Novel variant in Nudix hydrolase 15 gene influences 6-mercaptopurine toxicity in childhood acute lymphoblastic leukemia patients.

Acute lymphoblastic leukemia (ALL) is the most frequent pediatric cancer. 6-Mercaptopurine (6-MP) is a key component of ALL treatment. Its use, however, is also associated with adverse drug reactions, particularly myelosuppression. Thiopurine S-methyltransferase (TPMT) and, more recently, Nudix hydrolase 15 (NUDT15) deficiency, due to no-function variants in their respective genes, are well known for their role in the development of this toxicity. Two novel genetic variants, rs12199316 in TPMT and rs73189762 in the NUDT15 gene, were recently identified by targeted sequencing. The latter is particularly interesting because of its potential association with 6-MP intolerance. Here, we assessed the relationship of this variant with the risk of myelosuppression and 6-MP dose intensity in 275 patients treated with Dana Farber Cancer Institute ALL protocols at the Sainte Justine University Health Center. Carriers of the NUDT15 rs73189762 variant allele were at a higher risk of myelosuppression, as shown by absolute phagocyte count reduction during consolidation II and maintenance phases of therapy. Reduction in 6-MP dose intensity was observed in patients with both rs73189762 and known no-function variants in the NUDT15 and TPMT genes. This finding supports the initial observation and suggests that 6-MP dose reduction might be beneficial for individuals with this genotype combination.

IL16 and factor V gene variations are associated with asparaginase-related thrombosis in childhood acute lymphoblastic leukemia patients.

Aim: We previously conducted exome-wide association study in acute lymphoblastic leukemia patients and identified association of five SNPs with asparaginase-related thrombosis. Here we aimed to replicate these findings in an independent patient cohort and through analyses in vitro. Patients & methods: SNPs located in IL16, MYBBP1A, PKD2L1, RIN3 and MPEG1 genes were analyzed in patients receiving Dana-Farber Cancer Institute acute lymphoblastic leukemia treatment protocols 05-001 and 11-001. Thrombophilia-related variations were also analysed. Results: IL16 rs11556218 conferred higher risk of thrombosis and higher in vitro sensitivity to asparaginase. The association was modulated by the treatment protocol, risk group and immunophenotype. A crosstalk between factor V Leiden, non-O blood groups and higher risk of thrombosis was also seen. Conclusion: IL16 and factor V Leiden variations are implicated in asparaginase-related thrombosis.

This study looked at how certain genetic variations are related to a higher risk of blood clots in children with a type of cancer called acute lymphoblastic leukemia who are receiving a certain treatment (asparaginase). The study found that one specific genetic variation (IL16 rs11556218) was linked to a higher risk of blood clots (thrombosis), and that this risk was influenced by disease and treatment features. The study also found that a certain genetic variation (factor V Leiden), which makes blood more likely to clot, and blood type (non-O) were linked to a higher risk of thrombosis. The conclusion of this study is that genetic variations may play a role in blood clots in children with acute lymphoblastic leukemia receiving asparaginase, and if further confirmed, these variations can serve to advance personalized treatment strategies.

Predictors of thrombosis in children receiving therapy for acute lymphoblastic leukemia: Results from Dana-Farber Cancer Institute ALL Consortium trial 05-001.

