Coli Asparaginase Research Articles

Recombinant Erwinia asparaginase (JZP458) in ALL/LBL: complete follow-up of the Children’s Oncology Group AALL1931 study

AbstractThe Children’s Oncology Group study AALL1931 investigated the efficacy and safety of recombinant Erwinia asparaginase (JZP458) in patients with acute lymphoblastic leukemia/lymphoblastic lymphoma and hypersensitivity reactions/silent inactivation to Escherichia coli–derived asparaginases. Each pegylated E coli asparaginase dose remaining in a patient’s treatment plan was replaced by intramuscular (IM) or IV JZP458 (6 doses) administered Monday/Wednesday/Friday (MWF). Three IM cohorts (1a [25 mg/m2 MWF], n = 33; 1b [37.5 mg/m2 MWF], n = 83; 1c [25/25/50 mg/m2 MWF], n = 51) and 1 IV cohort (25/25/50 mg/m2 MWF, n = 62) were evaluated. The proportion of patients maintaining nadir serum asparaginase activity (NSAA) levels of ≥0.1 IU/mL at the last 72 (primary end point) and 48 hours during course 1 was 90% (95% confidence interval [CI], 81-98) and 96% (95% CI, 90-100) in IM cohort 1c, respectively, and 40% (95% CI, 26-54) and 90% (95% CI, 82-98) in the IV cohort. Population pharmacokinetic modeling results were comparable with observed data, predicting the vast majority of patients would maintain therapeutic NSAA levels when JZP458 is administered IM or IV 25 mg/m2 every 48 hours, or IM 25/25/50 mg/m2 MWF, or with mixed administration of IM and IV (IV/IV/IM 25/25/50 mg/m2 MWF). Drug discontinuation occurred in 23% and 56% of patients in the IM and IV cohorts, respectively; 13% and 33% because of treatment-related adverse events (mainly allergic reactions and pancreatitis). JZP458 achieves therapeutic NSAA levels via multiple IM and IV dosing schedules based on a combination of observed and modeled data with a safety profile consistent with other asparaginases. This trial was registered at www.ClinicalTrials.gov as #NCT04145531.

Long-Acting E. coli-Derived Asparaginase Potentiates the Anti-Leukemic Effect of BCL2 Inhibition, but Not MCL1 Inhibition, in Preclinical Models of Acute Myeloid Leukemia

Background: Asparaginases are enzymes that deplete circulating asparagine and glutamine from plasma and can therefore be used therapeutically for cancers that are sensitive to amino acid depletion. Commercially available asparaginases are isolated fromeither E. coli or Erwinia chrysanthemi (also called crisantaspase), the latter having a higher glutaminase activity. Our previous studies have shown that pegcrisantaspase (PegC), a long-acting pegylated crisantaspase, synergizes with the BCL2 inhibitor, Venetoclax (Ven), to kill several AML cell lines and patient-derived primary AML cells with complex karyotype in vitro and in vivo in a xenograft mouse model. Whether long-acting E. coli-derived asparaginases will have similar anti-AML activity as a single agent or in combination with BCL-2 inhibition, and the potential of asparaginases to synergize with inhibitors of MCL1, a key resistance factor of BCL2 inhibition, has yet to be determined. Methods: Using a panel of 4 human AML cell lines (MOLM14, MV411, MonoMac6, HL60) as well as primary AML patient samples, weestablished the anti-leukemic activity of the BCL2 inhibitor S55746 and the MCL1 inhibitor S63845 alone and in combination with the long-acting E. coli asparaginase, calaspargase pegol-mknl (CalPegA). To determine the ability of S55746 or S63845 with or without CalPegA to inhibit mRNA translation, an established mechanism of Ven-PegC anti-leukemic activity, we measured the dissociation of the translation initiation factor eIF4E from 4EBP1, a negative regulator of cap-dependent mRNA translation, which then allows the formation of translation initiation complexes. The in vivo anti-leukemic efficacy of S55746 and S63845 alone and in combination with CalPegA was tested using an orthotopic AML xenograft mouse model with luciferase-expressing MV411 cells. Results: We found that CalPegA treatment resulted in a dose-dependent inhibition of AML cell proliferation, with IC 50 values ranging from 0.78 to 2.8 IU/mL. Single agent S55746 and S63845 treatment inhibited AML cell proliferation with IC 50 values ranging from 0.01 to 6.7 µM and 0.0001 to 0.08 µM, respectively. In 3 of the human AML cell lines (MOLM-14, MV4-11, and MonoMac6), the addition of a small dose (IC 20) of CalPegA potentiated the anti-leukemic effect of S55746, reducing the IC 50 by approximately 1- 4-fold, and by 10-fold in HL60 cells (Figure 1). This potentiation was also observed in 3 out of 4 primary AML patient samples tested, with the IC 50 of S55746 reduced by 4.5, 18, and 156-fold by the addition of CalPegA. The activity of S63845 was not substantially impacted by the addition of CalPegA in either AML cell lines (Figure 1) or primary samples. Immunoprecipitation of 4EBP1 revealed that treatment with a combination of either S63845 or S55746 with CalPegA increased the binding of eIF4E to 4EBP1 compared to single agent treatments, suggesting an inhibition of translational complex formation. In a MV411 tumor-bearing model, treatment withS55746-CalPegA combination reduced tumor burden over time significantly more than either single agent. S63845 treatment was highly effective at inhibiting leukemia growth over time and was not improved by the addition of CalPegA, as tumor burden in the S63845 and S63845 + CalPegA-treated groups was not significantly different over the course of the study (Figure 2). Conclusions: We report that the E. coli asparaginase, CalPegA, enhances the anti-leukemic effect of the BCL2 inhibitor, S55746, but does not impact the activity of the MCL1 inhibitor, S63845, in AML cell lines, patient derived primary AML samples, and in an AML xenograft mouse model. Ongoing studies are further investigating the anti-leukemic mechanism of S55476/S63845 + CalPegA and examining the efficacy and pharmacodynamic/pharmacokinetic effects of these agents in a patient derived xenograft model of AML.

Protein re-surfacing of E. coli L-Asparaginase to evade pre-existing anti-drug antibodies and hypersensitivity responses.

