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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.

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.

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.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.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).We recommend further evaluation of these risk factors and consideration of thromboprophylaxis for patients ≥10 years (especially those ≥15 years) when receiving asparaginase.

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.

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 (

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.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.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.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.

BACKGROUND Children and adolescents with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) are reported to have increased relapse rates and therapy-related mortality (TRM). Treatment regimens for DS-ALL patients often include therapy modifications. Dana-Farber Cancer Institute (DFCI) ALL Consortium protocols have used same risk-stratified treatment for patients with and without DS. PROCEDURES We compared clinical and outcome data of DS (n = 38) and non-DS (n = 1,248) patients enrolled on two consecutive DFCI ALL trials 00-001 (2000-2004) and 05-001 (2005-2011) with similar risk adapted therapy regardless of DS status. RESULTS There was no difference in demographic or presenting clinical features between two groups except absence of T-cell phenotype and lower frequency of hyperdiploidy in DS-ALL group. All DS-ALL patients achieved complete remission; four relapsed and one subsequently died. There was no TRM in DS-ALL patients. DS-ALL patients had significantly higher rates of mucositis (52% vs. 12%, p

Summary Background l-asparaginase is a universal component of treatment for childhood acute lymphoblastic leukaemia, and is usually administered intramuscularly. Pegylated Escherichia coli asparaginase (PEG-asparaginase) has a longer half-life and is potentially less immunogenic than the native Escherichia coli ( E coli ) preparation, and can be more feasibly administered intravenously. The aim of the Dana-Farber Cancer Institute Acute Lymphoblastic Leukaemia Consortium Protocol 05-001 (DFCI 05-001) was to compare the relative toxicity and efficacy of intravenous PEG-asparaginase and intramuscular native E coli l-asparaginase in children with newly diagnosed acute lymphoblastic leukaemia. Methods DFCI 05-001 enrolled patients aged 1–18 years with newly diagnosed acute lymphoblastic leukaemia from 11 consortium sites in the USA and Canada. Patients were assigned to an initial risk group on the basis of their baseline characteristics and then underwent 32 days of induction therapy. Those who achieved complete remission after induction therapy were assigned to a final risk group and were eligible to participate in a randomised comparison of intravenous PEG-asparaginase (15 doses of 2500 IU/m 2 every 2 weeks) or intramuscular native E coli l-asparaginase (30 doses of 25 000 IU/m 2 weekly), beginning at week 7 after study entry. Randomisation (1:1) was unmasked, and was done by a statistician-generated allocation sequence using a permuted blocks algorithm (block size of 4), stratified by final risk group. The primary endpoint of the randomised comparison was the overall frequency of asparaginase-related toxicities (defined as allergy, pancreatitis, and thrombotic or bleeding complications). Predefined secondary endpoints were disease-free survival, serum asparaginase activity, and quality of life during therapy as assessed by PedsQL surveys. All analyses were done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00400946. Findings Between April 22, 2005, and Feb 12, 2010, 551 eligible patients were enrolled. 526 patients achieved complete remission after induction, of whom 463 were randomly assigned to receive intramuscular native E coli l-asparaginase (n=231) or intravenous PEG-asparaginase (n=232). The two treatment groups did not differ significantly in the overall frequency of asparaginase-related toxicities (65 [28%] of 232 patients in the intravenous PEG-asparaginase group vs 59 [26%] of 231 patients in the intramuscular native E coli l-asparaginase group, p=0·60), or in the individual frequency of allergy (p=0·36), pancreatitis (p=0·55), or thrombotic or bleeding complications (p=0·26). Median follow-up was 6·0 years (IQR 5·0–7·1). 5-year disease-free survival was 90% (95% CI 86–94) for patients assigned to intravenous PEG-asparaginase and 89% (85–93) for those assigned to intramuscular native E coli l-asparaginase (p=0·58). The median nadir serum asparaginase activity was significantly higher in patients who received intravenous PEG-asparaginase than in those who received intramuscular native E coli l-asparaginase. Significantly more anxiety was reported by both patients and parent-proxy in the intramuscular native E coli l-asparaginase group than in the intravenous PEG-asparaginase group. Scores for other domains were similar between the groups. The most common grade 3 or worse adverse events were bacterial or fungal infections (47 [20%] of 232 in the intravenous PEG-asparaginase group vs 51 [22%] of 231 patients in the intramuscular E coli l-asparaginase group) and asparaginase-related allergic reactions (14 [6%] vs 6 [3%]). Interpretation Intravenous PEG-asparaginase was not more toxic than, was similarly efficacious to, and was associated with decreased anxiety compared with intramuscular native E coli l-asparaginase, supporting its use as the front-line asparaginase preparation in children with newly diagnosed acute lymphoblastic leukaemia. Funding National Cancer Institute and Enzon Pharmaceuticals.

