Michalowski MB, Cecconello DK, Lins MM, et al. - Recently, it was noted that use of the (ASNase) formulation, available in Brazil from 2017 to 2018, at the same dose and frequency as the formulation offered previously did not reach the activity considered therapeutic, thus, researchers investigated how these facts could influence prognosis of children suffering from ALL at different oncology centers. They identified patients aged >1 and <18 years in first-line therapy observed at 10 referral centres, between 2014 and 2018 who received the formulation Leuginase (Group B). For each patient, the centre registered 2 patients who were administered ASNase in the presentation of Aginasa exclusively (Group A). The 3-year OS and EFS in Group A were estimated to be 91·8% and 84·8% respectively, while these estimates were 83·8% and 76·1%, respectively, in Group B. Experts found that receipt of a formulation influenced 3-year OS and EFS of children. Thus, assessing ASNase and monitoring its activity is important.