Asparaginase antibody and asparaginase activity in children with higher-risk acute lymphoblastic leukemia: Children's Cancer Group Study CCG-1961

Mitigation of acrylamide in fried food systems using a combination of zein-pectin hydrocolloid complex and a food-grade l-asparaginase

Acrylamide, a Maillard reaction product, formed in fried food poses a serious concern to food safety due to its neurotoxic and carcinogenic nature. A "Green Approach" using L-Asparaginase enzyme from GRAS-status bacteria synergized with hydrocolloid protective coating could be effective in inhibiting acrylamide formation. To fill this void, the present study reports a new variant of type-II L-asparaginase (AsnLb) from Levilactobacillus brevis NKN55, a food-grade bacterium isolated using a unique metabolite profiling approach. The recombinant AsnLb enzyme was characterized to study acrylamide inhibition ability and showed excellent specificity towards L-asparagine (157.2 U/mg) with Km, Vmax of 0.833 mM, 4.12 mM/min respectively. Pretreatment of potato slices with AsnLb (60 IU/mL) followed by zein-pectin nanocomplex led to >70% reduction of acrylamide formation suggesting synergistic effect of this dual component system. The developed strategy can be employed as a sustainable treatment method by food industries for alleviating acrylamide formation and associated health hazard in fried foods.

Continuous PEGasparaginase Dosing Reduces Hypersensitivity Reactions in Pediatric ALL: A Dutch Childhood Oncology Group ALL11 Randomized Trial

PURPOSE

The primary objective of this randomized study was to determine whether a continuous dosing schedule (without the asparaginase-free interval) would result in less hypersensitivity reactions to PEGasparaginase (PEGasp) compared with the standard noncontinuous dosing schedule.

METHODS

Eight hundred eighteen patients (age 1-18 years) with ALL were enrolled in the Dutch Childhood Oncology Group-ALL11 protocol and received PEGasp. Three hundred twelve patients stratified in the medium-risk arm were randomly assigned to receive 14 individualized PEGasp doses once every two weeks in either a noncontinuous or continuous schedule after the first three doses in induction (EudraCT: 2012-000067-25). Hypersensitivity reactions were defined as allergies, allergic-like reactions, and silent inactivation. Secondary end points were other asparaginase-related toxicities, asparaginase activity and antibody levels, and outcome.

RESULTS

During induction, 27 of 818 patients (3.3%) experienced hypersensitivity reactions. After random assignment, 4 of 155 (2.6%) in the continuous treatment arm versus 17 of 157 (10.8%) patients in the noncontinuous treatment arm had hypersensitivity reactions (P < .01), of which two (1.3%) versus 13 (8.3%) were inactivating reactions (P < .01). The occurrence of inactivating hypersensitivity reactions was seven times lower in the continuous arm (odds ratio, 0.15 [0.032-0.653]). In addition, antibody levels were significantly lower in the continuous arm (P < .01). With exception of a lower incidence of increased amylase in the continuous arm, there were no significant differences in total number of asparaginase-associated toxicities between arms. However, the timing of the toxicities was associated with the timing of the asparaginase administrations. No difference in 5-year cumulative incidence of relapse, death, or disease-free survival was found between both treatment arms.

CONCLUSION

A continuous dosing schedule of PEGasp is an effective approach to prevent antibody formation and inactivating hypersensitivity reactions. The continuous PEGasp schedule did not increase toxicity and did not affect the efficacy of the therapy.

Asparaginase-specific basophil recognition and activation predict Asparaginase hypersensitivity in mice

Background

Asparaginase (ASNase) is a crucial part of acute leukemia treatment, but immune responses to the agent can reduce its effectiveness and increase the risk of relapse. Currently, no reliable and validated biomarker predicts ASNase-induced hypersensitivity reactions during therapy. We aimed to identify predictive biomarkers and determine immune cells responsible for anaphylaxis using a murine model of ASNase hypersensitivity.

Methods

Our preclinical study uses a murine model to investigate predictive biomarkers of ASNase anaphylaxis, including anti-ASNase antibody responses, immune complex (IC) levels, ASNase-specific binding to leukocytes or basophils, and basophil activation.

Results

Our results indicate that mice immunized to ASNase exhibited dynamic IgM, IgG, and IgE antibody responses. The severity of ASNase-induced anaphylaxis was found to be correlated with levels of IgG and IgE, but not IgM. Basophils from immunized mice were able to recognize and activate in response to ASNase ex vivo, and the extent of recognition and activation also correlated with the severity of anaphylaxis observed. Using a multivariable model that included all biomarkers significantly associated with anaphylaxis, independent predictors of ASNase-induced hypersensitivity reactions were found to be ASNase IC levels and ASNase-specific binding to leukocytes or basophils. Consistent with our multivariable analysis, we found that basophil depletion significantly protected mice from ASNase-induced hypersensitivity reactions, supporting that basophils are essential and can be used as a predictive marker of ASNase-induced anaphylaxis.

Conclusions

Our study demonstrates the need for using tools that can detect both IC- and IgE-mediated hypersensitivity reactions to mitigate the risk of ASNase-induced hypersensitivity reactions during treatment.

Engineering Antigen-Specific Tolerance to an Artificial Protein Hydrogel

Artificial protein hydrogels are an emerging class of biomaterials with numerous prospective applications in tissue engineering and regenerative medicine. These materials are likely to be immunogenic due to their frequent incorporation of novel amino acid sequence domains, which often serve a functional role within the material itself. We engineered injectable "self" and "nonself" artificial protein hydrogels, which were predicted to have divergent immune outcomes in vivo on the basis of their primary amino acid sequence. Following implantation in mouse, the nonself gels raised significantly higher antigel antibody titers than the corresponding self gels. Prophylactic administration of a fusion antibody targeting the nonself hydrogel epitopes to DEC-205, an endocytic receptor involved in Treg induction, fully suppressed the elevated antibody titer against the nonself gels. These results suggest that the clinical immune response to artificial protein biomaterials, including those that contain highly antigenic sequence domains, can be tuned through the induction of antigen-specific tolerance.

Correlation of ex vivo and in vivo ammonia production with L-asparaginase biological activity in adults with lymphoid malignancies

Silent inactivation of L-asparaginase (L-Asp) represents rapid clearance of L-Asp by anti-L-Asp IgG antibodies without clinical symptoms. Measurement of L-Asp activity is the gold standard for diagnosis of silent inactivation, but this test is not commercially available in Japan as of 2023. We evaluated ex vivo and in vivo ammonia production in relation to L-Asp activity. Blood samples from ten adult patients treated with L-Asp were collected to measure ammonia levels and L-Asp activity before the first dose and 24 h after the last dose of L-Asp, during each cycle of treatment. Plasma ammonia levels were analyzed immediately and 1 h after incubation at room temperature, and ex vivo ammonia production was defined as the increase in ammonia concentration. Ex vivo ammonia production correlated with L-Asp activity (R2 = 0.741), and ammonia levels measured immediately after blood collection were moderately correlated with L-Asp activity (R2 = 0.709). One patient with extranodal NK/T-cell lymphoma showed an increase in ammonia levels during the first cycle, but no increase in ammonia levels or L-Asp activity after L-Asp administration during the second cycle. Both ex vivo and in vivo ammonia production and surrogate markers are used for L-Asp biological activity.

PEGylation versus glycosylation: effect on the thermodynamics and thermostability of crisantaspase

Thermostability is an important and desired feature of therapeutic proteins and is critical for the success or failure of protein drugs development. It can be increased by PEGylation-binding of poly(ethylene glycol) moieties-or glycosylation-post-translational modification to add glycans. Here, the thermostability and thermodynamic parameters of native, PEGylated, and glycosylated versions of the antileukemic enzyme crisantaspase were investigated. First-order kinetics was found to describe the irreversible deactivation process. Activation energy of the enzyme-catalyzed reaction (E*) was estimated for native, PEGylated, and glycosylated enzyme (10.2, 14.8, and 18.8 kJ mol-1 respectively). Half-life decreased progressively with increasing temperature, and longer half-life was observed for PEG-crisantaspase (87.74 min) at 50 °C compared to the native form (9.79 min). The activation energy of denaturation of PEG-crisantaspase (307.1 kJ mol-1) was higher than for crisantaspase (218.1 kJ mol-1) and Glyco-crisantaspase (120.0 kJ mol-1), which means that more energy is required to overcome the energy barrier of the unfolding process. According to our results, PEG-crisantaspase is more thermostable than its native form, while Glyco-crisantaspase is more thermosensitive.

