L-asparaginase is essential in treating pediatric acute lymphoblastic leukemia (ALL) but is limited by hypersensitivity reactions in up to 70% of patients, leading to severe, dose-limiting complications and compromised event-free survival.

This study conducted a genome-wide association study (GWAS) in a discovery cohort of 221 pediatric cancer patients who experienced l-asparaginase-induced hypersensitivity reactions (≥CTCAE grade 2) and 705 controls without hypersensitivity despite equivalent exposure. Results were replicated in an independent cohort of 41 cases and 139 controls.

Significant associations were identified between hypersensitivity and four genes crucial for amino acid stress response: CYP1B1 (rs59569490; odds ratio [OR]  =  8.5; 95% confidence interval [CI], 3.9-18.5; p  =  1.5 × 10-10), SEC16B (rs115461320; OR  =  4.2; 95% CI, 2.5-7.9; p  =  1.2 × 10-6), OPLAH (rs11993268; OR  =  4.8; 95% CI, 2.4-9.9; p  =  2.0 × 10-6), and SORCS2 (rs11940340; OR  =  6.7; 95% CI, 2.8-15.7; p  =  5.7 × 10-7). Variants in SEC16B, OPLAH, and SORCS2 remained significant in the analysis of the replication cohort (p < 0.05). Patients who carried risk alleles in two or more of these genes experienced an 86.4% increased incidence of hypersensitivity reactions in the discovery cohort (OR  =  25.2; 95% CI, 7.4-86.2; p  =  1.0 × 10-10), which was replicated in the independent cohort with a 100% incidence in carriers (p  =  0.04).

The cumulative incidence of these large effect variants highlights their significance for the identification of patients at high risk of l-asparaginase-induced hypersensitivity. Successfully identifying patients at increased risk of hypersensitivity reactions can inform personalized treatment strategies and limit these harmful dose-limiting reactions in pediatric ALL.

In the Dutch Childhood Oncology Group ALL11 protocol, PEGasparaginase dosing was individualized for standard-risk and medium-risk patients with acute lymphoblastic leukemia. After using our pragmatic old guideline, we aimed to improve individualized PEGasparaginase dosing by developing a population pharmacokinetic model-based dosing guideline.

After the 3 doses of 1500 IU/m 2 administered in induction, standard-risk patients received 1 individualized dose and medium-risk patients 14, targeting trough activity levels between 100 and 250 IU/L. The effectiveness, adherence, and toxicity of our new dosing guideline was assessed and compared with the old guideline.

In total, 92 patients (714 samples) were included in the new dosing group and 509 patients (4539 samples) were included in the old dosing group. Comparing the effectiveness, we found that 32% (22/67) of patients in the new and 13% (47/354) of patients in the old dosing group were within the target range after the first individualized dose ( P < 0.001). Among medium-risk patients, a median of 3 dose reductions was needed to reach and maintain levels within the target range in the new dosing group compared with 5 in the old dosing group ( P < 0.001). With a continuous PEGasparaginase dosing schedule, target trough activity levels were reached after 2 dose reductions in the new group versus 4 in the old dosing group. The adherence to the new guideline was >99%, with 6/714 recommended doses deviating from the guideline. With exception of a lower proportion of patients with increased (≥grade 3) serum alanine transaminase (34% new vs 64% old, P < 0.05) in the new dosing group, toxicity was comparable between guidelines.

With the new dosing guideline, fewer dose-reduction steps are necessary to reach and remain within the target. The high adherence rate emphasized its simplicity and practicality, confirming that it can be easily integrated into clinical practice.

Therapeutic drug monitoring (TDM) is important to optimize drug exposure and minimize toxicity for the individual patient.

This narrative review covers the pharmacokinetics (PK), -dynamics (PD) and -genetics of classic chemotherapeutic drugs used in frontline therapy for acute lymphoblastic leukemia (ALL), including anthracyclines, asparaginase, busulfan, cyclophosphamide, cytarabine, glucocorticoids, methotrexate, nelarabine, thiopurines, tyrosine kinase inhibitors, and vincristine. Furthermore, novel immunotherapies including blinatumomab, inotuzumab ozogamicin, and chimeric antigen receptor T-cells that are rapidly moving into frontline therapy are addressed. This review focuses on TDM already used in clinical practice as well as the unused potential and feasibility of TDM. Finally, important factors affecting PK/PD such as obesity and transition to adolescence and young adulthood are discussed.

Investigation of TDM as standard of care for antileukemic agents is highly warranted to personalize curative yet toxic anticancer regimens within frontline ALL treatment. Some of the drugs have been used in ALL treatment regimens for decades, but a wide range of new compounds are being introduced, some like blinatumomab reaching standard-of-care designation. Not least, optimized drug efficacy and reduction of the risk of serious toxicities may render TDM implementation cost-effective.

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

L-asparaginase (L-ASNase) is crucial in treating pediatric acute lymphoblastic leukemia (ALL), but its use is hampered by side effects from the immunogenicity and L-glutaminase (L-GLNase) co-activity of FDA-approved bacterial L-ASNases, often leading to treatment discontinuation and poor outcomes. The toxicity of these L-ASNases makes them especially challenging to use in adult cancer patients. To overcome these issues, we developed EBD-200, a humanized guinea pig L-ASNase with low Km and no L-GLNase activity, eliminating glutamine-related toxicity. EBD-200 showed comparable anti-cancer effects to PEGylated L-ASNase in ASNSlow ALL, melanoma and liver cancer models, with improved tolerability. Its potent anti-cancer efficacy and enhanced safety profile suggest that EBD-200 could benefit ALL patients and broaden treatment options for ASNSlow solid cancers.

