In conclusion, PEG-asparaginase administered in the context of the UKALLXII/ECOG E2993-based chemotherapy regimen at 2000 IU/m2 per dose is safe for adults with standard-risk ALL, and substitution of PEG-asparaginase for E. coli-asparaginase during induction and intensification conferred a statistically significant advantage in the CR rate on day 14 but was not sufficient to detect a difference in the EFS and OS. This evidence concerns the gene ASPG and acute lymphoblastic leukemia.