Asparaginase activity levels and monitoring in patients with acute lymphoblastic leukemia

A comprehensive review on microbial l-asparaginase: Bioprocessing, characterization, and industrial applications

l-Asparaginase (E.C.3.5.1.1.) is a vital enzyme that hydrolyzes l-asparagine to l-aspartic acid and ammonia. This property of l-asparaginase inhibits the protein synthesis in cancer cells, making l-asparaginase a mainstay of pediatric chemotherapy practices to treat acute lymphoblastic leukemia (ALL) patients. l-Asparaginase is also recognized as one of the important food processing agent. The removal of asparagine by l-asparaginase leads to the reduction of acrylamide formation in fried food items. l-Asparaginase is produced by various organisms including animals, plants, and microorganisms, however, only microorganisms that produce a substantial amount of this enzyme are of commercial significance. The commercial l-asparaginase for healthcare applications is chiefly derived from Escherichia coli and Erwinia chrysanthemi. A high rate of hypersensitivity and adverse reactions limits the long-term clinical use of l-asparaginase. Present review provides thorough information on microbial l-asparaginase bioprocess optimization including submerged fermentation and solid-state fermentation for l-asparaginase production, downstream purification, its characterization, and issues related to the clinical application including toxicity and hypersensitivity. Here, we have highlighted the bioprocess techniques that can produce improved and economically viable yields of l-asparaginase from promising microbial sources in the current scenario where there is an urgent need for alternate l-asparaginase with less adverse effects.

Prospective, real-time monitoring of pegylated Escherichia coli and Erwinia asparaginase therapy in childhood acute lymphoblastic leukaemia and non-Hodgkin lymphoma in Belgium

Asparaginase (ASNase) is an important anti-leukaemic drug in the treatment of childhood acute lymphoblastic leukaemia (ALL) and non-Hodgkin lymphoma (NHL). A substantial proportion of patients develop hypersensitivity reactions with anti-ASNase neutralising antibodies, resulting in allergic reactions or silent inactivation (SI), and characterised by inactivation and rapid clearance of ASNase. We report results of a prospective, real-time therapeutic drug monitoring of pegylated Escherichia coli (PEG-)ASNase and Erwinia ASNase in children treated for ALL and NHL in Belgium. Erwinia ASNase was given as second-line after hypersensitivity to PEG-ASNase. In total, 286 children were enrolled in the PEG-ASNase cohort. Allergy was seen in 11·2% and SI in 5·2% of patients. Of the 42 patients treated with Erwinia ASNase, 7·1% experienced allergy and 2·4% SI. The median trough PEG-ASNase activity was high in all patients without hypersensitivity. After Erwinia administration significantly more day 3 samples had activities <100 IU/l (62·5% vs. 10% at day 2 (D2)). The median D2 activity was significantly higher for intramuscular (IM; 347 IU/l) than for intravenous Erwinia administrations (159 IU/l). This prospective, multicentre study shows that monitoring of ASNase activity during treatment of children with ALL and NHL is feasible and informative. Treatment with Erwinia ASNase warrants close monitoring and optimally adherence to a 2-day interval of IM administrations.

Clinical decisions following implementation of asparaginase activity monitoring in pediatric patients with acute lymphoblastic leukemia: Experience from a single-center study

We undertook this retrospective study to describe decisions made following asparaginase activity monitoring implementation at our center. Clinically apparent reactions (CARs) and asparaginase activity monitoring costs were described. Patients with acute lymphoblastic leukemia, aged <18 years who received asparaginase between April 2016 and September 2017, were included. Decisions made following receipt of asparaginase activity results were categorized as continuation, modification, premedication, or discontinuation. We included 129 patients (median age: 5.33 years) receiving 565 asparaginase doses. CARs were observed following 25 asparaginase doses (19/361 [5.3%] pegaspargase). A total of 224 asparaginase activity levels were ordered in 88 patients. Following receipt of 190 asparaginase activity results, asparaginase therapy was continued, modified, or premedicated in 188 (98.9%), 1 (0.005%), and 1 (0.005%) cases, respectively. Inadequate asparaginase activity was observed in three patients receiving Erwinia asparaginase. Asparaginase activity monitoring allowed patients with pegaspargase-associated CAR and adequate activity to continue therapy unchanged and was cost neutral.

