Erwinia asparaginase in pediatric acute lymphoblastic leukemia

Kinetics characterization of a low immunogenic recombinant l-asparaginase from Phaseolus vulgaris with cytotoxic activity against leukemia cells

l-asparaginases play a crucial role in the treatment of acute lymphoblastic leukemia (ALL), a type of cancer that mostly affects children and teenagers. However, it is common for these molecules to cause adverse reactions during treatment. These downsides ignite the search for novel asparaginases to mitigate these problems. Thus, this work aimed to produce and characterize a recombinant asparaginase from Phaseolus vulgaris (Asp-P). In this study, Asp-P was expressed in Escherichia coli with high yields and optimum activity at 40 °C, pH 9.0. The enzyme Km and Vmax values were 7.05 mM and 1027 U/mg, respectively. Asp-P is specific for l-asparagine, showing no activity against l-glutamine and other amino acids. The enzyme showed a higher cytotoxic effect against Raji than K562 cell lines, but only at high concentrations. In silico analysis indicated that Asp-P has lower immunogenicity than a commercial enzyme. Asp-P induced biofilm formation by Candida sp. due to sublethal dose, showing an underexplored potential of asparaginases. The absence of glutaminase activity, lower immunogenicity and optimal activity similar to physiological temperature conditions are characteristics that indicate Asp-P as a potential new commercial enzyme in the treatment of ALL and its underexplored application in the treatment of other diseases.

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.

Possible mechanism of metabolic and drug resistance with L-asparaginase therapy in childhood leukaemia

L-asparaginase, which hydrolyzes asparagine into aspartic acid and ammonia, is frequently used to treat acute lymphoblastic leukaemia in children. When combined with other chemotherapy drugs, the event-free survival rate is 90%. Due to immunogenicity and drug resistance, however, not all patients benefit from it, restricting the use of L-asparaginase therapy in other haematological cancers. To solve the problem of immunogenicity, several L-ASNase variants have emerged, such as Erwinia-ASNase and PEG-ASNase. However, even when Erwinia-ASNase is used as a substitute for E. coli-ASNase or PEG-ASNase, allergic reactions occur in 3%-33% of patients. All of these factors contributed to the development of novel L-ASNases. Additionally, L-ASNase resistance mechanisms, such as the methylation status of ASNS promoters and activation of autophagy, have further emphasized the importance of personalized treatment for paediatric haematological neoplasms. In this review, we discussed the metabolic effects of L-ASNase, mechanisms of drug resistance, applications in non-ALL leukaemia, and the development of novel L-ASNase.

Asparaginase encapsulated in erythrocytes as second-line treatment in hypersensitive patients with acute lymphoblastic leukaemia

Asparaginase is essential in treating acute lymphoblastic leukaemia (ALL). Asparaginase-related hypersensitivity causes treatment discontinuation, which is associated with decreased event-free survival. To continue asparaginase treatment after hypersensitivity, a formulation of asparaginase encapsulated in erythrocytes (eryaspase) was developed. In NOR-GRASPALL 2016 (NCT03267030) the safety and efficacy of eryaspase was evaluated in 55 patients (aged 1-45 years; median: 6.1 years) with non-high-risk ALL and hypersensitivity to asparaginase conjugated with polyethylene glycol (PEG-asparaginase). Eryaspase (150 u/kg) was scheduled to complete the intended course of asparaginase (1-7 doses) in two Nordic/Baltic treatment protocols. Forty-nine (96.1%) patients had asparaginase enzyme activity (AEA) ≥100 iu/l 14 ± 2 days after the first eryaspase infusion [median AEA 511 iu/l; interquartile range (IQR), 291-780], whereas six of nine (66.7%) patients had AEA ≥100 iu/l 14 ± 2 days after the fourth infusion (median AEA 932 iu/l; IQR, 496-163). The mean terminal half-life of eryaspase following the first infusion was 15.3 ± 15.5 days. Few asparaginase-related adverse events were reported; five patients (9.1%) developed clinical allergy associated with enzyme inactivation. Replacement therapy was successfully completed in 50 patients (90.9%). Eryaspase was well tolerated, and most patients had AEA levels above the therapeutic target after the first infusion. The half-life of eryaspase confirmed that a 2-week schedule is appropriate.

