Outcomes Following Discontinuation of E. coli l-Asparaginase Upon Severe Allergic Reactions in Children With Acute Lymphoblastic Leukemia

Quality comparison of a state-of-the-art preparation of a recombinant L-asparaginase derived from Escherichia coli with an alternative asparaginase product

L-asparaginase (ASNase) is a protein that is essential for the treatment of acute lymphoblastic leukemia (ALL). The main types of ASNase that are clinically used involve native and pegylated Escherichia coli (E. coli)-derived ASNase as well as Erwinia chrysanthemi-derived ASNase. Additionally, a new recombinant E. coli-derived ASNase formulation has received EMA market approval in 2016. In recent years, pegylated ASNase has been preferentially used in high-income countries, which decreased the demand for non-pegylated ASNase. Nevertheless, due to the high cost of pegylated ASNase, non-pegylated ASNase is still widely used in ALL treatment in low- and middle-income countries. As a consequence, the production of ASNase products from low- and middle-income countries increased in order to satisfy the demand worldwide. However, concerns over the quality and efficacy of these products were raised due to less stringent regulatory requirements. In the present study, we compared a recombinant E. coli-derived ASNase marketed in Europe (Spectrila®) with an E. coli-derived ASNase preparation from India (Onconase) marketed in Eastern European countries. To assess the quality attributes of both ASNases, an in-depth characterization was conducted. Enzymatic activity testing revealed a nominal enzymatic activity of almost 100% for Spectrila®, whereas the enzymatic activity for Onconase was only 70%. Spectrila® also showed excellent purity as analyzed by reversed-phase high-pressure liquid chromatography, size exclusion chromatography and capillary zone electrophoresis. Furthermore, levels of process-related impurities were very low for Spectrila®. In comparison, the E. coli DNA content in the Onconase samples was almost 12-fold higher and the content of host cell protein was more than 300-fold higher in the Onconase samples. Our results reveal that Spectrila® met all of the testing parameters, stood out for its excellent quality and, thus, represents a safe treatment option in ALL. These findings are particularly important for low- and middle-income countries, where access to ASNase formulations is limited.

L-Asparaginase as the gold standard in the treatment of acute lymphoblastic leukemia: a comprehensive review

L-Asparaginase is an antileukemic drug long approved for clinical use to treat childhood acute lymphoblastic leukemia, the most common cancer in this population worldwide. However, the efficacy and its use as a drug have been subject to debate due to the variety of adverse effects that patients treated with it present, as well as the prompt elimination in plasma, the need for multiple administrations, and high rates of allergic reactions. For this reason, the search for new, less immunogenic variants has long been the subject of study. This review presents the main aspects of the L-asparaginase enzyme from a structural, pharmacological, and clinical point of view, from the perspective of its use in chemotherapy protocols in conjunction with other drugs in the different treatment phases.

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.

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.

Efficacy of the BNT162b2 mRNA COVID-19 vaccine in patients with B-cell non-Hodgkin lymphoma

Patients diagnosed with B-cell non-Hodgkin lymphoma (B-NHL), particularly if recently treated with anti-CD20 antibodies, are at risk of severe COVID-19 disease. Because studies evaluating humoral response to COVID-19 vaccine in these patients are lacking, recommendations regarding vaccination strategy remain unclear. The humoral immune response to BNT162b2 messenger RNA (mRNA) COVID-19 vaccine was evaluated in patients with B-NHL who received 2 vaccine doses 21 days apart and compared with the response in healthy controls. Antibody titer, measured by the Elecsys Anti-SARS-CoV-2S assay, was evaluated 2 to 3 weeks after the second vaccine dose. Patients with B-NHL (n = 149), aggressive B-NHL (a-B-NHL; 47%), or indolent B-NHL (i-B-NHL; 53%) were evaluated. Twenty-eight (19%) were treatment naïve, 37% were actively treated with a rituximab/obinutuzumab (R/Obi)-based induction regimen or R/Obi maintenance, and 44% had last been treated with R/Obi >6 months before vaccination. A seropositive response was achieved in 89%, 7.3%, and 66.7%, respectively, with response rates of 49% in patients with B-NHL vs 98.5% in 65 healthy controls (P < .001). Multivariate analysis revealed that longer time since exposure to R/Obi and absolute lymphocyte count ≥0.9 × 103/μL predicted a positive serological response. Median time to achieve positive serology among anti-CD20 antibody-treated patients was longer in i-B-NHL vs a-B-NHL. The humoral response to BNT162b2 mRNA COVID-19 vaccine is impaired in patients with B-NHL who are undergoing R/Obi treatment. Longer time since exposure to R/Obi is associated with improved response rates to the COVID-19 vaccine. This study is registered at www.clinicaltrials.gov as #NCT04746092.