Purpose This study compared the relative incidence of treatment-related toxicities and the event-free and overall survival between Hispanic and non-Hispanic children undergoing therapy for acute lymphoblastic leukemia (ALL) on Dana-Farber Cancer Institute ALL Consortium protocol 05-001. Patients and methods Secondary analysis of prospectively collected data from a phase III multicenter study in children and adolescents of 1–18 years with previously untreated ALL. Results Between 2005 and 2011, 794 eligible patients enrolled on DFCI 05-001, 730 of whom were included in this analysis (19% [N = 150] Hispanic, 73% [N = 580] non-Hispanic). Hispanic patients were more likely to be ≥10 years of age (32% vs. 24%, P = 0.045) at diagnosis. Toxicity analyses revealed that Hispanic patients had significantly lower cumulative incidence of bone fracture (P

Background: Despite outstanding cure rates of pediatric acute lymphoblastic leukemia (ALL), Blacks and Hispanics have inferior survival than Whites. We recently reported that among 794 children from DFCI ALL Consortium Protocol 05-001 trial, Hispanic patients had significantly lower rates of fracture and osteonecrosis, but higher risk of relapse and death compared with non-Hispanic Whites (PMID: 29090520). Studies from other groups have reported inferior ALL outcomes in children with Native American ancestry, however the association between genetic ancestry and skeletal toxicities has not been explored. We examined whether genetic inheritance could provide an explanation for the reduced incidence of skeletal toxicities in Hispanic patients in DFCI 05-001. Methods: A total of 576 DNA samples extracted from bone marrow samples or blood samples obtained during remission, including 2% blind duplicates, were genotyped using the Illumina OmniExpress Beadchip array. After data QC and cleaning, 449 ALL patients were retained in the final analysis. Estimates of global genetic ancestry were derived from STRUCTURE program, which was used to re-classify individuals with discordant clinical race/ethnicity as reported by study site, and to assign individuals with unknown race/ethnicity information to an ethnic group when possible. Regression model for the subdistribution hazard of the cumulative incidence function was used to relate clinical race/ethnicity, genetically reclassified race/ethnicity, and genetic ancestry respectively with risk of fracture and osteonecrosis, with death and recurrence as competing risk factors while controlling for age, gender and baseline clinical factors. Cox proportional regression models were used to test race/ethnicity and ancestry with overall survival (OS) and event-free survival (EFS). Results: Among the 449 patients analyzed, average age was 6.7 years; 26% of patients were ≥10 years and 44% were female. The demographic and clinical characteristics of patients with genotype data were similar to those of the overall cohort, although the proportion of Hispanics was slightly lower in the genotyped sub-cohort (17% vs. 21%), whereas the rates of fracture and osteonecrosis were higher (fracture: 25% vs. 18%; osteonecrosis: 10% vs. 8%). Based on clinical race/ethnicity, 66% of patients were non-Hispanic White, 17% were Hispanic, 5% were non-Hispanic Black, 3% were Asian, and 10% were reported as Other. Genetic ancestry analyses revealed that non-Hispanic White patients had a median of 96% European ancestry, non-Hispanic Black patients had a median of 76% African ancestry, and Asian patients had a median of 58% Asian ancestry. The genetic make-up of Hispanic patients in the 05-001 cohort was more admixed, with 23% Native American and 17% African ancestry, higher than the national average (18% and 6%, respectively). After genetic reassignment, racial/ethnic groups were as follows: 68% non-Hispanic White, 17% Hispanic, 9% non-Hispanic Black, 6% Asian, and 1% unassigned. In analysis of genetically reassigned race/ethnicity with skeletal toxicities, Hispanic and Black patients had significantly lower risk of fracture compared with white patients (Hispanic: subdistribution hazard ratio [SHR]=0.42, 95% confidence interval [CI]=0.22, 0.81; Black: HR=0.28, 95%CI=0.10, 0.75). These groups also had significantly less osteonecrosis (Hispanic: SHR=0.24, 95%CI=0.08, 0.78; Black: SHR=0.12, 95%CI=0.02, 0.93). Similar results were observed when using clinical race/ethnicity. Further analyses revealed that African genetic ancestry, but not Native American ancestry was associated with lower risk of fracture and osteonecrosis in a dose-dependent manner (Table 1). In analysis of death and recurrence, those with higher proportion of Native American ancestry had significantly higher risk of death/recurrence after adjustment (OS: hazard ratio [HR]=4.00, 95%CI=1.45, 11.02; EFS: HR=2.07, 95%CI=1.13, 3.79). Analysis of single variants and polygenic risk scores with skeletal toxicities and survival outcomes is ongoing. Conclusion: Hispanic children and adolescents from the DFCI 05-001 cohort, had highly heterogenous genetic ancestral make-up. Among Hispanic patients, the observed lower risk of skeletal toxicities might be driven by African ancestry, whereas poorer survival observed might be driven by Native American ancestry. Disclosures Silverman: Servier: Consultancy, Research Funding; Takeda: Consultancy.

