Search

Introduction: Asparaginase is a key component in the treatment of childhood acute lymphoblastic leukemia (ALL), but the treatment is jeopardized by 20% or more developing asparaginase-associated toxicities (asp-tox), mostly hypersensitivity, osteonecrosis, pancreatitis and thromboembolism (Albertsen et al 2019). Therapeutic drug monitoring (TDM) of asparaginase enzyme activity (AEA) levels is widely used to identify patients with no AEA and to ensure sufficient treatment (Sluis et al 2016), but is not commonly used to identify patients with high levels. In this study, we investigate AEA-levels and the association with risk and severity of asp-tox. Methods: Children aged 1-17.9 years with non high-risk ALL treated according to the NOPHO ALL2008 protocol from July 2008 to March 2016 in the Nordic and Baltic countries were included in the study. Based on median AEA-level measured 14 days (+/-2 days) after administration, patients were grouped into four groups; 'no enzyme activity' (0 IU/L, n=201), 'fast clearance' (1-99 IU/L, n=82), 'therapeutic levels' (100-249 IU/L, n=543), and 'high levels' (≥250 IU/L, n=330). Furthermore, groups with AEA-levels Results: We included 1,156 patients and 6,929 samples for AEA-measurements in the study. The median number of samples for each patient was 5 [IQR: 3;9]. A total of 328 asp-tox events were registered in 311 patients (27.5%). The median age for patients with asp-tox was 5 years [Interquartile range (IQR): 2;9] compared with 4 years [IQR: 2;6] for patients without asp-tox (p Conclusion: We found no difference in the incidence of toxicities between AEA in ´therapeutic levels´ and ´high levels´ group, and there will be no clinical advantage in using TDM to identify patients with high AEA-levels for dose adjustment. The significantly lower incidence of asp-tox in patients without AEA and AEA-levels Disclosures Ranta: Roche: Other: Amember of Steering committee for a Roche study on Hemlibra (the contract is between Karolinska University Hospital and Roche). No financial benefits.. Wolthers:Novo Nordisk: Current Employment. Heyman:Servier: Other: Research funding in ALLTogether (research protocol). Schmiegelow:Jazz Pharmaceuticals: Other: Speaker and/or Advisory Board Honoraria ; Medscape: Other: Speaker fee; Servier: Other: Educational grant. Speaker and/or Advisory Board Honoraria ; Amgen: Other: Speaker fee. Albertsen:Erytech Pharma: Other: Sponsor of the investigator initiated study: NOR-GRASPALL 2016. No financial benefits..