Activity and toxicity of intramuscular 1000 iu/m2 polyethylene glycol-E. coli L-asparaginase in the UKALL 2003 and UKALL 2011 clinical trials

Adverse Impacts of PEGylated Protein Therapeutics: A Targeted Literature Review

The beneficial effects of polyethylene glycol (PEG)-conjugated therapeutics, such as increased half-life, solubility, stability, and decreased immunogenicity, have been well described. There have been concerns, however, about adverse outcomes with their use, but understanding of those adverse outcomes is still relatively limited. The present study aimed to characterize adverse outcomes associated with PEGylation of protein-based therapeutics on immunogenicity, pharmacologic properties, and safety. A targeted review of English language articles published from 1990 to September 29, 2023, was conducted. Of the 29 studies included in this review, 18 reported adverse safety outcomes such as hematologic complications, hepatic toxicity, injection site reactions, arthralgia, nausea, infections, grade 3 or 4 adverse events (AEs), and AE-related discontinuations and dose modifications. Fifteen studies reported immunogenicity-related outcomes, such as the prevalence of pre-existing antibodies to PEG, treatment-emergent antibody response, and hypersensitivity reactions to PEGylated drugs. Seven studies reported pharmacological outcomes such as increased clearance and reduced activity in response to PEGylated drugs. This review aims to contribute to a balanced view of PEGylated therapies by summarizing the adverse outcomes or lack of benefit associated with PEGylated therapeutics reported in the literature. We identified several studies characterizing adverse outcomes, pharmacological effects, and immunogenicity associated with the use of PEGylated therapeutics. Our findings suggest that using PEGylated therapeutics may require careful monitoring for adverse safety outcomes, including screening and monitoring for pre-existing antibodies and those induced in response to PEGylated therapy, as well as monitoring and adjusting the dosing of PEGylated therapeutics.

The correlation of asparaginase enzyme activity levels after PEG-asparaginase administration with clinical characteristics and adverse effects in Chinese paediatric patients with acute lymphoblastic leukaemia

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.

Impact of asparaginase discontinuation on outcomes of children with acute lymphoblastic leukaemia receiving the Japan Association of Childhood Leukaemia Study ALL-02 protocol

Asparaginase is an essential drug for acute lymphoblastic leukaemia (ALL) treatment, but has several side effects, and its discontinuation often compromises patient outcomes. In the prospective Japan Association of Childhood Leukaemia Study ALL-02 protocol, two major changes were made: (1) additional chemotherapies to compensate for the reduction of treatment intensity when asparaginase was discontinued and (2) more intensive concomitant corticosteroid administration, relative to our previous ALL-97 protocol. In ALL-02 study, 1192 patients were included and L-asparaginase was discontinued for 88 (7.4%). Discontinuation due to allergy was markedly decreased relative to the ALL-97 protocol (2.3% vs 15.4%). Event-free survival (EFS) among patients with T-ALL was compromised when L-asparaginase was discontinued, as well as among patients with high-risk B-cell ALL, especially when discontinued before maintenance therapy. Moreover, multivariate analysis identified discontinuation of L-asparaginase as an independent poor prognostic factor for EFS. In the current study, additional chemotherapies failed to fully compensate for L-asparaginase discontinuation, illustrating the difficulty of replacing asparaginase with other classes of drugs, although this study was not designed to evaluate the effect of these modifications. Concomitant intensive corticosteroid treatment may help to reduce allergy to asparaginase. These results will assist in further optimization of asparaginase use.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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