Silent inactivation (SI) of L-asparaginase (ASP) is a phenomenon by which a neutralizing antibody for ASP (AAA) decreases ASP activity (ASA) in patients without a clinical allergy to ASP. Acute lymphoblastic leukemia (ALL) has a poor prognosis in patients with SI. Therefore, measurement of ASA levels, not AAA levels, is needed to identify patients with SI. We herein report the results of the prospective clinical trial ALL-ASP19, the first study in Japan to measure ASA and AAA to identify patients with SI. A total of 110 newly diagnosed ALL patients were enrolled, and ASA levels were measured three times during ALL treatment. Besides the 12 patients who discontinued the study, 32 were excluded due to inappropriate frequency and timing of ASA measurements and inappropriate ASP dosing. The remaining 66 patients were analyzed, and 3 patients with SI (4.5%) were identified. The incidence of SI is lower in Japan than in other countries. AAA was detected in all patients with SI, but four of the seven patients with AAA did not develop SI. Clinical characteristics did not significantly differ between patients with and without SI. Therefore, ASA levels must be measured to identify patients receiving insufficient ASP treatment.

 Biosimilar pegylated L-asparaginase offers a promising alternative to the innovator molecule for treating acute lymphoblastic leukemia (ALL) in Indian children. It addresses challenges associated with drug availability and cost while providing similar therapeutic advantages. This biosimilar ensures wider access to essential treatment in resource-limited settings such as India.

 A retrospective study was conducted at the Pediatric Oncology unit of the Department of Medical Oncology, Sher-I-Kashmir Institute of Medical Sciences (SKIMS) Srinagar. The study evaluated the efficacy and safety of biosimilar polyethylene glycol-asparaginase (PEG-ASP) (Asviia) in newly diagnosed pediatric ALL patients treated between January 2021 and December 2023. Each patient received two induction doses of PEG-ASP.

 The study included 45 patients (29 boys, 16 girls) with a median age of 7.5 years (range: 1-16 years), with most patients diagnosed with Pre-B ALL. The median PEG-ASP dose administered intravenously was 1175 IU (range: 1125-3750 IU). Significant improvements in hemoglobin and platelet counts were observed following the first dose of PEG-ASP. The biosimilar PEG-ASP was well tolerated, with no life-threatening events reported. At the end of the induction phase, 40 patients (88.89%) achieved complete remission with minimal residual disease (MRD) negativity, while five patients had MRD positivity.

 The study provides valuable insights into the efficacy and safety of biosimilar PEG-ASP for pediatric ALL in resource-limited settings, with strong data on remission rates and minimal adverse events.

l-asparaginase is an enzyme catalyzing the hydrolysis of l-asparagine into l-aspartate and ammonia, which is of great therapeutic importance in tumor treatment. However, commercially available enzymes are associated with adverse effects, and searching for a new l-asparaginase with better pharmaceutical properties was the aim of this work. The coding sequence for Mycobacterium smegmatisl-asparaginase (MsA) was cloned and expressed. The recombinant protein showed high activity toward l-asparagine, whereas none was detected for l-glutamine. The enzymatic properties (K m = 1.403 ± 0.24 mM and k cat = 708.1 ± 25.05 s-1) indicate that the enzyme would be functional within the expected blood l-asparagine concentration, with good activity, as shown by k cat. The pH and temperature profiles suggest its use as a biopharmaceutical in humans. Molecular dynamics analysis of the MsA model reveals the formation of a hydrogen bond network involving catalytic residues with l-asparagine. However, the same is not observed with l-glutamine, mainly due to steric hindrance. Additionally, the structural feature of residue 119 being a serine rather than a proline has significant implications. These findings help explain the low glutaminase activity observed in MsA, like what is described for the Wolinella succinogenes enzyme. This establishes mycobacterial asparaginases as key scaffolds to develop biopharmaceuticals against acute lymphocytic leukemia.

While Pegaspargase is an essential component of the treatment of acute lymphoid leukemia (ALL) in children, it causes adverse events (AEs) that sometimes make full use impossible.

The objective was to investigate the safety of Pegaspargase biosimilar in pediatric ALL patients undergoing treatment according to ICiCLe ALL-14 protocol.

A prospective study was carried out in a university teaching hospital located in the state of Maharashtra, India. Data on clinical factors and adverse reaction characteristics were gathered from hospital medical records. Suspected AEs were classified according to causality and severity.

During the study period, 72 children had 52 suspicions of AEs during treatment with biosimilar Pegaspargase. The odds ratio of 1.11 (95%CI, 0.41-2.98) suggested that males and females were both equally likely to experience adverse drug events, despite the fact that the frequency of suspected AEs was higher in boys (66%) than in girls (33%). None of the patients experienced allergic reactions. The high-risk category had the highest number of suspected AEs (56%), followed by intermediate risk (20%) and standard risk (20%). These patients showed a high frequency of suspected AEs during the induction phase (43%) followed by the consolidation phase (26%). Sixty percent of the reactions were classified as grade 1 or 2. ALL cell type (p = 0.02), risk category (p = 0.04) and length of hospitalization (p = 0.003) were significantly correlated with suspected AEs.

Bio-similar Pegaspargase in combination with chemotherapy was safe and tolerable in the pediatric ALL patients treated according to ICiCLe ALL-14 protocol. Suspected AEs ranged from mild to moderate and hepatic failure and hyperglycemia being severe.

