A Study Comparing the Blood Levels of Both Pegaspargase (S95014) Formulations (Liquid vs Lyophilized) in the Treatment of Paediatric Patients With Acute Lymphoblastic Leukemia (ALL)

Inclusion Criteria:

* Patients aged 1 to \< 18 years
* Patients with cytologically confirmed and documented newly diagnosed ALL according to National Comprehensive Cancer Network guidelines 2020 (see Appendix 2), excluding B-cell Burkitt ALL
* Eastern Cooperative Oncology Group performance status (ECOG PS) 0-2 (see Appendix 3)
* Highly effective contraception method
* Signed informed consent and assent, when appropriate

Non-inclusion Criteria:

* Unlikely to cooperate in the study
* Pregnant and lactating women
* Participation in another interventional study at the same time; participation in non-interventional registries or epidemiological studies is allowed
* Participant already enrolled in the study (informed consent signed)
* Women of childbearing potential tested positive in a serum pregnancy test within 7 days prior to the treatment period
* Inadequate hepatic function (bilirubin \> 1.5 times upper limit of normal (ULN), transaminases \> 5x ULN)
* Inadequate renal function defined as serum creatinine \> 1.5 x ULN
* Prior treatment with chemotherapy or radiotherapy (except steroids and intrathecal therapy)
* Prior surgery or bone marrow transplant related to the studied disease
* Down Syndrome
* Psychiatric illness/social situation that would limit compliance with study requirements
* Known history of pancreatitis
* Known history of significant liver disease
* Known carriers of HIV antibodies
* Significant laboratory abnormality likely to jeopardize the patients' safety or to interfere with the conduct of the study, in the investigator's opinion
* Pre-existing known coagulopathy (e.g. haemophilia and known protein S deficiency)
* History of previous or concurrent malignancy
* History of sensitivity to polyethylene glycol (PEG) or PEG-based drugs
* Severe or uncontrolled active acute or chronic infection
* Uncontrolled intercurrent illness including life-threatening acute tumor lysis syndrome (e.g. with renal failure), symptomatic congestive heart failure, cardiac arrhythmia