In pediatric patients with acute lymphoblastic leukemia, adherence to oral chemotherapy relies largely on a parent's comprehension of the drug's indication and administration guidelines. We assessed how pediatric oncology providers educate families about oral chemotherapy. We conducted a cross-sectional survey of 68 physicians and nurses from 9 institutions in the Dana-Farber Cancer Institute Acute Lymphoblastic Leukemia Consortium. The inter-individual approach to patient education is variable and may consist of handouts, treatment calendars, and discussions. The extent of teaching often varies depending on a provider's subjective assessment of a family's needs. Twenty-five percent of providers suggested standardizing patient teaching. When developing educational models, care teams should consider approaches that (a) objectively identify families in need of extensive teaching, (b) designate allotted teaching time by nursing staff during clinic visits, and (c) maintain the variation and dynamism that informs a successful provider-patient relationship.

Cardiac signaling proteins regulate the intrinsic cardioprotective and repair response to doxorubicin cardiotoxicity. We estimated the relationship between these proteins, serum biomarkers of cardiac status and imaging in doxorubicin-treated children with ALL. Concentrations of the proteins

BACKGROUND Pediatric patients receiving induction chemotherapy for newly diagnosed acute lymphoblastic leukemia (ALL) are at high risk of developing life-threatening infections. We investigated whether uniform antibacterial guidelines, including mandatory antibacterial prophylaxis in afebrile patients during induction, decreases the incidence of microbiologically documented bacteremia. METHODS Between 2012 and 2015, 230 patients with newly diagnosed ALL (aged 1-21) were enrolled on Dana-Farber Cancer Institute ALL Consortium Protocol 11-001 (DFCI 11-001). Induction therapy, regardless of risk group, included vincristine, prednisone, doxorubicin, methotrexate, and PEG-asparaginase. Afebrile patients received fluoroquinolone prophylaxis at the initiation of induction and those presenting with fever received broad-spectrum antibiotics; antibiotics were continued until blood count recovery. Rates of documented bacteremias and fungal infections on DFCI 11-001 were compared to those on the predecessor protocol (DFCI 05-001), which included the same induction phase without antibiotic prophylaxis guidelines. RESULTS Sixty-six (28.7%) patients received fluoroquinolone prophylaxis, the remaining patients received broad-spectrum antibiotics. Twenty-four (36.4%) patients on prophylaxis developed fever and seven (10.6%) developed bacteremia. The overall rate of infection during induction on DFCI 11-001 was lower than on DFCl 05-001 (14.3% vs. 26.3%, P