BACKGROUND/OBJECTIVES: Although thromboembolism (TE) is a serious complication in patients with acute lymphoblastic leukemia (ALL), thromboprophylaxis is not commonly used due to the inherent bleeding risk in this population. Identifying prothrombotic risk factors will help target thromboprophylaxis to those at highest thrombotic risk. We aimed to define predictors and the impact of TE on ALL outcome in children (1-18 years) treated on the Dana-Farber Cancer Institute ALL 05-001 trial. METHODS: Clinical and laboratory data including TE events were prospectively collected. PCR-based allelic discrimination assay identified single-nucleotide polymorphisms (SNP) for prothrombin G20210A (rs1799963) and Factor V G1691A (rs6025). Univariate and multivariable competing risk regression models evaluated the effect of diagnostic clinical (age, sex, body mass index, ALL-immunophenotype, risk group) and laboratory variables (presenting leukocyte count, blood group, SNPs) on the cumulative incidence of TE. Cox regression modeling explored the impact of TE on survival. RESULTS: Of 794 patients [median age 4.97 (range, 1.04-17.96) years; males 441], 100 developed TE; 25-month cumulative incidence 13.0% (95% CI, 10.7%-15.5%). Univariate analyses identified older age (≥10 years), presenting leucocyte count, T-ALL, high-risk ALL, and non-O blood group as risk factors. Age and non-O blood group were independent predictors of TE on multivariable regression; the blood group impact being most evident in patients 1-5 years of age (P = 0.011). TE did not impact survival. Induction TE was independently associated with induction failure (OR 6.45; 95% CI, 1.64-25.47; P = 0.008). CONCLUSION: We recommend further evaluation of these risk factors and consideration of thromboprophylaxis for patients ≥10 years (especially those ≥15 years) when receiving asparaginase.

Whole-transcriptome analysis in acute lymphoblastic leukemia: a report from the DFCI ALL Consortium Protocol 16-001.

The molecular hallmark of childhood acute lymphoblastic leukemia (ALL) is characterized by recurrent, prognostic genetic alterations, many of which are cryptic by conventional cytogenetics. RNA sequencing (RNA-seq) is a powerful next-generation sequencing technology that can simultaneously identify cryptic gene rearrangements, sequence mutations and gene expression profiles in a single assay. We examined the feasibility and utility of incorporating RNA-seq into a prospective multicenter phase 3 clinical trial for children with newly diagnosed ALL. The Dana-Farber Cancer Institute ALL Consortium Protocol 16-001 enrolled 173 patients with ALL who consented to optional studies and had samples available for RNA-seq. RNA-seq identified at least 1 alteration in 157 patients (91%). Fusion detection was 100% concordant with results obtained from conventional cytogenetic analyses. An additional 56 gene fusions were identified by RNA-seq, many of which confer prognostic or therapeutic significance. Gene expression profiling enabled further molecular classification into the following B-cell ALL (B-ALL) subgroups: high hyperdiploid (n = 36), ETV6-RUNX1/-like (n = 31), TCF3-PBX1 (n = 7), KMT2A-rearranged (KMT2A-R; n = 5), intrachromosomal amplification of chromosome 21 (iAMP21) (n = 1), hypodiploid (n = 1), Philadelphia chromosome (Ph)-positive/Ph-like (n = 16), DUX4-R (n = 11), PAX5 alterations (PAX5 alt; n = 11), PAX5 P80R (n = 1), ZNF384-R (n = 4), NUTM1-R (n = 1), MEF2D-R (n = 1), and others (n = 10). RNA-seq identified 141 nonsynonymous mutations in 93 patients (54%); the most frequent were RAS-MAPK pathway mutations. Among 79 patients with both low-density array and RNA-seq data for the Philadelphia chromosome-like gene signature prediction, results were concordant in 74 patients (94%). In conclusion, RNA-seq identified several clinically relevant genetic alterations not detected by conventional methods, which supports the integration of this technology into front-line pediatric ALL trials. This trial was registered at www.clinicaltrials.gov as #NCT03020030.

Efficacy and Toxicity of Pegaspargase and Calaspargase Pegol in Childhood Acute Lymphoblastic Leukemia: Results of DFCI 11-001.