Therapeutic drug monitoring of pegylated L-asparaginase (ASNase) ensures the drug effectiveness in childhood acute lymphoblastic leukaemia (ALL) patients. The biological drug property with variable immunogenic host clearance, and the prescription of its generic formulation urge the need for a reliable assay to ensure an optimal treatment and improve outcome. This study aimed to optimise an existing isocratic reversed-phase high performance liquid chromatography (RP-HPLC) method with an automated pre-column sample derivatisation and injection program, and a computational algorithm for measuring serum pegylated ASNase activity in children with ALL. Nath et al.'s method in 2009 was adopted and modified using a pegylated ASNase. A set of Microsoft Excel macros was developed for the serum drug activity computation. An Agilent InfinityLab LC Series 1260 Infinity II Quaternary System with fluorescence detection was employed with an Agilent Poroshell 120 EC-C18 4.6×100 mm, 2.7 µm analytical column. System flow rate was optimised to 2.0 mL/min with 40×10-6/bar pump compressibility. The O-phthaldialdehyde (OPA) solution composition was optimised to 1 % o-phthaldialdehyde, 0.8 % 2-mercaptoethanol, 7.13 % methanol, and 1.81 % sodium tetraborate. The pre-column derivatisation program mixed 0.1 µL sample with 25 µL OPA solution before the automated injection. Method validation was according to the ICH guidelines. Total analysis time was 15 min, with L-aspartic acid eluted at 0.96 min and internal standard at 4.7 min. The calibration curves showed excellent linearity (R ≥0.9999). Interday precision for the drug activity at 0.1 IU/mL, 0.5 IU/mL, and 1 IU/mL were 4.15 %, 3.05 %, and 3.09 % (n = 6). Mean %error for the drug activity at 0.1 IU/mL, 0.5 IU/mL, and 1 IU/mL were 0.90±4.41 %, -1.37±3.04 %, and -3.03±3.02 % (n = 6). Limit of quantitation was 0.03 IU/mL. Majority of the patients' serum drug activity fell within the assay calibration range. Our improved method is automated, having shorter analysis time with a well-maintained separation resolution that enables a high-throughput analysis for application.

Acute lymphoblastic leukemia represents the most prevalent childhood cancer. Modern chemotherapy has significantly improved outcomes, achieving EFS rates of 80% and OS rates nearing 90% in developed nations, while in developing regions, rates remain below 50%, highlighting disparities, and this difference is due to several factors. Genetic variability plays a role in these drug response disparities, presenting single-nucleotide variations (SNVs). Pharmacogenetic research aims to pinpoint these SNVs early in treatment to predict specific drug responses effectively. This review aims to explore advancements in pharmacogenetics associated with asparaginase (ASNase). ASNase plays a crucial role in the treatment of ALL and is available in three formulations: E. coli, Erwinia, and PEG ASNase. ASNase therapy presents challenges due to adverse effects, like hypersensitivity reactions. Identifying predictive markers for hypersensitivity development beforehand is crucial for optimizing treatments. Several pharmacogenetic studies have investigated the association between SNVs and the risk of hypersensitivity. Key genes include GRIA1, NFATC2, CNTO3, ARHGAP28, MYBBP1A, and HLA. Studies have highlighted associations between SNVs within these genes and hypersensitivity reactions. Notably, most pharmacogenetic investigations of hypersensitivity have focused on patients treated with E. coli, emphasizing the need for broader exploration across different formulations. Future research investigating these variants holds promise for advancing our understanding of ASNase's pharmacogenetics.

The aims of this work were to optimize the production of Erwinia carotovoral-asparaginase II enzyme in Escherichia coli by different fed-batch cultivation strategies using a benchtop bioreactor and to evaluate the therapeutic potential of the recombinant enzyme against different acute lymphoblastic leukemia cell lines. The highest enzyme activities (∼98,000 U/L) were obtained in cultures using the DO-stat feeding strategy with induction in 18 h of culture. Under these experimental conditions, the maximum values for recombinant l-asparaginase II (rASNase) yield per substrate, rASNase yield per biomass, and productivity were approximately 1204 U/gglucose, 3660 U/gcells, and 3260 U/(L·h), respectively. This condition was efficient for achieving high yields of the recombinant enzyme, which was purified and used in in vitro antileukemic potential tests. Of all the leukemic cell lines tested, RS4;11 showed the highest sensitivity to rASNase, with an IC50 value of approximately 0.0006 U/mL and more than 70% apoptotic cells. The study demonstrated that the cultivation strategies used were efficient for obtaining high yield and productivity of rASNase with therapeutic potential inasmuch as cytotoxic activity and induction of apoptosis were demonstrated for this protein.

Studies on asparaginase enzyme activity (AEA) monitoring in Chinese patients receiving PEG-asparaginase remain limited. We monitored AEA in paediatric patients diagnosed with acute lymphoblastic leukaemia (ALL) and treated according to the Chinese Children's Cancer Group study protocols, CCCG-ALL-2015/CCCG-ALL-2020 protocols. We measured the AEA at days 7 ± 1 and 14 ± 1 and analysed their association with patient characteristics and PEG-asparaginase-related adverse effects (AEs). We measured 2147 samples from 329 patients. Mean AEA levels (interquartile range) were 931 iu/L (654-1174 iu/L) at day 7 ± 1 and 664 iu/L (463-860 iu/L) at day 14 ± 1. The AEA levels were higher in younger children and increased with the cumulative dose numbers. PEG-asparaginase inactivation rate was 19.1%, and the silent inactivation (SI) rate was 12.5%. Nine patients were identified with allergic-like reactions. Hypofibrinogenaemia, hypertriglyceridaemia, pancreatitis and thrombosis were associated with older age, whereas hypoglycaemia was associated with younger age. The risk of hypertriglyceridaemia and hypoglycaemia increased with cumulative dose numbers of PEG-asparaginase. Except for hypofibrinogenaemia, elevated AEA levels did not increase the risk of PEG-asparaginase-related AEs. Drug monitoring can be utilized as guidance for treatment decision-making. Individualizing asparaginase doses do not reduce toxicities. The treatment target of PEG-asparaginase remains to achieve sustained and adequate activity.