Background Children with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) are shown to have increased therapy-related morbidity and mortality. Hence, therapy modifications and/or dose-reductions are common treatment strategies for this patient (pt) population. Dana-Farber Cancer Institute (DFCI) ALL Consortium protocols have used same risk-stratified treatment for children with and without DS and ALL. Aim: To define the toxicity profile and outcome of children with DS and de novo ALL treated on DFCI ALL Consortium therapy protocols 00-001 and 05-001 using therapy identical to non-DS patients. Methods: Demographic, clinical and outcome data of DS and non-DS patients enrolled on the DFCI ALL protocols 00-001 (2000-2004) and 05-001 (2005-2011) were analyzed. Risk categorization and protocol therapy have previously been described (J Clin Oncol 2013; 31:1202-10; Lancet Oncol 2015;16:1677-90). On both protocols, DS ALL pts were treated identically to non-DS pts without any dose reduction or modification, except for the option for DS ALL pts to receive 3 doses of leucovorin after IT methotrexate. Fisher's exact test was used to compare toxicities in the DS and non-DS pts and Gray test was used to compare the cumulative incidence of fracture and osteonecrosis. Overall survival (OS) was defined as time from registration to death. Event-free survival (EFS) was defined as time from registration to first event (defined as induction failure, relapse, second malignant neoplasm (SMN) or death due to any cause). Induction failure and induction death were included as events at time zero. Disease-free survival (DFS) was defined as time from complete remission (CR) to relapse, SMN or death. Pts without an event were censored at the last known follow-up. The Kaplan-Meier method was used for survival estimation and Greenwood's formula for calculation of 95% confidence interval (CI) of survival estimates. Outcome of DS patients was also examined using Ponte di Legno (PdL) risk group [Low risk (LR) was defined as age at diagnosis ≤ 6 yr. and white cell count < 10X109/L and, remainder as high risk (HR)].(Blood 2014;123:70-7). Two-sided p values Results: Of 1286 eligible pts aged 1-18 yrs. with de novo ALL enrolled on protocols 00-001 and 05-001, 38 (3%) had DS. There was no difference in demographic or presenting clinical features between DS and non-DS ALL pts except immunophenotype (absence of T-ALL in DS vs 11.7% in non-DS, p=0.017) and presence of high hyperdiploidy (51-65 chromosomes) (8.8% in DS vs 25.1% in non-DS, p=0.027) (Table 1). Two DS-ALL pts withdrew from the study after achieving CR. There was no difference in the CR rates (DS: 100% vs non-DS: 95.2%, p=0.47) or proportion of pts with low end of induction minimal residual disease (MRD) between DS and non-DS groups (p=0.73). Toxicities were comparable except DS pts had significantly higher rates of ≥Grade 3 mucositis (data available for protocol 05-001 only) (DS: 52.0% vs. non-DS: 12.0%, p Conclusion: DS pts treated on DFCI ALL Consortium protocols without dose reduction or modifications achieved similar outcomes to non-DS pts. DS pts had a higher frequency of mucositis, infection, and seizures, but did not experience any treatment-related deaths. Other than a higher risk of thrombotic complications, they did not develop excessive toxicity to asparaginase. The low rates of relapse and toxicity-related mortality support the approach of unified therapy protocol for DS and non-DS ALL pts with emphasis on supportive care interventions to prevent toxicities. Overall and event free survival Overall and event free survival Disclosures Asselin: Jazz Pharmaceuticals: Consultancy, Speakers Bureau; Sigma Tau Pharamceuticals: Consultancy.

