Acute Lymphoblastic Leukemia Protocols Research Articles

Older age, CNS leukaemic involvement and induction tumour lysis increases the risk of methotrexate (MTX)-induced neurotoxicity in childhood acute lymphoblastic leukaemia/lymphoma: Experience from a tertiary care centre in South India.

Methotrexate (MTX), although an indispensable part of contemporary treatment protocols for childhood acute lymphoblastic leukaemia (ALL)/lymphomas (LBL) in improving outcomes, can lead to serious neurotoxicity with long-term consequences. The aetiopathogenesis, predisposing factors and treatment for MTX-induced neurotoxicity are not yet well defined. The aim of our study was to detect the incidence, risk factors and to assess the overall outcomes of MTX-induced neurotoxicity among large cohort of paediatric ALL/LBL patients treated on a uniform protocol. We conducted retrospective audit of medical records of 622 consecutive children (≤14 years) diagnosed with ALL and LBL between January 2018 and December 2022 and treated on modified BFM-95 protocol at the Department of Pediatric Oncology, Regional Cancer Centre, Thiruvananthapuram. Risk factors predisposing to MTX-induced neurotoxicity were identified using binary logistic regression analysis. Forty-three children were diagnosed with MTX-induced neurotoxicity with an incidence rate of 6.9%. More than two-thirds of them had high-grade MTX-induced neurotoxicity CTCAE v5.0 with a median age of 9 years (range: 9 months to 14 years). Almost half of them developed MTX neurotoxicity during Protocol M followed by Phase-Ib consolidation (15%). Majority of these patients (84%, 36/43) were challenged again with MTX, with 11% (4/36) developing recurrence. Fifteen per cent had persistent neurological deficits at last follow-up. Univariate analysis found older age (age > 5 years) (p < 0.001), T-cell phenotype (p = 0.040), tumour lysis syndrome during induction (p < 0.001), baseline renal problems prior to MTX exposure (p < 0.001) and CNS leukaemic involvement (p < 0.003) to be significantly associated with MTX neurotoxicity. On multivariate analysis, older age (>5 years), tumour lysis during induction and CNS leukaemia retained statistical significance (p < 0.05). Methotrexate-induced neurotoxicity during paediatric acute lymphoblastic leukaemia/lymphoma therapy is a transient phenomenon in majority and re-challenge with MTX is generally safe. Older age children who develop tumour lysis during induction and CNS leukaemic involvement are at increased risk for MTX-induced neurotoxicity during ALL/LBL treatment.

Significance of immunophenotypic, cytogenetic, and molecular markers in adult patients with T-cell lymphoblastic leukemia

Background. Current chemotherapy protocols for T-cell acute lymphoblastic leukemia (T-ALL) allow achieving a 5-year overall survival of 60–90 %, but relapsed and refractory forms remain incurable situations.Aim. To determine the significance of immunophenotypic, cytogenetic and molecular markers in adult T-ALL patients receiving therapy according to the ALL-2016 protocol.Materials and methods. From December 2016 to June 2022, 113 patients with primary T-ALL were included in the study. Cytogenetic study was performed in 104 (92 %) patients; anomalies in the IKZF1 and NOTCH1 genes were investigated in 43 (38 %) patients.Results. The worst prognosis was in patients with ETP and near-ETP variants of T-ALL (3-year disease-free survival was 54 % in ETP group, 33 % in near-ETP group vs TI/II – 79 %, TIII – 89 %, TIV – 75 %). In early T-ALL variants, abnormal karyotype was most common (ETP – 80.7 %, near-ETP – 60 %). Aberrations in NOTCH1 gene were found in 53 % of cases (in 23 out of 43 patients), and no mutations were found in IKZF1 gene in our study. In the group with no NOTCH1 abnormalities, the overall survival was significantly worse than in the group with abnormalities (NOTCH1– – 52 % vs NOTCH1+ –81 %; p = 0.05).

Central Retinal Vein Occlusion (CRVO) in Acute Lymphoblastic Leukaemia (ALL) Adult Patient Treated with Peg Asparaginase