Improved L-Asparaginase Properties and Reusability by Immobilization onto Functionalized Carbon Xerogels

Enzyme immobilization can offer a range of significant advantages, including reusability, and increased selectivity, stability, and activity. In this work, a central composite design (CCD) of experiments and response surface methodology (RSM) were used to study, for the first time, the L-asparaginase (ASNase) immobilization onto functionalized carbon xerogels (CXs). The best results were achieved using CXs obtained by hydrothermal oxidation with nitric acid and subsequent heat treatment in a nitrogen flow at 600 °C (CX-OX-600). Under the optimal conditions (81 min of contact time, pH 6.2 and 0.36 g/L of ASNase), an immobilization yield (IY) of 100 % and relative recovered activity (RRA) of 103 % were achieved. The kinetic parameters obtained also indicate a 1.25-fold increase in the affinity of ASNase towards the substrate after immobilization. Moreover, the immobilized enzyme retained 97 % of its initial activity after 6 consecutive reaction cycles. All these outcomes confirm the promising properties of functionalized CXs as support for ASNase, bringing new insights into the development of an efficient and stable immobilization platform for use in the pharmaceutical industry, food industry, and biosensors.

Lack of benefit from premedication for pegylated asparaginase during pediatric acute lymphoblastic leukemia/lymphoma therapy: A side-by-side comparison

BACKGROUND

Pegylated l-asparaginase (PEG) is integral to treatment regimens for acute lymphoblastic leukemia (ALL) and lymphoma. Hypersensitivity reactions (HSRs) to PEG are common and can preclude continued administration. Data supporting recommendations for universal premedication (UPM) prior to PEG infusion to reduce incidence of HSRs are limited; UPM has become common practice.

PROCEDURES

Two free-standing children's hospitals independently implemented UPM prior to PEG infusions in 2016 and 2019, respectively. In a side-by-side retrospective analysis, incidence and severity of HSRs were analyzed pre- and postimplementation of UPM in youth ≥1 years old treated with frontline PEG-containing ALL regimens (2015-2018, 2016-2020). All HSRs were centrally reviewed within each institution to confirm and grade the HSR (Common Terminology Criteria for Adverse Events, v5). Planned analyses of subsets at potentially greater risk for HSRs included intensive PEG regimens (≥5 doses), adolescent and young adults (AYA), Hispanic/Latinx ethnicity, and obesity.

RESULTS

In 410 patients (by institution, n = 282 and n = 128), the overall incidence of Grade ≥ 3 HSRs was 20% (56 out of 282) and 18% (23 out of 128), respectively. No difference in incidence of Grade ≥ 3 HSRs in patients with versus without UPM was found at either institution (23 vs. 19%, p = .487 and 19 vs. 17%, p = .845). UPM also did not reduce the severity of HSRs, nor influence HSR risk within any patient subset.

CONCLUSIONS

UPM prior to PEG infusion did not alter incidence or severity of HSRs at either institution. HSR remains a common complication of PEG therapy, impacting the patient experience. Alternative strategies to reduce HSRs are urgently required.

Utility of ASNS gene methylation evaluated with the HPLC method as a pharmacogenomic biomarker to predict asparaginase sensitivity in BCP-ALL

Asparaginase is an important agent for the treatment of acute lymphoblastic leukaemia (ALL), but it is occasionally associated with severe adverse events. Thus, for safer and more efficacious therapy, a clinical biomarker predicting asparaginase sensitivity is highly anticipated. Asparaginase depletes serum asparagine by deaminating asparagine into aspartic acid, and ALL cells are thought to be sensitive to asparaginase due to reduced asparagine synthetase (ASNS) activity. We have recently shown that allele-specific methylation of the ASNS gene is highly involved in asparaginase sensitivity in B-precursor ALL (BCP-ALL) by using next-generation sequence (NGS) analysis of bisulphite PCR products of the genomic DNA. Here, we sought to confirm the utility of methylation status of the ASNS gene evaluated with high-performance liquid chromatography (HPLC) analysis of bisulphite PCR products for future clinical applications. In the global methylation status of 23 CpG sites at the boundary region of promoter and exon 1 of the ASNS gene, a strong positive correlation was confirmed between the mean percent methylation evaluated with the HPLC method and that with the NGS method in 79 BCP-ALL cell lines (R2 = 0.85, p = 1.3 × 10-33) and in 63 BCP-ALL clinical samples (R2 = 0.84, p = 5.0 × 10-26). Moreover, methylation status of the ASNS gene evaluated with the HPLC method was significantly associated with in vitro asparaginase sensitivities as well as gene and protein expression levels of ASNS. These observations indicated that the ASNS gene methylation status evaluated with the HPLC method is a reliable biomarker for predicting the asparaginase sensitivity of BCP-ALL.

Screening of endophytic fungi from Antarctic mosses: Potential production for L-asparaginase free of glutaminase and urease activity

Studies involving endophytic fungi aim to identify organisms inhabiting extreme and relatively unexplored environments, as these fungi possess unique characteristics and uncommon biochemical pathways that enable them to produce compounds with biotechnological potential. Among various enzymes, L-Asparaginase is employed in the treatment of Acute Lymphoblastic Leukemia. In this study, we identified endophytic fungi from Sanionia uncinata and Polytrichastrum alpinum collected on King George Island in Antarctica. The fungi were categorized into morphological groups based on their characteristics, molecularly identified, and assessed for L-Asparaginase (L-ASNase) enzyme production. Subsequently, production optimization was conducted. A total of 161 endophytes were isolated from 504 moss gametophytes, with 107 originating from P. alpinum and 54 from S. uncinata. These isolates were categorized into 31 morphotypes. Fungi exhibiting high enzyme production were identified molecularly. Among them, nine identified isolates belonged to the genera Aspergillus, Collariella, Diaporthe, Epicoccum, Peroneutypa, Xylaria, and Trametes. Three of these isolates were identified at the species level through multigene phylogeny, namely Epicoccum nigrum, Collariella virescens, and Peroneutypa scoparia. All 31 fungi were subjected to solid media testing for L-ASNase enzyme production, with 22 isolates demonstrating production capability, and 13 of them produced L-ASNase free from Urease and Glutaminase. The isolates displaying solid media production underwent further testing in liquid media, all of which exhibited enzyme production ranging from 0.75 to 1.29 U g-1. Notably, the three fungi identified at the species level were the highest producers of the enzyme (1.29, 1.17, and 1.13 U g-1). The production of these fungi was optimized using the Taguchi method, resulting in production values ranging from 0.687 to 2.461 U g-1. In conclusion, our findings indicate that Antarctic moss endophytic fungi exhibit significant potential for the production of the anti-leukemic enzyme L-ASNase.

Enzyme Engineering Strategies for the Bioenhancement of L-Asparaginase Used as a Biopharmaceutical

Over the past few years, there has been a surge in the industrial production of recombinant enzymes from microorganisms due to their catalytic characteristics being highly efficient, selective, and biocompatible. L-asparaginase (L-ASNase) is an enzyme belonging to the class of amidohydrolases that catalyzes the hydrolysis of L-asparagine into L-aspartic acid and ammonia. It has been widely investigated as a biologic agent for its antineoplastic properties in treating acute lymphoblastic leukemia. The demand for L-ASNase is mainly met by the production of recombinant type II L-ASNase from Escherichia coli and Erwinia chrysanthemi. However, the presence of immunogenic proteins in L-ASNase sourced from prokaryotes has been known to result in adverse reactions in patients undergoing treatment. As a result, efforts are being made to explore strategies that can help mitigate the immunogenicity of the drug. This review gives an overview of recent biotechnological breakthroughs in enzyme engineering techniques and technologies used to improve anti-leukemic L-ASNase, taking into account the pharmacological importance of L-ASNase.

