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Introduction: Asparaginase is a key component in the treatment of childhood acute lymphoblastic leukemia (ALL), but the treatment is jeopardized by 20% or more developing asparaginase-associated toxicities (asp-tox), mostly hypersensitivity, osteonecrosis, pancreatitis and thromboembolism (Albertsen et al 2019). Therapeutic drug monitoring (TDM) of asparaginase enzyme activity (AEA) levels is widely used to identify patients with no AEA and to ensure sufficient treatment (Sluis et al 2016), but is not commonly used to identify patients with high levels. In this study, we investigate AEA-levels and the association with risk and severity of asp-tox. Methods: Children aged 1-17.9 years with non high-risk ALL treated according to the NOPHO ALL2008 protocol from July 2008 to March 2016 in the Nordic and Baltic countries were included in the study. Based on median AEA-level measured 14 days (+/-2 days) after administration, patients were grouped into four groups; 'no enzyme activity' (0 IU/L, n=201), 'fast clearance' (1-99 IU/L, n=82), 'therapeutic levels' (100-249 IU/L, n=543), and 'high levels' (≥250 IU/L, n=330). Furthermore, groups with AEA-levels Results: We included 1,156 patients and 6,929 samples for AEA-measurements in the study. The median number of samples for each patient was 5 [IQR: 3;9]. A total of 328 asp-tox events were registered in 311 patients (27.5%). The median age for patients with asp-tox was 5 years [Interquartile range (IQR): 2;9] compared with 4 years [IQR: 2;6] for patients without asp-tox (p Conclusion: We found no difference in the incidence of toxicities between AEA in ´therapeutic levels´ and ´high levels´ group, and there will be no clinical advantage in using TDM to identify patients with high AEA-levels for dose adjustment. The significantly lower incidence of asp-tox in patients without AEA and AEA-levels Disclosures Ranta: Roche: Other: Amember of Steering committee for a Roche study on Hemlibra (the contract is between Karolinska University Hospital and Roche). No financial benefits.. Wolthers:Novo Nordisk: Current Employment. Heyman:Servier: Other: Research funding in ALLTogether (research protocol). Schmiegelow:Jazz Pharmaceuticals: Other: Speaker and/or Advisory Board Honoraria ; Medscape: Other: Speaker fee; Servier: Other: Educational grant. Speaker and/or Advisory Board Honoraria ; Amgen: Other: Speaker fee. Albertsen:Erytech Pharma: Other: Sponsor of the investigator initiated study: NOR-GRASPALL 2016. No financial benefits..

When offered participation in clinical trials, families of children with cancer face a delicate balance between cure and toxicity. Since parents and children may perceive this balance differently, this paper explores whether adolescent patients have different enrollment patterns compared to younger children in trials with different toxicity profiles.

Thromboembolism frequently occurs during acute lymphoblastic leukemia (ALL) therapy. We prospectively registered thromboembolic events during the treatment of 1772 consecutive Nordic/Baltic patients with ALL aged 1 to 45 years who were treated according to the Nordic Society of Pediatric Hematology and Oncology ALL2008 protocol (July 2008-April 2017). The 2.5-year cumulative incidence of thromboembolism (N = 137) was 7.9% (95% confidence interval [CI], 6.6-9.1); it was higher in patients aged at least 10 years (P < .0001). Adjusted hazard ratios (HRas) were associated with greater age (range, 10.0-17.9 years: HRa, 4.9 [95% CI, 3.1-7.8; P < .0001]; 18.0-45.9 years: HRa, 6.06 [95% CI, 3.65-10.1; P < .0001]) and mediastinal mass at ALL diagnosis (HRa, 2.1; 95% CI, 1.0-4.3; P = .04). In a multiple absolute risk regression model addressing 3 thromboembolism risk factors, age at least 10 years had the largest absolute risk ratio (RRage, 4.7 [95% CI, 3.1-7.1]; RRenlarged lymph nodes, 2.0 [95% CI, 1.2-3.1]; RRmediastinal mass, 1.6 [95% CI, 1.0-2.6]). Patients aged 18.0 to 45.9 years had an increased hazard of pulmonary embolism (HRa, 11.6; 95% CI, 4.02-33.7; P < .0001), and patients aged 10.0 to 17.9 years had an increased hazard of cerebral sinus venous thrombosis (HRa, 3.3; 95% CI, 1.5-7.3; P = .003) compared with children younger than 10.0 years. Asparaginase was truncated in 38/128 patients with thromboembolism, whereas thromboembolism diagnosis was unassociated with increased hazard of relapse (P = .6). Five deaths were attributable to thromboembolism, and patients younger than 18.0 years with thromboembolism had increased hazard of dying compared with same-aged patients without thromboembolism (both P ≤ .01). In conclusion, patients aged at least 10 years could be candidates for preemptive antithrombotic prophylaxis. However, the predictive value of age 10 years or older, enlarged lymph nodes, and mediastinal mass remain to be validated in another cohort.

Background Asparaginase is an essential drug for childhood acute lymphoblastic leukemia (ALL) and is frequently given for months to obtain continuous asparagine depletion. This causes significant toxicity. We randomized patients to continuous versus intermittent asparaginase, hypothesizing decreased toxicity with unchanged efficacy (www.clinicaltrials.gov: NCT00819351). Methods Children (median age: 4·2 years) treated for non-high risk ALL according to the NOPHO ALL2008 protocol received five intramuscular pegylated asparaginase injections (1·000 IU/m2) biweekly and were then randomized to additional three (6 weeks intervals, N=309, experimental arm) versus ten (two weeks intervals, N=316, standard arm) doses. Primary endpoint was non-inferior (6% margin) disease free survival (DFS). Toxicity reduction was secondary endpoint. Occurrence of asparaginase-associated hypersensitivity, osteonecrosis, pancreatitis and thromboembolism were prospectively registered at quarterly intervals. Findings After a median follow-up of 4·1 years, the 7-year DFS was 90·4% (95% confidence interval, 85·4-95·4) and 90·8% (95% confidence interval, 87·0-94·6) in the experimental and standard arms, respectively. The 3-year cumulative incidence of any first toxicity (hypersensitivity (N=13), osteonecrosis (N=29), pancreatitis (N=24), thromboembolism (N=17)) was 9·3% in the experimental arm and 18·1% in the standard arm (P=0·001). Toxicity reduction was confirmed in sex- and risk group-adjusted Cox regression analysis stratified by age (≥10 and