Asparagine Synthetase in Cancer: Beyond Acute Lymphoblastic Leukemia

Asparagine Synthetase (ASNS) catalyzes the synthesis of the non-essential amino acid asparagine (Asn) from aspartate (Asp) and glutamine (Gln). ASNS expression is highly regulated at the transcriptional level, being induced by both the Amino Acid Response (AAR) and the Unfolded Protein Response (UPR) pathways. Lack of ASNS protein expression is a hallmark of Acute Lymphoblastic Leukemia (ALL) blasts, which, therefore, are auxotrophic for Asn. This peculiarity is the rationale for the use of bacterial L-Asparaginase (ASNase) for ALL therapy, the first example of anti-cancer treatment targeting a tumor-specific metabolic feature. Other hematological and solid cancers express low levels of ASNS and, therefore, should also be Asn auxotrophs and ASNase sensitive. Conversely, in the last few years, several reports indicate that in some cancer types ASNS is overexpressed, promoting cell proliferation, chemoresistance, and a metastatic behavior. However, enhanced ASNS activity may constitute a metabolic vulnerability in selected cancer models, suggesting a variable and tumor-specific role of the enzyme in cancer. Recent evidence indicates that, beyond its canonical role in protein synthesis, Asn may have additional regulatory functions. These observations prompt a re-appreciation of ASNS activity in the biology of normal and cancer tissues, with particular attention to the fueling of Asn exchange between cancer cells and the tumor microenvironment.

Pharmacotherapy in Children and Adolescents: Oncology

Pharmacotherapy in paediatric oncology is a difficult task. It is challenging to determine the optimal dose in children of different age groups. In addition, anticancer drugs display severe side effects reducing the quality of life. Late effects like secondary tumours and cardiotoxicity can be apparent years after treatment and must be taken into account when planning treatment schedules. Classical cytoreducing agents are still of great importance in treating children with leukaemia and solid tumours. In addition, drugs developed by rational drug design (targeted drugs) are a very important part of many treatment protocols, and newer drugs are emerging in several types of cancer. Unfortunately, there is only limited experience with newer drugs in children, because new drugs are mostly developed for adults. Complicated therapy regimens require a solid knowledge of the pharmacology of the drugs applied. This chapter attempts to introduce some pharmacological knowledge for the most important anticancer drugs in children with a focus on side effects and age-specific considerations.

Desensitization to pegaspargase in children with acute lymphoblastic leukemia and lymphoblastic lymphoma

Hypersensitivity to pegaspargase is associated with inferior survival in pediatric patients with acute lymphoblastic leukemia and lymphoblastic lymphoma. In the past year, drug-supply shortages have led to the lack of an available alternative to pegaspargase. Rather than omit asparaginase from the treatment of acute lymphoblastic leukemia or lymphoblastic lymphoma patients with hypersensitivity to pegaspargase, we continued pegaspargase treatments for nine pediatric patients, utilizing a rapid desensitization protocol. There were no adverse events related to the pegaspargase during desensitization, and all patients who were checked had asparaginase serum levels above the threshold of 0.1 IU/mL at 7 to 14 days after pegaspargase therapy.

Asparaginase: an old drug with new questions

The long-term outcome of acute lymphoblastic leukemia has improved dramatically due to the development of more effective treatment strategies. L-asparaginase (ASNase) is one of the main drugs used and causes death of leukemic cells by systematically depleting the non-essential amino acid asparagine. Three main types of ASNase have been used so far: native ASNase derived from Escherichia coli, an enzyme isolated from Erwinia chrysanthemi and a pegylated form of the native E. coli ASNase, the ASNase PEG. Hypersensitivity reactions are the main complication related to this drug. Although clinical allergies may be important, a major concern is that antibodies produced in response to ASNase may cause rapid inactivation of ASNase, leading to a worse prognosis. This reaction is commonly referred to as "silent hypersensitivity" or "silent inactivation". We are able to analyze hypersensitivity and inactivation processes by the measurement of the ASNase activity. The ability to individualize the ASNase therapy in patients, adjusting the dose or switching patients with silent inactivation to an alternate ASNase preparation may help improve outcomes in those patients. This review article aims to describe the pathophysiology of the inactivation process, how to diagnose it and finally how to manage it.

Universal premedication and therapeutic drug monitoring for asparaginase-based therapy prevents infusion-associated acute adverse events and drug substitutions

BACKGROUND

Asparaginase is a critical component of lymphoblastic leukemia therapy, with intravenous pegaspargase (PEG) as the current standard product. Acute adverse events (aAEs) during PEG infusion are difficult to interpret, representing a mix of drug-inactivating hypersensitivity and noninactivating reactions. Asparaginase Erwinia chrysanthemi (ERW) is approved for PEG hypersensitivity, but is less convenient, more expensive, and yields lower serum asparaginase activity (SAA). We began a policy of universal premedication and SAA testing for PEG, hypothesizing this would reduce aAEs and unnecessary drug substitutions.

PROCEDURE

Retrospective chart review of patients receiving asparaginase before and after universal premedication before PEG was conducted, with SAA performed 1 week later. We excluded patients who had nonallergic asparaginase AEs. Primary end point was substitution to ERW. Secondary end points included aAEs, SAA testing, and cost.

RESULTS

We substituted to ERW in 21 of 122 (17.2%) patients pre-policy, and 5 of 68 (7.4%) post-policy (RR, 0.427; 95% CI, 0.27-0.69, P = 0.028). All completed doses of PEG yielded excellent SAA (mean, 0.90 units/mL), compared with ERW (mean, 0.15 units/mL). PEG inactivation post-policy was seen in 2 of 68 (2.9%), one silent and one with breakthrough aAE. The rate of aAEs pre/post-policy was 17.2% versus 5.9% (RR, 0.342; 95% CI, 0.20-0.58, P = 0.017). Grade 4 aAE rate pre/post-policy was 15% versus 0%. Cost analysis predicts $125 779 drug savings alone per substitution prevented ($12 402/premedicated patient).