To compare the efficacy and safety of different asparaginase formulations in the treatment of acute lymphoblastic leukemia (ALL) based on nano-magnetic bead immunoassay.

Retrospective analysis of adult ALL patients' clinical data who admitted to The Affiliated Hospital of Changsha Health Vocational College from August 2020 to August 2023. Finally, 65 adult ALL patients were included in this study, including the polyethylene glycol conjugated asparaginase (PEG-ASNase) group (n = 32) and the L-asparaginase (L-ASNase) group (n = 33). Enzyme-linked immunosorbent assay (ELISA) based on magnetic nanoparticles was used to determine the activity of ASNase in both groups. The levels of asparagine or glutamine in two groups were detected by automatic biochemical analyzer during induction therapy, and the adverse events of the two groups were observed during the treatment.

PEG-ASNase demonstrated a slower decrease in enzyme activity, longer action duration, and higher safety profile compared to L-ASNase. PEG-ASNase group and L-ASNase group demonstrated a similar complete remission rate (71.88% vs. 60.61%). Event-free survival was higher in patients receiving PEG-ASNase than those receiving L-ASNase (42.4% and 18.7%). The observed adverse reactions included allergic reactions, pancreatic lesions, gastrointestinal reactions and liver function damage. The incidence of gastrointestinal reactions and liver function damage was higher in the L-ASNase group than that in PEG-ASNase group (45.45% and 33.33%).

This study provides valuable insights into the asparaginase treatments in clinical, highlighting the importance of PEG-ASNase for improving treatment protocols in adult ALL patients.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease without meaningful therapeutic options beyond the first salvage therapy. Targeting PDAC metabolism through amino acid restriction has emerged as a promising new strategy, with asparaginases, enzymes that deplete plasma glutamine and asparagine, reaching clinical trials. In this study, we investigated the anti-PDAC activity of the asparaginase formulation Pegcrisantaspase (PegC) alone and in combination with standard-of-care chemotherapeutics.

Using mouse and human PDAC cell lines, we assessed the impact of PegC on cell proliferation, cell death, and cell cycle progression. We further characterized the in vitro effect of PegC on protein synthesis as well as the generation of reactive oxygen species and levels of glutathione, a major cellular antioxidant. Additional cell line studies examined the effect of the combination of PegC with standard-of-care chemotherapeutics. In vivo, the tolerability and efficacy of PegC, as well as the impact on plasma amino acid levels, was assessed using the C57BL/6-derived KPC syngeneic mouse model.

Here we report that PegC demonstrated potent anti-proliferative activity in a panel of human and murine PDAC cell lines. This decrease in proliferation was accompanied by inhibited protein synthesis and decreased levels of glutathione. In vivo, PegC was tolerable and effectively reduced plasma levels of glutamine and asparagine, leading to a statistically significant inhibition of tumor growth in a syngeneic mouse model of PDAC. There was no observable in vitro or in vivo benefit to combining PegC with standard-of-care chemotherapeutics, including oxaliplatin, irinotecan, 5-fluorouracil, paclitaxel, and gemcitabine. Notably, PegC treatment increased tumor expression of asparagine and serine biosynthetic enzymes.

Taken together, our results demonstrate the potential therapeutic use of PegC in PDAC and highlight the importance of identifying candidates for combination regimens that could improve cytotoxicity and/or reduce the induction of resistance pathways.

Asparagine is a non-essential amino acid crucial for protein biosynthesis and function, and therefore cell maintenance and growth. Furthermore, this amino acid has an important role in regulating several metabolic pathways, such as tricarboxylic acid cycle and the urea cycle. When compared to normal cells, tumor cells typically present a higher demand for asparagine, making it a compelling target for therapy. In this review article, we investigate different facets of asparagine bioavailability intricate role in malignant tumors raised from solid organs. We take a comprehensive look at asparagine synthetase expression and regulation in cancer, including the impact on tumor growth and metastasis. Moreover, we explore asparagine depletion through L-asparaginase as a potential therapeutic method for aggressive solid tumors, approaching different formulations of the enzyme and combinatory therapies. In summary, here we delve into studies about endogenous and exogenous asparagine availability in solid cancers, analyzing therapeutic implications and future challenges.

Monitoring the blood serum activity of L-asparaginase in children with acute lymphoblastic leukaemia (ALL) has been highly recommended to detect enzyme inactivation that can cause relapse and to avoid unwanted toxicity. Nevertheless, perhaps at least partially due to the lack of clinically approved commercially available kits or standardized and independently reproduced and validated in-house protocols, laboratory assay-based determination of the optimal doses of L-asparaginase is not carried out routinely. In this study, we adapted previously published protocols for two plate reader-based colorimetric methods, indooxine and Nessler, to measure asparaginase activity. Mock samples with dilutions of the enzyme for initial optimization steps, and patient samples were used as a proof of principle and to compare the two protocols. For the first time the indooxine and the Nessler methods are adapted for a plate reader and L-asparaginase serum activity levels are compared by both protocols. Passing-Bablok and Bland-Altman's statistical analyses found very little difference, strong correlation (r = 0.852), and bias of only 6% between the data from the two methods when used for fresh patient samples. Furthermore, we demonstrate that the Nessler method could also be applied for frozen sera as the results, compared to fresh samples, showed little difference, strong correlation (r = 0.817), and small bias (9%). We successfully adapted and validated two methods for measuring L-asparaginase activity in cALL and provided the most detailed description to date on how to reproduce and implement them in other clinical laboratories.

