithms. Chemotherapy-associated costs were calculated separately. Health care utilisation and costs were compared between patients receiving Children's Oncology Group (COG) versus Dana-Farber Cancer Institute (DFCI)-based treatment.

FINDINGS

Of 802 patients, 146 (18.2%) were treated on DFCI-based protocols. COG patients experienced significantly higher rates of emergency department (ED) visits (adjusted rate ratio [aRR]: 1.3, 95% confidence interval [CI]: 1.1-1.5; p = 0·01), whereas outpatient visit rates were 60% higher among DFCI patients (aRR: 1.6, 95% CI: 1.5-1.7, p < 0.0001). In adjusted analyses, DFCI-associated cost intensity was 70% higher (aRR: 1.7, 95% CI: 1.5-1.9; p < 0.0001), mainly attributable to outpatient visit costs. Total chemotherapy costs were higher among COG-treated patients ($39,400 ± $1100 versus $33,400 ± $2800; p = 0.02). Among PEG-ASNase-treated patients, total chemotherapy costs were highest among DFCI patients (median $54,200 ± $7400; p = 0.003 versus COG patients).

INTERPRETATION

COG and DFCI treatments were associated with higher ED visit rates and higher outpatient visit rates, respectively. Overall utilisation-associated costs were increased in DFCI-treated patients. Administration of some intravenous chemotherapy at home and decreases in PEG-ASNase cost would decrease health care utilisation and costs for all patients and mitigate differences between COG and DFCI protocols.

FUNDING

C¹⁷ Research Network.