ntroduction Asparaginase, available as native asparaginase or polyethylene glycol (Peg-aspa), is an essential component of multi-agent treatment protocols for Acute Lymphoblastic Leukaemia (ALL). It works by deaminating L-asparagine, leading to apoptosis and cell cycle arrest in leukemic cells. However, peg-asp is associated with various toxicities, including thrombotic complications mainly cavernous sinuses thrombosis and venous thrombosis. Methods and Results: We report a 48-year-old Indian gentleman, known to be hypertensive, diagnosed to have Precursor T-Lymphoblastic leukaemia/ lymphoma (NOS), when he presented with bicytopenia and a mediastinal mass. He was treated as per ALL protocol for adult at National centre for cancer care and research (NCCCR)Doha, which is adopted from UKALL-14 protocol. He received induction treatment (1A&amp; 1B) and has achieved a morphological remission. He received prophylactic anticoagulation with low molecular weight heparin (LMWH) which was stopped only in the cytopenic nadir. During the ascending phase of induction 1B, He presented with acute onset of floaters and blurred vision in the left eye. Urgent CT head scan revealed vitreous haemorrhage. Full blood count was normal except Platelets of 20*10 9ul. Coagulation screen, fibrinogen level and anti-thrombin level was within normal limit. Ophthalmological evaluation revealed vitreous and retinal haemorrhages, indicating Central Retinal Vein Occlusion (CRV). MRI/MRV brain ruled out intracranial venous thrombosis. CSF analysis excluded CNS disease. He received supportive transfusion; however, he has progressed to permanent loss of vision in the left eye. Therapeutic anticoagulation is not indicated in his case. Thrombotic events can occur during induction therapy for ALL mainly cavernous sinuses thrombosis and venous thrombosis, yet CRVO is an unusual site for thrombotic events and associated predominately with age-associated vasculopathies. In the reported case, several factors contribute to thrombosis, including acute leukaemia, prolonged hospitalization, age, presentation with a mediastinal mass, steroid use as well as Peg-aspa and the patient was managed with prophylactic anticoagulation while on therapy. Asparaginase induces a hypercoagulable state by decreasing antithrombin III, protein C, and protein S levels, leading to hypofibrinogenemia and augmenting the risk of thrombotic events. Thrombosis can negatively impact disease-free survival and long-term outcomes, resulting in complications such as therapy delays, post-thrombotic syndrome, and central nervous system-related issues (seizures, neurocognitive deficits, blindness). While these complications may lead to hesitancy or discontinuation of peg-asp use, early recognition and vigilant monitoring of antithrombin III and fibrinogen levels can help to guide management. In cases where the treatment course is complicated by thrombotic events, a high index of suspicion should arise considering strongly the causative agent to be Asparaginase. Thromboprophylaxis with low-molecular-weight heparin (LMWH) is widely accepted as supportive therapy in ALL management. Conclusion: ALL patients receiving Asparaginase therapy are at risk of developing thrombotic events. Early identification of symptoms and risk stratification are essential for improved disease outcomes. Awareness and understanding of peg-asp-induced thrombosis, including unusual site thrombosis can help guide treatment decisions and improve patient outcomes in ALL therapy.

The efficacy and toxicity of L-asparaginase in the treatment of acute lymphoblastic leukemia in children

L-asparaginase, an enzyme used as an anticancer drug, was one of the first drugs included in the treatment protocols for acute lymphoblastic leukemia. It has become widely used when an important metabolic feature of leukemia cells – their high demand for asparagine to maintain viability – was discovered. Three L-asparaginase preparations are currently used in clinical practice: native E. coli asparaginase, pegylated E. coli asparaginase (PEG-asparaginase), and native E. chrysanthemi-derived asparaginase, which have different half-lives, immunogenic profiles, and the spectrum and frequency of toxic effects. One of the main factors limiting the use of L-asparaginase is its high immunogenicity which can cause acute allergic reactions and the phenomenon of silent inactivation. The development of the immune response leads to an accelerated asparaginase clearance and a shortening of its half-life. To monitor the effectiveness of therapy with L-asparaginase, therapeutic drug monitoring of serum asparaginase activity can be used. When choosing management strategies for patients experiencing acute hypersensitivity reactions to L-asparaginase, the following factors should be taken into consideration: the severity of reaction, the number of previous exposures to L-asparaginase and serum asparaginase activity. The use of PEG-asparaginase is the best first-line treatment strategy for children acute lymphoblastic leukemia, its advantages include a significant reduction in the risk of developing acute allergic reactions, higher therapeutic efficacy and, as a result, improved treatment outcomes.

Relationship of &lt;i&gt;SLCO1B1&lt;/i&gt; and &lt;i&gt;ABCB1&lt;/i&gt; gene polymorphisms with clinical variants of methotrexate toxicity in pediatric acute lymphoblastic leukemia therapy

Background. Despite the significant clinical efficacy of current treatment protocols for acute lymphoblastic leukemia (ALL) in children, high-dose methotrexate demonstrates significant interindividual variability in drug toxicity and disease outcomes due to polymorphisms of drug transporter genes and genes responsible for cytostatic metabolism, which makes pharmacogenetic studies increasingly relevant.Aim. To evaluate the association of ABCB1 (C3435T rs1045642, rs1128503, rs2032582, rs4148738), SLCO1B1 T521C rs4149056 gene polymorphisms with the main types of methotrexate toxicity and the onset of clinical events (death, recurrence, progression) during the treatment of childhood ALL.Materials and methods. The study enrolled 103 patients diagnosed with ALL who received therapy according to BFM group protocols (2002/2009), using high-dose (2000 and 5000 mg/m2) methotrexate. Laboratory methods using NCI toxicity scales (CTCAE v5.0 2018) were used to assess adverse reactions. Real-time polymerase chain reaction method was used to study ABCB1 and SLCO1B1 gene polymorphisms. The study material was peripheral blood. Material was sampled once, regardless of the duration of methotrexate therapy. SPSS Statistics 21.0 software was used for statistical processing of the results. Analysis of associations was performed using the χ2 criterion and Fisher’s exact test.Results. Development of infectious complications, oropharyngeal mucositis, delayed MTX elimination, events were significantly associated with polymorphisms of the studied genes: SLCO1B1 T521C rs4149056, ABCB1 rs4148738, ABCB1 rs1128503, which correlates with the data of world scientific literature.Conclusion. Determination of polymorphisms of genes responsible for the transport and metabolism of methotrexate is a promising and dynamically developing area of clinical oncology.