Experience with Generic Pegylated L-asparaginase in Children with Acute Lymphoblastic Leukemia from a Tertiary Care Oncology Center in South India

Dhaarani JayaramanBackground  Acute lymphoblastic leukemia (ALL) is a common type of leukemia in children. The innovator pegylated L-asparaginase has several advantages over native L-asparaginase; however, its use in India is limited due to availability and cost. Therefore, a generic pegylated L-asparaginase can be considered as an alternative to the innovator molecule. Methods  A retrospective study was conducted to assess the outcome (minimal residual disease [MRD]) and toxicity of a generic pegylated L-asparaginase (Hamsyl) at the end of induction therapy. Results  Eighty-eight (80.7%) and 21 (19.3%) patients had received generic pegylated L-asparaginase and conventional asparaginase, respectively, as a part of their treatment protocol. Nearly 82% of patients had B-type ALL. Eight-one percent of children had a white blood cell count of fewer than 50,000/mm 3 . At the end of induction, 80.7% (88) of children were minimal residual disease (MRD)-negative, and at the end of augmented consolidation therapy, 20.2% were MRD-negative. Ten percent of patients exhibited allergic reactions. Two children had pancreatitis, and one child had central venous thrombosis. Conclusion  The generic pegylated L-asparaginase (Hamsyl) was effective and safe for use in pediatric ALL.

Back to the future: the amazing journey of the therapeutic anti-leukemia enzyme asparaginase Erwinia chrysanthemi

For several decades, asparaginase has been considered world-wide as an essential component of combination chemotherapy for the treatment of childhood acute lymphoblastic leukemia (ALL). Discovered over 60 years ago, two main unmanipulated asparaginase products originated from primary bacteria sources, namely Escherichia coli and Erwinia chrysanthemi, have been available for clinical use. A pegylated product of the Escherichia coli asparaginase was subsequently developed and is now the main product used by several international co-operative groups. The various asparaginase products all display the same mechanism of action (hydrolysis of circulating asparagine) and are associated with similar efficacy and toxicity patterns. However, their different pharmacokinetics, pharmacodynamics and immunological properties require distinctive modalities of application and monitoring. Erwinia chrysanthemi asparaginase was initially used as a first-line product, but subsequently became a preferred second-line product for children who experienced immunological reactions to the Escherichia coli asparaginase products. An asparaginase product displaying the same characteristics of the Erwinia chrysanthemi asparaginase has recently been produced by use of recombinant technology, thus securing a preparation available for use as an alternative, or as a back-up in case of shortages, for the non-recombinant product. The long journey of the Erwinia chrysanthemi asparaginase product as it has developed throughout the last several decades has made it possible for almost every child and adult with ALL to complete the asparaginase-based protocol treatment when an immunological reaction has occurred to any Escherichia coli asparaginase product.

A comparison of hypersensitivity reactions between intravenous and intramuscular applications of native E. coli asparaginase in children with acute lymphoblastic leukemia

INTRODUCTION

Asparaginase is an indispensable drug in treating childhood acute lymphoblastic leukemia (ALL). Hypersensitivity reactions (HSR) are the most common side effects and interfere with the antineoplastic activity of the drug. This study aims to compare the intramuscular (IM) and intravenous (IV) administration routes of Native Escherichia coli Lasparaginase (L-ASNase) in terms of hypersensitive reactions.

METHODS

L-ASNase was randomly administered IV or IM to newly diagnosed ALL patients and HSR was monitored in all patients for 1 h following the end of the IV infusion and for 2 h following the end of the IM administration of L-ASNase. Based on a retrospective review of clinical charts, reactions were identified. In order to determine the severity of each allergic reaction, we used the Common Terminology Criteria for Adverse Events (CTCAE) version 4.03 for allergic reactions.

RESULTS

A total of 1032 doses of L-ASNase were administered to 85 patients (42 males and 43 females) during the study period. Among 85 patients, 30 reactions were recorded, which means that 35% of the patients reacted. According to the CTCAE, twenty-nine out of 30 reactions (97%) were grade 2, while one (3%) was grade 4. In terms of individual doses, there was a non-significant trend toward increased incidence of reactions with IV administration (3.8% versus 0.9%, p = 0.064). The rate of reactions was higher in patients who received all IV doses (n: 60) as compared to those who received all IM doses (n: 25) (31.7% vs. 3.5%; chi-square= 8.415, p value=0.04). Based on the risk groups and HSR incidence, it was found that high risk group (HRG) patients were significantly more likely to develop HSR compared to the standart risk group (SRG) and intermediate risk group (MRG) patients (chi-square p = 0.003, CI: 95%; odds ratio: 3.12 and 5.91, respectively).

CONCLUSIONS

In conclusion, IM administration of L-ASNase causes significantly less HSR to L-ASNase than the IV route. Patients with HRGALL have a higher risk of HSR. Since L-ASNase is still used in many developing countries and there are problems in the supply of Erwinia chrysanthemi ASNase (Erwinia), LASNase can be administered IM to reduce the frequency of HSR.

Evaluating the Frequencies of CNOT3, GRIA1, NFATC2, and PNPLA3 Variant Alleles and Their Association with L-Asparaginase Hypersensitivity in Pediatric Acute Lymphoblastic Leukemia in Addis Ababa, Ethiopia

Introduction

L-asparaginase is a vital component for the treatment of childhood acute lymphoblastic leukemia (ALL); however, hypersensitivity reactions and hepatotoxicity hinder its anti-neoplastic efficacy. Previous reports indicated that genetic variants in CNOT3, GRIA1, and NFATC2 genes might be associated with hypersensitivity reactions and PNPLA3 with liver function.

Objective

In this study, it was investigated whether this association also exists in a pediatric ALL cohort from Ethiopia.

Methods

Three variants GRIA1 rs4958351, CNOT3 rs73062673, and NFATC2 rs6021191 were genotyped in a cohort of 160 patients. Association analysis to investigate the association with hypersensitivity reactions was performed using logistic regression analyses. Besides these variants, a variant in PNPLA3 (rs738409) was genotyped to assess the association with liver function.

Results

Genotype frequencies of GRIA1 rs4958351, CNOT3 rs73062673, and NFATC2 rs6021191 were higher/lower than previously reported. One hundred and forty-four patients were included in the association analysis of which, 18 (12.5%) developed L-ASP hypersensitivity. Though the frequency of hypersensitivity was higher in patients that carried the risk alleles of the three investigated genes, no statistically significant differences were observed. Association analysis between PNPLA3 rs738409 and liver function could not be investigated due to a lack of clinical information.

Conclusion

In conclusion, none of the tested genes did predict L-asparaginase hypersensitivity in an Ethiopian pediatric ALL patients.

Our Experiences with Asparaginase Activity Measurements in Children with Lymphoblastic Diseases

BACKGROUND

Asparaginase is a key component of chemotherapy protocols for the treatment of lymphoblastic malignancies among children. Adequate asparagine depletion is an important factor to achieve optimal therapeutic outcomes.

METHODS

Over a 3.5 year period, 106 patients were monitored for asparaginase activity (329 samples) in a single center of the Hungarian Pediatric Oncology-Hematology Group. In Hungary, three asparaginase products are available: native E. coli ASNase (Kidrolase), a pegylated form of this enzyme (Pegaspargase) and another native product from Erwinia chrysanthemi (Erwinase). A retrospective data analysis was performed.

RESULTS

In 81% (268/329) of our patients, AEA levels were in the optimal therapeutic range of over 100 IU/L. Of 106 patients, 13 (12%) were diagnosed with 'silent inactivation'.

CONCLUSIONS

Monitoring of AEA can help to identify patients with 'silent inactivation' and their asparaginase therapy can thus be optimized.

A comprehensive strategy to address shortage of Erwinia asparaginase in pediatric acute lymphoblastic leukemia

BACKGROUND

Pegylated form of E. coli derived asparaginase (PEG) is a crucial component of pediatric ALL therapy. Patients who develop a hypersensitivity (HSR) reaction with PEG receive an alternative form - Erwinia asparaginase (EA). However, an international shortage in 2017 had made it challenging to treat these patients. We have developed a comprehensive strategy to address this need.

PATIENTS AND METHODS

This is a single center, retrospective analysis. All patients receiving PEG were premedicated to reduce infusion reactions. Patients who developed HSR underwent PEG desensitization. Patients were compared to historic controls.