The optimal use of many biotherapeutics is restricted by Anti-drug antibodies (ADAs) and hypersensitivity responses which can affect potency and ability to administer a treatment. Here we demonstrate that Re-surfacing can be utilized as a generalizable approach to engineer proteins with extensive surface residue modifications in order to avoid binding by pre-existing ADAs. This technique was applied to E. coli Asparaginase (ASN) to produce functional mutants with up to 58 substitutions resulting in direct modification of 35% of surface residues. Re-surfaced ASNs exhibited significantly reduced binding to murine, rabbit and human polyclonal ADAs, with a negative correlation observed between binding and mutational distance from the native protein. Reductions in ADA binding correlated with diminished hypersensitivity responses in an in vivo mouse model. By using computational design approaches to traverse extended distances in mutational space while maintaining function, protein Re-surfacing may provide a means to generate novel or second line therapies for life-saving drugs with limited therapeutic alternatives.

Vitamin A and association with asparaginase-associated pancreatitis in children with acute lymphocytic leukemia.

10021 Background: Asparaginase is a key component of treatment of acute lymphoblastic leukemia (ALL), which is the most common cancer in the pediatric population. However, asparaginase is associated with many toxicities, including pancreatitis, which is observed in up to 10% of patients and can lead to severe sequelae. Methods: We performed analysis of (1) transcriptomic data from (a) asparaginase-treated leukemic cells, and (b) the pancreas of mice that were induced with a chemical form of pancreatitis; (2) the US FDA Adverse Reporting System (FAERS) and electronic health records (TriNetX); (3) global plasma metabolomic screen and dietary intake evaluation from ALL patients; and (4) experimental animal studies to identify factors that impact asparaginase-associated pancreatitis (AAP). Results: Connectivity map analysis showed that asparaginase-induced gene signatures are potentially reversed by the retinoids (vitamin A and its natural and synthetic analogs). Analysis of TriNetX and FAERES demonstrated a 2-fold reduction in AAP risk with concomitant exposure to vitamin A. Further, we performed a case-control metabolomic study of 50 subjects with ALL enrolled in the Dana-Farber Cancer Institute DFCI ALL clinical trial protocols 05-001 (NCT00400946) and 11-001 (NCT01574274). All subjects were given a single dose of pegylated E. Coli asparaginase during induction therapy. Twenty-four subjects developed pancreatitis within 9 months from the start of induction therapy and were considered cases. The median time to develop pancreatitis among cases was 3.68 months (interquartile range: 3.58 months). Twenty-six control subjects were identified among patients who did not develop pancreatitis within the same evaluation period. The controls were matched for age, sex, and initial ALL risk. The screening revealed that the plasma levels of carotene diol isomers, from the start of induction to its end, were reduced by about 60% in the cases compared to the controls. A detailed 30-day dietary recall showed that the cases had received less dietary vitamin A than the controls during induction therapy. Notably, the median value for the composite intake of vitamin A constituents, termed the RAE (retinol activity equivalents) was 656.92 mcg per day among the controls, but was 34.6% lower among in the cases (median of 429.40 mcg per day, which is just above the recommended dietary allowance level of 400 mcg per day for the 4–8 year-old age group). In mice, asparaginase administration as a single agent was sufficient to reduce circulating and hepatic retinol levels. Conclusions: Based on these data, we propose that circulating retinoids maintain pancreatic health, that asparaginase reduces circulating retinoids, and AAP is more likely to develop with reduced dietary vitamin A intake. The systems approach provides the impetus to examine the role of dietary vitamin A supplementation for preventing or treating AAP.

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.

Effectiveness and Security of a Modified CALGB10403 in Adolescents and Young Adults with Acute Lymphoblastic Leukemia in Low-and-Middle-Income Countries: A Multicentric Experience in Central America

▪Background:Mexico and Central America have a high incidence of acute lymphoblastic leukemia (ALL) in adolescents and young adults (AYA). Chemotherapy with Hyper-CVAD has been widely used with poor outcomes, with a 3-year overall survival (OS) of 25.7% in this group of age.In low-and middle-income countries (LMIC), limitations in supportive care such as low access to neutrophil stimulant agents, antifungal prophylaxis and limited intensive care access, may increase treatment-related mortality. On the other hand, reports suggest that specific high-risk subgroups may be more frequent in Hispanic patients from Mexico and Central America.We hypothesize that the use of a less-myeloablative regimen, based on L-asparaginase could overcome the bad outcomes previously reported.MethodsWe modified the original CALGB 10403 based on local drug-access. We include patients with newly diagnosed Philadelphia-negative B- or T-cell ALL between 14-49 years from 4 centers in Mexico and one in Guatemala.We modified the regimen as following: replaced pegaspargase by E. Coli asparaginase, thioguanine by 6-mercapatopurine and incorporate rituximab 375mg/m2 for 6 doses in CD20 positive patients. After the first interim analysis (October 2019), we replaced the prednisone by dexamethasone during induction. Minimal residual disease (MRD) was assessed by flow cytometry after induction and after first consolidation. We considered high-risk karyotype if MLL-rearrangements, complex or hypodiploid and high-white blood cell count (WBC) if >30 x10 3/mcL for B-ALL or >100 x10 3/mcL for T-ALL.The main objective was to evaluate OS and as secondary objectives to evaluate complete response (CR) rate, relapse-free survival (RFS) and to assess the safety of this regimen.ResultsFrom January 2017 to December 2020, 95 patients have been enrolled with a median age of 23 years (range 14-49). One third (34.6%) had overweight and 11.7% were obese.The majority (92.6%) had a B-cell ALL and a normal karyotype (81.2%). The median WBC was 18.4 x10 3/mcL (0.2-427.7) and 40.9% had a high-WBC.During induction, adverse events (AE) included grade 3/4 elevated bilirubin (21.1%), transaminases (14.7%), hyperglycemia (14.7%), hypofibrinogenemia (44.2%), thrombosis (10.5%), hypersensitivity (2.2%) and pancreatitis (2.1%). During consolidation, AE included grade 3/4 hepatic toxicity (18.9%), hypertriglyceridemia (14.8%), thrombosis (5.3%) and pancreatitis (2.1%).Neutropenic fever occurred in 55.8% during induction (grade 4: 31.5%), and in 32.9% during consolidation (grade 4/5: 5.3%).A dose adjustment due to AE was required in 22.1% during induction and in 23.2% during consolidation. The induction related-mortality (IRM) rate was 7.4%The CR rate was 87.8%. After-induction, MRD was <0.01% in 39.1%, 0.01-0.1% in 39.1% and > 0.1% in 24.6%. Post-consolidation MRD was only measured in 43 patients and was <0.01% in 37.2%. During follow-up, 26.7% relapsed: 62.5% bone marrow (BM) relapses, 25.0% central nervous system (CNS) relapses and 12.5% CNS + BM relapses. Eight patients (8.4%) received an allogeneic-stem cell transplant (HSCT) as consolidation.The 2-year OS was 72.1%. The post-induction MRD <0.1% was associated with a better OS (figure 1A) (HR: 0.17 (95%CI: 0.06-0.55), p=0.003) and a high-WBC with an inferior OS (figure 1B) (HR: 4.13 (95%CI: 1.68-10.14), p=0.002).The 2-year RFS was 65.2%. The post-induction MRD <0.1% was associate with a better RFS (figure 1C) (HR: 0.19 (95%CI: 0.07-0.50), p=0.001) and a high-WBC and overweight / obesity with an inferior RFS (HR: 4.08 (95%CI: 1.71-9.73), p=0.001 and 2.50 (95%CI: 1.06-5.86), p=0.036 respectively) (figure 1D).Conclusions:The adoption of modified CALGB10403 regimen in Central America based on local resources is feasible. It is associated with a significant improvement in the OS and decrease in IRM when compared with previous reports. Despite a very high-rate of hepatic and metabolic toxicities, these were manageable. As reported by other groups, MRD, high-WBC and overweight/obesity are associated with poor outcomes.Despite being encouraging results, a significant number of patients persist with positive MRD and the main cause of dead is disease progression. Access to cellular therapies, and BiTes is cost restricted in LMIC. Hence, we should generate strategies to intensify treatment in MRD positive patients and expand transplant access to overcome outcomes. [Display omitted] DisclosuresRangel-Patiño: Bristol: Consultancy; Abbvie: Speakers Bureau. Ceniceros: Amgen: Speakers Bureau. Espinosa: Amgen: Speakers Bureau; Janssen: Consultancy; Pfizer: Consultancy. Amador: Abbvie: Consultancy, Speakers Bureau; Bristol: Consultancy. Cabrero Garcia: Takeda: Speakers Bureau; Abbvie: Speakers Bureau; Roche: Speakers Bureau; Janssen: Speakers Bureau; Astellas: Consultancy; BD: Speakers Bureau. Inclan-Alarcon: Janssen: Speakers Bureau; Boehringer: Speakers Bureau. Neme Yunes: Janssen: Consultancy, Speakers Bureau; Bristol: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Bristol: Consultancy, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Abbvie: Speakers Bureau. Meillon-García: Amgen: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Roche: Speakers Bureau; Astellas: Consultancy. Apodaca: Sanofi: Consultancy; Asofarma: Consultancy, Speakers Bureau; Abbvie: Speakers Bureau. Demichelis: Bristol/Celgene: Consultancy, Speakers Bureau; Astellas: Consultancy; Gilead: Consultancy; ASH: Research Funding; Abbvie: Consultancy, Speakers Bureau; AMGEN: Consultancy, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau; Jazz: Consultancy.

