Protocol IA': Only two doses of DNR on days 8 and 15 given to patients eligible for randomization R1 and randomized into the experimental arm Protocol IA-CPM: additional cyclophosphamide (CPM) on day 10 only in T-ALL patients with prednisone poor-response Protocol IA-Dexa (IAD): Dexamethasone (DXM) instead of PDN is given to all patients with T-ALL without any high-risk criteria as identified by day 8.