Population pharmacokinetics and pharmacodynamics of L-asparaginase and its impact on the development of pancreatitis and hypersensitivity reactions in children with leukemia under treatment.

L-asparaginase (L-Asp) is an essential enzyme in the treatment of patients with Acute Lymphoblastic Leukemia (ALL), commonly associated with adverse events (AE). Knowing the pharmacokinetic and pharmacodynamic (PK/PD) parameters of L-Asp as well as its relationship with the development of AE is an important strategy in the search to improve the efficacy and safety of the treatment. Seventy-four children with ALL that were being treated with L-Asp, were included. One to three blood samples were randomly obtained from each patient, at times from 0 to 30 hours, until completing a total of 211 samples. The L-Asp activity and the Asparagine (Asp) concentration were quantified, in addition, the presence of anti-L-Asp antibodies (Anb) was determined. A population PK/PD model of L-Asp was developed to determine the association of covariates with PK/PD parameters. The presence of Anb was associated with the increase in L-Asp clearance (CL) and with the decrease of volume of distribution 1 (V1). On the other hand, female sex was significantly associated with the increase of V1, while the age from 1 to 6 years was significantly associated with the increase of V1. The presence of Anb as well as the female sex were related to the increase IC50 (concentration-needed to deplete-50% of Asp). Patients who presented Asp depletion before the first 24 hours after administration presented pancreatitis, this could be a risk marker. Significant results were found in this study, use of these results may contribute to the safe and effective use of L-Asp.