Unraveling Dexamethasone-Induced Neurobehavioral and Sleep Problems in Children With ALL: Which Determinants Are Important?

Dexamethasone, the preferred corticosteroid in most treatment protocols for pediatric acute lymphoblastic leukemia (ALL), can induce undesirable side effects. Neurobehavioral and sleep problems are frequently reported, but the interpatient variability is high. We therefore aimed to identify determinants for parent-reported dexamethasone-induced neurobehavioral and sleep problems in pediatric ALL. Our prospective study included patients with medium-risk ALL and their parents during maintenance treatment. Patients were assessed before and after one 5-day dexamethasone course. Primary end points were parent-reported dexamethasone-induced neurobehavioral and sleep problems, measured with the Strengths and Difficulties Questionnaire and Sleep Disturbance Scale for Children, respectively. Analyzed determinants included patient and parent demographics, disease and treatment characteristics, parenting stress (Parenting Stress Index and Distress Thermometer for Parents), dexamethasone pharmacokinetics, and genetic variation (candidate single-nucleotide polymorphisms rs41423247 and rs4918). Statistically significant determinants identified in univariable logistic regression analyses were incorporated in a multivariable model. We included 105 patients: median age was 5.4 years (range, 3.0-18.8) and 61% were boys. Clinically relevant dexamethasone-induced neurobehavioral and sleep problems were reported by parents in 70 (67%) and 61 (59%) patients, respectively. In our multivariable regression models, we identified parenting stress as a significant determinant for parent-reported neurobehavioral (odds ratio [OR], 1.16; 95% CI, 1.07 to 1.26) and sleep problems (OR, 1.06; 95% CI, 1.02 to 1.10). Furthermore, parents who experienced more stress before start of a dexamethasone course reported more sleep problems in their child (OR, 1.16; 95% CI, 1.02 to 1.32). We identified parenting stress, and not dexamethasone pharmacokinetics, genetic variation, patient/parent demographics, or disease/treatment characteristics, as a significant determinant for parent-reported dexamethasone-induced neurobehavioral and sleep problems. Parenting stress may be a modifiable target to reduce these problems.

Treatment-related deaths and non-fatal severe toxicities during the intensive treatment phases of the icicle-all-14 risk-stratified treatment protocol for newly-diagnosed acute lymphoblastic leukaemia

Treatment-related deaths and non-fatal severe toxicities during the intensive treatment phases of the icicle-all-14 risk-stratified treatment protocol for newly-diagnosed acute lymphoblastic leukaemia

Pediatric Acute Lymphoblastic Leukemia: Russian Experience with the ALL-IC BFM 2002 Protocol

Background: Treatment protocols for pediatric acute lymphoblastic leukemia (ALL) developed by the BFM (Berlin-FrankfurtMunster) group are among the most effective in the world. The longstanding overall survival rate of children with ALL is more than 90%. The highly successful treatment results obtained for ALL are the reason that the ALL-IC BFM 2002 protocol is widely used in Russia. Aim: This study presents the results of the Russian multicenter study for pediatric ALL treatment by the ALL ICBFM 2002 rotocol. Materials and Methods: In total, 433 patients with primary ALL from 10 Russian pediatric hematology/oncology clinics were included in retrospective and prospective studies from 01.11.2003 to 12.10.2021. The ages of the patients ranged from 3 months to 21 years. All patients were treated according to the ALL IC-BFM 2002 protocol. The overall survival (OS), relapse-free survival (RFS), and event-free survival (EFS) were assessed on 11.12.2021. Results: An overwhelming majority of patients, 97.9% (n=424), achieved clinical and laboratory remission by 33 days of treatment based on the ALL IC-BFM 2002 protocol. The 10-year OS was 91.8+/-1.5%, the RFS was 87.4+/-1.8%, and the EFS was 84.1+/-1.9%. The results of the 10-year OS in the standard-risk and intermediate-risk groups were 92+/-1.7%, and 93.1+/- 3.0%, respectively, and the percentage of relapse in the high-risk group was 71.1+/-11.1%. Conclusion: The ALL-IC BFM 2002 protocol for pediatric ALL could be performed in Russian federal and regional clinics. The treatment results for ALL using the ALL-IC BFM 2002 protocol are dramatic and comparable to those of leading clinics in Europe and the United States. To improve the survival rate in high-risk groups of patients, it is necessary to use additional risk-stratifying factors such as minimal residual disease (MRD).