PURPOSE: Dana-Farber Cancer Institute Acute Lymphoblastic Leukemia (ALL) Consortium Protocol 11-001 assessed efficacy and toxicity of calaspargase pegol (calaspargase), a novel pegylated asparaginase formulation with longer half-life, compared with the standard formulation pegaspargase. METHODS: Patients age 1 to ≤ 21 years with newly diagnosed ALL or lymphoblastic lymphoma were randomly assigned to intravenous pegaspargase or calaspargase, 2,500 IU/m2/dose. Patients received one induction dose. Beginning week 7, pegaspargase was administered every 2 week for 15 doses and calaspargase every 3 week for 10 doses (30 weeks). Serum asparaginase activity (SAA) (≥ 0.1 IU/mL considered therapeutic) was assessed 4, 11, 18, and 25 days after the induction dose and before each postinduction dose. RESULTS: Between 2012 and 2015, 239 eligible patients enrolled (230 ALL, nine lymphoblastic lymphoma); 120 were assigned to pegaspargase and 119 to calaspargase. After the induction dose, SAA was ≥ 0.1 IU/mL in ≥ 95% of patients on both arms 18 days after dosing. At day 25, more patients had SAA ≥ 0.1 IU/mL with calaspargase (88% v 17%; P ˂ .001). Postinduction, median nadir SAAs were similar (≥ 1.0 IU/mL) for both arms. Of 230 evaluable patients, 99% of pegaspargase and 95% of calaspargase patients achieved complete remission (P = .12), with no difference in frequency of high end-induction minimal residual disease among evaluable patients with B acute lymphoblastic leukemia (B-ALL). There were no differences in frequencies of asparaginase allergy, pancreatitis, thrombosis, or hyperbilirubinemia. With 5.3 years median follow-up, 5-year event-free survival for pegaspargase was 84.9% (SE ± 3.4%) and 88.1% (± SE 3.0%) for calaspargase (P = .65). CONCLUSION: Every 3-week calaspargase had similar nadir SAA, toxicity, and survival outcomes compared with every 2-week pegaspargase. The high nadir SAA observed for both preparations suggest dosing strategies can be further optimized.

Pneumococcal vaccination during chemotherapy in children treated for acute lymphoblastic leukemia.

BACKGROUND: Children treated for acute lymphoblastic leukemia (ALL) are at high risk of invasive pneumococcal disease (IPD). We assessed immunity to S. pneumoniae among children after ALL treatment, and the impact of pneumococcal immunization during and after chemotherapy. METHODS: We performed an observational retrospective study of children treated for ALL at a single center. All children were fully immunized with three routine doses of pneumococcal conjugate vaccine (PCV) prior to ALL diagnosis. Children from Group 1 received a 13-valent PCV (PCV13) dose during the maintenance phase as well as a PCV13 booster after completing chemotherapy, while Group 2 only received the postchemotherapy dose. Serologic testing was performed after chemotherapy and again after the postchemotherapy dose. A serotype-specific antibody level ≥0.35 µg/ml was considered protective, and patients with protective levels for ≥70% of serotypes in the PCV7 vaccine were defined as seroprotected. RESULTS: A total of 71 children (median age 46 months, range 12-160) were included. At the end of chemotherapy, 53.1% of children in Group 1 (17/32) and 25.6% in Group 2 (10/39) were seroprotected (p = .018). After the postchemotherapy booster, seroprotection rates increased to 96.9% in Group 1 (31/32) and 100% in Group 2. CONCLUSIONS: Rates of pneumococcal seroprotection among children with ALL are low following chemotherapy, despite prior routine immunization. A PCV booster during chemotherapy may shorten the period of susceptibility to IPD in some children. However, irrespective of a booster during chemotherapy, a PCV dose postchemotherapy appears sufficient to confer high rates of seroprotection against IPD.

Genetic ancestry and skeletal toxicities among childhood acute lymphoblastic leukemia patients in the DFCI 05-001 cohort.