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.

Metagenomic discovery and functional validation of L-asparaginases with anti-leukemic effect from the Caspian Sea.

SummaryBy screening 27,000 publicly available prokaryotic genomes, we recovered ca. 6300 type I and ca. 5200 type II putative L-asparaginase highlighting the vast potential of prokaryotes. Caspian water with similar salt composition to the human serum was targeted for in silico L-asparaginase screening. We screened ca. three million predicted genes of its assembled metagenomes that resulted in annotation of 87 putative L-asparaginase genes. The L-asparagine hydrolysis was experimentally confirmed by synthesizing and cloning three selected genes in E. coli. Catalytic parameters of the purified enzymes were determined to be among the most desirable reported values. Two recombinant enzymes represented remarkable anti-proliferative activity (IC50 <1IU/ml) against leukemia cell line Jurkat while no cytotoxic effect on human erythrocytes or human umbilical vein endothelial cells was detected. Similar salinity and ionic concentration of the Caspian water to the human serum highlights the potential of secretory L-asparaginases recovered from these metagenomes as potential treatment agents.

Evaluation of hypersensitivity reactions to cancer chemotherapeutic agents in pediatric patients

BackgroundHypersensitivity reactions (HSRs) to chemotherapeutic agents have been increasingly documented. ObjectiveThe aim of this study was to investigate HSRs due to chemotherapeutics agents in childhood. MethodsFrom January 2007 to June 2019, the patients who were treated for neoplastic diseases in our hospital were evaluated. Patients who developed a HSR to a chemotherapeutic agent were included. ResultsFifty-seven patients with 65 reactions (60% anaphylaxis) were evaluated. Escherichia coli asparaginase was responsible for 38 (58.5%) of these 65 reactions. The other agents were polyethylene glycol (PEG)–asparaginase (n = 11), etoposide (n = 7), methotrexate (n = 4), carboplatin (n = 4), and procarbazine (n = 1). Of the 38 patients who had a reaction to E coli–asparaginase, 33 patients received alternative treatment (PEG-asparaginase or Erwinia asparaginase), 3 patients continued with desensitization, and 2 patients underwent bone marrow transplantation. Five patients who had an initial reaction to PEG-asparaginase continued their treatment with Erwinia asparaginase or E coli asparaginase uneventfully. Of 7 patients who had a reaction to etoposide (4 had anaphylaxis), 3 patients continued with desensitization, and 2 patients used the drug with premedication and prolonged infusion. Two patients had anaphylaxis with methotrexate. Treatment was continued with desensitization in 1 patient and methotrexate treatment was discontinued in the other patient. Of the 4 patients with carboplatin hypersensitivity, 2 had anaphylaxis. Desensitization was performed in 2 patients. One patient had procarbazine HSR, drug was given with premedication. ConclusionAmong all chemotherapeutic agents reviewed in our study that caused HSRs, asparaginase was the most common culprit agent in children. Most of reactions are immediate type. Many of the patients can take their treatment by drug replacement or desensitization.