Background: E.coli L-asparaginase (L-ASP) is an important component of treatment for childhood acute lymphoblastic leukemia (ALL), but the optimal preparation and dosing remain to be determined. Pegaspargase (SS-PEG) is a pegylated L-ASP formulation commonly used in frontline therapy. Calaspargase pegol (SC-PEG) is a novel formulation that uses the same ASP enzyme and PEG moiety as SS-PEG but a different linker molecule that is more hydrolytically stable, leading to a longer half-life. On Dana-Farber Cancer Institute (DFCI) ALL Consortium protocols, patients (pts) typically receive a single dose SS-PEG during induction, and then 15 doses every 2-weeks (wks) during post-induction in order to maintain therapeutic serum asparaginase activity (SAA), defined as ≥ 0.1 IU/mL, for 30 consecutive wks. We hypothesized that SC-PEG could be administered less frequently than SS-PEG during post-induction therapy with a similar SAA and toxicity profile. Methods: Between 2012-2015, pts aged 1-21 years with newly diagnosed ALL or lymphoblastic lymphoma (LL) were eligible to enroll on DFCI ALL Consortium Protocol 11-001. Pts were randomized at study entry to receive either SS-PEG (N=120) or SC-PEG (N=119), each given intravenously (IV) at a dose of 2500 IU/m2. Both groups received a single dose during multi-agent remission induction. Post-induction, pts assigned to SS-PEG received 15 doses every 2-wks and those assigned to SC-PEG received 10 doses every 3-wks along with other risk-stratified chemotherapy. Serum samples were obtained 4, 11, 18 and 25 days after the induction dose to determine SAA and prior to each post-induction dose (2 wks after each SS-PEG and 3 wks after each SC-PEG dose) to determine nadir SAA (NSAA) by a validated biochemical assay. Pts were switched to Erwinia asparaginase for Grade 2 or higher allergy or for silent inactivation (defined as 2 consecutive non-detectable NSAA). Asparaginase was permanently discontinued for pancreatitis and held for thrombosis (but re-started once the clot improved). End-induction minimal residual disease (MRD) was assessed in ALL pts by IGH/TCRPCR assay, with low MRD defined as < 0.001. Results: 239 eligible pts were enrolled (230 ALL and 9 LL). There were no significant differences in presenting characteristics between randomized arms. SAA during induction and NSAA during post-induction are displayed in Figure 1. SAA was similar for the two preparations at 4, 11 and 18 days after the induction dose, with SAA ≥ 0.1 IU/mL in ≥ 95% of pts at these time points on both arms. 25 days after the induction dose, SAA was higher with SC-PEG (median 0.298 IU/mL vs 0.056 for SS-PEG), with significantly more pts on SC-PEG arm with SAA ≥ 0.1 IU/mL (88% vs 15%, p Conclusion: During remission induction, a single dose of SC-PEG (2500 IU/m2) leads to more sustained SAA without excess toxicity or significant difference in the proportion of pts with low end-induction MRD. During post-induction therapy, SC-PEG can be given less frequently (every 3-wks) than SS-PEG (every 2-wks) with similar NSAA and toxicity. The high NSAA observed during post-induction therapy with each preparation suggests that a longer dosing interval and/or reduced dose may be feasible while still maintaining NSAA ≥ 0.1 IU/mL. Longer follow-up is necessary to determine event-free survival by randomized arm. Disclosures No relevant conflicts of interest to declare.

Background: Deletions in the Ikaros gene (IKZF1) have been associated with a poor outcome in pediatric B-ALL, but the interaction of IKZF1 deletions with other established prognostic factors, such as minimal residual disease (MRD), is still under investigation. Here we report the IKZF1 deletion status of 405 patients (pts) with acute lymphoblastic leukemia (ALL) and its association with other presenting features, end-induction MRD, and outcome. Methods: Between 2005-2011, 794 eligible pts (aged 1-18 yrs) with newly diagnosed pediatric ALL (B-ALL: 697; T-ALL: 97) were enrolled on DFCI ALL Consortium Protocol 05-001. End-induction MRD was assessed prospectively on all pts by allele-specific oligonucleotide-PCR assay. DNA was extracted from archived diagnostic blood or bone marrow samples from 399 B-ALL and 6 T-ALL pts with sufficient available material. Using a commercially available kit (SALSA MLPA P202 IKZF1, MRC-Holland), IKZF1 deletion status was assessed by multiplex ligation-dependent probe amplification (MLPA). Event free survival (EFS) and relapse free survival (RFS) were estimated using the method of Kaplan and Meier. Results: IKZF1 deletion was detected in 69 (17%) of the 405 evaluated pts. IKZF1 deletion was more common in pts over 10 years old (p 315 Ph-negative B-ALL pts achieving complete remission (CR) had assessable end-induction MRD. Significantly more IKZF1 non-deleted pts had low MRD compared with IKZF1-deleted pts (95% vs 82%, p=0.006). For the 293 MRD-low pts, relapse occurred in 7% of IKZF1 non-deleted and 24% of IKZF1-deleted pts (p=0.004); for 22 MRD-high pts (all of whom received intensified therapy), there was no significant difference in relapse between IKZF1 non-deleted and IKZF1-deleted pts (21% vs 37%, p=0.62). The 5-yr relapse-free survival (RFS) was significantly worse for MRD-low pts with IKZF1 deletions versus those without these deletions (Figure 1). In multivariable analysis, IKZF1 status, but not MRD, was significantly associated with RFS for Ph-negative B-ALL pts. (Table 1) Conclusions: IKZF1 deletion is associated with higher rates of induction failure and relapse, and is a significant predictor of inferior outcome in pediatric B-ALL. IKZF1 deletion was associated with significantly higher rates of relapse in Ph-negative B-ALL patients with low end-induction MRD, and thus may be useful factor to consider when stratifying treatment intensity in this subset of pts. We conclude that IKZF1 deletion should be incorporated into risk stratification for pediatric B-ALL. Table 1. Prognostic Factors for RFS for B-ALL, Ph-negative pts with evaluable end-induction MRD Univariate Multivariable HR [95% CI] p-value HR [95% CI] p-value Age, ≥10 vs Disclosures No relevant conflicts of interest to declare.

