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

Summary 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.