High-Dose Cytarabine Is Indispensable for the Survival of Children with Myeloid Leukemia of Down Syndrome Despite Negative Minimal Residual Disease Post-Induction

Introduction. Myeloid leukemia in children with Down syndrome (ML-DS) is a unique subtype of acute myeloid leukemia, distinguished by an earlier age of onset (under 4 years of age); somatic mutations of GATA1; hypersensitivity of leukemic blasts to cytarabine and other chemotherapeutic agents; lack of CNS involvement; and superior event-free survival (EFS, 85-90% at 5 years). Due to these excellent outcomes, successive protocols by the Children's Oncology Group (COG) have aimed for a reduction of treatment intensity but continue to include a course containing high-dose cytarabine (HD-AraC) for all patients, which is associated with the bulk of infectious toxicity. COG AAML1531 is the first study to evaluate differential treatment for ML-DS patients based on risk-stratification. We report the outcomes for patients with Standard Risk (SR) ML-DS enrolled on AAML1531, who were treated without inclusion of HD-AraC (https://clinicaltrials.gov/ct2/show/NCT02521493?term=AAML1531&amp;rank=1). Methods. Patients older than 90 days and younger than 4 years of age with ML-DS were eligible, including those presenting with myelodysplastic syndrome (&amp;lt; 20% blasts in the bone marrow) and trisomy 21 mosaicism. Pathological and cytogenetic data were reviewed centrally. All patients received the same first course of induction therapy (cytarabine 200 mg/m2/24h IV as continuous infusion, day 1-4; daunorubicin 20 mg/m2IV, day 1-4; thioguanine 50 mg/m2/dose PO twice daily, day 1-4; and a single dose of age-based intrathecal cytarabine on day 1). After this first course, measureable residual disease (MRD) in the bone marrow by multi-dimensional flow cytometry in a reference laboratory was used for risk stratification. Patients with negative MRD (&amp;lt;0.05%) were assigned to Standard Risk (SR) therapy, which was modeled after the AAML0431 predecessor study, but with further reduction of treatment by omission of the course containing HD-AraC/E. coli asparaginase (Induction II of AAML0431). Courses #2 and #3 of SR therapy were identical to the first course except that no further intrathecal chemotherapy was administered. Courses #4 and #5 (cytarabine 100 mg/m2/24h IV as continuous infusion day 1-7; etoposide 125 mg/m2 IV, day 1-3) were identical to the corresponding courses of AAML0431. For patients younger than 36 months, chemotherapy doses were calculated based on weight. Use of dexrazoxane during anthracycline-containing courses was at the discretion of the treating center but was captured by the data collection of the study. Patients with positive MRD (&amp;gt;0.05%) after the first course were assigned to the High Risk (HR) Arm and received intensified therapy (equivalent to that used for non-DS AML). Accrual to the HR arm is ongoing. Results. Interim analysis of SR therapy was performed after 50% of expected EFS events had occurred as of June 30, 2018. The observed EFS was 89.3 +/- 6.1% at 2 years from study entry and significantly lower than expected for comparable MRD-negative patients whose treatment in predecessor study AAML0431 included a course of HD-AraC/E. coliasparaginase (p=0.0002). OS at 2 years was 88.7 +/- 6.8%. Among a total of 114 SR ML-DS patients, 11 developed a relapse, all within the first year from study entry (range 136-327 days). OS at 1 year from relapse was 9.1 +/- 17.3%. Based on the results of interim analysis, the SR arm of AAML1531 was closed to accrual due to lack of efficacy. Cytogenetic analysis showed that complex karyotypes (defined as &amp;gt;3 independent abnormalities including &amp;gt;1 structural one) were significantly more frequent in SR patients who relapsed (40%, n=10) compared to SR patients who did not (9%; n=100; p=0.017). The most common abnormalities were trisomies (61% of cases) of chromosomes 3 and 8, and a gain of a fourth copy of chromosome 21. Monosomy 7 was present in 20% of relapsed vs. 5% of patients without a relapse (p=0.122). Conclusions. MRD measured by multi-dimensional flow cytometry is insufficient to identify a subset of ML-DS patients for whom HD-AraC/E.coliasparaginase can be eliminated from treatment. Cytogenetic profiling may aid in further refining risk-based subsets of ML-DS patients. Additional approaches to risk stratification of ML-DS should be pursued, which take into account the emerging genetic events that co-operate with mutant GATA1 in the development of ML-DS. At this time, HD-AraC/E.coli asparaginase should be included in the treatment of ML-DS, regardless of MRD. Disclosures Druley: Washington University: Employment; ArcherDX Inc.: Employment, Equity Ownership. Loken:Hematologics, Inc: Employment, Equity Ownership. Eidenschink Brodersen:Hematologics, Inc: Employment.

Pediatric-Inspired Regimens Are Associated with Better Outcomes When Compared with Hypercvad in Hispanic Adolescents and Young Adults with Acute Lymphoblastic Leukemia