Hispanic children have a higher incidence of acute lymphoblastic leukemia (ALL) and inferior treatment outcomes relative to non-Hispanic White children. We previously reported that Hispanic children with ALL had lower risk of fracture and osteonecrosis. To unravel the genetic root of such ethnic differences, we genotyped 449 patients from the DFCI 05-001 cohort and analyzed their ancestry. Patients with discordant clinical and genetic ancestral groups were reclassified, and those with unknown ancestry were reassigned on the basis of genetic estimates. Both clinical and genetic ancestries were analyzed in relation to risk of bone toxicities and survival outcomes. Consistent with clinically reported race/ethnicity, genetically defined Hispanic and Black patients had significantly lower risk of fracture (Hispanic: subdistribution hazard ratio [SHR], 0.42; 95% confidence interval [CI], 0.22-0.81; P = .01; Black: SHR, 0.28; 95% CI, 0.10-0.75; P = .01), and osteonecrosis (Hispanic: SHR, 0.12; 95% CI, 0.02-0.93; P = .04; Black: SHR, 0.24; 95% CI, 0.08-0.78; P = .02). The lower risk was driven by African but not Native American or Asian ancestry. In addition, patients with a higher percentage of Native American ancestry had significantly poorer overall survival and event-free survival. Our study revealed that the lower risk of bone toxicities among Black and Hispanic children treated for ALL was attributed, in part, to the percentage of African ancestry in their genetic admixture. The findings provide suggestive evidence for the protective effects of genetic factors associated with African decent against bone damage caused by ALL treatment and clues for future studies to identify underlying biological mechanisms.

The timing of cyclic cytotoxic chemotherapy can worsen neutropenia and neutrophilia.

Despite recent advances in immunotherapies, cytotoxic chemotherapy continues to be a first-line treatment option for the majority of cancers. Unfortunately, a common side effect in patients undergoing chemotherapy treatment is neutropenia. To mitigate the risk of neutropenia and febrile neutropenia, prophylactic treatment with granulocyte-colony stimulating factor (G-CSF) is administered. Extensive pharmacokinetic/pharmacodynamic modelling of myelosuppression during chemotherapy has suggested avenues for therapy optimization to mitigate this neutropenia. However, the issue of resonance, whereby neutrophil oscillations are induced by the periodic administration of cytotoxic chemotherapy and the coadministration of G-CSF, potentially aggravating a patient's neutropenic/neutrophilic status, is not well-characterized in the clinical literature. Here, through analysis of neutrophil data from young acute lymphoblastic leukaemia patients, we find that resonance is occurring during cyclic chemotherapy treatment in 26% of these patients. Motivated by these data and our previous modelling studies on adult lymphoma patients, we examined resonance during treatment with or without G-CSF. Using our quantitative systems pharmacology model of granulopoiesis, we show that the timing of cyclic chemotherapy can worsen neutropenia or neutrophilia, and suggest clinically-actionable schedules to reduce the resonant effect. We emphasize that delaying supportive G-CSF therapy to 6-7 days after chemotherapy can mitigate myelosuppressive effects. This study therefore highlights the importance of quantitative systems pharmacology for the clinical practice for developing rational therapeutic strategies.

Identification of prognostic factors in childhood T-cell acute lymphoblastic leukemia: Results from DFCI ALL Consortium Protocols 05-001 and 11-001.

BACKGROUND/OBJECTIVES: While outcomes for pediatric T-cell acute lymphoblastic leukemia (T-ALL) are favorable, there are few widely accepted prognostic factors, limiting the ability to risk stratify therapy. DESIGN/METHODS: Dana-Farber Cancer Institute (DFCI) Protocols 05-001 and 11-001 enrolled pediatric patients with newly diagnosed B- or T-ALL from 2005 to 2011 and from 2012 to 2015, respectively. Protocol therapy was nearly identical for patients with T-ALL (N = 123), who were all initially assigned to the high-risk arm. End-induction minimal residual disease (MRD) was assessed by reverse transcription polymerase chain reaction (RT-PCR) or next-generation sequencing (NGS), but was not used to modify postinduction therapy. Early T-cell precursor (ETP) status was determined by flow cytometry. Cases with sufficient diagnostic DNA were retrospectively evaluated by targeted NGS of known genetic drivers of T-ALL, including Notch, PI3K, and Ras pathway genes. RESULTS: The 5-year event-free survival (EFS) and overall survival (OS) for patients with T-ALL was 81% (95% CI, 73-87%) and 90% (95% CI, 83-94%), respectively. ETP phenotype was associated with failure to achieve complete remission, but not with inferior OS. Low end-induction MRD (<10-4 ) was associated with superior disease-free survival (DFS). Pathogenic mutations of the PI3K pathway were mutually exclusive of ETP phenotype and were associated with inferior 5-year DFS and OS. CONCLUSIONS: Together, our findings demonstrate that ETP phenotype, end-induction MRD, and PI3K pathway mutation status are prognostically relevant in pediatric T-ALL and should be considered for risk classification in future trials. DFCI Protocols 05-001 and 11-001 are registered at www.clinicaltrials.gov as NCT00165087 and NCT01574274, respectively.