Asparaginase-Associated Pancreatitis in Pediatric Patients with Acute Lymphoblastic Leukemia: Current Perspectives

Asparaginase therapy is a vital agent in the treatment of acute lymphoblastic leukemia (ALL), with increasing evidence of its high importance in high-risk ALL populations. However, despite the clear clinical and biological benefits of asparaginase therapy, many patients experience toxicities. A well-known treatment-limiting toxicity is asparaginase-associated pancreatitis (AAP). If severe, it necessitates discontinuation of asparaginase therapy, which can lead to a higher risk of relapse in patients with ALL. New protocols for ALL therapy have increased overall total doses of asparaginase therapy in select high-risk populations and have incorporated longer half-life formulations of pegylated asparaginase. Treatment drug monitoring has also allowed assurance of adequate levels of asparagine depletion throughout treatment. It is currently unknown if these changes will increase rates of AAP. Interestingly, important pharmacogenomics data, such as single nucleotide polymorphisms, can identify patients at the highest risk for severe AAP. The incidence of AAP in recent trials, current pharmacogenomic data that could further our understanding of the disease, and the importance of cautiously re-exposing patients to further asparaginase treatment after an initial episode of AAP are discussed.

Evaluation of hypersensitivity reactions to cancer chemotherapeutic agents in pediatric patients

BACKGROUND

Hypersensitivity reactions (HSRs) to chemotherapeutic agents have been increasingly documented.

OBJECTIVE

The aim of this study was to investigate HSRs due to chemotherapeutics agents in childhood.

METHODS

From 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.

RESULTS

Fifty-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.

CONCLUSION

Among 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.

Insights into the Microbial L-Asparaginases: from Production to Practical Applications

L-asparaginase is a valuable protein therapeutic drug utilized for the treatment of leukemia and lymphomas. Administration of asparaginase leads to asparagine starvation causing inhibition of protein synthesis, growth, and proliferation of tumor cells. Besides its clinical significance, the enzyme also finds application in the food sector for mitigation of a cancer-causing agent acrylamide. The numerous applications ensue huge market demands and create a continued interest in the production of costeffective, more specific, less immunogenic and stable formulations which can cater both the clinical and food processing requirements. The current review article approaches the process parameters of submerged and solid-state fermentation strategies for the microbial production of the L-asparaginase from diverse sources, genetic engineering approaches used for the production of L-asparaginase enzyme and major applications in clinical and food sectors. The review also addresses the immunological issues associated with the L-asparaginase usage and the immobilization strategies, drug delivery systems employed to circumvent the toxicity complications are also discussed. The future prospects for microbial Lasparaginase production are discussed at the end of the review article.

Amino acid metabolism in hematologic malignancies and the era of targeted therapy

Tumor cells rewire metabolic pathways to adapt to their increased nutritional demands for energy, reducing equivalents, and cellular biosynthesis. Alternations in amino acid metabolism are 1 modality for satisfying those demands. Amino acids are not only components of proteins but also intermediate metabolites fueling multiple biosynthetic pathways. Amino acid-depletion therapies target amino acid uptake and catabolism using heterologous enzymes or recombinant or engineered human enzymes. Notably, such therapies have minimal effect on normal cells due to their lower demand for amino acids compared with tumor cells and their ability to synthesize the targeted amino acids under conditions of nutrient stress. Here, we review novel aspects of amino acid metabolism in hematologic malignancies and deprivation strategies, focusing on 4 key amino acids: arginine, asparagine, glutamine, and cysteine. We also present the roles of amino acid metabolism in the immunosuppressive tumor microenvironment and in drug resistance. This summary also offers an argument for the reclassification of amino acid-depleting enzymes as targeted therapeutic agents.