Background Acute lymphoblastic leukemia (ALL) is frequent in Mexico, representing 51% of acute leukemia in adults. Hispanic ethnicity is associated with high-risk features and poor outcomes. We previously reported a multicenter experience in Mexico, where the majority of our ALL-patients (67%) were adolescents and young adults (AYA), mostly treated with HyperCVAD and with poor outcomes: 3-year overall survival (OS) of 25.7%. Many groups have demonstrated better outcomes with pediatric-inspired regimens (PIR) in the AYA-group, with long term OS &gt; 60%. In 2016-2017 we changed the standard of care from HyperCVAD to PIR in two of the centers from the previously mentioned study. Methods We included AYA-patients with the diagnosis of Philadelphia-negative ALL treated with PIR (ALL-BFM 90 or CALGB 10403) between March 2016 and June 2019 in two centers in Mexico City. Both regimens were modified from the original: we used E. Coli asparaginase instead of pegaspargase and mercaptopurine instead of thioguanine. We compared these patients with our common historic database of patients with the same characteristics diagnosed between February 2009 and June 2015, treated with HyperCVAD. Hyperleukocytosis was defined as a white blood cell count &gt; 30 x103/mcL for B-cell ALL and &gt; 100 x103/mcL for T-cell ALL. Patients with t(v;11q23), hypodyploid or complex karyotype were considered high-risk. Baseline characteristics of both groups were compared with Chi-square or Mann-Whitney U test. We estimate OS by Kaplan-Meier method and compared groups by log-rank test. Multivariate Cox proportional hazards regression was used to evaluate independent prognostic factors associated with OS. Results We compared 73 patients treated with PIR with a control group of 137 patients treated with HyperCVAD. The patients treated with PIR received either ALL-BFM 90 (N=46) or CALGB 10403(N=27). The median follow-up was 49.8, 23.3 and 12.7 months for HyperCVAD, ALL-BFM 90 and CALGB 10403 respectively. Patients treated with PIR were slightly older than those in the control group (median 24 vs. 20 years, p=0.005) and presented with high-risk karyotype more frequently (31.9% vs. 12.2%, p=0.042). Most of the patients were B-cell ALL (91.8% for PIR and 95.6% for HyperCVAD; p=0.349). Comparing PIR vs. HyperCVAD, there were no differences in the proportion of patients with hyperleukocytosis (33.3% vs. 25.0%, p=0.128) or obesity (24.7% vs. 16.4%, p=0.192). The induction related mortality was 5.7% for the entire group with a trend that favors PIR (1.4% vs. 8.0%, p=0.061). In patients treated with PIR, the 4-week complete remission (CR) rate was higher (79.5% vs. 64.2%, p=0.027) and the relapse rate was lower (41.5% vs. 60.0%, p=0.027). Patients treated with PIR were more frequently treated with allogeneic stem-cell transplant (alloSCT) in first CR: 19.2% vs. 7.3%, p=0.017. The median OS was significantly higher with PIR than with HyperCVAD, with a median of 19.0 months (3.3-25.4 months) vs. 11.1 months (7.3-14.8 months), and a 18-month OS of 53% vs. 33%, p=0.017. When comparing the two different PIR (ALL-BFM 90 vs. CALGB 10403), the patients treated with ALL-BFM 90 had more frequently high-risk karyotypes (46% vs. 10.5%, p=0.012). Both regimens were associated with similar 4-week CR rate (78.3% vs. 81.5%, p=1). OS was higher with the CALGB 10403 with an 18 month-OS of 79% vs. 42% with the ALL-BFM 90 (p=0.044). When adjusted for high-risk karyotype, the benefit on OS was no longer significant. In the multivariate analysis for OS, the independent significant prognostic factors were: treatment with a PIR (HR 0.428, 95% CI 0.221-0.826, p=0.011), alloSCT in first CR (HR 0.316, 95% CI 0.106-0.938, p=0.038) and high-risk karyotype (HR 2.695 95% CI 1.272-5.560, p=0.009). Discussion Although different groups have shown the benefit of PIR in the AYA-patients, the MD Anderson group couldn´t found any benefit from using the augmented BFM when compared to HyperCVAD. In our experience, the outcomes with HyperCVAD are poor in this group. In this report, the treatment with PIR was associated with a higher CR rate, lower relapse rate and better OS when compared with our historical HyperCVAD in AYA-patients. The benefit on survival was independent of other risk factors or alloHSCT. The main limitation of the study is the comparison with a historical group. However, given the general trend to treat these patients with RIP, a prospective randomized study in this regard is unlikely. Disclosures Demichelis: Abbvie: Speakers Bureau; AMGEN: Research Funding, Speakers Bureau; Celgene: Speakers Bureau; Novartis: Research Funding, Speakers Bureau; Shire: Speakers Bureau.

A Modified CALGB-10403 in Hispanic Adolescent and Young Adults with Philadelphia -Negative Acute Lymphoblastic Leukemia: Promising Results Despite a High-Rate of Metabolic and Hepatic Toxicities

Background: Acute lymphoblastic leukemia (ALL) represents 51% of acute leukemias in adults in Mexico. Poor outcomes have been reported, with a 3-year overall survival (OS) of 25.7% in the group of adolescents and young adults (AYA). In ALL, Hispanic ethnicity has been associated with more high-risk features and more treatment-related toxicity. Recently the results of the pediatric-inspired regimen CALGB 10403 in AYA ALL-patients have been published with encouraging results. We modified the original regimen based on the drug-access in Mexico and we incorporate Rituximab in CD20 positive patients. Methods We included patients with newly diagnosed B- or T-cell ALL between 17 and 45 years. Patients with Philadelphia chromosome-ALL were excluded. We enrolled patients from 4 centers in Mexico. We replicated the CALGB 10403 protocol, with the following modifications: replaced pegaspargase (2,500 IU/m2) with E. Coli asparaginase (6,000 IU/m2/day for 6 doses in alternate days). During the delayed intensification we replaced thioguanine 60mg/m2/day with 6-mercapatopurine 60mg/m2/day. We incorporated rituximab 375mg/m2 at D1 and D29 during remission consolidation, D1 and D21 in interim maintenance and D1, D29 and D50 in delayed intensification. The central nervous system (CNS) prophylaxis was given as a triple-drug (methotrexate 12.5mg, cytarabine 60mg and dexamethasone 8mg), with a total of 11 intratecal administrations, 7 during the induction/consolidation courses and 4 during maintenance. Minimal residual disease (MRD) was assessed by flow cytometry after induction and after first consolidation. The aims of this study were to evaluate complete response (CR) rate, progression-free survival (PFS), overall survival (OS), and to assess the safety of this regimen. Result From January 2017 to May 2019 thirty-eight patients (23 men, 15 women) have been enrolled. Median follow-up is 11 months (range 1-30). Median age is 23 years (range 18-41). The 100% of patients are of Hispanic ethnicity. Obesity (BMI≥30) was reported in 18%. Thirty patients had an evaluable karyotype: 83% were normal, and 13% with MLL-rearrangements. The majority were B-cell ALL (90%), and 10% were T-cell ALL. Median WBC was 19.5 x103/mcL (range: 0.7-427.7) and 32% had hyperleukocytosis. Among the B-cell ALL patients, 53% were CD20 positive. CNS disease was presented at diagnosis in only one patient (3%). Thirty-three patients (86%) achieved CR, thirty (81%) after the first induction and three after the extended induction therapy. There was only one death during induction therapy (2.6%). After induction, 41% had negative MRD (&amp;lt;0.01%). Grade 3 /4 hepatic toxicity was reported in 58% patients, hyperglycemia in 24% and hypertriglyceridemia in 34%. The rest of toxicities are summarized in Table 1. During induction ten patients (19%) required dose adjustment because of toxicity. During consolidation, 42% required treatment modifications because of toxicity. After induction, we had no treatment-related mortality. At the last follow-up twenty-three patients continue in the protocol. Four patients already received Allo-SCT. The relapse-rate is 31.2% with half of these patients with CNS-disease at relapse. Nine patients have died: one during induction, six with progression or refractory disease and one after Allo-SCT. The 18-months PFS and OS rates were 80% and 84%, respectively. Median PFS is 23 months (CI 95% 17 to 29 months), and median OS was not been reached. Negative-MRD after induction was associated with excellent outcomes: 18-months OS 100% vs. 45.3%, p=0.008 (figure 1). Obesity was associated with worse OS (18-month 22% vs. 80%, p=0.03) and PFS (22% vs. 79.1%, p=0.026) Conclusion: Mexican patients treated with a modified CALGB 10403 protocol had similar response rates than reported in the original protocol but with more toxicity, mainly hepatic and metabolic. However, induction-related mortality was low and we had no treatment-related toxicity after induction. We presume that the high-rate of toxicities can be related with the genetic and environmental metabolic risk factors plenty described in our population. The modified CALGB showed encouraging results in this Hispanic population, hence we have to explore lower dose schedule based in patient characteristics and asparaginase levels. Disclosures Neme Yunes: Abbvie: Speakers Bureau; Janssen: Speakers Bureau; Novartis: Speakers Bureau. Demichelis:Abbvie: Speakers Bureau; Celgene: Speakers Bureau; AMGEN: Research Funding, Speakers Bureau; Novartis: Research Funding, Speakers Bureau; Shire: Speakers Bureau.

