A still major question in the field of acute lymphoblastic leukemia (ALL) in children - an extremely heterogeneous disease though curable in 80-90% of children and 70-80% of the adolescents - is the optimal use of L-asparaginase (ASNase). It is known that administering ASNase results in the depletion of asparagine circulating in the blood, which starves the leukemic cells and results in their death. But indeed the use of ASNase varies between protocols considering the different brands, the dose and the administration modalities. Oncaspar (PEGylated E. coli asparaginase, pegaspargase) was thus developed with the goal of reducing the immunogenicity of the native ASNase.