Drug-induced amino acid deprivation as strategy for cancer therapy

Cancer is caused by uncontrollable growth of neoplastic cells, leading to invasion of adjacent and distant tissues resulting in death. Cancer cells have specific nutrient(s) auxotrophy and have a much higher nutrient demand compared to normal tissues. Therefore, different metabolic inhibitors or nutrient-depleting enzymes have been tested for their anti-cancer activities. We review recent available laboratory and clinical data on using various specific amino acid metabolic pathways inhibitors in treating cancers. Our focus is on glutamine, asparagine, and arginine starvation. These three amino acids are chosen due to their better scientific evidence compared to other related approaches in cancer treatment. Amino acid-specific depleting enzymes have been adopted in different standard chemotherapy protocols. Glutamine starvation by glutaminase inhibitior, transporter inhibitor, or glutamine depletion has shown to have significant anti-cancer effect in pre-clinical studies. Currently, glutaminase inhibitor is under clinical trial for testing anti-cancer efficacy. Clinical data suggests that asparagine depletion is effective in treating hematologic malignancies even as a single agent. On the other hand, arginine depletion has lower toxicity profile and can effectively reduce the level of pro-cancer biochemicals in patients as shown by ours and others’ data. This supports the clinical use of arginine depletion as anti-cancer therapy but its exact efficacy in various cancers requires further investigation. However, clinical application of these enzymes is usually hindered by common problems including allergy to these foreign proteins, off-target cytotoxicity, short half-life and rapidly emerging chemoresistance. There have been efforts to overcome these problems by modifying the drugs in different ways to circumvent these hindrance such as (1) isolate human native enzymes to reduce allergy, (2) isolate enzyme isoforms with higher specificities and efficiencies, (3) pegylate the enzymes to reduce allergy and prolong the half-lives, and (4) design drug combinations protocols to enhance the efficacy of chemotherapy by drug synergy and minimizing resistance. These improvements can potentially lead to the development of more effective anti-cancer treatment with less adverse effects and higher therapeutic efficacy.

Population pharmacokinetics of intravenous Erwinia asparaginase in pediatric acute lymphoblastic leukemia patients

Erwinia asparaginase is an important component in the treatment of pediatric acute lymphoblastic leukemia. A large variability in serum concentrations has been observed after intravenous Erwinia asparaginase. Currently, Dutch Childhood Oncology Group protocols dose alterations are based on trough concentrations to ensure adequate asparaginase activity (≥100 IU/L). The aim of this study was to describe the population pharmacokinetics of intravenous Erwinia asparaginase to quantify and gather insight into inter-individual and inter-occasion variability. The starting dose was evaluated on the basis of the derived population pharmacokinetic parameters. In a multicenter prospective observational study, a total of 714 blood samples were collected from 51 children (age 1–17 years) with acute lymphoblastic leukemia. The starting dose was 20,000 IU/m² three times a week and adjusted according to trough levels from week three onwards. A population pharmacokinetic model was developed using NONMEM^®. A 2-compartment linear model with allometric scaling best described the data. Inter-individual and inter-occasion variability of clearance were 33% and 13%, respectively. Clearance in the first month of treatment was 14% higher (P<0.01). Monte Carlo simulations with our pharmacokinetic model demonstrated that patients with a low weight might require higher doses to achieve similar concentrations compared to patients with high weight. The current starting dose of 20,000 IU/m² might result in inadequate concentrations, especially for smaller, lower weight patients, hence dose adjustments based on individual clearance are recommended. The protocols were approved by the institutional review boards. (Registered at NTR 3379 Dutch Trial Register; www.trialregister.nl).