Impact of Asparaginase Discontinuation on Outcome in Childhood Acute Lymphoblastic Leukemia: A Report From the Children's Oncology Group

PURPOSE

Asparaginase (ASNase) is an important component of acute lymphoblastic leukemia (ALL) treatment, but is often discontinued because of toxicity. Erwinia chrysanthemi ASNase (Erwinia) substitution was approved in 2011 for allergic reactions. Erwinia has, however, been intermittently unavailable because of drug supply issues. The impact of Erwinia substitution or complete ASNase discontinuation is unknown.

METHODS

Patients aged 1-30.99 years in frontline Children's Oncology Group trials for B-cell acute lymphoblastic leukemia between 2004 and 2011 (National Cancer Institute [NCI] standard risk [SR]: AALL0331; NCI high risk: AALL0232) were included. The number of prescribed pegaspargase (PEG-ASNase) doses varied by trial and strata. Maintenance therapy did not contain ASNase. Landmark analyses at maintenance compared disease-free survival (DFS) among those receiving all prescribed PEG-ASNase doses versus switching to Erwinia but receiving all doses versus not receiving all ASNase doses.

RESULTS

We included 5,195 AALL0331 and 3,001 AALL0232 patients. The cumulative incidence of PEG-ASNase discontinuation was 12.2% ± 4.6% in AALL0331 and 25.4% ± 0.8% in AALL0232. In multivariable analyses, NCI high-risk patients not receiving all prescribed ASNase doses had inferior DFS (hazard ratio [HR], 1.5; 95% CI, 1.2 to 1.9; P = .002) compared with those receiving all prescribed PEG-ASNase doses. Patients with Erwinia substitution who completed subsequent courses were not at increased risk (HR, 1.1; 95% CI, 0.7 to 1.6; P = .69). NCI SR patients who discontinued ASNase were not at elevated risk (HR, 1.2; 95% CI, 0.9 to 1.6; P = .23), except when restricted to those with slow early response, who were prescribed more ASNase because of therapy intensification (HR, 1.7; 95% CI, 1.1 to 2.7; P = .03).

CONCLUSION

Discontinuation of ASNase doses is associated with inferior DFS in higher-risk patients. Our results illustrate the severe consequences of Erwinia shortages.

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.

Do immunoglobulin G and immunoglobulin E anti-l-asparaginase antibodies have distinct implications in children with acute lymphoblastic leukemia? A cross-sectional study

Background

l-Asparaginase is essential in the treatment of childhood acute lymphoblastic leukemia. If immunoglobulin G anti-l-asparaginase antibodies develop, they can lead to faster plasma clearance and reduced efficiency as well as to hypersensitivity reactions, in which immunoglobulin E can also participate. This study investigated the presence of immunoglobulin G and immunoglobulin E anti-l-asparaginase antibodies and their clinical associations.

Methods

Under 16-year-old patients at diagnosis of B-cell acute lymphoblastic leukemia confirmed by flow cytometry and treated with a uniform l-asparaginase and chemotherapy protocol were studied. Immunoglobulin G anti-l-asparaginase antibodies were measured using an enzyme-linked immunosorbent assay. Intradermal and prick skin testing was performed to establish the presence of specific immunoglobulin E anti-l-asparaginase antibodies in vivo. Statistical analysis was used to investigate associations of these antibodies with relevant clinical events and outcomes.

Results

Fifty-one children were studied with 42 (82.35%) having anti-l-asparaginase antibodies. In this group immunoglobulin G antibodies alone were documented in 10 (23.8%) compared to immunoglobulin E alone in 18 (42.8%) patients. Immunoglobulin G together with immunoglobulin E were simultaneously present in 14 patients. Children who produced exclusively immunoglobulin G or no antibodies had a lower event-free survival (p-value = 0.024). Eighteen children (35.3%) relapsed with five of nine of this group who had negative skin tests suffering additional relapses (range: 2–4), compared to none of the nine children who relapsed who had positive skin tests (p-value < 0.001).

Conclusion

Children with acute lymphoblastic leukemia and isolated immunoglobulin G anti-l-asparaginase antibodies had a higher relapse rate, whereas no additional relapses developed in children with immunoglobulin E anti-l-asparaginase antibodies after the first relapse.