Objectives This randomized controlled trial tested the hypothesis that children with non-high risk acute lymphoblastic leukemia could benefit from individualized 6-mercaptopurine increments during consolidation therapy (NCT00816049). Primary and secondary end points were end of consolidation minimal residual disease (MRD) positivity and event-free survival. Methods 392 patients were randomized to experimental and 396 to standard therapy. Patients allocated to standard therapy received oral 6-mercaptopurine (25 mg/m2/day) from days 30 to 85, while the experimental arm received stepwise increments of additional 25 mg/m2/day beginning on days 50 and/or 71 unless dose-limiting myelosuppression had occurred. Results In the experimental arm, 166 patients (42%) received one dose increment, and 62 (16%) received two. 57 of 387 (15%) in the experimental arm were MRD positive at end of consolidation versus 77 of 389 (20%) in the control arm (P=0.08). Five-year probability of event-free survival was 0.89 (95% CI: 0.85–0.93) in the experimental arm versus 0.93 (0.90–0.96) in the control arm (P=0.13). The median accumulated length of 6-mercaptopurine treatment interruptions was 7 (IQR 2–12) in the experimental arm versus 4 (IQR 0–10) in the control arm (P=0.002). Conclusion This study found no benefit from individualized 6-mercaptopurine increments compared to standard therapy. This article is protected by copyright. All rights reserved.

The survival rate of childhood acute lymphoblastic leukemia (ALL) is now close to 90 %. However, 15-20 % of patients still experience relapse, which is caused by persistence of minimal residual disease (MRD) in the bone marrow during chemotherapy. Thus, a method for identification of drugs that are capable of eliminating this cell population is necessary, but not currently available. Indeed, current and past ALL in vitro sensitivity assays demand high cell numbers (100,000 ALL cells per well in a 96-well plate), which is beyond what can routinely be harvested from the MRD population in the BM at the end of induction therapy. Accordingly, we developed a cell death assay that is far more sensitive and needs only 1,000 cells per well in a 96-well plate. It is based on stainings with annexinV-V450, a marker for early apoptosis, and Live/Dead Yellow, a marker for loss of cell membrane integrity, which can be quantified by flow cytometry. In order to compare patient samples, the viable fraction of treated cells were normalized to the viable fraction of untreated cells and classified as the survival index (SI). Assay time was set to 24 hours. When developing the assay we included the drugs that are currently used in the NOPHO ALL2008 induction therapy, namely vincristine, doxorubicin, dexamethasone and prednisolone. We determined one empirically derived cut-off concentration per drug and per cell density that produced a large scatter of SIs. Thereby only one drug concentration per cell density was needed for in vitro sensitivity testing (Vincristine: 0.09 and 9.23 mg/ml; doxorubicin: 0.5 and 2 mg/ml; prednisolone: 50 and 200 mg/ml; dexamethasone 2 and 100 mg/ml). The cell death assay showed only minor day-to-day variation (e.g. 0.09 mg/ml vincristine: N=15; rS= 0.92, p < 0.001) (Figure 1). In order to simulate a situation where FACS would be used for isolation of ALL subpopulations or MRD prior to in vitro sensitivity testing, ALL cells were mixed with peripheral blood mononuclear cells (MNCs) from healthy individuals to a final leukemic cell concentration of 10-2 and thereafter Fluorescence-activated cell sorted (FACSed) directly into a 96-well plate for exposure to chemotherapeutic drugs. The SI obtained was highly correlated to that of ALL cells that were not sorted, but directly and manually pipetted into the 96-well plate (e.g. 0.09 mg/ml vincristine: N=9; rS= 0.90, p = 0.001) (Figure 2). Next, we tested whether the in vitro sensitivity results obtained using 1,000 cells per well would resemble results obtained using 100,000 cells per well (i.e. the current standard). We exposed 1,000 and 100,000 cells per well in a 96-well plate from 36 ALL patients and three healthy individuals to the drugs listed above. For all drugs the SI for 1,000 and 100,000 cells per well were significantly correlated (vincristine: rs=0.65, p < 0.001; doxorubicin: rs= 0.48, p = 0.003; dexamethasone: rs= 0.55, p < 0.001; prednisolone: rs=0.35, p=0.04). Thus, we have developed a sensitive, yet robust in vitro sensitivity testing platform that includes FACS prior to cell death analysis. It demands only 3,000 ALL cells per drug to be tested in triplicates, and 3,000 cells that serve as untreated controls. Since a standard follow-up BM sample at day 28 after diagnosis contains at least 20 million MNCs in total, it enables in vitro sensitivity profiling of patients with MRD value > 0.1 %, potentially allowing future tailored chemotherapy according to the chemosensitivity profile of residual leukemia. Disclosures No relevant conflicts of interest to declare.

Background L-Asparaginase is an effective drug in the treatment of childhood acute lymphoblastic leukemia (ALL). The use of L-asparaginase may be limited by serious adverse events of which allergy is the most frequent. The objective of this study was to describe the clinical aspects of PEG-asparaginase allergy in children treated according to the Nordic Society of Paediatric Haematology and Oncology (NOPHO) ALL2008 protocol. Procedure Children (1–17 years) enrolled in the NOPHO ALL2008 protocol between July 2008 and August 2011, who developed PEG-asparaginase allergy were identified through the NOPHO ALL2008 toxicity registry. In the NOPHO ALL2008 protocol, patients are randomized to 8 or 15 doses of intramuscular PEG-asparaginase (Oncaspar®) 1,000 IU/m2/dose administered at 2 or 6 weeks intervals during a total period of 30 weeks. (Clinical trials.gov no: NCT00819351). Results Of 615 evaluable patients, 79 patients developed clinical PEG-asparaginase allergy (cumulative risk; 13.2%) and discontinued PEG-asparaginase therapy for that reason. PEG-asparaginase allergy occurred after a median of two doses (75% range 2–4, max 14). In 58% of PEG-asparaginase hypersensitive patients, the clinical allergic reactions appeared within 2 hr after PEG-asparaginase administration and ranged from mild symptoms to systemic anaphylaxis. Nine patients experienced an anaphylactic reaction within 1 hr and 50 min from asparaginase administration; none were fatal. Four of 68 patients (6%) who subsequently received Erwinase therapy also reacted allergic to Erwinase. Conclusion Clinical allergy to PEG-asparaginase occurred early in treatment, was in general moderate in severity, and mostly developed within 2 hr after PEG-asparaginase administration. The risk of subsequent Erwinase allergic reactions was low. Pediatr Blood Cancer 2015;62:427–433. © 2014 Wiley Periodicals, Inc.