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.

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.

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.

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.

Engineering human enzymes for therapeutic applications is attractive but introducing new amino acids may adversely affect enzyme stability and immunogenicity. Here we used a mammalian membrane-tethered screening system (ECSTASY) to evolve human lysosomal beta-glucuronidase (hBG) to hydrolyze a glucuronide metabolite (SN-38G) of the anticancer drug irinotecan (CPT-11). Three human beta-glucuronidase variants (hBG3, hBG10 and hBG19) with 3, 10 and 19 amino acid substitutions were identified that display up to 40-fold enhanced enzymatic activity, higher stability than E. coli beta-glucuronidase in human serum, and similar pharmacokinetics in mice as wild-type hBG. The hBG variants were two to three orders of magnitude less immunogenic than E. coli beta-glucuronidase in hBG transgenic mice. Intravenous administration of an immunoenzyme (hcc49-hBG10) targeting a sialyl-Tn tumor-associated antigen to mice bearing human colon xenografts significantly enhanced the anticancer activity of CPT-11 as measured by tumor suppression and mouse survival. Our results suggest that genetically-modified human enzymes represent a good alternative to microbially-derived enzymes for therapeutic applications.

L-asparaginase is an essential drug used to treat acute lymphoid leukemia (ALL), a cancer of high prevalence in children. Several adverse reactions associated with L-asparaginase have been observed, mainly caused by immunogenicity and allergenicity. Some strategies have been adopted, such as searching for new microorganisms that produce the enzyme and applying protein engineering. Therefore, this work aimed to elucidate the molecular structure and predict the immunogenic profile of L-asparaginase from Penicillium cerradense, recently revealed as a new fungus of the genus Penicillium and producer of the enzyme, as a motivation to search for alternatives to bacterial L-asparaginase. In the evolutionary relationship, L-asparaginase from P. cerradense closely matches Aspergillus species. Using in silico tools, we characterized the enzyme as a protein fragment of 378 amino acids (39 kDa), including a signal peptide containing 17 amino acids, and the isoelectric point at 5.13. The oligomeric state was predicted to be a homotetramer. Also, this L-asparaginase presented a similar immunogenicity response (T- and B-cell epitopes) compared to Escherichia coli and Dickeya chrysanthemi enzymes. These results suggest a potentially useful L-asparaginase, with insights that can drive strategies to improve enzyme production.

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy characterized by disrupted blood cell production and function. Recent investigations have highlighted the potential of targeting glutamine metabolism as a promising therapeutic approach for AML. Asparaginases, enzymes that deplete circulating glutamine and asparagine, are approved for the treatment of acute lymphoblastic leukemia, but are also under investigation in AML, with promising results. We previously reported an elevation in plasma serine levels following treatment with Erwinia-derived asparaginase (also called crisantaspase). This led us to hypothesize that AML cells initiate the de novo serine biosynthesis pathway in response to crisantaspase treatment and that inhibiting this pathway in combination with crisantaspase would enhance AML cell death. Here we report that in AML cell lines, treatment with the clinically available crisantaspase, Rylaze, upregulates the serine biosynthesis enzymes phosphoglycerate dehydrogenase (PHGDH) and phosphoserine aminotransferase (PSAT1) through activation of the Amino Acid Response (AAR) pathway, a cellular stress response mechanism that regulates amino acid metabolism and protein synthesis under conditions of nutrient limitation. Inhibition of serine biosynthesis through CRISPR-Cas9-mediated knockout of PHGDH resulted in a ~250-fold reduction in the half-maximal inhibitory concentration (IC50) for Rylaze, indicating heightened sensitivity to crisantaspase therapy. Treatment of AML cells with a combination of Rylaze and a small molecule inhibitor of PHGDH (BI4916) revealed synergistic anti-proliferative effects in both cell lines and primary AML patient samples. Rylaze-BI4916 treatment in AML cell lines led to the inhibition of cap-dependent mRNA translation and protein synthesis, as well as a marked decrease in intracellular glutathione levels, a critical cellular antioxidant. Collectively, our results highlight the clinical potential of targeting serine biosynthesis in combination with crisantaspase as a novel therapeutic strategy for AML.

Asparaginase is an essential component of acute lymphoblastic leukemia (ALL) therapy, yet its associated toxicities often lead to treatment discontinuation, increasing the risk of relapse. Hypersensitivity reactions include clinical allergies, silent inactivation, or allergy-like responses. We hypothesized that even moderate increases in asparaginase clearance are related to later inactivation. We therefore explored mandatory monitoring of asparaginase enzyme activity (AEA) in patients with ALL aged 1-45 years treated according to the ALLTogether pilot protocol in the Nordic and Baltic countries to relate mean AEA to inactivation, to build a pharmacokinetic model to better characterize the pharmacokinetics of peg-asparaginase and assess whether an increased clearance relates to subsequent inactivation. The study analyzed 1631 real-time AEA samples from 253 patients, identifying inactivation in 18.2% of the patients. This inactivation presented as mild allergy (28.3%), severe allergy (50.0%), or silent inactivation (21.7%). A pharmacokinetic transit compartment model was used to describe AEA-time profiles, revealing that 93% of patients with inactivation exhibited prior increased clearance, whereas 86% of patients without hypersensitivity maintained stable clearance throughout asparaginase treatment. These findings enable prediction of inactivation and options for either dose increments or a shift to alternative asparaginase formulations to optimize ALL treatment strategies.