A case report of pediatric acute lymphoblastic leukemia with e8a2 BCR/ABL1 fusion transcript

BackgroundAcute lymphoblastic leukemia is the most common type of cancer in children. Most often it affects the age group between 2 and 5 years of age. Studies have shown an improvement in general survivability, more than 90% 5-year overall survival (OS). Current treatment protocols for acute lymphoblastic leukemia require verification of the presence of favorable and unfavorable genetic abnormalities, which help qualify patients to the appropriate risk group and select a more suitable treatment. The presence of the BCR/ABL1 fusion gene stratifies the patient into a high-risk group and requires special treatment with tyrosine kinase inhibitors (TKI). The three dominant mRNA transcripts are e1a2, e13a2, and e14a2. Nevertheless, cases of atypical BCR/ABL1 transcripts have also been reported.Case presentationThis paper presents the case of a pediatric patient with Ph + B-cell precursor acute lymphoblastic leukemia with rare atypical e8a2 BCR/ABL1 fusion transcript. Our patient achieved complete remission after 33 days of treatment. Molecular and cytogenetic studies in TP1 did not reveal the presence of the BCR/ABL1 transcript. The PCR-MRD test in TP1b was negative, the patient did not require hematopoietic stem cell transplantation.ConclusionGenetic evaluation of the bone marrow sample is crucial in the initial stage of the diagnosis. Fluorescent in situ hybridization and reverse transcriptase polymerase chain reaction with Sanger sequencing are the appropriate methods used in the detection of rare variants of BCR/ABL1 transcripts.

Asparaginase drugs: a new view of the mechanism of action, side effects and experience in BFM (Berlin–Frankfurt–Munster) protocols

Asparaginase drugs are integrated to multicomponent chemotherapy protocols for acute lymphoblastic leukemia (ALL) in children and adults. Despite the use of different treatment protocols for ALL therapy, drugs are the same there and the differences include the doses and the frequency of administration of cytostatics. Native L-asparaginase obtained from Escherichia coli was the first asparaginase drug for the treatment of ALL. With accumulated knowledge about undesirable and side effects another asparaginase drugs with less expressed side effects were created: pegylated form (PEG-asparaginase), asparaginase derived from Erwinia chrysanthemi (erwinase) and pegylated form of erwinase (crisantaspase). This review is devoted to modern ideas about the mechanisms of action of various asparaginase drugs, pharmacological properties and adverse effects. There is a particular attention to the development of new forms of asparaginase, which will help minimize side effects and increase the effectiveness of the drug. Of no less importance is drug monitoring of asparaginase in the blood to detect side effect at the time and to understand the effectiveness of the therapy. The introduction of drug monitoring will help to individualize and improve the effectiveness of ALL treatment.

The pharmacogenomics of vincristine-induced peripheral neuropathy in pediatric acute lymphoblastic leukemia patients in Serbia - a single center experience

Introduction/Objective. Vincristine (VCR) is one of the key drugs in current treatment protocols for pediatric acute lymphoblastic leukemia (ALL). By destabilizing microtubules, VCR arrests cells in metaphase, inducing apoptosis of malignant cells. VCR also causes axonal degradation and impairment of axonal transport, which leads to VCR-induced peripheral neuropathy (VIPN). This study aimed to investigate the association of five variants in pharmacogenes involved in VCR metabolism with VIPN in Serbian ALL children. We also wanted to discover candidate pharmacogenomic markers of VIPN in Serbian population. Methods. PCR and sequencing-based methodology was used to detect variants in CYP3?5, CEP72, ACTG1, MIR3117, and MIR4481 genes. Statistical analyses were performed for investigating their association with VIPN in 56 pediatric ALL patients. Population VCR pharmacogenomics analysis of 17 pharmacogenes from in-house next-generation sequencing data was also done. Data on allele frequency distribution for the European population were extracted from public databases. Results. During the treatment, 17.86% of patients developed VIPN. Association analyses have shown that none of the genetic variants contributed to the occurrence of VIPN in our study. Population pharmacogenomics study did not reveal valid candidate pharmacovariants for VIPN. Our results suggested that pre-emptive pharmacogenetic testing for VCR is not applicable presently. Conclusion. More comprehensive approaches are needed to identify the panel of genes that could explain the VIPN development after VCR administration in ALL patients. Utilizing better designed genome-wide association studies and more robust artificial intelligence-based tools would provide a panel of pharmacogenes for pre-emptive tests of VIPN to individualize therapy for ALL in children.

Hypersensitivity to Pegylated E.coli asparaginase as first-line treatment in contemporary paediatric acute lymphoblastic leukaemia protocols: a meta-analysis of the Ponte di Legno Toxicity working group

BackgroundHypersensitivity reactions to asparaginase challenge its use and occur frequently (30–75%) after native Escherichia Coli (E.coli) asparaginase. Comparison of incidence of allergic reactions to pegylated E.coli asparaginase (PEGasparaginase) across contemporary paediatric acute lymphoblastic leukaemia (ALL) protocols is lacking. Method and patientsQuestionnaires were sent to all members of the international ALL Ponte di Legno Toxicity Working Group. Meta-analyses were conducted to estimate the incidence of three types of hypersensitivity (allergy, allergic-like reaction and silent inactivation). Information on protocol level regarding PEGasparaginase dosing regimen, administration route and use of therapeutic drug monitoring was collected for risk analysis. ResultsNewly diagnosed patients with ALL (n = 5880), aged 1–24 years old, were enrolled in seven different upfront ALL protocols using PEGasparaginase as first-line treatment. The incidence of allergic reactions (sum of allergies and allergic-like reactions) [95% confidence interval] was 2% [1%; 3%] during induction and 8% [5%; 11%] during postinduction. Route of administration, number of doses, dosage and number of PEGasparaginase-free weeks did not significantly influence risk of hypersensitivity. Multivariate meta-regression analysis suggests that initiation of PEGasparaginase in postinduction and higher number of PEGasparaginase-free intervals increased the risk for allergic reactions. 9–16% and 23–29% of all hypersensitivities were allergic-like reactions and silent inactivation, respectively. ConclusionThe incidence of allergic reactions is lower in protocols using PEGasparaginase as first-line treatment compared with that reported for E.coli asparaginase or PEGasparaginase after E.coli asparaginase.Postinduction phase, a higher number of PEGasparaginase-free intervals, and initiation of PEGasparaginase in postinduction phase are risk factors for allergic reactions. These results are important for planning of PEGasparaginase administrations in future frontline therapy.