BACKGROUND: Hepatic sinusoidal obstruction syndrome (SOS) during treatment of childhood acute lymphoblastic leukemia (ALL) has mainly been associated with 6-thioguanine. The occurrence of several SOS cases after the introduction of extended pegylated asparaginase (PEG-asparaginase) therapy in the Nordic Society of Paediatric Haematology and Oncology (NOPHO) ALL2008 protocol led us to hypothesize that PEG-asparaginase, combined with other drugs, may trigger SOS during 6-thioguanine-free maintenance therapy.PROCEDURE: In children with ALL treated in Denmark according to the NOPHO ALL2008 protocol, we investigated the risk of SOS during methotrexate (MTX)/6-mercaptopurine (6MP) maintenance therapy that included PEG-asparaginase until week 33 (randomized to two- vs. six-week intervals), as well as alternating high-dose MTX or vincristine/dexamethasone pulses every four weeks.RESULTS: Among 130 children receiving PEG-asparaginase biweekly, 29 developed SOS (≥2 criteria: hyperbilirubinemia, hepatomegaly, ascites, weight gain ≥2.5%, unexplained thrombocytopenia CONCLUSIONS: PEG-asparaginase increases cytotoxic 6MP metabolite levels and risk of SOS, potentially interacting with other chemotherapy pulses.

Steroid-induced osteonecrosis (ON) is a serious complication of anti-leukemic therapy in children and young adults with acute lymphoblastic leukemia (ALL). Patients with ON experience severe pain and reduced mobility, ultimately leading to surgery with arthroplasty. Survival of ALL has increased to

BACKGROUND: As pegylated asparaginase is becoming the preferred first-line asparaginase preparation in the chemotherapy regimens of childhood acute lymphoblastic leukemia (ALL), there is a need to evaluate this treatment.METHODS: The aim of this study was to evaluate the pharmacokinetics of prolonged upfront biweekly PEG-asparaginase (where PEG is polyethylene glycol) treatment by measuring serum l-asparaginase activity and formation of anti-PEG-asparaginase antibodies. A total of 97 evaluable patients (1-17 years), diagnosed with ALL, and treated according to the NOPHO ALL2008 protocol (where NOPHO is Nordic Society of Paediatric Haematology and Oncology) were included. In the NOPHO ALL2008 protocol, patients are randomized to 8 or 15 doses of intramuscular PEG-asparaginase (Oncaspar(®) ) 1,000 IU/m²/dose, at 2-week or 6-week intervals with a total of 30-week treatment (Clinical trials.gov. no.: NCT00819351).RESULTS: The pharmacological target of treatment (l-asparaginase activity above 100 IU/l) was reached in 612 of 652 (94%) samples obtained 14 ± 2 days after PEG-asparaginase administration. Mean l-asparaginase activity was 338 IU/l. Six patients had l-asparaginase activity below 50 IU/l in all samples. A total of 25 patients (26%) developed Immunoglobulin G (IgG) anti-PEG-asparaginase antibodies, but there was no correlation between anti-PEG-asparaginase antibodies and low levels of asparaginase activity.CONCLUSION: We conclude that prolonged first-line biweekly PEG-asparaginase therapy, 1,000 IU/m²/dose was above the pharmacological target in the vast majority of patients. Presence of anti-PEG-asparaginase antibodies was not a predictor of l-asparaginase activity.