RESULTS

Fifty-six patients were treated within the study period. There was no difference in the frequency of reactions before and after the adoption of universal premedication (p = 0.78). Eight patients (14.2%) developed either ≥ Grade 2 HSR or silent inactivation and 5 patients (62.5%) successfully underwent desensitization. The remaining three patients received EA asparaginase. This intervention led to a decrease in PEG substitution, with 3 patients (5.3%) requiring EA compared to 8 patients (15.09%) in the pre-intervention period. (p = 0.11) PEG desensitization was more cost effective than EA administration.

CONCLUSION

PEG desensitization is a safe, cost effective, and practical alternative in children with ALL and a Grade 2 or higher HSR.

Incidence and Characteristics of Hypersensitivity Reactions to PEG-asparaginase Observed in 6136 Children With Acute Lymphoblastic Leukemia Enrolled in the AIEOP-BFM ALL 2009 Study Protocol

The incidence of hypersensitivity reactions (HSRs) to PEG-asparaginase (PEG-ASNase) was evaluated in 6136 children with ALL enrolled in the AIEOP-BFM ALL 2009 study. Patients with B-cell precursor-acute lymphoblastic leukemia (BCP-ALL) were stratified as standard-risk/medium-risk (MR)/high-risk (HR) and those with T-ALL as non-High/HR. PEG-ASNase was administered intravenously at 2500 IU/sqm/dose. All patients received 2 PEG-ASNase doses in induction; thereafter non-HR versus HR patients received 1 versus 6 PEG-ASNase doses, respectively. After the single regular dose of PEG-ASNase at the beginning of delayed intensification, BCP-ALL-MR patients were randomized to receive 9 additional PEG-ASNase doses every 2 weeks (experimental arm [EA]) versus none (standard arm [SA]); HR patients were randomized to receive, in consolidation, 4 weekly PEG-ASNase doses (EA) versus none (SA). The HSR cumulative incidence (CI) was estimated adjusting for competing risks. An HSR occurred in 472 of 6136 (7.7%) patients. T-non- HR/BCP-Standard-Risk, BCP-MR-SA, BCP-MR-EA, HR-SA and HR-EA patients had 1-year-CI-HSR (±SE) rates of 5.2% (0.5), 5.2% (0.5), 4.0% (0.8), 20.2% (1.2), and 6.4% (1.3), respectively. The randomized intensification of PEG-ASNase did not significantly impact on HSR incidence in BCP-MR patients (1-y-CI-HSR 3.8% [0.8] versus 3.2% [0.6] in MR-EA versus MR-SA; P = 0.55), while impacted significantly in HR patients (1-y-CI-HSR 6.4% [1.3] versus 17.9% [1.8] in HR-EA and HR-SA, respectively; P < 0.001). The CI-HSR was comparable among non-HR groups and was not increased by a substantial intensification of PEG-ASNase in the BCP-MR-EA group whilst it was markedly higher in HR-SA than in HR-EA patients, suggesting that, in such a chemotherapy context, a continuous exposure to PEG-ASNase reduces the risk of developing an HSR.

L-asparaginase anti-tumor activity in pancreatic cancer is dependent on its glutaminase activity and resistance is mediated by glutamine synthetase

l-Asparaginase is a cornerstone of acute lymphoblastic leukemia (ALL) therapy since lymphoblasts lack asparagine synthetase (ASNS) and rely on extracellular asparagine availability for survival. Resistance mechanisms are associated with increased ASNS expression in ALL. However, the association between ASNS and l-Asparaginase efficacy in solid tumors remains unclear, thus limiting clinical development. Interestingly, l-Asparaginase also has a glutaminase co-activity that is crucial in pancreatic cancer where KRAS mutations activate glutamine metabolism. By developing l-Asparaginase-resistant pancreatic cancer cells and using OMICS approaches, we identified glutamine synthetase (GS) as a marker of resistance to l-Asparaginase. GS is the only enzyme able to synthesize glutamine, and its expression also correlates with l-Asparaginase efficacy in 27 human cell lines from 11 cancer indications. Finally, we further demonstrated that GS inhibition prevents cancer cell adaptation to l-Asparaginase-induced glutamine starvation. These findings could pave the way to the development of promising drug combinations to overcome l-Asparaginase resistance.

The anticancer effect of PASylated calreticulin-targeting L-ASNase in solid tumor bearing mice with immunogenic cell death-inducing chemotherapy

L-Asparaginase (L-ASNase), a bacterial enzyme that degrades asparagine, has been commonly used in combination with several chemical drugs to treat malignant hematopoietic cancers such as acute lymphoblastic leukemia (ALL). In contrast, the enzyme was known to inhibit the growth of solid tumor cells in vitro, but not to be effective in vivo. We previously reported that two novel monobodies (CRT3 and CRT4) bound specifically with calreticulin (CRT) exposed on tumor cells and tissues during immunogenic cell death (ICD). Here, we engineered L-ASNases conjugated with monobodies at the N-termini and PAS200 tags at the C-termini (CRT3LP and CRT4LP). These proteins were expected to possess four monobody and PAS200 tag moieties, which did not disrupt the L-ASNase conformation. These proteins were expressed 3.8-fold more highly in E. coli than those without PASylation. The purified proteins were highly soluble, with much greater apparent molecular weights than expected ones. Their affinity (Kd) against CRT was about 2 nM, 4-fold higher than that of monobodies. Their enzyme activity (∼6.5 IU/nmol) was similar to that of L-ASNase (∼7.2 IU/nmol), and their thermal stability was significantly increased at 55 °C. Their half-life times were > 9 h in mouse sera, about 5-fold longer than that of L-ASNase (∼1.8 h). Moreover, CRT3LP and CRT4LP bound specifically with CRT exposed on tumor cells in vitro, and additively suppressed the tumor growth in CT-26 and MC-38 tumor-bearing mice treated with ICD-inducing drugs (doxorubicin and mitoxantrone) but not with a non-ICD-inducing drug (gemcitabine). All data indicated that PASylated CRT-targeted L-ASNases enhanced the anticancer efficacy of ICD-inducing chemotherapy. Taken together, L-ASNase would be a potential anticancer drug for treating solid tumors.

Asparaginase therapy in patients with acute lymphoblastic leukemia: expert opinion on use and toxicity management

The addition of asparaginase to acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LBL) treatment regimens provides significant patient benefits. Asparaginase therapies vary in origin (Escherichia coli- or Erwinia-derived) and preparation (native or pegylated), conferring distinct pharmacokinetic and immunogenic profiles. Clinical hypersensitivity reactions (HSRs) are commonly reported in patients and range from localized erythema to systemic anaphylaxis. Due to its favorable pharmacokinetic profile and reduced immunogenicity compared to native E. coli preparations, pegaspargase is the first-line asparaginase therapeutic option. Switching to an Erwinia-derived asparaginase is recommended for patients who experience HSRs or antibody-mediated inactivation to achieve the significant clinical benefit observed in patients who complete asparaginase treatment. Previous global shortages of asparaginase Erwinia chrysanthemi necessitated conversion mitigation strategies such as premedication protocols, desensitization, and asparaginase activity level monitoring. Here, we discuss the efficacy, safety, pharmacokinetics, current use, and administration of asparaginase therapies for pediatric and adolescent patients with ALL/LBL.

Asparaginase activity monitoring in pediatric acute lymphoblastic leukemia: A cross-sectional nationwide study in Spain

BACKGROUND

A cross-sectional nationwide study was designed to assess national compliance with international consensus/guidelines of monitoring asparaginase levels in children with acute lymphoblastic leukemia (ALL) treated with asparaginase in routine clinical practice.

METHODS

An ad hoc questionnaire was designed and completed by staff physicians from Hemato-Oncology Units throughout Spain.

RESULTS

A total of 39 physicians (64% pediatricians) with a mean (SD) age 43.5 (7.9) years and 15.3 (17.6) years of professional activity participated in the study. They accounted for 90% of hospitals in which children with ALL are treated in Spain. A total of 19 participants (48.7%) reported that asparaginase levels were routinely monitored (own center in 2 cases [10.5%], another hospital in 17 cases [89.5%]). Asparaginase was not monitored in 51.3% of the cases, mostly (80%) because unavailability of testing. When asparaginase was monitored, 68% of participants reported that this was done in all asparaginase-treated patients and 84% in all phases of the disease (induction, consolidation, re-induction, maintenance) with a time interval of 7 days for the pegylated form, 48 h for Erwinia asparaginase and 14 days for maintenance with the pegylated form. All participants reported that they modified treatment according to results of testing, with a limit of total depletion of ≥100 IU/L. Levels <100 or 20 IU/L were considered indicative of hypersensitivity by 46% of physicians.