NGS-Based MRD Quantitation: An Alternative to qPCR Validated on a Large Consecutive Cohort of Children with ALL

Together with multicolor flow cytometry, quantitation of clonal immunoglobulin (IG) and T-cell receptor (TR) gene rearrangements represents the current standard for the detection of minimal / measurable residual disease (MRD) in treatment protocols for pediatric acute lymphoblastic leukemia (ALL) patients. Despite the adoption of next generation sequencing (NGS) in the routine identification of clonal IG/TR gene rearrangements as markers for MRD detection, real-time quantitative (q)PCR is still the standard for MRD quantitation in follow-up samples. So far, no large-scale direct comparison of qPCR- and NGS-based MRD quantitation has been performed.We compared qPCR- and NGS-MRD evaluation in a cohort of children with B-cell precursor (BCP) ALL treated on the AIEOP-BFM ALL 2009 protocol and assessed the feasibility and relevance of this method for the stratification at day 33 (EOI).In total, 459 patients were diagnosed with BCP-ALL from 2010 to 2018, and 437 of them were included in our study based on the availability of residual DNA material isolated from day 33 bone marrow aspirates and having at least one IG/TR MRD marker detectable by standard qPCR with protocol-required sensitivity of 10 -4. Sequencing libraries were prepared according to the EuroClonality-NGS group SOP (Brüggemann et al, Leukemia 2019) with the total DNA input normalized to the equivalent of 150,000 nucleated cells to reach MRD sensitivity of 10 -5 and sequenced on Illumina NovaSeq and MiSeq instruments. In total of 780 IG/TR markers evaluated by both NGS and qPCR. Sequencing data were analyzed using the ARResT/Interrogate (Bystry et at, Bioinformatics 2017) pipeline and a custom bioinformatic analysis process and the NGS-MRD results were normalized to the EuroClonality-NGS central in-tube quality/quantification control (cIT-QC; Knecht et al, Leukemia 2019).From the total 780 IG/TR MRD markers evaluated by both methods, 629 (80.6%) were concordant with 242 markers being MRD positive and 387 negative. From 82 markers that were only positive by qPCR and not by NGS, 76 were positive below the quantitative range (positive non-quantifiable). Specificity analysis was performed for each marker by searching for the junction sequence across the dataset of all patients' NGS results. Based on these results, 22 out of 82 markers positive only by qPCR were classified as potentially unspecific (false positive) and similarly 32 unspecific markers were identified among the 69 positive only by NGS. This was also supported by unspecific amplification of the polyclonal control in 27 out of these 32 corresponding qPCR systems, in some cases leading to qPCR negative classification determined by the EuroMRD guidelines.Overall stratification of patients based only on day 33 MRD by qPCR or NGS was concordant in 76% of patients by both methods, while in 19% of patients, NGS-MRD quantitation led to the assignment to a lower-risk group, mainly due to the elimination of false-positive results. Furthermore, analysis of all positive markers across all patients' NGS libraries showed, that one out of 10 markers (mainly in the IGK, TRG and TRD loci) used for qPCR-MRD stratification did not provide satisfactory specificity, although they fully met EuroMRD criteria during the optimization of qPCR patient-specific assays.Our results show that NGS-MRD is highly concordant with traditional qPCR-based strategy and has comparable sensitivity and clinical value in the setting of a BFM-based clinical protocol, while being less laborious and providing significantly more specific results and additional information on the IG/TR repertoire (Kotrova et al, Blood 2016). Our study also emphasizes the importance of selecting MRD markers of adequate specificity at diagnosis. Currently, this selection can be assisted by these broad sequencing data on IG/TR repertoire of large number of patients. Based on these results, we propose that frontline NGS-MRD evaluation developed by the EuroClonality-NGS working group can be used as an alternative to traditional qPCR-based MRD quantitation in future MRD-based treatment protocols.Supported by grants NU20-03-00284 and NU20-07-00322 from the Czech Health Research Council and 534120 from Charles University. All methods were established through collaboration within the EuroClonality-NGS and EuroMRD groups. Disclosuresvan der Velden: Agilent: Research Funding; Navigate: Other: Service Level Agreement; Janssen: Other: Service Level Agreement; EuroFlow: Other: Service Level Agreement, Patents & Royalties: for network, not personally; BD Biosciences: Other: Service Level Agreement. Brüggemann: Incyte: Other: Advisory Board; Janssen: Speakers Bureau; Amgen: Other: Advisory Board, Travel support, Research Funding, Speakers Bureau. Langerak: Erasmus MS, University Medical Center: Current Employment; F. Hoffmann-La Roche Ltd/Genentech, Inc.: Research Funding; Gilead: Research Funding; Janssen: Speakers Bureau.