Background: Central nervous system (CNS) involvement is common in childhood acute lymphoblastic leukemia (ALL). Today all patients receive intensive prophylactic CNS-directed therapy, which is associated with short- and long-term neurotoxicity. The conventional method for diagnosing CNS leukemia is by microscopic examination of cytospin preparations of cerebrospinal fluid (CSF). Both high (CNS3: ≥5 x 109 cells/L) and low level CNS disease (CNS2: Methods: Cytospin results were collected from local oncology clinics for patients treated according to the Nordic Society of Pediatric Hematology (NOPHO) ALL2008 protocol from July 2008 to December 2017 (N=1841). CSF samples for FCM were obtained from patients enrolled from September 2012 to December 2017 at 17 participating centers (N=669). CSF samples were collected into Transfix® tubes (Intermedico Ltd., Hellerup, Denmark) and shipped to Rigshospitalet, Copenhagen, Denmark for centralized analysis as previously described (Levinsen at al., Pediatr Blood Cancer 2016). FCM positivity required detection of ≥10 cells with a leukemia-associated phenotype. CSF FCM results were blinded to the treating physician. Time to relapse was analyzed using Cox proportional hazards models with delayed entry at remission and with death and second malignant neoplasm as competing events. Results: At diagnosis, 241 of 1841 (13.1%; CNS2: 8.9% and CNS3: 4.2%) patients were positive by cytospin, whereas 167 of 669 (25.0%) patients were positive by FCM. FCM positivity was not associated with shipment duration (median: 2 days). In total, 191 of the 669 patients (28.6%) were CNS positive by cytospin and/or FCM. CNS positivity was associated with higher white blood cell (WBC) count at diagnosis, T-cell ALL, lack of t(12;21), and traumatic lumbar puncture (TLP) (all comparisons: p < 0.001). However, patients with CNS positivity did not differ in their end of induction bone-marrow minimal residual disease (MRD) levels compared to the remaining patients (cytospin: median MRD 1.2 x 10-4 vs. 0.9 x 10-4, p = 0.058; FCM: median MRD 2.0 x 10-4 vs. 1.7 x 10-4, p = 0.62). During follow-up, 30 patients relapsed with nine of the relapses involving the CNS and 16 relapses isolated to the bone-marrow. The 4-year cumulative incidence of any relapse was higher for patients who were CNS positive by cytospin (16.1% vs. 8.9%), FCM (18.6% vs. 6.0%), and combined cytospin/FCM (19.0% vs. 5.5%) (Figure 1a). Simple Cox regressions yielded relapse hazard ratio (HR) estimates of CNS positivity at diagnosis of 2.4 for cytospin (95% CI 1.0-5.7, p = 0.04), 3.5 for FCM (95% CI 1.7-7.2, p < 0.001), and 4.1 for combined cytospin/FCM (95% CI 2.0-8.7, p < 0.001). Cytospin and/or FCM was associated with increased risk of both isolated bone-marrow relapse (16 events, HR 3.1, 95% CI 1.2-8.4, p = 0.024) and of any CNS relapse (9 events, HR 4.9, 95% CI 1.2-19.5, p = 0.025). In a multiple Cox model stratified by immunophenotype and risk group, predictors of relapse were age (per year: HR 1.1, 95% CI 1.0-1.2, p = 0.003), WBC at diagnosis (per doubling: HR 1.3, 95% CI 1.1-1.6, p = 0.005), and cytospin and/or FCM (HR 3.2, 95% CI 1.4-7.2, p = 0.006) (Figure 1b). Cytospin and/or FCM was associated with a significantly higher risk of relapse for BCP-ALL (N=581; 23 relapses; HR 4.5, 95% CI 1.9-10.4, p = < 0.001). For T-cell ALL no significant association was observed (N=85; 7 relapses; HR 1.6, 95% CI 0.3-8.2, p = 0.58), however the number of T-cell ALL was too small to allow reliable conclusions. In a simple Cox model, TLP was associated with a significantly higher risk of relapse than no TLP (HR 2.7, 95% CI 1.3-5.9, p = 0.011), but this was only the case for patients who were positive by FCM (FCM pos: HR 2.7, 95% CI 1.0-7.0, p = 0.043; FCM neg: 0.7, 95% CI 0.1-5.0, p = 0.68). Conclusion: FCM markedly increases the detection rate for CNS involvement at diagnosis, and distinguish between patients at high and low risk of relapse. Diagnosis of CNS leukemia by combined cytospin and FCM analysis should be the standard for accurate classification of CNS status, which will enable better stratification of CNS-directed and systemic therapy. Disclosures No relevant conflicts of interest to declare.

Asparaginase (ASP)-associated pancreatitis (AAP) occurs during acute lymphoblastic leukemia treatment. Among 1285 children (1.0-17.9 years) diagnosed during July 2008-December 2014 and treated according to the Nordic/Baltic ALL2008 protocol, 86 (cumulative incidence=6.8%) developed AAP. Seventy-three cases were severe (diagnostic AAP criteria persisting >72 h) and 13 mild. Cases were older than controls (median: 6.5 vs 4.5 years; P=0.001). Pseudocysts developed in 28%. Of the 20 re-exposed to ASP, 9 (45%) developed a second AAP. After a median follow-up of 2.3 years, 8% needed permanent insulin therapy, and 7% had recurrent abdominal pain. Germline DNA on 62 cases and 638 controls was genotyped on Omni2.5exome-8-v1.2 BeadChip arrays. Overall, the ULK2 variant rs281366 showed the strongest association with AAP (P=5.8 × 10(-7); odds ratio (OR)=6.7). Cases with the rs281366 variant were younger (4.3 vs 8 years; P=0.015) and had lower risk of AAP-related complications (15% vs 43%; P=0.13) compared with cases without this variant. Among 45 cases and 517 controls

ESSENTIALS: Children with acute lymphoblastic leukemia (ALL) are at risk of thromboembolism (TE). This is a prospective evaluation of the incidence, risk factors and outcomes of TE in 1038 children with ALL. TE occurred in 6.1% of children, with the highest incidence (20.5%) among those aged 15-17 years. A TE-associated case fatality of 6.4% indicates that TE is a severe complication of ALL treatment.Thromboembolism (TE) is a major toxicity in children with acute lymphoblastic leukemia (ALL) and may have a negative impact on ALL treatment.To examine the cumulative incidence, outcomes and risk factors associated with TE in children with leukemia.We prospectively evaluated TE in 1038 Nordic children and adolescents (≥ 1 and18 years) diagnosed with ALL during 2008-2013 and treated according to the NOPHO (Nordic Society of Pediatric Hematology and Oncology)-ALL 2008 protocol. The cohort was followed until December 2014. Cox proportional regression was used to compute hazard ratios (HRs).TE events (n = 63) occurred most frequently in conjunction with asparaginase (ASP) administration (52/63). The cumulative incidence of TE was 6.1% (95% confidence interval [CI], 4.8-7.7). Being aged 15-17 years was associated with an increased risk of TE (adjusted HR of 4.0; 95% CI, 2.1-7.7). We found a TE-associated 30-day case fatality of 6.4% (95% CI, 1.8-15.5) and TE-related truncation of ASP therapy in 36.2% (21/58). Major hemorrhage occurred in 3.5% (2/58) of anticoagulated patients. Minor hemorrhage was reported in two out of 58 patients. No major bleeds occurred in children who received low-molecular-weight heparin.Methods to identify children and adolescents who will benefit from thromboprophylaxis during ALL treatment are called for. The truncation of ASP should be avoided. The long-term survival outcomes for ALL patients with TE require close monitoring in the future.