CONCLUSION

There is still a gap between what is recommended and what is done in clinical practice, with more than 50% of centers not monitoring the level of asparaginase activity in pediatric ALL. Protocols for asparaginase testing in daily practice should be implemented.

Asparaginase: How to Better Manage Toxicities in Adults

PURPOSE OF REVIEW

This review aims to help oncologists who predominantly treat adults better understand and manage asparaginase associated toxicities and prevent unnecessary discontinuation or reluctance of its use.

RECENT FINDINGS

Given the data supporting the benefit of incorporating multiple doses of asparaginase in pediatric type regimens, it is prudent to promote deeper understanding of this drug, particularly its toxicities, and its use so as to optimize treatment of ALL. Although asparaginase is associated with a variety of toxicities, the vast majority are not life threatening and do not preclude repeat dosing of this important drug. Understanding the pharmacology and toxicity profile of asparaginase is critical to dosing asparaginase appropriately in order to minimize these toxicities.

Evaluation of PEG-L-asparaginase in asparagine suppression and anti-drug antibody development in healthy Beagle dogs: A multi-phase preclinical study

L-asparaginase is a frequently used drug in the treatment of canine malignant lymphoma. Since production and availability of native E. coli-derived L-asparaginase are limited, PEG-L-asparaginase (PEG-ASP) is an alternative. However, recommended doses and dosing intervals are mainly empirically determined. A multi-phase clinical dose-finding study with seven healthy Beagle dogs was conducted to find the minimum effective dose and, potentially, a dosing interval for PEG-ASP in dogs. Plasma concentrations of amino acids and PEG-ASP activity were measured at various time points after administration of different doses of PEG-ASP. Anti-PEG and anti-asparaginase antibody titres were measured. Administration of 10 IU/kg PEG-ASP resulted in asparagine depletion in all dogs, albeit for various durations: for 9 days in all dogs, 15 days in five dogs, 21 days in three dogs and 29 days in one dog. Asparagine suppression occurred at PEG-ASP plasma concentrations < 25 IU/L. Subsequent administrations of a second and third dose of 20 IU/kg and 40 IU/kg PEG-ASP resulted in asparagine suppression at < 9 days in five dogs, accompanied by the development of antibodies against PEG and L-asparaginase. Two dogs with prolonged asparagine suppression after the second and third administration did not develop antibodies. Marked individual variation in the mechanism and duration of response to PEG-ASP was noted. Antibody formation against PEG-ASP was frequently observed and sometimes occurred after one injection. This study suggests that PEG-ASP doses as high as the currently used dose of 40 IU/kg might not be needed in treatment of canine malignant lymphoma.

Novel Insights on the Use of L-Asparaginase as an Efficient and Safe Anti-Cancer Therapy

Simple Summary

L-asparaginase (L-ASNase) therapy is key for achieving the very high cure rate of pediatric acute lymphoblastic leukemia (ALL), yet its use is mostly confined to this indication. One main reason preventing the expansion of today’s FDA-approved L-ASNases to solid cancers is their high toxicity and side effects, which become especially challenging in adult patients. The design of optimized L-ASNase molecules provides opportunities to overcome these unwanted toxicities. An additional challenge to broader application of L-ASNases is how cells can counter the pharmacological effect of this drug and the identification of L-ASNases resistance mechanisms. In this review, we discuss recent insights into L-ASNase adverse effects, resistance mechanisms, and how novel L-ASNase variants and drug combinations can expand its clinical applicability, with a focus on both hematological and solid tumors.

Abstract

L-Asparaginase (L-ASNase) is an enzyme that hydrolyses the amino acid asparagine into aspartic acid and ammonia. Systemic administration of bacterial L-ASNase is successfully used to lower the bioavailability of this non-essential amino acid and to eradicate rapidly proliferating cancer cells with a high demand for exogenous asparagine. Currently, it is a cornerstone drug in the treatment of the most common pediatric cancer, acute lymphoblastic leukemia (ALL). Since these lymphoblasts lack the expression of asparagine synthetase (ASNS), these cells depend on the uptake of extracellular asparagine for survival. Interestingly, recent reports have illustrated that L-ASNase may also have clinical potential for the treatment of other aggressive subtypes of hematological or solid cancers. However, immunogenic and other severe adverse side effects limit optimal clinical use and often lead to treatment discontinuation. The design of optimized and novel L-ASNase formulations provides opportunities to overcome these limitations. In addition, identification of multiple L-ASNase resistance mechanisms, including ASNS promoter reactivation and desensitization, has fueled research into promising novel drug combinations to overcome chemoresistance. In this review, we discuss recent insights into L-ASNase adverse effects, resistance both in hematological and solid tumors, and how novel L-ASNase variants and drug combinations can expand its clinical applicability.

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

BACKGROUND

Hypersensitivity 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 PATIENTS

Questionnaires 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.

RESULTS

Newly 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.

CONCLUSION

The 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.

Erythrocyte-enabled immunomodulation for vaccine delivery

Erythrocytes capture pathogens in circulation and present them to antigen-presenting cells (APCs) in the spleen. Senescent or apoptotic erythrocytes are physiologically eliminated by splenic APCs in a non-inflammatory manner as to not induce an immune reaction, while damaged erythrocytes tend to induce immune activation. The distinct characteristics of erythrocytes in their lifespan or different states inspire the design of targeting splenic APCs for vaccine delivery. Specifically, normal or damaged erythrocyte-driven immune targeting can induce antigen-specific immune activation, whereas senescent or apoptotic erythrocytes can be tailored to achieve antigen-specific immune tolerance. Recent studies have revealed the potential of erythrocyte-based vaccine delivery; however, there is still no in-depth review to describe the latest progress. This review summarizes the characteristics, different immune functions, and diverse vaccine delivery behaviors and biomedical applications of erythrocytes in different states. This review aims to contribute to the rational design and development of erythrocyte-based vaccine delivery systems for treating various infections, tumors, inflammatory diseases, and autoimmune diseases.

The impact of the host intestinal microbiome on carcinogenesis and the response to chemotherapy

The microbiome consists of all microbes present on and within the human body. An unbalanced, or 'dysbiotic' intestinal microbiome is associated with inflammatory bowel disease, diabetes and some cancer types. Drug treatment can alter the intestinal microbiome composition. Additionally, some chemotherapeutics interact with microbiome components, leading to changes in drug safety and/or efficacy. The intestinal microbiome is a modifiable target, using strategies such as antibiotic treatment, fecal microbial transplantation or probiotic administration. Understanding the impact of the microbiome on the safety and efficacy of cancer treatment may result in improved treatment outcome. The present review seeks to summarize relevant research and look to the future of cancer treatment, where the intestinal microbiome is recognized as an actionable treatment target.

Pediatric-inspired regimen with late intensification and increased dose of L-asparaginase for adult acute lymphoblastic leukemia: the KALLA 1406/1407 study

BACKGROUND/AIMS

The objective of this study was to evaluate the efficacy and feasibility of the pediatric-inspired regimen of the adult acute lymphoblastic leukemia (ALL) Working Party, the Korean Society of Hematology.

METHODS

Data of 99 patients with newly diagnosed ALL, who were treated with the KALLA 1406/1407 protocol, were retrospectively analyzed. All patients equally received age-adjusted daunorubicin, vincristine, and prednisolone. L-asparaginase was additionally administered to Philadelphia (Ph)-negative patients according to age, whereas Ph-positive patients received 600 mg/day of imatinib.