PB1664 ASPARAGINASE ACTIVITY AND ANTI‐ E. COLI ASPARAGINASE ANTIBODY LEVEL MONITORING FOR DIFFERENT ASPARAGINASE PREPARATIONS IN HONG KONG CHILDHOOD ALL PATIENTS

Background:Asparaginase is effective for treating paediatric ALL, nonetheless, hypersensitivity reaction is the most prevalent form of adverse events in patients. Silent inactivation has been reported that some patients develop anti‐asparaginase antibodies against the preparations without showing any allergic symptoms.Currently, native E.Coli asparaginase (Leuanse) is the only licensed preparation in Hong Kong whereas pegylated E.Coli asparaginase (Oncaspar) and Erwinia asparaginase are the second‐line and third‐line treatment on name‐patient basis respectively. In Hong Kong, the switch of preparation is guided by the presence of clinical reaction, the efficacy of the Oncaspar and difference of effectiveness between the two available brands of Erwinia asparaginase are not known. Monitoring of asparaginase activity and anti‐asparaginase antibody for guiding the switch of asparaginase preparation was shown to improve patients’ outcome but have not been exercised in Hong Kong.Aims:We aim to evaluate the implementation of asparaginase activity measurement for monitoring the efficacy of different asparaginase preparations in clinical settings.Methods:28 patients who were undergoing asparaginase treatment were recruited including 19 newly diagnosed patients who were followed up from the start of chemotherapy. Serum was collected during induction, continuation and re‐induction phase with time points corresponding to the half‐life of different preparations and after allergic reaction. Serum asparaginase activity and anti‐E.Coli asparaginase antibody were measured, evaluated and analysed with the grading of severity of hypersensitivity reaction.Results:Among the 28 patients, 53.5% (N = 15) of them experienced allergic reaction to Leunase; 9 of them were checked for asparaginase activity and all displayed low enzyme activity (&lt;100U/L); anti‐E.Coli asparaginase antibody level was measured for 13 of them, 75.0% (N = 10) were antibody positive (&gt;0.625 ng/mL). Among the 12 patients without reaction,61.5%(N = 8) of them were positive for the antibody while all of them could maintain good activity. Most of the patients had reaction at post‐induction phase, they tolerated an average of 11.4 doses of Leunase. 15 patients allergic to Leunase were switched to Oncaspar but 73.3% (N = 11) were hypersensitive to the preparation at a mean dose of 1.67. Enzyme activity was quantified for 6 of them, all of them failed to maintain normal activity while 3 patients without clinical reaction and 2 of them showed suboptimal asparagianse activity. 11 patients after hypersensitivity reaction to Oncaspar were treated with two brands of Erwinia asparaginase from UK or China, namely Erwinase and Baiyun Erwinase, depending on their availability. Among them, 3 patients (27.3%) were clinically hypersensitive but all samples collected before reaction were with normal activity. Both preparation of Erwinia asparaginase achieved good anti‐asparaginase activities.Summary/Conclusion:Our results high incidence of allergy to Leunase in Chinese children. Patients allergic to Leunase were either clinically hypersensitive or silently inactivated to Oncaspar, suggesting that Oncaspar may not be a suitable alternative after Leunase allergy while the two brands of Erwinia asparaginase displayed satisfactory efficacy without triggering much hypersensitive response. Given the specificity and sensitivity, measurement of asparaginase activity should be part of the clinical monitoring to ensure adequate efficacy of different preparations.

Results of successive EORTC-CLG 58881 and 58951 trials in paediatric T-cell acute lymphoblastic leukaemia (ALL).

Outcomes in childhood T-cell acute lymphoblastic leukaemia (T-ALL) are steadily improving due to intensive therapy. Between 1989 and 2008, 599 children with newly diagnosed T-ALL were enrolled in two successive European Organization for Research and Treatment of Cancer-Children's Leukaemia Group trials (58881 and 58951), both based onthe Berlin-Frankfurt-Munster protocol and without cranial irradiation. In the lattertrial induction chemotherapy was intensified. The most important randomizations were Medac Escherichia coli asparaginase versus Erwinia asparaginase in trial 58881, and dexamethasone (6mg/m2 /day) versus prednisolone (60mg/m2 /day) and prolonged versus conventional asparaginase duration in trial 58951. 8-year event-free survival (EFS) increased from 65·1% to 74·0% in trial 58951. Improvement was most profound for patients with white blood cell (WBC) counts <100×109 /l and "good responders" to prephase. Medac E.coli asparaginase was associated with longer EFS [hazard ratio (HR) 0·54, P=0·0015] and overall survival (HR 0·51, P=0·0018). Induction therapy with dexamethasone did not improve EFS compared to prednisolone. Remarkably, intensification of central nervous system (CNS)-directed therapy in trial 58951 resulted in fewer bone marrow relapses, while the incidence of CNS relapses remained low. In summary, we showed that adequate asparaginase therapy, intensified induction treatment and intensification of CNS-directed chemotherapy can result in an improvement of outcome in T-ALL patients with good prephase response and initial WBC counts <100×109 /l, representing approximately 50% of T-ALL patients.

PSY87 - Pegaspargase In The Treatment of Acute Lymphoblastic Leukemia: A CMA Model Demonstrates Its Economic Benefit For The Italian National Health System

Pegaspargase is a pegylated form of native E. Coli asparaginase used as an agent in the treatment of acute lymphoblastic leukemia (ALL). Compared to the native form, it presents two main benefits: (i) a longer half-life, thus reducing the number of administrations and (ii) a lower immunogenicity, both in terms of hypersensitivity/allergic reactions as well as antibody formation, thus avoiding to switch to second line costly treatment, such as that with Erwinia Chrisanthemi asparaginase. We present here a cost-minimization analysis (CMA) to show that pegaspargase leads to an economic benefit to the Italian National Health System (SSN). For the model, we constructed a decision tree based upon the clinical practice for the treatment of ALL, with inputs derived from Italian protocols AIEOP-BFM 2009 (for pediatrics) and GIMEMA LAL 1913 (for adults). The native E. Coli asparaginase has been selected as comparator since some patients still use this enzyme in the first-line treatment of ALL. Branch point probabilities representing immunogenic rates were obtained from the best available published literature. Direct costs (hospitalization, drug administration, allergic reactions management) were derived from Gazzetta Ufficiale. Our base-case analysis revealed that the cost-per-patient (both for pediatrics and adults) for pegaspargase was ~6000 € lower than that for native E. coli asparaginase mainly due to the reduced number of administrations and to the lower incidence of immunogenic reactions. The latter has in turn led to a lower hospitalization rate and to a lower switch to the more expensive second line treatment with Erwinia Chrisanthemi. The costs associated with the use of pegaspargase for the first line treatment of ALL are lower than those deriving from the native form of native E. coli asparaginase. Thus, pegaspargase is a cost saving option, with a potential beneficial budget impact for the Italian SSN.