PEGasparaginase is known to be a critical drug for treating pediatric acute lymphoblastic leukemia (ALL), however, there is insufficient evidence to determine the optimal dose for infants who are less than one year of age at diagnosis. This international study was conducted to identify the pharmacokinetics of PEGasparaginase in infants with newly diagnosed ALL and gather insight into the clearance and dosing of this population.

Infants with ALL who received treatment with PEGasparaginase were included in our population pharmacokinetic assessment employing non-linear mixed effects modelling (NONMEM).

68 infants with ALL, with a total of 388 asparaginase activity samples, were included. PEGasparaginase doses ranging from 400 to 3,663 IU/m2 were administered either intravenously or intramuscularly. A one-compartment model with time-dependent clearance, modeled using a transit model, provided the best fit to the data. Body weight was significantly correlated with clearance and volume of distribution. The final model estimated a half-life of 11.7 days just after administration, which decreased to 1.8 days 14 days after administration. Clearance was 19.5% lower during the post-induction treatment phase compared to induction.

The pharmacokinetics of PEGasparaginase in infants diagnosed under one year of age with ALL is comparable to that of older children (1-18 years). We recommend a PEGasparaginase dosing at 1,500 IU/m2 for infants without dose adaptations according to age, and implementing therapeutic drug monitoring as standard practice.

L-Asparaginase is a crucial component of acute lymphoblastic leukemia (ALL) treatment. However, hypersensitivity is a common adverse event. This study aimed to identify risk factors for L-asparaginase hypersensitivity in childhood ALL.

Children treated for ALL at Chiang Mai University Hospital, Thailand, between 2005 and 2020 were included. Demographic data, clinical characteristics, and factors related to L-asparaginase were retrospectively reviewed.

L-Asparaginase hypersensitivity was observed in 24 of 216 children with ALL (11.1%). All patients received native L-asparaginase intramuscularly, and events occurred exclusively during the post-induction phase without concurrent corticosteroid use. Univariable analysis showed that relapsed ALL, higher accumulated doses, increased exposure days, and longer interval between drug administrations were potential risk factors. In multivariable logistic regression analysis, interruption of L-asparaginase administration for ≥ 52 weeks and exposure duration of ≥ 15 days were independent risk factors, with adjusted odds ratio of 16.481 (95% CI 3.248-83.617, p = 0.001) and 4.919 (95% CI 1.138-21.263, p = 0.033), respectively.

Children with ALL who require re-exposure to L-asparaginase after 52-week interruption or who have received L-asparaginase for ≥ 15 exposure days are at risk of developing L-asparaginase hypersensitivity. Further management strategies in this setting should be evaluated.

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.

Pegaspargase is a therapeutic enzyme that is utilized in treatment regimens targeting pediatric acute lymphoblastic leukemia. However, many patients experience hypersensitivity reactions, requiring discontinuation of the therapy. Historically, this necessitated switching to an alternative form of the drug, most commonly asparaginase Erwinia chrysanthemi; however, in recent years this was difficult due to drug shortages and eventually commercial discontinuation. We report here our experience performing pegaspargase desensitizations in patients with prior hypersensitivity reactions.

Patients with a clinical hypersensitivity reaction to pegaspargase were identified. When due for their next dose, patients were admitted to the pediatric intensive care unit, bone marrow transplant unit, or oncology unit, and underwent desensitization utilizing a rigorous premedication and multistep dilution-based protocol. Serum asparaginase activity levels were drawn after desensitization to assess for therapeutic levels of enzyme activity.

We identified 11 patients who underwent a total of 33 desensitizations to pegaspargase and calaspargase pegol-mknl. No patients experienced clinically significant hypersensitivity reactions necessitating stopping the infusion, nor administration of rescue medications. All serum asparaginase activity levels collected demonstrated enzyme activity levels above predefined therapeutic thresholds. Cost analysis revealed substantial savings when patients received asparaginase desensitization over the now commercially available asparaginase E. chrysanthemi (recombinant) rywn.

Performing desensitization to pegaspargase in the pediatric acute lymphoblastic leukemia population is feasible, safe, and effective. It is financially advantageous over available alternative approaches, and requires fewer injections and presentations to care.

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.

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.

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.

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.

Mixed phenotype acute leukaemia (MPAL) is associated with worse overall survival, compared with other acute leukaemias in adults. Lack of clear treatment guidelines makes the therapy challenging. ALL-like induction and consolidation treatment followed by allo-HSCT is the preferred first-line treatment. We present a case of a 36-year-old woman diagnosed with MPAL (EGIL Myelo/B) with KMT2A rearrangement, treated with the PALG-ALL-7 (including PEG-asparaginase) protocol. On day 25 after the induction therapy initiation, numbness of limbs and dizziness were observed. Therefore, the imaging studies (CT and MRI) were performed and a diagnosis of thrombosis of superior sagittal sinus of the brain was established. Routinely performed blood coagulation tests showed prolonged APTT and PT, decreased antithrombin III activity and decreased free protein S concentration. LMWH treatment and substitutional therapy with antithrombin III were started, which resulted in a significant reduction in the thrombosis associated symptoms and improvement of the neurological status after 3 days. After induction and consolidation therapy, the patient obtained complete haematological remission and negative measurable residual disease. Six months after the diagnosis, allo-HSCT was successfully performed. During the 4 months follow-up, the patient remained MRD negative and thrombotic symptoms free. To the best of our knowledge, our communication has been the first report of such complication in an MPAL patient treated with PEG-asparaginase containing protocol in adults. We recommend increased vigilance in patients manifesting any mild neurological symptoms and early decision about the MRI study performance.