RESULTS

A total of 99 patients were enrolled in this study, of whom 62 (62.6%) were diagnosed with Ph-negative ALL and 37 (37.3%) were diagnosed with Ph-positive ALL. The median age of patients in the Ph-negative ALL group was 46 years, and that of patients in the Ph-positive ALL group was 49 years. In patients with Ph-negative ALL, 57 (92%) patients achieved complete remission (CR) and CR with incomplete hematologic recovery (CRi). Disease-free survival (DFS) and overall survival (OS) rates at 2 years were estimated to be 42% and 63%, respectively. In patients with Ph-positive ALL, 32 (86%) patients achieved CR/CRi, and 2-year DFS and OS were 31.2% and 49.1%, respectively. Patients who were able to proceed to the allogeneic hematopoietic cell transplantation and younger patients showed significantly superior survival in both Ph-negative ALL and Ph-positive ALL. Neutropenic fever and bacterial infection were the most common and severe adverse events.

CONCLUSION

The KALLA 1406/1407 protocol showed tolerable toxicities in adult ALL patients. Especially, younger patients had more survival benefits with KALLA 1406/1407 protocol.

Asparaginase Enzyme Activity Levels and Toxicity in Childhood Acute Lymphoblastic Leukemia: a NOPHO ALL2008 study

Overall asparaginase-associated toxicity and relapse were not significantly associated with increased asparaginase enzyme activity levels.

The risk of pancreatitis and osteonecrosis were significantly associated with increasing asparaginase enzyme activity.

Asparaginase treatment is a mainstay in contemporary treatment of acute lymphoblastic leukemia (ALL), but substantial asparaginase-related toxicity may lead to jeopardized protocol compliance and compromises survival. We investigated the association between risk of asparaginase-associated toxicities (AspTox) and asparaginase enzyme activity (AEA) levels in 1155 children aged 1.0 to 17.9 years, diagnosed with ALL between July 2008 and March 2016, and treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol. Patients with ≥2 blood samples for AEA measurement drawn 14 ± 2 days after asparaginase administration were included (6944 trough values). AEA was measurable (or >0 IU/L) in 955 patients, whereas 200 patients (17.3%) had asparaginase inactivation and few AspTox recorded. A time-dependent multiple Cox model of time to any first asparaginase-associated toxicity adjusted for sex and age was used. For patients with measurable AEA, we found a hazard ratio (HR) of 1.17 per 100 IU/L increase in median AEA (95% confidence interval [CI], 0.98-1.41; P = .09). For pancreatitis, thromboembolism, and osteonecrosis, the HRs were 1.40 (95% CI, 1.12-1.75; P = .002), 0.99 (95% CI, 0.70-1.40; P = .96), and 1.36 (95% CI, 1.04-1.77; P = .02) per 100 IU/L increase in median AEA, respectively. No significant decrease in the risk of leukemic relapse was found: HR 0.88 per 100 IU/L increase in AEA (95% CI, 0.66-1.16; P = .35). In conclusion, these results emphasize that overall AspTox and relapse are not associated with AEA levels, yet the risk of pancreatitis and osteonecrosis increases with increasing AEA levels.

L-Asparaginase Toxicity in the Treatment of Children and Adolescents with Acute Lymphoblastic Leukemia

Asparaginase is a basic component of chemotherapy in pediatric acute lymphoblastic leukemia (ALL) and has played a crucial role in improving the long-term survival of this disease. The objectives of this retrospective study were to elucidate the toxicity profile associated with asparaginase in children and adolescents with ALL, to analyze the impact of each type of toxicity on long-term outcomes, and to identify risk factors. We analyzed the medical charts of 165 patients diagnosed with ALL at Sf. Maria Iasi Children’s Hospital from 2010 to 2019 and treated according to a chemotherapeutic protocol containing asparaginase. The median duration of follow-up was 5 years (0.1–11.5 years). Groups of patients with specific types of toxicity were compared to groups of patients without toxicity. We found the following incidence of asparaginase-associated toxicity: 24.1% clinical hypersensitivity, 19.4% hepatotoxicity, 6.7% hypertriglyceridemia, 4.2% hyperglycemia, 3.7% osteonecrosis, 3% pancreatitis, 2.4% thrombosis, and 1.2% cerebral thrombosis. Overall, 82 patients (49.7%) had at least one type of toxicity related to asparaginase. No type of toxicity had a significant impact on overall survival or event-free survival. Being older than 14 years was associated with a higher risk of osteonecrosis (p = 0.015) and hypertriglyceridemia (p = 0.043) and a lower risk of clinical hypersensitivity (p = 0.04). Asparaginase-related toxicity is common and has a varied profile, and its early detection is important for realizing efficient and appropriate management.

Premedication prior to PEG-asparaginase is cost-effective in pediatric patients with acute lymphoblastic leukemia

BACKGROUND

PEG-asparaginase is critical in pediatric acute lymphoblastic leukemia (ALL) therapy but is highly immunogenic. Severe allergic reactions lead to substitution of further PEG-asparaginase with Erwinia. Erwinia is associated with more frequent dosing, increased expense, and limited availability. Premedication may reduce rates of allergic reactions.

PROCEDURES

This Markov model evaluated the cost-effectiveness of three strategies: premedication plus therapeutic drug monitoring (TDM), TDM alone, and no premedication or TDM. We modeled two scenarios: a standard-risk (SR) B-ALL patient receiving two asparaginase doses and a high-risk (HR) patient receiving seven asparaginase doses. The model incorporated costs of asparaginase, premedication, TDM and clinic visits, and lost parental wages associated with each additional Erwinia dose. We incorporated a five-year time horizon with a societal perspective. Outcomes were Erwinia substitutions avoided and differences in quality-adjusted life years (QALYs). Probabilistic and one-way sensitivity analyses evaluated model uncertainty.

RESULTS

In both scenarios, premedication was the least costly strategy. In SR and HR scenarios, premedication with monitoring resulted in 8% and 7% fewer changes to Erwinia compared with monitoring alone and 3% and 2% fewer changes compared with no premedication/monitoring, respectively. Premedication resulted in the most QALYs gained in the SR patients. Individual variation of model inputs did not change premedication/monitoring favorability for either scenario. In probabilistic sensitivity analyses, premedication/monitoring was favored in >87% of iterations in both scenarios.

CONCLUSION

Compared with other strategies, premedication use and asparaginase level monitoring in children with B-ALL is potentially cost-saving.

Efficacy and adverse events of continuous l-asparaginase administration for canine large cell lymphoma of presumed gastrointestinal origin

We examined the efficacy and adverse events of continuous l-asparaginase administration in dogs with large cell lymphoma of presumedgastrointestinal (GI) origin. We retrospectively reviewed medical records of dogs with large cell lymphoma of presumed GI origin treated with continuous l-asparaginase administration from 2009 to 2018. We collected information on the signalment, lesion site, complete blood count, serum biochemical profile, diagnostic imaging findings, cytological and histopathological findings, immunophenotype, l-asparaginase administration frequency, treatment response, adverse events, rescue protocol, and patient outcomes. Clinical outcomes were assessed using medical records or by contacting the owner or referring veterinarian. Thirty-two dogs with large cell lymphoma of presumed GI origin received weekly l-asparaginase administration. The median number of l-asparaginase injections was seven (range: 1-30). Although two of the 32 dogs had GI toxicity of grade 3 or higher, none developed a hypersensitivity reaction. The response rate based on ultrasonographic findings was 18/32 (56%) and that based on clinical signs was 30/32 (94%). The median overall progression-free survival was 50 days (range: 2-214 days), and median overall survival was 147 days (range: 2-482 days). Adverse events associated with continuous l-asparaginase administration were rare. Clinical signs at diagnosis improved in most cases. Based on these results, continuous l-asparaginase administration appears to be a reasonable treatment option for dogs with large cell lymphoma of presumed GI origin.

Asparagine: A Metabolite to Be Targeted in Cancers

Amino acids play central roles in cancer progression beyond their function as building blocks for protein synthesis. Thus, targeting amino acid acquisition and utilization has been proved to be therapeutically beneficial in various pre-clinical models. In this regard, depletion of circulating asparagine, a nonessential amino acid, by L-asparaginase has been used in treating pediatric acute lymphoblastic leukemia (ALL) for decades. Of interest, unlike most solid tumor cells, ALL cells lack the ability to synthesize their own asparagine de novo effectively. However, only until recently, growing evidence suggests that solid tumor cells strive to acquire adequate amounts of asparagine to support tumor progression. This process is subjected to the regulation at various levels, including oncogenic signal, tumor-niche interaction, intratumor heterogeneity and dietary accessibility. We will review the literature on L-asparaginase-based therapy as well as recent understanding of asparagine metabolism in solid tumor progression, with the hope of shedding light into a broader cancer therapeutic strategy by perturbing its acquisition and utilization.