Background: Risk-adapted treatment strategies have contributed to excellent outcomes in pediatric acute lymphoblastic leukemia (ALL); however, treatment-associated acute and long-term toxicities persist. Therapy-associated toxicities of note in pediatric ALL are related to a treatment backbone that relies heavily on corticosteroids (prednisone and dexamethasone) and asparaginase (ASP). The most frequently observed toxicities include, but are not limited to, serious infection, pancreatitis, thrombosis and bony morbidities including osteonecrosis (ON) and fracture. Previous studies suggest that children of racial and ethnic minorities are at higher risk for treatment-associated toxicities. We assessed the incidence of treatment-related toxicities in Hispanic and non-Hispanic patients undergoing treatment for pediatric ALL. Patients and Methods: Retrospective cohort study investigating the incidence of treatment-related toxicities including infection, allergy to ASP, pancreatitis, thrombosis and bony morbidities in Hispanic and non-Hispanic children and adolescents with newly diagnosed ALL undergoing therapy on Dana-Farber Cancer Institute (DFCI) ALL Consortium Protocol 05-001. The ethnicity of each patient was designated at the time of study enrollment by research coordinators. Descriptive statistics were calculated, mean +/- SD for continuous variables and frequency and percentages for categorical variables. Toxicity rates were based on number of patients. Comparison between groups was done by Chi-square test or FisherÕs exact test and p -value < 0.05 was considered significant. Results: Between 2005 and 2011, 794 children and adolescents (ages 1 - 18 years) were enrolled on Protocol 05-001, 730 of whom were evaluable for this investigation: 150 Hispanic (18%), 580 non-Hispanic (73%). Sixty-four patients did not have ethnicity documented. There was no significant difference in disease-risk group, age or gender between the two groups. Weight was significantly higher in Hispanic patients (31.9 ± 24.4 kg in Hispanic and 26.9 ± 18.7 kg in non-Hispanic, p = 0.021). There was no significant difference in the incidence of ASP-related toxicities (allergy, pancreatitis, thrombosis) between Hispanic and non-Hispanic patients. There was no significant difference in the overall incidence of infection between the two groups (42% in Hispanic and 50% in non-Hispanic, p = 0.081). Non-Hispanic patients had significantly higher rates of opportunistic infection (Pneumocystis pneumonia) than Hispanic patients (0.7% in Hispanic and 4% in non-Hispanic, p = 0.041). A similar difference in the incidence of bacteremia between the two groups approached, but did not reach statistical significance (p = 0.052). The overall incidence of fracture in all patients was 14.5% and was significantly higher in non-Hispanic patients (6% in Hispanic and 16.7% in non-Hispanic, p < 0.001). The overall incidence of ON was 8.9% and was significantly higher in non-Hispanic patients (3.3% in Hispanic and 10.3% in non-Hispanic, p = 0.007). (Table 1) Conclusion: The incidence of opportunistic infections and bony morbidities was significantly higher in non-Hispanic patients undergoing treatment for pediatric ALL on the DFCI ALL Consortium Protocol 05-001. The risk for, and impact of therapy-related toxicities varies by a patientÕs treatment tolerance, perhaps as a function of age and gender or as a result of disease biology or genetic polymorphisms affecting drug metabolism. Additionally, non-biologic factors such as medication adherence and nutritional status may also contribute to toxicity incidence in patients undergoing treatment for pediatric ALL. Prospective studies to further investigate our findings are warranted. Table. All Patients, (N = 730) Non-Hispanic, (N = 580) Hispanic, (N = 150) p -value Overall Infection 353/730 (48.4%) 290/580 (50%) 63/150 (42%) 0.081 Bacteremia 289/730 (39.6%) 240/580 (41.4%) 49/150 (9.3%) 0.052 Opportunistic Infection 24/730 (3.3%) 23/580 (4%) 1/150 (0.7%) 0.041 Fracture 106/730 (14.5%) 97/580 (16.7%) 9/150 (6%) Disclosures No relevant conflicts of interest to declare.