PSY86 - Cost-minimization Analysis of Pegaspargase And Native E. Coli Asparaginase To Treat Children And Adults with Acute Lymphoblastic Leukemia In Belgium

PSY86 - Cost-minimization Analysis of Pegaspargase And Native E. Coli Asparaginase To Treat Children And Adults with Acute Lymphoblastic Leukemia In Belgium

Asparaginase Erwinia chrysanthemi as a component of a multi-agent chemotherapeutic regimen for the treatment of patients with acute lymphoblastic leukemia who have developed hypersensitivity to E. coli-derived asparaginase

SUMMARYAsparaginase has been a mainstay of therapy in the treatment of acute lymphoblastic leukemia since the 1970s. There are two major preparations available and FDA approved in the United States today, one derived from Escherichia coli and the other from Erwinia chrysanthemi. Erwinia asparaginase is antigenically distinct from and has a considerably shorter biological half-life than E coli asparaginase. Erwinia asparaginase has been used in cases of hypersensitivity to E. coli-derived asparaginases, which has been reported in up to 30% of patients. While PEG asparaginase is increasingly used in front-line therapy for ALL, hypersensitivity still occurs with this preparation, and a change to a non-cross-reactive preparation may be necessary.

Effect of Asparaginase and Dexamethasone on FVIIa-at Complex and F1.2 in Children with Acute Lymphoblastic Leukemia: Evidence of Hypercoagulable State

Purpose:Concomitant administration of asparaginase (ASP) and steroids, the backbone of front line acute lymphoblastic leukemia (ALL) therapy, are shown to increase the risk of thromboembolism (TE). On Dana-Farber Cancer Institute (DFCI) ALL Consortium studies TE is frequent during ASP intensification phase (Consolidation II) where pulse steroids are administered for 5 days at commencement of 3-week multiagent chemotherapy cycles (Grace et al, 2011). These observations indicate that combination therapy with ASP and steroids leads to a hypercoagulable state. However, there are no in vivo or in vitro data to support these clinical observations. Hence we undertook a study to evaluate the impact of concomitant administration of ASP and steroids on markers of endogenous thrombin generation namely prothrombin activation fragment 1.2 (F1.2) and, activated coagulation factor VII (FVIIa) and antithrombin (AT) complex (FVIIa-AT).Hypothesis:ASP administered with steroids results in increased levels of endogenous thrombin generation when compared to baseline or with ASP only therapy.Methods:Children (>1 to ≤18 yrs. of age) treated according to DFCI ALL 05-001 therapy protocol who are in remission following consolidation I therapy, without prior TE or ASP allergy, were eligible. Blood samples collected at 3 time points: prior to the first post-induction dose of E. Coli ASP ("baseline"), prior to Week 2 therapy (effects of ASP and Dex therapy) and prior to subsequent Week 1 (effect of ASP only) of three week cycle of Consolidation II therapy, were analyzed for F1.2 and FVIIa-AT complex. F1.2 levels were estimated by enzyme-linked immunosorbent assay (ELISA). FVIIa-AT levels were analyzed using the Asserachrome FVIIa-AT ELISA kits (Diagnostica Stago). Baseline parameters [time point (TP) 1] were compared to parameters after ASP and Dex (TP2), and after ASP only (TP3) therapy, using paired t-tests. Pearson correlation was used to evaluate the relationship between FVIIa-AT complex and F1.2.Results:This exploratory study included 9 patients (7 boys; 2 with high-risk ALL). The average age was 4.7 yrs. (range 1 to 8 yrs.). All patients received weekly E. Coli ASP during Consolidation II phase. As shown in Table 1, compared to baseline both F1.2 and FVIIa-AT complex levels were significantly increased at TP2 (ASP and Dex) and TP3 (ASP alone). In all but one patient the FVIIa-AT levels were higher following Dex therapy (TP2) compared to ASP alone (TP3). However this difference was not statistically significant [mean difference 83.4 (SD152.1), 95% CI -33.5, 200.4; p=0.138]. Similarly F1.2 levels were higher at TP2 compared to TP3 in all but 2 patients, but the difference was not statistically significant [mean difference -5.9 (SD 38.2), 95% CI-35.2, 23.4; p=0.656]. Following ASP alone therapy F1.2 and FVIIa-AT were significantly correlated (Pearson correlation coefficient 0.716, p=0.046).Conclusions:E. Coli ASP and Dex therapy is associated with significantly increased levels of F1.2 and FVIIa-AT levels compared to baseline, indicating activation of the coagulation cascade with increased endogenous thrombin generation. In the majority of patients combination of ASP and Dex had increased levels of F1.2 and FVIIa-AT compared to ASP alone therapy. However as a group this comparison was statistically insignificant. This may explain the increased risk of TE with concomitant ASP and Dex therapy as in Consolidation II phase on DFCI ALL therapy protocol. Small sample size is a limitation of our study. Hence we recommend a larger study to confirm our findings.Table 1VariableTP1 Mean(SD)TP2 Mean (SD)Mean Difference TP1/TP2 (SD)[95% CI]P valueTP3 Mean (SD)Mean Difference TP1/TP3 (SD)[95% CI]P valueFVIIa-AT (pmol/L)77.4 (25.7)296.4 (132.3)-291.0 (133.9)[-322.0,-116.0]0.001213.0 (131.4)-135.6 (117.6)[-226.0, -45.1]0.009F1.2 (nmol/L)110.7 (45.9)153.0 (78.8)-42.3 (50.4) [-81.1,-3.6]0.036158.9 (80.4)-48.2 (61.3)[-95.3,-1.1]0.046 DisclosuresNo relevant conflicts of interest to declare.