CONCLUSIONS

Universal premedication reduced substitutions to ERW and aAE rate. SAA testing demonstrated low rates of silent inactivation, and higher SAA for PEG. A substantial savings was achieved. We propose universal premedication for PEG be standard of care.

Retrospective cohort study monitoring PEG-asparaginase activity in acute lymphoblastic leukemia patients with and without premedication

Background: PEG-L-asparaginase (pegaspargase) is a critical component of therapy for children and adults with acute lymphoblastic leukemia (ALL). Allergic reactions, which may occur in up to one third of patients, are the major cause for discontinuation. One study reported lower rates of allergic reactions with premedication. Besides allergy, an unknown number of patients develop silent neutralizing antibodies not associated with allergic reactions. The purpose of this retrospective cohort study was to determine the incidence of silent inactivation of pegasparaginase and compare incidence of allergic reactions with and without premedication. Methods: Using a commercial assay, asparaginase activity was monitored following pegaspargase (2500 units/m 2) in newly diagnosed children and young adults with B- and T-cell ALL from February 2013 to May 2017. The incidence of allergic reactions before and after initiation of premedication in May 2015 was compared. Results: One patient out of 59 (1.7%) had silent inactivation after the second dose. No patient had silent inactivation after the first pegaspargase dose and no standard risk B-cell ALL patients, who received only two pegaspargase doses in combination with oral dexamethasone, had silent inactivation. The incidence of grade 3 or 4 allergic reactions was 3.7% per dose with premedication (methylprednisolone, acetaminophen and diphenhydramine) versus 5.2% without.  The incidence per patient with premedication given for most of the doses was 8.3% versus 17% without. These values are not statistically significant. Premedication did not affect pegaspargase activity. Conclusions: Due to the low incidence of silent inactivation with intravenous pegaspargase and the unlikely event patients receiving only two doses of pegasparaginase would receive erwinase for this possible transient silent inactivation, we recommend routine monitoring of pegaspargase activity only in patients scheduled to receive more than two doses.

A single-center multidisciplinary approach to managing the global Erwinia asparaginase shortage

The availability of Erwinia Asparaginase has been limited across the world due to manufacturing shortages or for some countries due to the high acquisition cost, putting patients at risk for inferior outcomes. This manuscript provides guidance on how to manage hypersensitivity reactions and utilize therapeutic drug monitoring (TDM) to conserve and limit Erwinia use. The clinical and financial impact of a multidisciplinary committee are also discussed. Faced with a global Erwinia shortage, a multidisciplinary asparaginase allergy committee was created to review all hypersensitivity reactions to asparaginase therapy, staff education was performed on the management of asparaginase hypersensitivity reactions, an institution-wide premedication policy was mandated, and standardized guidelines were created for TDM. This multidisciplinary approach reduced the PEG-asparaginase to Erwinia switch rate from 21% (35 of 163) to 7% (10 of 134) (p = .0035). A multifaceted approach can safely maintain patients on PEG-asparaginase and conserve Erwinia for patients who need it most.

Optimizing pegylated asparaginase use: An institutional guideline for dosing, monitoring, and management

The incorporation of L-asparaginase and pegylated asparaginase into pediatric-inspired regimens has conferred a survival advantage in treatment of adults with acute lymphoblastic leukemia. Use of asparaginase products requires careful prevention, monitoring, and management of adverse effects including hypersensitivity, hepatotoxicity, pancreatitis, coagulopathy, and thrombosis. Currently, there is limited published literature to offer guidance on management of these toxicities. At the University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, a standard of practice guideline was created to prevent and manage asparaginase-related adverse events. By sharing our long-term experience with asparaginase products and clinical management of asparaginase-induced toxicities, this article aims to improve patient safety and optimize treatment outcomes.

Pegaspargase-induced hypertriglyceridemia in a patient with acute lymphoblastic leukemia

Pegaspargase, a long acting formulation of L-asparaginase, is an asparagine specific enzyme that selectively kills leukemic cells by depleting plasma asparagine. Pegaspargase is FDA approved for the first-line treatment of adult acute lymphoblastic leukemia and is a critical component of numerous multi-chemotherapeutic regimens. Pegaspargase is associated with well-described toxicities including hypersensitivity reactions, hepatotoxicity, and thrombosis. However, hypertriglyceridemia is a much rarer complication of pegaspargase and has only been described in a limited number of reports. We present a case of severe hypertriglyceridemia after a single dose of pegaspargase. The patient was re-challenged with pegaspargase and again developed hypertriglyceridemia which was complicated by pancreatitis. Here, we summarize published reports and a literature review describing the incidence of pegaspargase-induced hypertriglyceridemia in common acute lymphoblastic leukemia protocols.