Indications for Allogeneic HCT in Adults with Acute Lymphoblastic Leukemia in First Complete Remission

OPINION STATEMENT

Acute lymphoblastic leukemia (ALL) in adults is associated with poor outcomes as compared to children when treated with chemotherapy, leading to a considerably inferior cure rate. Historically, consolidation with allogeneic hematopoietic cell transplant (alloHCT) was routinely recommended for eligible adults with ALL in first complete remission (CR1) if a donor was available, since randomized studies showed superiority over continuing chemotherapy. With the increasing use of pediatric-inspired frontline regimens in young adults with ALL and the availability of novel salvage agents for relapsed/refractory B-cell ALL that have high potential in inducing a second CR, the role of early alloHCT in the treatment paradigm for ALL needs to be reevaluated, and the decision should be individualized for each patient. Simultaneously, alloHCT has evolved considerably lately, and historical randomized studies that have proven the benefit of alloHCT in adults with ALL in CR1 did not included the increasing use of reduced intensity conditioning and haploidentical transplants, and therefore, data may not entirely apply. Nowadays, detectable minimal residual disease (MRD) is the most prognostic determinant of ALL outcome and should be a major consideration in the decision to perform alloHcT in CR1. Nonetheless, other biological and clinical factors remain relevant and can support the complex decision-making. Such factors include high-risk leukemia genetics, the type of administered chemotherapy regimen and the ability of the patient to tolerate all key components of the regimen, and the availability of effective salvage therapies that allow alloHCT to be performed in CR2 in case of relapse after chemotherapy.

Relapse risk following truncation of pegylated asparaginase in childhood acute lymphoblastic leukemia

Truncation of asparaginase treatment due to asparaginase-related toxicities or silent inactivation (SI) is common and may increase relapse risk in acute lymphoblastic leukemia (ALL). We investigated relapse risk following suboptimal asparaginase exposure among 1401 children aged 1 to 17 years, diagnosed with ALL between July 2008 and February 2016, treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol (including extended asparaginase exposure [1000 IU/m2 intramuscularly weeks 5-33]). Patients were included with delayed entry at their last administered asparaginase treatment, or detection of SI, and followed until relapse, death, secondary malignancy, or end of follow-up (median, 5.71 years; interquartile range, 4.02-7.64). In a multiple Cox model comparing patients with (n = 358) and without (n = 1043) truncated asparaginase treatment due to clinical toxicity, the adjusted relapse-specific hazard ratio (HR; aHR) was 1.33 (95% confidence interval [CI], 0.86-2.06; P = .20). In a substudy including only patients with information on enzyme activity (n = 1115), the 7-year cumulative incidence of relapse for the 301 patients with truncation of asparaginase treatment or SI (157 hypersensitivity, 53 pancreatitis, 14 thrombosis, 31 other, 46 SI) was 11.1% (95% CI, 6.9-15.4) vs 6.7% (95% CI, 4.7-8.6) for the 814 remaining patients. The relapse-specific aHR was 1.69 (95% CI, 1.05-2.74, P=.03). The unadjusted bone marrow relapse-specific HR was 1.83 (95% CI, 1.07-3.14, P=.03) and 1.86 (95% CI, 0.90- 3.87, P=.095) for any central nervous system relapse. These results emphasize the importance of therapeutic drug monitoring and appropriate adjustment of asparaginase therapy when feasible. This trial was registered at www.clinicaltrials.gov as #NCT03987542.

Circumventing the side effects of L-asparaginase

L-asparaginase is an enzyme that catalyzes the degradation of asparagine and successfully used in the treatment of acute lymphoblastic leukemia. L-asparaginase toxicity is either related to hypersensitivity to the foreign protein or to a secondary L-glutaminase activity that causes inhibition of protein synthesis. PEGylated versions have been incorporated into the treatment protocols to reduce immunogenicity and an alternative L-asparaginase derived from Dickeya chrysanthemi is used in patients with anaphylactic reactions to the E. coli L-asparaginase. Alternative approaches commonly explore new sources of the enzyme as well as the use of protein engineering techniques to create less immunogenic, more stable variants with lower L-glutaminase activity. This article reviews the main strategies used to overcome L-asparaginase shortcomings and introduces recent tools that can be used to create therapeutic enzymes with improved features.

Association of aberrant ASNS imprinting with asparaginase sensitivity and chromosomal abnormality in childhood BCP-ALL

Karyotype is an important prognostic factor in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL), but the underlying pharmacogenomics remain unknown. Asparaginase is an integral component in current chemotherapy for childhood BCP-ALL. Asparaginase therapy depletes serum asparagine. Normal hematopoietic cells can produce asparagine by asparagine synthetase (ASNS) activity, but ALL cells are unable to synthesize adequate amounts of asparagine. The ASNS gene has a typical CpG island in its promoter. Thus, methylation of the ASNS CpG island could be one of the epigenetic mechanisms for ASNS gene silencing in BCP-ALL. To gain deep insights into the pharmacogenomics of asparaginase therapy, we investigated the association of ASNS methylation status with asparaginase sensitivity. The ASNS CpG island is largely unmethylated in normal hematopoietic cells, but it is allele-specifically methylated in BCP-ALL cells. The ASNS gene is located at 7q21, an evolutionally conserved imprinted gene cluster. ASNS methylation in childhood BCP-ALL is associated with an aberrant methylation of the imprinted gene cluster at 7q21. Aberrant methylation of mouse Asns and a syntenic imprinted gene cluster is also confirmed in leukemic spleen samples from ETV6-RUNX1 knockin mice. In 3 childhood BCP-ALL cohorts, ASNS is highly methylated in BCP-ALL patients with favorable karyotypes but is mostly unmethylated in BCP-ALL patients with poor prognostic karyotypes. Higher ASNS methylation is associated with higher L-asparaginase sensitivity in BCP-ALL through lower ASNS gene and protein expression levels. These observations demonstrate that silencing of the ASNS gene as a result of aberrant imprinting is a pharmacogenetic mechanism for the leukemia-specific activity of asparaginase therapy in BCP-ALL.

Adequate asparaginase is important to prevent central nervous system and testicular relapse of pediatric Philadelphia chromosome-negative B-cell acute lymphoblastic leukemia

Asparaginase (Asp) is one of the most important drugs for treating acute lymphoblastic leukemia (ALL). However, off-protocol Asp administration (OPAA) or hypersensitivity may disturb its pharmacokinetic profile. In this retrospective study, we sought to determine whether OPAA and hypersensitivity to Escherichia coli asparaginase (E coli Asp) impaired extramedullary relapse prevention in a pediatric ALL cohort treated according to SCMC-ALL-2005 protocol from 2005 to 2014 at the Shanghai Children's Medical Center (SCMC). In total, 676 patients were enrolled in this study, including 369 with OPAA and 60 exhibiting hypersensitivity to E coli Asp. At the end of the most recent follow-up, 58 patients had extramedullary relapse. The 5-year cumulative extramedullary relapse incidence in patients with OPAA was 11.01%, whereas that in patients without OPAA was 5.28% (P = .0036). Moreover, the 5-year cumulative extramedullary relapse incidence in patients that exhibited hypersensitivity to E coli Asp was 16.48%, whereas that in patients without hypersensitivity was 7.59% (P = .0195). Concerning the relapse site, OPAA not only increased central nervous system (CNS) relapse but testicular relapse as well. Based on Fine and Gray multivariate analysis, OPAA and hypersensitivity to Asp were independent risk factors for extramedullary relapse. In conclusion, to prevent extramedullary relapse of ALL, adequate duration to administrate Asp was more important than the total dosage, and more attention should be paid to Asp inadequate due to hypersensitivity.

Ammonia level as a proxy of asparaginase inactivation in children: A strategy for classification of infusion reactions

INTRODUCTION

Allergic hypersensitivity reactions related to enzyme asparaginase may occur during intravenous infusion of drugs and other adverse reactions (non-allergic hypersensitivity and hyperammonemia), which do not require discontinuation of therapy as the first case. It makes differential diagnoses between infusion reactions essential to assure the team regarding the right decision to make after the adverse event. This study evaluated a pharmacovigilance strategy of differentiating infusion reactions to asparaginase in pediatric patients, based on the measurement of serum ammonia and the classification of the reactions by clinical symptoms and severity.

