- HR: Prednisone poor-response (≥1000 blast cells/µl in peripheral blood on day 8), blast cells ≥10% in bone marrow on day 15 as measured by FCM, non-remission on day 33, positivity for MLL/AF4 or t(4;11), hypodiploidy (< 45 chromosomes), PCR-MRD-HR (MRD ≥10E-3 on day 78) or PCR-MRD-MR SER (only in pB-ALL, MRD ≥ 10-3 on day 33 and MRD positive at a level of < 10E-3 on day 78)