A Meta-Analysis of Hypersensitivity to Pegylated Escherichia coli Asparaginase Used As First-Line Treatment in Contemporary Pediatric Acute Lymphoblastic Leukemia Protocols

PURPOSEAsparaginase is a key component of acute lymphoblastic leukemia (ALL) therapy. Hypersensitivity reactions challenge its use and occur frequently (30-75%) after native Escherichia. Coli (E.coli) asparaginase (Appel et al., 2008; Muller et al., 2001; Panosyan et al., 2004; Silverman et al., 2001). The international ALL Ponte di Legno Toxicity Work Group (PTWG) classifies hypersensitivity to asparaginase as (i) allergy in case of symptoms of allergy (always associated with undetectable asparaginase activity levels), (ii) allergic-like reactions in case of symptoms without inactivation, and (iii) silent inactivation (SI) with inactivation of asparaginase activity, but without hypersensitivity symptoms (Schmiegelow et al., 2016). Allergic-like reactions and SI can only be diagnosed with monitoring of asparaginase activity levels. A meta-analysis was performed based on data from the PTWG to estimate the incidence of hypersensitivity and risk factors for hypersensitivity to asparaginase in ALL protocols using pegylated E.coli asparaginase (PEGasparaginase) as first line of treatment.PATIENTS AND METHODSQuestionnaires were sent to all members of the PTWG. Information on protocol level regarding PEGasparaginase dose, dosing regimen (e.g. dosing frequency, total number of doses, PEGasparaginase-free intervals(s)), administration route, total induction and post-induction hypersensitivity rates per protocol and per risk group and use of therapeutic drug monitoring (TDM). To facilitate comparison between protocols with and without TDM, we defined allergic reactions as the sum of allergies and allergic-like reactions. Silent inactivation was analyzed separately.RESULTSA total of 5880 patients with newly diagnosed ALL, aged 1 to 24 years old, were enrolled in seven different upfront ALL protocols using PEGasparaginase as first-line treatment. The overall incidence of allergic reactions along with 95% confidence interval (CI) were 9% [6%; 13%], 2% [1%; 3%] and 8% [5%; 11%] in the overall protocol, induction and post-induction, respectively (Figure 1). Severity of allergic reactions were described, according to the CTCAE version 3.0 or 4.03, per protocol. 47% of the reactions were classified as grade 3/4.Univariate meta-regression analysis showed a positive association between the incidence of allergic reactions and number of PEGasparaginase-free intervals (P=0.005). High risk group stratification (P<0.001), post-induction treatment phase (P<0.001) and start of PEGasparaginase treatment in post-induction (P=0.006) were also associated with a higher incidence of allergic reactions. Route of administration (IV (8.9%, range 8.6-10.5%) versus IM (6.5%, range 5.5-14.8%)) did not significantly influence risk of hypersensitivity. Number of doses, duration of first PEGasparaginase-free interval and dosage did not significantly influence risk of hypersensitivity. Multivariate meta-regression analysis showed a positive association between the incidence of allergic reactions and the number of PEGasparaginase-free intervals (P=0.006) and start of PEGasparaginase in the post-induction treatment phase (P=0.02).Two out of seven study groups reported an incidence of allergic reactions of 1.6-2.0%, which was 9-16% of all hypersensitivity. Three out of seven study groups reported an incidence of SI of 3.7-4.1%, which was 23-29% of all hypersensitivity reactions.All protocols prescribed a switch to Erwinia asparaginase in case of clinical hypersensitivity and/or SI. 308 out of 348 (89%) of the patients with hypersensitivity to PEGasparaginase received Erwinia asparaginase. 19 out of these 308 (6%) exposed patients had an allergic reaction to Erwinia asparaginase, of which 7 out of 19 (37%) were grade 3/4.CONCLUSIONThe incidence of allergic reactions is lower in protocols using PEGasparaginase as first-line treatment compared to that reported for native E.coli asparaginase or PEGasparaginase after native E.coli asparaginase. Post-induction phase, a higher number of PEGasparaginase-free intervals, and initiation of PEGasparaginase in post-induction phase are risk factors for allergic reactions. These results are important for planning of PEGasparaginase administrations in future frontline therapy. [Display omitted] DisclosuresAlbertsen: Erytech: Honoraria, Speakers Bureau; Servier: Speakers Bureau; BKA: Other: Sponsor of the investigator-initiated trial NOR-GRASPALL2016.

Blastic Plasmacytoid Dendritic Cell Neoplasm: A Rare Case Report with Literature Review

AbstractBlastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematopoietic neoplasm for which there are no effective therapies. We present a 70-year-old male patient with multiple reddish painless, nonpruritic, and nonpedunculated nodules over the trunk, forearm, and thighs for a duration of 3 months. The nodules measured 0.5 to 2 cm in diameter. The peripheral smear findings were within normal limits. Excision biopsy was performed. Histomorphology and immunohistochemistry (CD123, CD 56, CD4, HLA-DR, CD43, and CD68) confirmed the diagnosis of BPDCN. Findings of marrow aspiration, biopsy and imaging studies were within normal limits. Patient demonstrated a good response with complete disappearance of all nodules by initial 2 weeks of therapy with a modified Berlin–Frankfurt–Munster (BFM) acute lymphoblastic leukemia (ALL) protocol and has completed 8 doses (LSAP [lincosamides, streptogramins A and pleuromutilins chemotherapy], 5,000 units/m2). The patient tolerated protocol extremely well.