Immunophenotype-defined sub-populations are common at diagnosis in childhood B-cell precursor acute lymphoblastic leukemia

When offered participation in clinical trials, families of children with cancer face a delicate balance between cure and toxicity. Since parents and children may perceive this balance differently, this paper explores whether adolescent patients have different enrollment patterns compared to younger children in trials with different toxicity profiles.Age-dependent participation rates in three consecutive, randomized childhood leukemia trials conducted by the Nordic Society of Paediatric Haematology and Oncology were evaluated. The ALL2000 dexamethasone/vincristine (Dx/VCR) trial tested treatment intensifications to improve cure, and the back-to-back ALL2008 6-mercaptopurine (6MP) and ALL2008 PEG-asparaginase (ASP) trials tested treatment intensifications (6MP) and toxicity reduction without compromising survival (ASP). Patient randomization and toxicity data were prospectively registered by the treating physicians.Parents of young children favored treatment intensifications (Dx/VCR: 12% refusal; 6MP: 14%; ASP: 21%), whereas parents of adolescents favored treatment reductions (Dx/VCR: 52% refusal; 6MP: 30%; ASP: 8%). Adolescents were more likely to refuse intensification trials than young children (adjusted ORs 6.3; P0.01 [Dx/VCR] and 2.1; P = 0.04 [6MP]). Adolescents were less likely to refuse the ASP trial, with varying effect size depending on the length of the preceding consolidation treatment (adjusted OR for median consolidation length 0.15; P = 0.01). Younger children participated more frequently in only 6MP than in only ASP (14% vs. 5%), and adolescents vice versa (2% vs. 17%; P = 0.001).Parents' and adolescents' divergent inclinations toward intensified or reduced therapy emphasize the necessity of actively involving adolescents in the informed consent process, which should also address motives for trial participation.

We present a prospective multicentre cohort of 20 children with acute lymphoblastic leukaemia (ALL) and cerebral sinus venous thrombosis (CSVT). The study covers a period of 5 years and comprises 1038 children treated according to the Nordic Society of Paediatric Haematology and Oncology (NOPHO) ALL 2008 protocol. The cumulative incidence of CSVT was 2%. Sixteen of the thromboses were related to asparaginase and 16 to steroids. Most CSVTs occurred in the consolidation phase. Nearly all were treated with low molecular weight heparin without bleeding complications. Mortality related to CSVT directly or indirectly was 10%, emphasizing the importance of this complication.

Background To evaluate if dissolution of asparaginase in lidocaine can relieve pain of an intramuscular injection in children without changes in bioavailability. Procedure The study was designed as a double-blinded study, randomizing 12 children with acute lymphoblastic leukemia (ALL) to four different combinations of injections, including two injections where asparaginase was dissolved in a lidocaine solution and two in sterile water. Seventeen treatment courses of asparaginase, each consisting of four injections, were evaluated. Pain intensity (Pain Visual Analog Scale, VAS-score) and pharmacokinetics of the drug was evaluated. Results The pain scores showed a significant difference between the two solutions of asparaginase (±lidocaine) (P value

Background Determination of the frequency of antibody formation during first and second exposure to Erwinia asparaginase after i.v. and i.m. administration. Procedure Thirty-nine children with newly diagnosed acute lymphoblastic leukemia (ALL) were included in this prospective study. Antibodies were determined (ELISA method) in plasma from these patients on specific days during and after therapy with 30,000 IU/m2 i.v. or i.m. every day for ten days during the induction phase (first exposure). For 19 children, antibodies were measured in plasma during and after the re-induction phase (second exposure) following treatment with 30,000 IU/m2 i.v. or i.m. twice a week for two weeks (Mondays and Thursdays). On the same days of therapy, enzyme activity (spectrophotometric method) and the concentration of asparagine (HPLC) was determined. Results During the first exposure, none of the patients developed anti-Erwinia asparaginase antibodies. During the second exposure, one patient (1 of 8 patients) treated intravenously developed antibodies, which were associated with disappearance of enzyme activity and reappearance of asparagine. Three of eleven patients developed antibodies of pharmacokinetic importance after i.m. therapy. None of the children had any clinical symptoms of hypersensitivity. Conclusions The formation of antibodies and subsequently altered pharmacokinetics of Erwinia asparaginase seemed to be of importance only during a second period of asparaginase therapy. Med. Pediatr. Oncol. 2002;38:310–316. © 2002 Wiley-Liss, Inc.

L-Asparaginase is an effective drug in the treatment of childhood acute lymphoblastic leukemia (ALL). The use of L-asparaginase may be limited by serious adverse events of which allergy is the most frequent. The objective of this study was to describe the clinical aspects of PEG-asparaginase allergy in children treated according to the Nordic Society of Paediatric Haematology and Oncology (NOPHO) ALL2008 protocol.Children (1-17 years) enrolled in the NOPHO ALL2008 protocol between July 2008 and August 2011, who developed PEG-asparaginase allergy were identified through the NOPHO ALL2008 toxicity registry. In the NOPHO ALL2008 protocol, patients are randomized to 8 or 15 doses of intramuscular PEG-asparaginase (Oncaspar®) 1,000 IU/m(2) /dose administered at 2 or 6 weeks intervals during a total period of 30 weeks. (Clinical trials.gov no: NCT00819351).Of 615 evaluable patients, 79 patients developed clinical PEG-asparaginase allergy (cumulative risk; 13.2%) and discontinued PEG-asparaginase therapy for that reason. PEG-asparaginase allergy occurred after a median of two doses (75% range 2-4, max 14). In 58% of PEG-asparaginase hypersensitive patients, the clinical allergic reactions appeared within 2 hr after PEG-asparaginase administration and ranged from mild symptoms to systemic anaphylaxis. Nine patients experienced an anaphylactic reaction within 1 hr and 50 min from asparaginase administration; none were fatal. Four of 68 patients (6%) who subsequently received Erwinase therapy also reacted allergic to Erwinase.Clinical allergy to PEG-asparaginase occurred early in treatment, was in general moderate in severity, and mostly developed within 2 hr after PEG-asparaginase administration. The risk of subsequent Erwinase allergic reactions was low.