METHODOLOGY

We included children, diagnosed with ALL, and treated with native Escherichia coli asparaginase in a university hospital. The professional team monitored and evaluated all asparaginase infusions for continuity of treatment (rechallenge), seeing the measurement of serum ammonia and classification of reactions for type and severity grade. Data from this monitoring was collected retrospectively. Chi-square and Mann-Whitney tests were used to compare the ratios between serum ammonia concentration posterior and before asparaginase infusion.

RESULTS

245 infusions in 32 patients were monitored, and 19 reactions were observed in 17 children (53%). Three children have hyperammonemia and continue their treatment. The variation of the serum ammonia levels before and after the infusion was statistically significant, comparing the groups with no reaction or hyperammonemia versus the group with the hypersensitivity reaction.

CONCLUSION

The pharmacovigilance strategy applied in the hospital investigated was a useful and inexpensive tool that supported clinical decision-making and enabled the maintenance of asparaginase therapy for three (9,4%) patients followed up.

Pseudomonas aeruginosa recombinant L-asparaginase: Large scale production, purification, and cytotoxicity on THP-1, MDA-MB-231, A549, Caco2 and HCT-116 cell lines

In previous studies Pseudomonas aeruginosal-ASNase complete coding sequence gene, 984 bp (GenBank accession number KU161101.2) was isolated by PCR, cloned into pET28a(+) vector, expressed in E. coli DE3(BL21) pLysS, purified to apparent homogeneity and biochemically characterized. In the present work we highlight large scale production, affinity purification of the recombinant enzyme, effect of osmolytes on the stability of the l-ASNase and cytotoxicity on different cancer cell lines. Successful overexpression was achieved in E. coli as a 6-His-Tag fusion protein after 18 h of induction with lactose at a concentration of 2 g/L in fermentation medium and at 37 °C. The recombinant enzyme was purified to homogeneity using Ni²⁺ chelated Fast Flow Sepharose resin with 19758.8 specific activity and 10.28 purification fold. With respect to the effect of osmolytes on the stability of the purified enzyme, the majority of the tested osmolytes namely 5% maltose, 5% mannitol, 30% glycerol and 5% BSA were found to increase the stability of the recombinant l-ASNase as compared to the free enzyme. Triple negative breast cancer cell line, MDA-MB-231 treated with recombinant l-ASNase showed significant morphological changes and the IC₅₀ of the purified enzyme was found to be 3.1 IU. Human leukemia cell line, THP-1 treated with l-ASNase showed apoptotic bodies and morphological changes with IC₅₀ of the purified enzyme 1.75 IU. Moreover, the purified recombinant l-ASNase was found to induced cytotoxic effects on colorectal adenocarcinoma cell line, Caco-2 with IC₅₀ of 68.28 IU. Results of apoptosis assay on THP-1 cells revealed that the purified l-ASNase induced early and late apoptosis at 14.16% and 7.56 respectively as compared to the control untreated cells.

Recent Strategies and Applications for l-Asparaginase Confinement

l-asparaginase (ASNase, EC 3.5.1.1) is an aminohydrolase enzyme with important uses in the therapeutic/pharmaceutical and food industries. Its main applications are as an anticancer drug, mostly for acute lymphoblastic leukaemia (ALL) treatment, and in acrylamide reduction when starch-rich foods are cooked at temperatures above 100 °C. Its use as a biosensor for asparagine in both industries has also been reported. However, there are certain challenges associated with ASNase applications. Depending on the ASNase source, the major challenges of its pharmaceutical application are the hypersensitivity reactions that it causes in ALL patients and its short half-life and fast plasma clearance in the blood system by native proteases. In addition, ASNase is generally unstable and it is a thermolabile enzyme, which also hinders its application in the food sector. These drawbacks have been overcome by the ASNase confinement in different (nano)materials through distinct techniques, such as physical adsorption, covalent attachment and entrapment. Overall, this review describes the most recent strategies reported for ASNase confinement in numerous (nano)materials, highlighting its improved properties, especially specificity, half-life enhancement and thermal and operational stability improvement, allowing its reuse, increased proteolysis resistance and immunogenicity elimination. The most recent applications of confined ASNase in nanomaterials are reviewed for the first time, simultaneously providing prospects in the described fields of application.

Implementation of the asparaginase activity assessment technique for clinical use: experience of a Brazilian Center

Acute lymphoid leukemia is a childhood cancer that in high-income countries has event-free survival rates of 80% and global survival rates of 90%. In Brazil these rates are under 70%. This difference may be due to the implementation of supportive care, including the assessment of asparaginase (ASNase) activity. ASNase may cause hypersensitivity reactions and silent drug inactivation. For this reason, ASNase activity monitoring is an essential tool to ensure an effective treatment. Our aim was to implement an ASNase activity measurement technique at a hospital setting. samples from children who were given Escherichia coli-derived ASNase were collected. The results of the analyses conducted in our laboratory Hospital de Clínicas de Porto Alegre were compared to those of two institutions: Centro Infantil Boldrini and University of Munster. 262 samples were assessed. The results of the first analyses were compared with those obtained at Centro Infantil Boldrini and showed an ICC of 0.954. Thirty samples were sent to the University of Munster and presented an ICC was 0.960. Our results, when compared to those of national and international centers, showed an excellent agreement. The study was able to implement an ASNase activity test to monitor the treatment.

Investigating the gut microbial community and genes in children with differing levels of change in serum asparaginase activity during pegaspargase treatment for acute lymphoblastic leukemia

Asparaginase (ASNase) is an effective treatment of pediatric acute lymphoblastic leukemia (ALL). Changes in ASNase activity may lead to suboptimal treatment and poorer outcomes. The gut microbiome produces metabolites that could impact ASNase therapy, however, remains uninvestigated. We examined gut-microbial community and microbial-ASNase and asparagine synthetase (ASNS) genes using 16SrRNA and metagenomic sequence data from stool samples of pediatric ALL patients. Comparing ASNase activity between consecutive ASNase-doses, we found microbial communities differed between decreased- and increased-activity samples. Escherichia predominated in the decreased-activity community while Bacteroides and Streptococcus predominated in the increased-activity community. In addition microbial ASNS was significantly (p=.004) negatively correlated with change in serum ASNase activity. These preliminary findings suggest microbial communities prior to treatment could affect serum ASNase levels, although the mechanism is unknown. Replication in an independent cohort is needed, and future research on manipulation of these communities and genes could prove useful in optimizing ASNase therapy.

Genetic inhibition of NFATC2 attenuates asparaginase hypersensitivity in mice

The family of nuclear factor of activated T cells (NFAT) transcription factors plays a critical role in mediating immune responses. Our previous clinical pharmacogenetic studies suggested that NFATC2 is associated with the risk of hypersensitivity reactions to the chemotherapeutic agent L-asparaginase (ASNase) that worsen outcomes during the treatment of pediatric acute lymphoblastic leukemia. We therefore hypothesized that the genetic inhibition of NFATC2 would protect against the development of anti-ASNase antibodies and ASNase hypersensitivity. Our study demonstrates that ASNase-immunized NFATC2-deficient mice are protected against ASNase hypersensitivity and develop lower antigen-specific and total immunoglobulin E (IgE) levels compared with wild-type (WT) controls. Furthermore, ASNase-immunized NFATC2-deficient mice develop more CD4+ regulatory T cells, fewer CD4+ interleukin-4-positive (IL-4+) cells, higher IL-10/TGF-β1 levels, and lower IL-4/IL-13 levels relative to WT mice. Basophils and peritoneal mast cells from ASNase-immunized, but not naïve, NFATC2-deficient mice had lower FcεRI expression and decreased IgE-mediated mast cell activation than WT mice. Furthermore, ASNase-immunized, but not naïve, NFATC2-deficient mice developed less severe shock than WT mice after induction of passive anaphylaxis or direct histamine administration. Thus, inhibition of NFATC2 protects against ASNase hypersensitivity by impairing T helper 2 responses, which may provide a novel strategy for attenuating hypersensitivity and the development of antidrug antibodies, including to ASNase.