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.

All clinically-used asparaginases convert L-asparagine (L-Asn) to l-aspartate (L-Asp) and l-glutamine (L-Gln) to L-glutamate (L-Glu), which has been useful in reducing bioavailable asparagine and glutamine in patients under treatment for acute lymphoblastic leukemia. The E. coli type 2 L-asparaginase (EcA2) can present different sequences among varying bacterial strains, which we hypothesized that might affect their biological function, stability and interchangeability. Here we report the analysis of two EcA2 provided by the public health system of a middle-income country. These enzymes were reported to have similar specific activity in vitro, whereas they differ in vivo. Protein sequencing by LC-MS-MS and peptide mapping by MALDI-ToF-MS of their tryptic digests revealed that Aginasa™ share similar sequence to EcA2 from E. coli strain BL21(DE3), while Leuginase™ has sequence equivalent to EcA2 from E. coli strain AS1.357. The two amino acid differences between Aginasa™ (64D and 252 T) and Leuginase™ (64 N and 252S) resulted in structural divergences in solution as accessed by small-angle X-ray scattering and molecular dynamics simulation trajectories. The conformational variability further results in dissimilar surface accessibility with major consequences for PEGylation, as well as different susceptibility to degradation by limited proteolysis. The present results reveal that the sequence variations between these two EcA2 variants results in conformational changes associated with differential conformational plasticity, potentially affecting physico-chemical and biological properties, including proteolytic and immunogenic silent inactivation.

The asparaginase's (ASP) utility for ALL treatment is limited by neutralizing antibodies, which is problematic in countries whose access limited to alternative preparations. ASP antibody levels and activity was measured during remission induction and associated with allergy manifestations.

E. coli ASP was dosed at 7500 IU/m2. ASP IgG antibody levels were quantified at the beginning and end of induction. ASP activity was measured 24 hours after 1st and 5th dose (standard-risk) or 7th dose (high-risk patients) administration, and within 24 hours in case of allergic reactions. Allergy was monitored by CTCAE version 3. Parametric and non-parametric was performed for data analysis.

ASP antibody and activity levels were available in 41/63 consecutive patients. Allergic manifestations occurred in 13/41, with urticaria being the most frequent. There were no significant differences in subject characteristics based on allergic reactions. The 5th dose was the most frequent time of onset. Antibody levels in allergy group at the end of induction did not differ from those at baseline (p<0.05). Using a 24-hour level of 100 mU/mL as a threshold for adequate ASP activity, 6/13 patients with allergy had adequate levels compared to 26/28 patients without (p<0.05). The ASP activity level at the end of induction phase in both groups did not show a significant decrement.

The E. coli ASP activity with adequate levels were significantly higher in non-allergy group. Its activity level was not accompanied by increment of IgG in allergic group indicates other factors might affect activity levels in allergy group.

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.

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.

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'.

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

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.

Asparaginase has played a crucial role in the improvement of survival in children with acute lymphoblastic leukaemia (ALL), which is the commonest cancer among children. Survival rates have steadily increased over decades since the introduction of asparaginase to ALL therapy, and overall survival rates reach 90% with the best contemporary protocols. Currently, polyethylene glycolated native Escherichia coli-derived L-asparaginase (PEG-asparaginase) is the preferred first-line asparaginase preparation. Besides its clinical benefits, PEG-asparaginase is well known for severe toxicities. Agreement on the optimal dose, treatment duration, and frequency of administration has never been reached among clinicians.

Primary objective To assess the effect of the number of PEG-asparaginase doses on survival and relapse in children and adolescents with ALL. Secondary objectives To assess the association between the number of doses of PEG-asparaginase and asparaginase-associated toxicities (e.g. hypersensitivity, thromboembolism, pancreatitis and osteonecrosis). To undertake a network meta-analysis at dose-level in order to generate rankings of the number of doses of PEG-asparaginase used in the treatment for ALL, according to their benefits (survival and relapse) and harms (toxicity).

We searched CENTRAL, PubMed, Embase, Web of Science databases and three trials registers in November 2021, together with reference checking, citation searching and contact with study authors to identify additional studies.

We included randomised controlled trials (RCTs) comparing different PEG-asparaginase treatment regimens in children and adolescents (< 18 years of age) with first-line ALL treated with multiagent chemotherapy including PEG-asparaginase.

Using a standardised data collection form, two review authors independently screened and selected studies, extracted data, assessed risk of bias for each outcome using a standardised tool (RoB 2.0) and assessed the certainty of evidence for each outcome using the GRADE approach. Primary outcomes included overall survival, event-free survival and leukaemic relapse. Secondary outcomes included asparaginase-associated toxicities (hypersensitivity, thromboembolism, pancreatitis, sinusoidal obstruction syndrome and osteonecrosis as well as overall asparaginase-associated toxicity). We conducted the review and performed the analyses in accordance with the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