Aims Evaluation of l-asparaginase therapy in the NOPHO-92 ALL-protocol (treatment protocol of acute lymphoblastic leukaemia of the Nordic Society of Paediatric Haematology and Oncology, initiated in 1992) after intravenous and intramuscular administration of Erwinia asparaginase during induction and re-induction therapy. Methods Forty children with newly diagnosed acute lymphoblastic leukaemia received Erwinia asparaginase (30 000 IU/m2 i.v. or i.m.) during induction therapy (every day for 10 days), and 19 children received Erwinia asparaginase (30 000 IU/m2 i.v. or i.m.) during re-induction therapy (twice a week for 2 weeks). Within the treatment periods asparaginase trough activity (using a spectrophotometric assay) was determined on specific days. The goal of therapy is complete l-asparagine depletion, which asparaginase activities above 100 IU l−1 have been shown to ensure. Therefore determination of l-asparagine (using a h.p.l.c. method) was performed only in plasma samples with asparaginase activities below 100 IU l−1. Results During induction therapy 92.2% of the trough enzyme activities were above 500 IU l−1 for the i.v.-treated patients, and 92.4% of the trough enzyme activities were above 500 IU l−1 for the i.m.-treated patients. During re-induction therapy 64.7% of the trough enzyme activities were below 100 IU l−1 in the i.v.-treated group, and 73.3% of the trough enzyme activities were below 100 IU l−1 in the i.m.-treated group. For trough enzyme activities below 100 IU l−1l-asparagine depletion was complete in two thirds of the samples. Conclusions In the NOPHO-92 ALL-protocol l-asparaginase treatment during induction therapy was unnecessarily intense, but during the re-induction phase it appeared inadequate.

SummaryL-asparaginase is an important drug in the treatment of childhood acutelymphoblastic leukaemia (ALL). Treatment is associated with several toxici-ties, including acute pancreatitis. Clinical course, presentation, re-exposureto L-asparginase after pancreatitis and risk of recurrent pancreatitis withinan asparaginase-intensive protocol has been poorly reported. Children (1–17 years) on the ongoing Nordic Society of Paediatric Haematology andOncology (NOPHO) ALL2008 protocol with asparaginase-associated pan-creatitis (AAP) diagnosed between 2008 and 2012 were identified throughthe online NOPHO ALL toxicity registry. NOPHO ALL2008 includes eightor 15 doses of intramuscular pegylated L-asparginase (PEG-asparaginase)1000 iu/m 2 /dose at 2–6 weeks intervals, with a total of 30 weeks of expo-sure to PEG-asparaginase (clinicaltrials.gov no: NCT00819351). Of 786children, 45 were diagnosed with AAP with a cumulative risk of AAP of5 9%. AAP occurred after a median of five doses (range 1–13), and 11 d(median) from the latest administration of PEG-Asparaginase. Thirteenpatients developed pseudocysts (30%) and 11 patients developed necrosis(25%). One patient died from pancreatitis. Twelve AAP patients werere-exposed to L-asparginase, two of whom developed mild AAP once more,after four and six doses respectively. In conclusion, re-exposure to PEG-asparaginase in ALL patients with mild AAP seems safe.Keywords: L-asparaginase, leukaemia, pancreatitis, toxicity, risk factors.

Asparaginase is essential in the treatment of lymphoproliferative malignancies, but it is associated with several side effects. The objective of this study was to compare asparaginase-induced alterations of the coagulation inhibitors and the impact on central line-associated thrombosis in children treated according to 2 different asparaginase regimens. The study enrolled 30 children treated for acute lymphoblastic leukemia, and they were divided into 2 groups with respect to asparaginase preparation and protocol (NOPHO ALL-1992 versus NOPHO ALL-2000). The coagulation inhibitors antithrombin, protein C, and proteins S were measured prior to and during asparaginase therapy, and incidence of central line-associated thromboses was compared to evaluate the protocols' thrombogenicity. Thirteen children received Erwinia asparaginase and 17 children received E. coli asparaginase. Independent of protocol, the coagulation inhibitors were significantly reduced during asparaginase therapy (p < .001), and central line-associated thromboses were frequent. Four children developed thrombosis in the course of asparaginase therapy, and there was a correlation between asparaginase-induced fall of antithrombin and occurrence of new thromboses (p = .01).

Introduction Children with acute lymphoblastic leukemia (ALL) are at high risk for VTE due to several thrombotic risk factors such as the disease itself, central venous line (CVL), immobilization, infections and treatment with asparaginase and steroids, leading to increased morbidity and mortality. Identifying the clinical risk factors and high risk treatment phases for VTE is important and can lead to a better outcome and quality of life for these children. We conducted this prospective study on symptomatic VTE in children with ALL to characterize the prevalence, the clinical characteristics, and potential clinical predictive factors for symptomatic VTE and the impact of thrombosis on treatment delays. Methods All patients (n=1083), age 1-18 years, diagnosed with B-cell precursor or T-cell ALL between June 2008 and July 2013 and enrolled in the NOPHO ALL 2008 treatment protocol in the Nordic countries (Denmark, Finland, Iceland, Norway and Sweden), Estonia or Lithuania were included in the study. Thrombotic events (TE) were prospectively recorded until the end of December 2013. TE was defined as objectively confirmed symptomatic TE. Main questions were: time of VTE occurrence, impact on treatment delay, type of CVL, dysfunction of the CVL, blood samples including D-dimers and thrombophilia screening, family history of TE, type and duration of antithrombotic therapy, and major bleeding during anticoagulation. Results The cumulative risk of symptomatic VTE was 6.0% (CI 95% 4.7-7.7) for children treated with the NOPHO- ALL 2008 protocol. No arterial TE was found. VTE occurred in median 80 (IQR 43-118) days in the SR and 104 (IQR 39-127) days in the IR protocol and were in majority of cases associated with asparaginase treatment (84.5%, 49/58). See figure 1 for the localization of the VTE. VTE had a high impact on the treatment in the patients. Treatment with asparaginase was shortened in half of patients with VTE and chemotherapy treatment delayed in 25%. Age ≥ 15 years and residual disease ≥ 5% after induction therapy was significantly associated with VTE in the multivariate analysis (Table 1). Conclusions Our findings indicate that Venous Thromboembolism (VTE): - is a major complication of ALL treatment - may lead to reduced intensity of the ALL treatment and subsequently possible long term impact on the EFS - risk is dependent on the patients age and residual disease after leukemia induction The possibility of identifying patients with elevated risk of VTE needs to be studied further and thromboprophylaxis for such patients during high-risk treatment phases can be considered in future ALL protocols. Table 1. Multivariate Cox regression analysis of the risk for VTE Factor HR (95% CI) P value Age category, years 1-7 8-14 15-17 Ref1.9 (1.0-3.7)6.2 (3.4-11.3) Figure 1. Localization of VTE Figure 1. Localization of VTE Disclosures No relevant conflicts of interest to declare.