Providing Suitable Pediatric Formulations for Canadian Children: A Call for Action.

BACKGROUND: Many medications given to children have no commercially available, age-appropriate formulations. This leads to manipulation of dosage forms designed for adults (compounding), which can result in an increased risk of dosing errors and adverse events, lack of medication adherence because of taste issues, and suboptimal dosing with therapeutic failure. OBJECTIVES: To determine which drugs required compounding for oral administration to children in a Canadian hospital and, for each compounded drug, to determine whether it was available as licensed oral pediatric formulations in the United States or the European Union. METHODS: Drugs requiring compounded liquid formulations for oral administration, dispensed from January 1 to December 31, 2015, at a Canadian university-affiliated tertiary pediatric hospital, and prepared in a quantity exceeding 0.5 L per year, were retrospectively identified. The online drug databases of Health Canada, the US Food and Drug Administration, the European Medicines Agency (EMA), and the UK Medicines and Healthcare Products Regulatory Agency were searched to determine the availability of child-friendly oral formulations for these drugs. The regulatory status in each jurisdiction was also compared. For licensed formulations with potential concerns about excipient safety, EMA guidelines for sorbitol, propylene glycol, ethanol, and sodium benzoate were used to determine pediatric suitability. RESULTS: Of the 56 compounded drugs investigated, 27 (48%) had a suitable commercialized child-friendly formulation available outside Canada. Overall, these drugs had been on the Canadian market for a median of 35 years, and almost half (27 [48%]) had a pediatric indication in Canada. CONCLUSIONS: Canada is lagging behind the United States and the European Union in ensuring availability of and access to suitable pediatric formulations. Potential explanations for this gap include small market size, regulatory uncertainties, and reimbursement shortcomings. Steps must be taken to implement pediatric-sensitive regulations and incentives, as well as reimbursement policies, to address these unmet needs.

CONTEXTE: Plusieurs médicaments administrés aux enfants ne sont pas disponibles commercialement sous une forme pharmaceutique adaptée à leur âge. Ceci entraîne une manipulation des formes destinées aux adultes (préparation magistrale) et peut conduire à une augmentation du risque d'erreurs de dosage et d'effets indésirables, un manque d'observance médicamenteuse secondairement à des problèmes de goût, et un dosage sous-optimal associé à des échecs thérapeutiques. OBJECTIFS: Définir les médicaments qui exigent une préparation magistrale pour être administrés par voie orale aux enfants dans un hôpital canadien et, pour chaque médicament faisant l'objet d'une préparation magistrale, déterminer s'il est disponible sous une forme pharmaceutique orale autorisée pour les enfants aux États-Unis ou dans l'Union européene. MÉTHODES: Les médicaments nécessitant des préparations magistrales liquides pour administration orale, distribués entre le 1er janvier et le 31 décembre 2015 dans un hôpital de soins pédiatriques tertiaires affilié à une université canadienne et dont la quantité préparée était supérieure à 0.5 L par an, ont été déterminés rétrospectivement. Les bases de données en ligne de médicaments de Santé Canada, de la Food and Drug Administration américaine, de l'Agence européenne des médicaments (AEM) et de la Medicines and Healthcare Products Regulatory Agency (Royaume-Uni) ont été interrogées pour déterminer la disponibilité de formes pharmaceutiques orales adaptées aux enfants pour ces médicaments. Le statut réglementaire de chaque pays a également fait l'objet d'une comparaison. Pour les formes pharmaceutiques autorisées présentant des problèmes potentiels d'innocuité des excipients, les directives de l'AEM concernant le sorbitol, le propylène glycol, l'éthanol et le benzoate de sodium ont servi à déterminer si un usage pédiatrique était acceptable. RÉSULTATS: Des 56 médicaments étudiés faisant l'objet d'une préparation magistrale, 27 (48 %) avaient une forme pharmaceutique commercialisée adaptée aux enfants en dehors du Canada. Au total, ces médicaments sont sur le marché canadien depuis une médiane de 35 ans et près de la moitié (27 [48 %]) ont une indication pédiatrique au Canada. CONCLUSIONS: Le Canada accuse un retard par rapport aux États-Unis et à l'Union européenne quant à la disponibilité et à l'accès à des formes pharmaceutiques adéquates pour les enfants. La petite taille du marché, les incertitudes en matière réglementaire et les lacunes concernant le remboursement pourraient notamment expliquer cet écart. Il est nécessaire de prendre des mesures pour mettre en place des réglementations et des incitatifs ainsi que des politiques de remboursement axés sur les enfants pour répondre à ces besoins criants.