Background. Pediatric patients with newly diagnosed acute lymphoblastic leukemia (ALL) are at high risk for developing bacterial infections, particularly during the induction treatment phase. Infections are the primary cause of treatment-related mortality during the induction phase, and also lead to prolonged hospitalization, as well as delays and dose modifications in planned chemotherapy. On DFCI ALL Consortium Protocol 05-001 (2005-2011), 26.6% of 794 enrolled patients (pts) experienced at least one infectious complication during induction. In the subsequent study, DFCI Protocol11-001, we studied whether the use of prophylactic fluoroquinolones during induction would decrease the incidence of bacterial infections. Patients and methods.Between 2012-2015, 229 pts with ALL (aged 1-21 years) were enrolled on Protocol 11-001 at 9 participating sites. Induction therapy, regardless of risk group, included vincristine, methylprednisolone, doxorubicin, low-dose methotrexate and pegylated L-asparaginase. Afebrile pts were started on fluoroquinolone prophylaxis at the time of initiation of therapy and continued until count recovery at the end of induction. Pts were switched to broad-spectrum antibiotics (eg, cefepime) for fever or documented infection. Pts with fever at presentation were started on broad spectrum antibiotics rather than fluoroquinolone, and either remained on broad-spectrum antibiotics or were switched to fluoroquinolone prophylaxis until count recovery per treating clinician. Antifungal prophylaxis was not required. All episodes of microbiologically documented bacterial infection, microbiologically and/or radiographically documented fungal infection, and Clostridium difficile (C. diff) enterocolitis were prospectively collected. Using a 1-sample binomial test, rates of infections on Protocol 11-001 were compared to those from the predecessor study, DFCI Protocol 05-001, which included nearly identical induction chemotherapy but did not include guidelines regarding antibiotic prophylaxis or duration during induction. Results. Of the 229 pts, 89% had B-ALL and 11% T-ALL. Median age was 5.1 yrs (range 1.0-20.9). Eighty-six afebrile pts (37.5%) were administered upfront antibiotic prophylaxis and 141 (61.6%) had fever at diagnosis and received broad-spectrum antibiotics; two afebrile patients did not receive antibiotic prophylaxis for unknown reasons. Of the 86 pts who began prophylaxis, 37 (43%) subsequently developed fever. Toxicity data was available for 222 pts. Thirty-eight episodes of infection occurred in 29 patients. Age, presenting white blood cell count and immunophenotype were not associated with the development of infection. The proportion of pts experiencing an infection on Protocol 11-001 (13.1%) was significantly lower than on Protocol 05-001 (26.6%, p Conclusion.The results of our prospective, multi-institutional non-randomized study indicate that treating newly diagnosed pediatric ALL pts with antibiotics throughout the induction phase (including the use of antibiotic prophylaxis for afebrile pts) is effective at reducing the incidence of bacterial infections, and does not result in an increase in fungal infections or a high incidence of C. diff colitis. Additional larger, randomized studies are necessary to confirm the safety and efficacy of this approach during the induction phase. Figure 1. Rate of induction (A) overall (bacterial/fungal), (B) bacterial, (C) fungal infections on Protocols 05-001 and 11-001 Figure 1. Rate of induction (A) overall (bacterial/fungal), (B) bacterial, (C) fungal infections on Protocols 05-001 and 11-001 Disclosures No relevant conflicts of interest to declare.