Inclusion Criteria:

          -  Morphologically confirmed diagnosis of 1st relapsed precursor B-cell or T-cell ALL

          -  Children less than 18 years of age at date of inclusion into the study

          -  Meeting HR criteria any BM relapse, early/very early isolated BM relapse, very early
             isolated/combined extramedullary relapse)

          -  Patient enrolled in a participating centre

          -  Written informed consent

          -  Start of treatment falling into the study period

          -  No participation in other clinical trials 30 day prior to study enrolment that
             interfere with this protocol, except trials for primary ALL

        Exclusion Criteria:

          -  Breakpoint cluster region-Abelson (BCR-ABL)/ t(9;22) positive ALL

          -  Pregnancy or positive pregnancy test (urine sample positive for β-humane
             choriongonadotropin (HCG) > 10 U/l)

          -  Sexually active adolescents not willing to use highly effective contraceptive method
             (pearl index <1) until 12 months after end of anti-leukemic therapy

          -  Breast feeding

          -  Relapse post allogeneic stem-cell transplantation

          -  Neuropathy > II°

          -  The whole protocol or essential parts are declined either by patient himself/herself
             or the respective legal guardian

          -  Objection to the study participation by a minor patient, able to object

          -  Any patient being dependent on the investigator

          -  No consent is given for saving and propagation of pseudonymized medical data for study
             reasons

          -  Severe concomitant disease that does not allow treatment according to the protocol at
             the investigator's discretion (e.g. malformation syndromes, cardiac malformations,
             metabolic disorders)

          -  Subjects unwilling or unable to comply with the study procedures

          -  Subjects who are legally detained in an official institute