HLA alleles associated with asparaginase hypersensitivity in childhood ALL: a report from the DFCI Consortium.

Aim: To evaluate the association between human leukocyte antigen (HLA) alleles and native Escherichia coli asparaginase hypersensitivity (AH) in children with acute lymphoblastic leukemia (ALL) who received Dana-Farber Cancer Institute treatment protocols. Patients & methods:HLA-DQA1, HLA-DRB1 and HLA-DQB1 alleles were retrieved from available whole exome sequencing data of a subset of childhood ALL patients from Quebec ALL cohort and analyzed for an association with AH. PCR assay was developed to analyze associated alleles in the entire discovery and replication cohorts. Results: Two alleles in linkage disequilibrium (HLA-DRB1*07:01 and DQA1*02:01) were associated with AH. Additional analyses, performed to distinguish between HLA-DRB1*07:01 haplotypes with and without DQB1*02:02 allele, showed that the association was dependent on the presence of DQB1*02:02. Conclusion: This study confirms the implication of HLA-DRB1*07:01, DQA1*02:01 and DQB1*02:02 alleles in developing AH in childhood ALL.

Protective Effects of Dietary Intake of Antioxidants and Treatment-Related Toxicity in Childhood Leukemia: A Report From the DALLT Cohort.

PURPOSE: The benefits and risks of supplementation with antioxidants during cancer therapy have been a controversial area. Few studies have systematically evaluated dietary intake of antioxidants with toxicity and survival in childhood cancer. We sought to determine the role of dietary intake of antioxidants on rates of infections, mucositis, relapse, and disease-free survival during induction and postinduction phases of therapy among children and adolescents with acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: We enrolled 794 children in a prospective clinical trial for treatment of ALL. Dietary intake was prospectively evaluated by a food frequency questionnaire. The association between dietary intake of antioxidants and treatment-related toxicities and survival were evaluated with the Benjamini-Hochberg false discovery rate (q) and logistic regression and the Kaplan-Meier method, respectively. RESULTS: Dietary surveys were available for analysis from 614 (77%), and 561 (71%) participants at diagnosis and at end of induction, respectively. Of 513 participants who completed the dietary surveys at both time points, 120 (23%) and 87 (16%) experienced a bacterial infection and 22 (4%) and 55 (10%) experienced mucositis during the induction or postinduction phases of treatment, respectively. Increased intake of dietary antioxidants was associated with significantly lower rates of infection and mucositis. No association with relapse or disease-free survival was observed. Supplementation was not associated with toxicity, relapse, or survival. CONCLUSION: Consumption of antioxidants through dietary intake was associated with reduced rates of infection or mucositis, with no increased risk of relapse or reduced survival. Dietary counseling on a well-balanced diet that includes an array of antioxidants from food sources alone may confer a benefit from infections and mucositis during treatment of childhood ALL.