We included three RCTs in the review, and identified an additional four ongoing studies. We judged outcomes of two RCTs to be at low risk of bias in all the Cochrane risk of bias (RoB 2) domains. We rated the remaining study as having some concerns regarding bias. Due to concerns about imprecision, we rated all outcomes as having low- to moderate-certainty evidence.  One study compared intermittent PEG-asparaginase treatment (eight doses of PEG-asparaginase, 1000 IU/m2, intramuscular (IM) administration) versus continuous PEG-asparaginase treatment (15 doses of PEG-asparaginase, 1000 IU/m2, IM) in 625 participants with non-high risk ALL aged 1.0 to 17.9 years. We found that treatment with eight doses probably results in little to no difference in event-free survival compared to treatment with 15 doses (RR 1.01, 95% CI 0.97 to 1.06; moderate-certainty evidence). Compared to treatment with 15 doses, treatment with eight doses may result in either no difference or a slight reduction in hypersensitivity (RR 0.64, 95% CI 0.21 to 1.93; low-certainty evidence), thromboembolism (RR 0.55, 95% CI 0.22 to 1.36; low-certainty evidence) or osteonecrosis (RR 0.68, 95% CI 0.35 to 1.32; low-certainty evidence). Furthermore, we found that treatment with eight doses probably reduces pancreatitis (RR 0.31, 95% CI 0.12 to 0.75; moderate-certainty evidence) and asparaginase-associated toxicity (RR 0.53, 95% CI 0.35 to 0.78; moderate-certainty evidence) compared to treatment with 15 doses. One study compared low-risk standard treatment with additional PEG-asparaginase (six doses, 2500 IU/m2, IM) versus low-risk standard treatment (two doses, 2500 IU/m2, IM) in 1857 participants aged one to nine years old with standard low-risk ALL. We found that, compared to treatment with two doses, treatment with six doses probably results in little to no difference in overall survival (RR 0.99, 95% CI 0.98 to 1.00; moderate-certainty evidence) and event-free survival (RR 1.01, 95% CI 0.99 to 1.04; moderate-certainty evidence), and may result in either no difference or a slight increase in osteonecrosis (RR 1.65, 95% CI 0.91 to 3.00; low-certainty evidence). Furthermore, we found that treatment with six doses probably increases hypersensitivity (RR 12.05, 95% CI 5.27 to 27.58; moderate-certainty evidence), pancreatitis (RR 4.84, 95% CI 2.15 to 10.85; moderate-certainty evidence) and asparaginase-associated toxicity (RR 4.49, 95% CI 3.05 to 6.59; moderate-certainty evidence) compared to treatment with two doses. One trial compared calaspargase (11 doses, 2500 IU/m2, intravenous (IV)) versus PEG-asparaginase (16 doses, 2500 IU/m2, IV) in 239 participants aged one to 21 years with standard- and high-risk ALL and lymphoblastic lymphoma. We found that treatment with 11 doses of calaspargase probably results in little to no difference in event-free survival compared to treatment with 16 doses of PEG-asparaginase (RR 1.06, 95% CI 0.97 to 1.16; moderate-certainty evidence). However, treatment with 11 doses of calaspargase probably reduces leukaemic relapse compared to treatment with 16 doses of PEG-asparaginase (RR 0.32, 95% CI 0.12 to 0.83; moderate-certainty evidence). Furthermore, we found that treatment with 11 doses of calaspargase results in either no difference or a slight reduction in hypersensitivity (RR 1.17, 95% CI 0.64 to 2.13; low-certainty evidence), pancreatitis (RR 0.85, 95% CI 0.47 to 1.52; low-certainty evidence), thromboembolism (RR 0.83, 95% CI 0.48 to 1.42; low-certainty evidence), osteonecrosis (RR 0.63, 95% CI 0.15 to 2.56; low-certainty evidence) and asparaginase-associated toxicity (RR 1.00, 95% CI 0.71 to 1.40; low-certainty evidence) compared to treatment with 16 doses of PEG-asparaginase.

We were not able to conduct a network meta-analysis, and could not draw clear conclusions because it was not possible to rank the interventions. Overall, we found that different numbers of doses of PEG-asparaginase probably result in little to no difference in event-free survival across all studies. In two studies, we found that a higher number of PEG-asparaginase doses probably increases pancreatitis and asparaginase-associated toxicities.

JZP458 is a recombinant Erwinia chrysanthemi asparaginase for patients with acute lymphoblastic leukemia (ALL)/lymphoblastic lymphoma (LBL) who have developed hypersensitivity to Escherichia coli-derived asparaginases. A population pharmacokinetic (PopPK) model was developed for intramuscular (i.m.) JZP458 using serum asparaginase activity (SAA) data from 166 patients with ALL/LBL enrolled in a phase II/III study conducted in collaboration with the Children's Oncology Group (AALL1931; NCT04145531). The pharmacokinetics of i.m. JZP458 is best characterized by a one-compartment model with mixed-order absorption and linear elimination, with body surface area included as an allometric covariate on JZP458 SAA clearance and volume, and race (i.e., Black/African American) and disease subtype (i.e., T-cell ALL) as covariates on JZP458 SAA clearance. The PopPK model was used to simulate SAA profiles to estimate the likelihood of achieving nadir SAA (NSAA) levels greater than or equal to 0.1 IU/mL with different dosing regimens. Model-based simulations suggest when JZP458 is administered i.m. at 25/25/50 mg/m2 Monday/Wednesday/Friday (MWF), 92.1% of subjects (95% confidence interval [CI]: 90.9%, 93.3%) are expected to achieve the last 72-h (after 50 mg/m2 dose) NSAA level greater than or equal to 0.1 IU/mL, and 93.8% (95% CI: 92.7%, 94.9%) are expected to achieve the last 48-h (after 25 mg/m2 dose) NSAA level greater than or equal to 0.1 IU/mL. When JZP458 is administered 25 mg/m2 i.m. every 48 h, 93.8% (95% CI: 92.7%, 94.8%) are expected to achieve the last 48-h NSAA level greater than or equal to 0.1 IU/mL. These data supported the i.m. dose of 25 mg/m2 every 48 h or 25/25/50 mg/m2 on a MWF dosing schedule in patients with ALL/LBL.