Erythrocyte encapsulated l-asparaginase (GRASPA) in acute leukemia

l-asparaginase, an enzyme originally derived from Escherichia coli, represents a major drug in the treatment of acute lymphoblastic leukemia. However, the occurrence of major adverse effects often leads to early withdrawal of the enzyme. Main side effects include immune-allergic reactions, coagulopathy, pancreatitis and hepatic disorders. Novel asparaginase formulations and alternative sources have been developed to address this issue, but the results were not totally satisfactory. l-asparaginase loaded red blood cells (RBCs; GRASPA) represent a new asparaginase presentation with reduced immunological adverse reactions. RBCs protect l-asparaginase, enhance its half-life and reduce the occurrence of adverse events. We reviewed the history, biology and clinical experiences with l-asparaginase, and the characteristics and first clinical experiences with GRASPA in the treatment of acute leukemia.

Asparaginase induces apoptosis and cytoprotective autophagy in chronic myeloid leukemia cells

The antitumor enzyme asparaginase, which targets essential amino acid L-asparagine and catalyzes it to L-aspartic acid and ammonia, has been used for years in the treatment of acute lymphoblastic leukemia (ALL), subtypes of myeloid leukemia and T-cell lymphomas, whereas the anti-chronic myeloid leukemia (CML) effect of asparaginase and its underlying mechanism has not been completely elucidated. We have shown here that asparaginase induced significant growth inhibition and apoptosis in K562 and KU812 cells. Apart from induction of apoptosis, we reported for the first time that asparaginase induced autophagic response in K562 and KU812 cells as evidenced by the formation of autophagosome, microtubule-associated protein light chain 3 (LC3)-positive autophagy-like vacuoles, and the upregulation of LC3-II. Further study suggested that the Akt/mTOR (mammalian target of rapamycin) and Erk (extracellular signal-regulated kinase) signaling pathway were involved in asparaginase-induced autophagy in K562 cells. Moreover, blocking autophagy using pharmacological inhibitors LY294002, chloroquine (CQ) and quinacrine (QN) enhanced asparaginase-induced cell death and apoptosis, indicating the cytoprotective role of autophagy in asparaginase-treated K562 and KU812 cells. Together, these findings provide a rationale that combination of asparaginase anticancer activity and autophagic inhibition might be a promising new therapeutic strategy for CML.

Asparaginase-associated toxicity in children with acute lymphoblastic leukemia

Asparaginase is an integral component of multiagent chemotherapy regimens for the treatment of children with acute lymphoblastic leukemia. Positive outcomes are seen in patients who are able to complete their entire prescribed course of asparaginase therapy. Toxicities associated with asparaginase use include hypersensitivity (clinical and subclinical), pancreatitis, thrombosis, encephalopathy, and liver dysfunction. Depending on the nature and severity of the toxicity, asparaginase therapy may be altered or discontinued in some patients. Clinical hypersensitivity is the most common asparaginase-associated toxicity requiring treatment discontinuation, occurring in up to 30% of patients receiving Escherichia coli-derived asparaginase. The ability to rapidly identify and manage asparaginase-associated toxicity will help ensure patients receive the maximal benefit from asparaginase therapy. This review will provide an overview of the common toxicities associated with asparaginase use and recommendations for treatment management.

Asparaginase pharmacokinetics and implications of therapeutic drug monitoring

Asparaginase is widely used in chemotherapeutic regimens for the treatment of acute lymphoblastic leukemia (ALL) and has led to a substantial improvement in cure rates, especially in children. Optimal therapeutic effects depend on a complete and sustained depletion of serum asparagine. However, pronounced interpatient variability, differences in pharmacokinetic properties between asparaginases and the formation of asparaginase antibodies make it difficult to predict the degree of asparagine depletion that will result from a given dose of asparaginase. The pharmacological principles underlying asparaginase therapy in the treatment of ALL are summarized in this article. A better understanding of the many factors that influence asparaginase activity and subsequent asparagine depletion may allow physicians to tailor treatment to the individual, maximizing therapeutic effect and minimizing treatment-related toxicity. Therapeutic drug monitoring provides a means of assessing a patient's current depletion status and can be used to better evaluate the potential benefit of treatment adjustments.