Background: Central nervous system (CNS)-directed treatment has reduced risk of CNS relapse for childhood acute lymphoblastic leukemia (ALL), which accounts for 30-40% of initial relapses. Compared with CNS-negative patients, patients with CNS leukemia (>5 leukocytes/µL cerebrospinal fluid (CSF) and lymphoblasts) suffer from more CNS+ relapses. Conventional cytology (CC) is specific (>95%), but nonsensitive ( Method: We prospectively assessed centralised multi-parameter flow cytometry (FCM) of fixated CSF versus local CC in Nordic/Baltic childhood ALL. Diagnostic samples from 172 children aged 0-18 years with de novo and eight children with relapsed ALL were investigated in 297 CSF samples from 180 patients. Kinetics of disappearance of leukemic cells in the CSF was evaluated until day 15. Antibody-combinations reflected the immunophenotype of leukemic blasts in bone marrow. Result: Of 172 newly diagnosed patients, 51 (30%) had CSF involvement by FCM, while CC was positive in 16 patients (9%) (p Conclusion: Leukemic blasts are present in spinal fluid of one third of newly diagnosed ALL. CSF involvement is associated with other higher risk characteristics. The prognostic value of these findings awaits prospective evaluation. Disclosures No relevant conflicts of interest to declare.

Introduction:The early treatment response, measured as minimal residual disease (MRD), is the most important tool for treatment stratification in T-cell acute lymphoblastic leukemia (T-ALL). Flow cytometry-based MRD (Flow-MRD) monitoring, in addition to the PCR-MRD method, is often important to ensure a sensitive MRD marker. Additionally, Flow-MRD investigation may add biological information to the MRD result itself, and allow cell sorting for biological and functional analyses. Flow-MRD in T-ALL consists of identification of cells with immature T-cell phenotype in bone marrow. However, important pitfalls in Flow-MRD, e.g. treatment-related marker modulation and intra-tumoral immunophenotypic heterogeneity, are poorly described. The aim of this study was to explore the implications of these pitfalls on T-ALL MRD detection and on the concordance between the two MRD methods. Potentially both PCR- and Flow-MRD methods might miss blast subpopulations, which is important if subpopulations have divergent chemosensitivity. Methods:The patient cohort included 49 Danish T-ALL patients (1-45 years of age) treated according to the NOPHO ALL2008 protocol. Standard PCR- and flow cytometry-based MRD data were obtained as part of routine MRD monitoring. We investigated intra-tumoral heterogeneity of the leukemia-associated immunophenotype by flow cytometry (diagnostic BM samples), including clonal T-cell receptor gene-rearrangements in flow-sorted blast subpopulations (22 patients). Immunophenotypic MRD markers (including assessment of modulation) were re-evaluated at follow-up in MRD-positive patients. Flow-MRD was validated by PCR-MRD analysis in flow-sorted cell populations (61 follow-up BM samples, 32 patients). Results:At diagnosis, more than 80% of the T-ALL patients had a heterogeneous immunophenotype, most often involving CD1a, CD4, and TdT. The degree of overall heterogeneity, as defined by the number of markers with heterogeneous expression showing distinct blast subpopulations, did not show association to day29 PCR-MRD. Except for one patient, the dominant T-cell receptor clonal gene rearrangements were conserved across phenotypically diverse blasts. Immunophenotypic changes in MRD-positive patients at early follow-up often included subpopulation-loss and/or marker down-modulation of CD1a, TdT and/or CD4. The marker modulations were frequently independent of each other in different subpopulations. Overall, flow cytometry-based identification of blasts and normal cells at Flow-MRD time points was verified by PCR in the flow-sorted cells: In patients where at least 90% of the blasts showed aberrant marker expression at diagnosis, the flow-sorted MRD cells were concordantly PCR-positive, and flow-sorted phenotypically normal cells were similarly PCR-negative in all but three samples that had very high MRD levels (>20%). However, many patients had only partly-informative immunophenotypes (less than 90% of blasts having aberrant marker). Three discrepant cases with Flow-MRD underestimation showed loss of CD1a- and TdT and down-modulation of CD99, verified in flow-sorting experiments. Conclusions and Discussion: We show that intra-tumoral immunophenotypic heterogeneity—a possible result of genetic instability—is common in T-ALL patients and involves several immaturity and T-linage markers commonly used in Flow-MRD. The dominant PCR-MRD targets are in most cases conserved across the diverse blast subpopulations at diagnosis, but in rare cases PCR-MRD might miss a subpopulation. The observed immunophenotypic changes in T-ALL blasts and blast subpopulations at early follow-up, including reduction of immaturity markers, represent important pitfalls in Flow-MRD. Flow-sorting experiments verified that, when all blasts of heterogeneous immunophenotypes were informative, MRD identified by flow cytometry at follow-up was highly concordant with PCR-MRD markers in sorted cells. The T-ALL blast heterogeneity and marker modulations, which are possibly treatment protocol-specific, are important to take into account to obtain reliable Flow-MRD and thus correct treatment stratification of T-ALL patients. Disclosures No relevant conflicts of interest to declare.

To evaluate if dissolution of asparaginase in lidocaine can relieve pain of an intramuscular injection in children without changes in bioavailability.The study was designed as a double-blinded study, randomizing 12 children with acute lymphoblastic leukemia (ALL) to four different combinations of injections, including two injections where asparaginase was dissolved in a lidocaine solution and two in sterile water. Seventeen treatment courses of asparaginase, each consisting of four injections, were evaluated. Pain intensity (Pain Visual Analog Scale, VAS-score) and pharmacokinetics of the drug was evaluated.The pain scores showed a significant difference between the two solutions of asparaginase (+/-lidocaine) (P value0.0001). Lidocaine did not influence the pharmacokinetics of the drug.Asparaginase with addition of lidocaine significantly decreases the pain as measured by the visual analog scale without changing the bioavailability or the absorption rate of the enzyme.