Langerhans Cell Histiocytosis With Vertebral Involvement Diagnosed and Treated Over the Last 15 Years in a Single Canadian Pediatric Academic Institution.

We report 11 children with vertebral lesion of Langerhans cell histiocytosis (LCH) diagnosed and treated between 2000 and 2015. Vertebral lesions were usually present at LCH diagnosis. No child developed neurologic symptoms. Among 29 vertebral lesions, only 2 were unstable. Chemotherapy was used in all children but 3. A LCH recurrence was observed in 6 patients, involving vertebrae in 4 cases. All children were disease-free at their last follow-up. Sequelae were more often radiologic than clinical. Since potential recurrences and incomplete bone regeneration exist, discussion about optimal treatment and long-term follow-up of vertebral lesions are essential.

Genes identified through genome-wide association studies of osteonecrosis in childhood acute lymphoblastic leukemia patients.

Aim: To evaluate top-ranking genes identified through genome-wide association studies for an association with corticosteroid-related osteonecrosis in children with acute lymphoblastic leukemia (ALL) who received Dana-Farber Cancer Institute treatment protocols. Patients & methods: Lead SNPs from these studies, as well as other variants in the same genes, pooled from whole exome sequencing data, were analyzed for an association with osteonecrosis in childhood ALL patients from Quebec cohort. Top-ranking variants were verified in the replication patient group. Results: The analyses of variants in the ACP1-SH3YL1 locus derived from whole exome sequencing data showed an association of several correlated SNPs (rs11553746, rs2290911, rs7595075, rs2306060 and rs79716074). The rs79716074 defines *B haplotype of the APC1 gene, which is well known for its functional role. Conclusion: This study confirms implication of the ACP1 gene in the treatment-related osteonecrosis in childhood ALL and identifies novel, potentially causal variant of this complication.

Antithrombin and fibrinogen levels as predictors for plasma L-asparaginase activity in children with acute lymphoblastic leukemia.

BACKGROUND: L-asparaginase is a cornerstone treatment for children with acute lymphoblastic leukemia (ALL). However, immune reaction to the drug may increase the clearance or impair the function of L-asparaginase and reduces its therapeutic efficacy. The objective of this study was to identify potential plasma proteins that could be used as proxies for L-asparaginase activity. METHODS: Fibrinogen, von Willebrand factor antigen (VWF:Ag), total protein, and albumin levels as well as antithrombin (AT) and L-asparaginase activities were measured in 97 children with ALL treated for prolonged period of time with L-asparaginase. Binary logistic regression and a receiver operating characteristic (ROC) curve analysis were performed to evaluate the predictive value of plasma proteins for L-asparaginase activity. RESULTS: Median E. coli L-asparaginase activity was 220 IU/L (range, 0-1308) throughout the treatment period. L-asparaginase activity was below 100 IU/L in 23% of measured samples. L-asparaginase activity was inversely associated with AT activity, fibrinogen, total protein, and albumin levels (r = -0.63, -0.62, -0.57, and -0.45, respectively; P < 0.0001), but not with VWF:Ag. ROC curve analyses showed an intermediate accuracy of AT activity (area under the ROC curve [AUC] = 0.77) to detect specimens with subtherapeutic level of L-asparaginase. An optimal accuracy was found when AT and fibrinogen were combined (AUC = 0.82; sensitivity = 75%; specificity = 82%; positive predictive value = 55%; negative predictive value = 92%) with cutoff values of 0.73 IU/mL and 1.85 g/L, respectively. CONCLUSIONS: AT combined with fibrinogen levels could be used as a proxy to identify patients with therapeutic level of L-asparaginase activity in the absence of real-time asparaginase measurement during prolonged exposure to L-asparaginase.

Molecular Profiling of Hard-to-Treat Childhood and Adolescent Cancers.