Genetic Variation in NFATC2 Is Associated with a Higher Risk of Asparaginase Allergy

Asparaginase is an important drug for the treatment of acute lymphoblastic leukemia (ALL); however, hypersensitivity reactions to asparaginase can lead to suboptimal asparaginase exposure and to a higher risk of disease recurrence. Factors influencing the frequency of asparaginase hypersensitivity include asparaginase formulation, the schedule of asparaginase administration, and concurrent chemotherapy. In addition, using a candidate gene approach, our group previously identified a genetic association between HLA-DRB1*07:01 and asparaginase hypersensitivity in patients of European ancestry.[PMID 24970932] The objective of our current study was to use a genome-wide approach to identify additional genetic loci associated with hypersensitivity and to assess the relative importance of HLA-DRB1 as a genetic risk factor.Asparaginase hypersensitivity was assessed in children with ALL enrolled on SJCRH protocols Total XIIIA (n = 154), Total XV (n = 498) and Total XVI (n = 271) or Children’s Oncology Group (COG) protocols POG 9906 (n = 222) and AALL0232 (n = 2,163). Patients enrolled on protocols Total XIIIA, Total XV and POG 9906 received native E. coli asparaginase during treatment, whereas patients on Total XVI and AALL0232 received PEGylated E. coli asparaginase. Hypersensitivities were graded according to the NCI common toxicity criteria, and reactions of grade 2 and above were considered cases. Germline DNA was genotyped using the Affymetrix 500K, Affymetrix 6.0, or the Illumina Exome Beadchip array. Univariate analysis of risk factors associated with asparaginase hypersensitivity using the combined cohort of patients (n = 3,308) identified a significant positive association with treatment arm (P < 2.2x10-16; highest risk in patients enrolled on Total XV), native E coli asparaginase formulation (P < 2.2x10-16), age < 10 years (P = 3.3x10-4), male gender (P = 0.06), and racial ancestry (P = 2.1x10-4; highest risk among African ancestry). In multivariate analysis, treatment arm (P < 2.2x10-16), gender (P = 0.04), racial ancestry (P = 0.07), and ALL lineage (P = 0.003) remained significant risk factors.A multivariate logistic regression model adjusted for treatment arm, racial ancestry, gender, age, and ALL lineage was used to identify genomic variants associated with asparaginase hypersensitivity in the combined patient cohort. The minor allele of an intronic polymorphism in NFATC2 (rs6021191) was associated with hypersensitivity at the genome-wide significance threshold (P = 2.6x10-8, OR = 3.17). The minor allele frequency (MAF) for the NFATC2 high-risk variant was highest in non-European ancestries (MAFEuropean = 0.001, MAFAfrican = 0.142, MAFHispanic = 0.043, MAFAsian = 0.151, MAFOther = 0.034). Using RNA-seq data available from the ALL tumor samples of 65 SJCRH patients, we found that patients carrying the variant had higher expression of NFATC2 compared to non-carriers (P = 1.0x10-3). NFATC2 is known to play a critical role in inducing T-cell gene transcription during immune responses.The strongest association detected using SNPs from the Illumina Exome array was found in HLA-DRB1 (rs17885382, P = 4.0x10-6, OR = 1.65), and the SNP is in near complete linkage disequilibrium with the HLA-DRB1*07:01 allele, which we previously found associated with asparaginase hypersensitivity. A gene-level analysis was performed using SNP-set Kernel Association Test (SKAT), and the gene with the strongest association with hypersensitivity was PPT2, located in the HLA class III region on chromosome 6 (P = 3.70x10-6). To determine potential biological pathways differentially represented by the genes identified by our analysis, we used Ingenuity Pathway Analysis on the top 1% of genes associated with hypersensitivity as identified by our single SNP (68 genes) and gene level analysis (18 genes). We found an enrichment of genes (8 out of 21 genes, P = 2.6x10-5) within the top network involved in humoral immunity, suggesting that other genes regulating immune responses may also contribute to the risk of developing asparaginase hypersensitivity.In conclusion, the top inherited genetic loci (NFATC2, HLA-DRB1*0701, PPT2) associated with asparaginase hypersensitivity are directly involved in human immune response, and pathway analysis suggests that inherited variations in other genes involved in humoral immunity likely play a role in the development of asparaginase hypersensitivity. DisclosuresEvans:St. Jude: In accordance with institutional policy (St. Jude), I and/or my spouse have in the past received a portion of the income St. Jude receives from licensing patent rights related to TPMT polymorphisms as clinical diagnostics. Patents & Royalties. Relling:St. Jude: In accordance with institutional policy (St. Jude), I and/or my spouse have in the past received a portion of the income St. Jude receives from licensing patent rights related to TPMT polymorphisms as clinical diagnostics. Patents & Royalties.

A prospective study on drug monitoring of PEGasparaginase and Erwinia asparaginase and asparaginase antibodies in pediatric acute lymphoblastic leukemia

AbstractThis study prospectively analyzed the efficacy of very prolonged courses of pegylated Escherichia coli asparaginase (PEGasparaginase) and Erwinia asparaginase in pediatric acute lymphoblastic leukemia (ALL) patients. Patients received 15 PEGasparaginase infusions (2500 IU/m2 every 2 weeks) in intensification after receiving native E coli asparaginase in induction. In case of allergy to or silent inactivation of PEGasparaginase, Erwinia asparaginase (20 000 IU/m2 2-3 times weekly) was given. Eighty-nine patients were enrolled in the PEGasparaginase study. Twenty (22%) of the PEGasparaginase–treated patients developed an allergy; 7 (8%) showed silent inactivation. The PEGasparaginase level was 0 in all allergic patients (grade 1-4). Patients without hypersensitivity to PEGasparaginase had serum mean trough levels of 899 U/L. Fifty-nine patients were included in the Erwinia asparaginase study; 2 (3%) developed an allergy and none silent inactivation. Ninety-six percent had at least 1 trough level ≥100 U/L. The serum asparagine level was not always completely depleted with Erwinia asparaginase in contrast to PEGasparaginase. The presence of asparaginase antibodies was related to allergies and silent inactivation, but with low specificity (64%). Use of native E coli asparaginase in induction leads to high hypersensitivity rates to PEGasparaginase in intensification. Therefore, PEGasparaginase should be used upfront in induction, and we suggest that the dose could be lowered. Switching to Erwinia asparaginase leads to effective asparaginase levels in most patients. Therapeutic drug monitoring has been added to our ALL-11 protocol to individualize asparaginase therapy.