Determination of the frequency of antibody formation during first and second exposure to Erwinia asparaginase after i.v. and i.m. administration.Thirty-nine children with newly diagnosed acute lymphoblastic leukemia (ALL) were included in this prospective study. Antibodies were determined (ELISA method) in plasma from these patients on specific days during and after therapy with 30,000 IU/m(2) i.v. or i.m. every day for ten days during the induction phase (first exposure). For 19 children, antibodies were measured in plasma during and after the re-induction phase (second exposure) following treatment with 30,000 IU/m(2) i.v. or i.m. twice a week for two weeks (Mondays and Thursdays). On the same days of therapy, enzyme activity (spectrophotometric method) and the concentration of asparagine (HPLC) was determined.During the first exposure, none of the patients developed anti-Erwinia asparaginase antibodies. During the second exposure, one patient (1 of 8 patients) treated intravenously developed antibodies, which were associated with disappearance of enzyme activity and reappearance of asparagine. Three of eleven patients developed antibodies of pharmacokinetic importance after i.m. therapy. None of the children had any clinical symptoms of hypersensitivity.The formation of antibodies and subsequently altered pharmacokinetics of Erwinia asparaginase seemed to be of importance only during a second period of asparaginase therapy.

PURPOSE: A case-control study was performed to determine whether patients who had been treated with Erwinia asparaginase as part of their treatment for childhood acute lymphoblastic leukemia (ALL) and who showed relapsed of their disease more often developed anti-asparaginase antibodies than patients who remained in remission.METHODS: A group of 13 patients who showed relapsed of their disease (median follow-up 35 months) were randomly matched with control patients of the same risk group (two control patients to each case), who had received therapy of the same intensity during the same period (median follow-up 70 months). Anti- Erwinia asparaginase antibodies were measured (ELISA method) during maintenance therapy after asparaginase treatment (30,000 IU/m(2) daily for 10 days in all patients plus twice weekly for 2 weeks in intermediate-risk and high-risk ALL patients).RESULTS: The overall incidence of anti- Erwinia asparaginase antibodies was 8% (3 of 39 patients). There was no statistically significant difference in the incidence of antibody formation between patients who had suffered relapse (1 of 13) and those who had not (2 of 26). In two of the three patients who developed antibodies, the antibodies disappeared after some time, whereas one patient had measurable antibody levels for more than a year after asparaginase therapy.CONCLUSIONS: In this study, the development of anti-Erwinia asparaginase antibodies was rare and was unrelated to the risk of relapse.

AIMS: Evaluation of L-asparaginase therapy in the NOPHO-92 ALL-protocol (treatment protocol of acute lymphoblastic leukaemia of the Nordic Society of Paediatric Haematology and Oncology, initiated in 1992) after intravenous and intramuscular administration of Erwinia asparaginase during induction and re-induction therapy.METHODS: Forty children with newly diagnosed acute lymphoblastic leukaemia received Erwinia asparaginase (30 000 IU/m2 i.v. or i.m.) during induction therapy (every day for 10 days), and 19 children received Erwinia asparaginase (30 000 IU/m2 i.v. or i.m.) during re-induction therapy (twice a week for 2 weeks). Within the treatment periods asparaginase trough activity (using a spectrophotometric assay) was determined on specific days. The goal of therapy is complete L-asparagine depletion, which asparaginase activities above 100 IU l(-1) have been shown to ensure. Therefore determination of L-asparagine (using a h.p.l.c. method) was performed only in plasma samples with asparaginase activities below 100 IU l(-1).RESULTS: During induction therapy 92.2% of the trough enzyme activities were above 500 IU l(-1) for the i.v.-treated patients, and 92.4% of the trough enzyme activities were above 500 IU l(-1) for the i.m.-treated patients. During re-induction therapy 64.7% of the trough enzyme activities were below 100 IU l(-1) in the i.v.-treated group, and 73.3% of the trough enzyme activities were below 100 IU l(-1) in the i.m.-treated group. For trough enzyme activities below 100 IU l(-1) L-asparagine depletion was complete in two thirds of the samples.CONCLUSIONS: In the NOPHO-92 ALL-protocol L-asparaginase treatment during induction therapy was unnecessarily intense, but during the re-induction phase it appeared inadequate.

Single Nucleotide Polymorphisms and Thromboembolism in Acute Lymphoblastic Leukemia – A NOPHO ALL2008 Study

Asparaginase-associated Pancreatitis in Acute Lymphoblastic Leukemia: Results from the NOPHO ALL2008 Treatment of Patients 1–45 Years

Therapeutic drug monitoring in children to reduce complications related to cytostatic drugs

Correlation between asparaginase enzyme activity levels and antithrombin levels during ALL treatment

PURPOSE: To describe the pharmacokinetics of Erwinia asparaginase (ASNase) after intravenous (i.v.) and intramuscular (i.m.) administration.METHODS: A group of 29 children with newly diagnosed acute lymphoblastic leukemia (ALL) received Erwinia ASNase 30,000 IU/m2 every day for 10 days during multiagent induction therapy. Of these patients. 13 received i.v. therapy and 16 received i.m. therapy. During the reinduction phase the patients received Erwinia ASNase 30,000 IU/m2 twice a week for 2 weeks (Mondays and Thursdays) (8 patients in the i.v.-treated group and 11 patients in the i.m.-treated group). ASNase activity (spectrophotometric assay) was measured in plasma samples obtained from the patients at various times during therapy.RESULTS: The estimated half-life was 6.4 +/- 0.5 h (n = 13), the absorption rate after i.m. administration was found to limit elimination. The apparent volume of distribution corresponded well with the volume of plasma. The estimated clearance suggested that Erwinia ASNase is a low-clearance drug. Bioavailability after i.m. administration was (mean +/- SEM) 27.0 +/- 4.5% (range 11-61%; n = 12).CONCLUSIONS: In this study the pharmacokinetic parameters after i.v. and i.m. administration of Erwinia ASNase were determined based on a substantial number of patients. The present findings emphasize the importance of conducting proper pharmacokinetic studies before a new drug or a new preparation of a drug is introduced in a different schedule.

Udgivelsesdato: Apr-May

NOR-GRASPALL 2016: Asparaginase encapsulated in erythrocytes – a promising alternative to PEG-asparaginase in case of hypersensitivity. Line Stensig Lynggaard