Importance: Little progress in pediatric cancer treatment has been noted in the past decade, urging the development of novel therapeutic strategies for adolescents and children with hard-to-treat cancers. Use of comprehensive molecular profiling in the clinical management of children and adolescents with cancer appears a suitable approach to improve patient care and outcomes, particularly for hard-to-treat cases. Objective: To assess the feasibility of identifying potentially actionable mutations using next-generation sequencing-based assays in a clinically relevant time frame. Design, Setting, and Participants: This diagnostic study reports the results of the TRICEPS study, a prospective genome sequencing study conducted in Québec, Canada. Participants, aged 18 years or younger at diagnosis, with refractory or relapsed childhood and adolescent cancers were enrolled from April 2014 through January 2018. Whole-exome sequencing (WES) of matched tumor normal samples and RNA sequencing of tumor were performed to identify single-nucleotide variants, fusion transcripts, differential gene expression, and copy number alterations. Results reviewed by a team of experts were further annotated, synthesized into a report, and subsequently discussed in a multidisciplinary molecular tumor board. Main Outcomes and Measures: Molecular profiling of pediatric patients with hard-to-treat cancer, identification of actionable and targetable alteration needed for the management of these patients, and proposition of targeted and personalized novel therapeutic strategies. Results: A total of 84 patients with hard-to-treat cancers were included in the analysis. These patients had a mean (range) age of 10.1 (1-21) years and a similar proportion of male (45 [54%]) and female (39 [46%]). Sixty-two patients (74%) had suitable tissues for multimodal molecular profiling (WES and RNA sequencing). The process from DNA or RNA isolation to genomic sequencing and data analysis steps took a median (range) of 24 (4-41) days. Potentially actionable alterations were identified in 54 of 62 patients (87%). Actions were taken in 22 of 54 patients (41%), and 18 (33%) either were on a second or third line of treatment, were in remission, or had stable disease and thus no actions were taken. Conclusions and Relevance: Incorporating genomic sequencing into the management of hard-to-treat childhood and adolescent cancers appeared feasible; molecular profiling may enable the identification of potentially actionable alterations with clinical implications for most patients, including targeted therapy and clinically relevant information of diagnostic, prognostic, and monitoring significance.

Fluctuations in dietary intake during treatment for childhood leukemia: A report from the DALLT cohort.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. Nutritional morbidities are a persistent problem facing pediatric patients during and after treatment and age-gender groups that are at risk for nutritional conditions have not been clearly identified. Therapy is a contributing factor; however, the role of dietary intake remains largely unknown. Prior to conduct of interventional trials, an understanding of the effects of treatment on fluctuations in dietary intake is necessary. METHODS: We enrolled 794 children with ALL in a prospective clinical trial. Dietary intake was collected with a food frequency questionnaire at diagnosis and throughout the course of treatment for pediatric ALL. Reported values were compared to the Dietary Recommended Intake (DRI), and normative values (NHANES). Hierarchical linear models and multilevel mixed-effects ordered logistic regression models were used to evaluate longitudinal changes in dietary intake; independent samples t-test with Bonferroni correction was performed to compare to NHANES. RESULTS: Of the evaluable participants at each timepoint, dietary intake was obtained on 81% (n = 640), 74% (n = 580) and 74% (n = 558) at diagnosis, end of induction phase of treatment, and continuation, respectively. Despite exposure to corticosteroids, caloric intake decreased over therapy for most age-gender groups. Predictive models of excess intake found reduced odds of over-consuming calories (OR 0.738, P < 0.05); however, increased odds of over-consuming fat (OR 6.971, P < 0.001). When compared to NHANES, we consistently found that ≥1/3 of children were consuming calories in excess of normative values. For select micronutrients, a small proportion of participants were above or below the DRI at each time evaluated. CONCLUSIONS: Our study suggests that dietary intake fluctuates during treatment for ALL as compared to age-gender recommended and normative values. Improving our understanding of nutrient fluctuations and dietary quality will facilitate subsequent analyses addressing relationships of dietary intake, toxicity, and survival.