Asparaginase activity levels and toxicity in children and adolescents with acute lymphoblastic leukemia.

Asparaginase (ASP) is a critical treatment component of acute lymphoblastic leukemia (ALL), yet associated with potentially severe complications. We assessed whether serum asparaginase activity (SAA) is associated with development of venous thrombosis, acute pancreatitis, bleeding and/or hypersensitivity events. We included 84 patients (median age 6.4 years, 66% male) with newly diagnosed ALL/lymphoblastic lymphoma who received ≥1 dose of ASP and with ≥1 available SAA level(s). Median peak and trough SAA levels were 2.36 IU/mL and 0.77 IU/mL. High peak SAA levels were associated with a trend toward increased venous thrombosis risk (HR: 1.51,  = 0.058). No association between SAA peak and/or trough levels and acute pancreatitis nor hypersensitivity was observed. SAA do not appear to predict the risk of ASP-related toxicities. Our data do not support individualized dosing to prevent toxicities such as thrombosis or pancreatitis. Larger prospective studies are required to help identify children at high risk of ASP-related toxicities.