15 years of ATTEMPTS: a macromolecular drug delivery system based on the CPP-mediated intracellular drug delivery and antibody targeting

Traditionally, any drug intended for combating the tumor would distribute profoundly to other organs and tissues as lack of targeting specificity, thus resulting in limited therapeutic effects toward the tumor but severe drug-induced toxic side effects. To prevail over this obstacle of drug-induced systemic toxicity, a novel approach termed "ATTEMPTS" (antibody targeted triggered electrically modified prodrug type strategy) was designed, which directly introduces both of the targeting and prodrug features onto the protein drugs. The ATTEMPTS system is composed of the antibody targeting component consisting of antibodies linked with heparin, and the cell penetrating peptide (CPP) modified drug component. The two components mentioned above self-assembled into a tight complex via the charge to charge interaction between the anionic heparin and cationic CPP. Once accumulated at the targeting site, the CPP modified drug is released from the blockage by a second triggering agent, while remaining inactive in the circulation during tumor targeting thus aborting its effect on normal tissues. We utilized the heparin-induced inhibition on the cell-penetrating activity of CPP to create the prodrug feature, and subsequently the protamine-induced reversal of heparin inhibition to resume cell transduction of the protein drug via the CPP function. Our approach is the first known system to overcome this selectivity issue, enabling CPP-mediated cellular drug delivery to be practically applicable clinically. In this review, we thoroughly discussed the historical and novel progress of the "ATTEMPTS" system.

Erwinia asparaginase achieves therapeutic activity after pegaspargase allergy: a report from the Children's Oncology Group

AALL07P2 evaluated whether substitution of Erwinia asparaginase 25000 IU/m(2) for 6 doses given intramuscularly Monday/Wednesday/Friday (M/W/F) to children and young adults with acute lymphoblastic leukemia and clinical allergy to pegaspargase would provide a 48-hour nadir serum asparaginase activity (NSAA) ≥ 0.10 IU/mL. AALL07P2 enrolled 55 eligible/evaluable patients. NSAA ≥ 0.1 IU/mL was achieved in 38 of 41 patients (92.7%) with acceptable samples 48 hours and in 38 of 43 patients (88.4%) 72 hours after dosing during course 1. Among samples obtained during all courses, 95.8% (252 of 263) of 48-hour samples and 84.5% (125 of 148) of 72-hour samples had NSAA ≥ 0.10-IU/mL. Pharmacokinetic parameters were estimated by fitting the serum asparaginase activity-time course for all 6 doses given during course 1 to a 1-compartment open model with first order absorption. Erwinia asparaginase administered with this schedule achieved therapeutic NSAA at both 48 and 72 hours and was well tolerated with no reports of hemorrhage, thrombosis, or death, and few cases of grade 2 to 3 allergic reaction (n = 6), grade 1 to 3 hyperglycemia (n = 6), or grade 1 pancreatitis (n = 1). Following allergy to pegaspargase, Erwinia asparaginase 25000 IU/m(2) × 6 intramuscularly M/W/F can be substituted for a single dose of pegaspargase.

Expression of CD203c on basophils as a marker of immunoglobulin E-mediated (L)-asparaginase allergy

Immediate allergy to l-asparaginase (ASP) is a major obstacle in treating lymphoid malignancies. ASP-specific immunoglobulin G (ASP-IgG) has been used as a surrogate marker. Recently, the CD203c-basophil activation test (BAT) was found to be useful in diagnosing IgE-mediated allergies. We compared the diagnostic utility of the CD203c-BAT to that of ASP-IgG levels in determining ASP allergies in children. Eight ASP allergic reactions occurred over 75 ASP treatment courses. The sensitivity, specificity and area under the receiver operating characteristic curve of CD203c-BAT were similar to the ASP-IgG levels (0.75 vs. 0.85, 0.82 vs. 0.78 and 0.81 vs. 0.85, respectively). Positive skin prick test results in patients with ASP allergy suggested that ASP-IgE was one of the key players in ASP allergy. A combination of the BAT with the ASP-IgG level had the highest specificity (0.95) and positive predictive value (0.62), which permitted us to identify ASP allergy more effectively.