ALL-414: Obesity is Not Associated with an Increased Risk of Venous Thromboembolism in AYA Patients with Acute Lymphoblastic Leukemia

<h3>Context:</h3> Acute venous thromboembolisms (VTEs) are a serious complication during intensive chemotherapy. Risk factors associated with VTEs, specifically in the adolescent and young adult (AYA) population being treated per pediatric protocols for acute lymphoblastic leukemia (ALL), are poorly described in the literature. <h3>Objective:</h3> To determine whether baseline demographic data, specifically obesity and asparaginase dose, are risk factors for VTEs in AYA patients. <h3>Design, Setting, and Patients:</h3> Patients were studied retrospectively from 2009 to 2020. Tertiary referral center. A cohort of 66 adolescent and young adult patients, ages 15 to 26 years, with previously untreated ALL was identified and divided into groups based on the presence or absence (controls) of VTEs during ALL treatment. All patients were treated with Berlin-Frankfurt-Münster (BFM)-based pediatric chemotherapy protocols. <h3>Main Outcome Measures:</h3> We hypothesized that AYA patients being treated per BFM-based pediatric protocols experience similar or higher rates of VTEs as the pediatric ALL population and that the risk of developing a VTE is increased in patients as body mass index (BMI) and asparaginase dose increases. <h3>Results:</h3> Fourteen patients (21%) experienced 17 VTEs. The majority of VTEs occurred during induction chemotherapy (47%), after asparaginase administration (88%), in the upper extremities (59%), were associated with a CVC (53%), and were treated with anticoagulation (94%). BMI or asparaginase dose during induction chemotherapy were not predictive of VTE risk (p=0.9). There were no statistical differences in age at diagnosis, sex distribution, race/ethnicity distribution, other treatment-related morbidities, relapse-free survival (79% <i>vs</i> 81% at 5 years), and overall survival (93% <i>vs</i> 81% at 5 years) in patients who experienced a VTE compared to controls. <h3>Conclusions:</h3> AYA patients with ALL experienced similar rates of VTE as their pediatric counterparts. Unlike adults with cancer, increased BMI and asparaginase dose were not associated with an elevated risk of VTE. Given the limited study size and retrospective nature of this study, future prospective studies are indicated before this information is appropriate for clinical application.

Clinical features and prognosis of children with acute leukemias of ambiguous lineage under different diagnostic criteria.

To study the clinical features and prognosis of children with acute leukemias of ambiguous lineage (ALAL) under different diagnostic criteria. A retrospective analysis was performed on the medical data of 39 children with ALAL who were diagnosed and treated from December 2015 to December 2019. Among the 39 children, 34 received treatment. According to the diagnostic criteria for ALAL by World Health Organization and European Group for the Immunological Characterization of Leukemias, the 39 children were divided into two groups: ALAL group (n=28) and myeloid expression group (n=11). The clinical features, treatment, and prognosis were compared between the two groups. The 34 children receiving treatment had a 3-year event-free survival (EFS) rate of 75%±9% and an overall survival rate of 88%±6%. The children treated with acute myeloid leukemia (AML) protocol had a 3-year EFS rate of 33%±27%, those treated with acute lymphoblastic leukemia (ALL) protocol had a 3-year EFS rate of 78%±10%, and those who had no remission after induction with AML protocol and then received ALL protocol had a 3-year EFS rate of 100%±0% (P<0.05). The children with negative minimal residual disease (MRD) after induction therapy had a significantly higher 3-year EFS rate than those with positive MRD (96%±4% vs 38%±28%, P<0.05). Positive ETV6-RUNX1 was observed in the myeloid expression group, and positive BCR-ABL1, positive MLL-r, and hyperleukocytosis (white blood cell count ≥50×109/L) were observed in the ALAL group. There was no significant difference in the 3-year EFS rate between the myeloid expression and ALAL groups (100%±0% vs 66%±11%, P>0.05). ALL protocol has a better clinical effect than AML protocol in children with ALAL, and positive MRD after induction therapy suggests poor prognosis. Hyperleukocytosis and adverse genetic changes are not observed in children with myeloid expression, and such children tend to have a good prognosis, suggesting that we should be cautious to take it as ALAL in diagnosis and treatment.

BTK inhibition sensitizes acute lymphoblastic leukemia to asparaginase by suppressing the amino acid response pathway

AbstractAsparaginase (ASNase) therapy has been a mainstay of acute lymphoblastic leukemia (ALL) protocols for decades and shows promise in the treatment of a variety of other cancers. To improve the efficacy of ASNase treatment, we used a CRISPR/Cas9-based screen to identify actionable signaling intermediates that improve the response to ASNase. Both genetic inactivation of Bruton's tyrosine kinase (BTK) and pharmacological inhibition by the BTK inhibitor ibrutinib strongly synergize with ASNase by inhibiting the amino acid response pathway, a mechanism involving c-Myc–mediated suppression of GCN2 activity. This synthetic lethal interaction was observed in 90% of patient-derived xenografts, regardless of the genomic subtype. Moreover, ibrutinib substantially improved ASNase treatment response in a murine PDX model. Hence, ibrutinib may be used to enhance the clinical efficacy of ASNase in ALL. This trial was registered at www.clinicaltrials.gov as # NCT02884453.

Individualized 6-Mercaptopurine Increments in Consolidation Treatment of Childhood Acute Lymphoblastic Leukemia: A NOPHO ALL2008 Randomized Controlled Trial

Introduction: In contemporary treatment protocols for childhood acute lymphoblastic leukemia (ALL), most chemotherapeutic agents are prescribed as a fixed dose per m2. 6-mercaptopurine (6-MP) is frequently used during consolidation therapy and mediates its effect through incorporation into DNA as thioguanine nucleotides (DNA-TGN), higher levels of which are associated with a decreased risk of relapse. In this randomized controlled trial on children with non-high risk ALL, we tested the hypothesis that individualized, toxicity-titrated 6-mercaptopurine (6-MP) increments during consolidation therapy with high-dose methotrexate were superior to the standard fixed-dose 6-MP regimen. The primary end point was minimal residual disease (MRD) positivity at end of consolidation, and the secondary end point was event-free survival. The trial was registered at clinicaltrials.gov (NCT00816049).Methods: Between January 2009 and March 2016 we randomized 392 children aged 1-17 years to experimental and 396 to standard therapy. Patients allocated to standard therapy received oral 6-MP (25 mg/m2/day) from day 30 to 85, while the experimental arm received stepwise increments with 25 mg/m2/day beginning on days 50 and/or 71 unless they had experienced dose-limiting myelosuppression (neutrophil count ≤ 0.5 x 109/L or thrombocyte count < 50 x 109/L) following the preceding dose of high-dose methotrexate (days 36 and 57). MRD was measured using PCR for T-cell ALL and flow cytometry for B-cell precursor ALL (or PCR, if flow was not technically possible). MRD positivity was defined as any detectable marker with PCR and more than 10 leukemic events with flow cytometry. As a measure of treatment intensity and physician and patient compliance, we analyzed concentrations of DNA-TGN and methylated 6-MP metabolites (MeMP) in blood samples collected throughout consolidation therapy. Analyses were carried out on an intention-to-treat basis.Results: In the experimental arm, 166 patients (42%) received one dose increment, and 62 (16%) received two. Of 387 patients in the experimental arm, 57 (15%) 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 cumulative length of 6-mercaptopurine treatment interruptions was 7 days (IQR 2-12) in the experimental arm versus 4 (IQR 0-10) in the control arm (P=0.002), but duration of treatment interruption was not associated with risk of relapse (P=0.99). There were seven treatment-related deaths in the experimental arm versus three in the control arm (P=0.22), and none of the deaths in the experimental arm were related to 6-MP increments. At the final risk stratification on day 79, one patient in the experimental arm and seven in the control arm (P=0.07) had MRD values ≥0.1%, which is the cutoff for stratification to high risk treatment with stem cell transplantation. The mean DNA-TGN levels at end of consolidation in patients given zero, one, or two dose increments were 162 fmol/µg DNA (95% CI 144-179), 237 (194-280), and 293 (156-430) respectively, P<0.0001. The corresponding MeMP values were 1 879 nmol/mmol Hb (1 397-2 360), 5 930 (4 368-7 492), and 12 173 (7 625-16 721), P<0.0001.Conclusion: Despite 6-MP dose intensifications in 58% of patients in the experimental arm and a strong association between dose increments and DNA-TGN levels, as well as a non-significant improvement in MRD at end of consolidation, we found no survival benefit from individualized 6-MP increments compared to standard therapy. DisclosuresNo relevant conflicts of interest to declare.

Structural and biochemical properties of L‐asparaginase

l-Asparaginase (a hydrolase converting l-asparagine to l-aspartic acid) was the first enzyme to be used in clinical practice as an anticancer agent after its approval in 1978 as a component of a treatment protocol for childhood acute lymphoblastic leukemia. Structural and biochemical properties of l-asparaginases have been extensively investigated during the last half-century, providing an accurate structural description of the enzyme isolated from a variety of sources, as well as clarifying the mechanism of its activity. This review provides a critical assessment of the current state of knowledge of primarily structural, but also selected biochemical properties of 'bacterial-type' l-asparaginases from different organisms. The most extensively studied members of this enzyme family are l-asparaginases highly homologous to one of the two enzymes from Escherichiacoli (usually referred to as EcAI and EcAII). Members of this enzyme family, although often called bacterial-type l-asparaginases, have been also identified in such divergent organisms as archaea or eukarya. Over 100 structural models of l-asparaginases have been deposited in the Protein Data Bank during the last 30years. One of the prime achievements of structure-centered approaches was the elucidation of the details of the mechanism of enzymatic action of this unique hydrolase that utilizes a side chain of threonine as the primary nucleophile. The molecular basis of other important properties of these enzymes, such as their substrate specificity, is still being evaluated. Results of structural and mechanistic studies of l-asparaginases are being utilized in efforts to improve the clinical properties of this important anticancer drug.