The aim of the present EWALL-INO study is to confirm very promising results obtained with a combination of INO and mild chemotherapy in older de novo CD22+ B-ALL patients. For that purpose, safety and efficacy of a weekly INO administration combined to mild-intensity chemotherapy will be evaluated in a cohort of patients aged more than 55 years with newly diagnosed previously untreated Ph-negative (CD22+) BCP-ALL. Conversely to the MDACC miniHCVD-INO study and in order to lower the overall toxicity of the combination, INO will be given as part of the remission induction treatment phase during the first 2 treatment cycles only, in combination with corticosteroid, vincristine, cyclophosphamide and intrathecal prophylaxis only; then, all responding patients will received standard INO-free chemotherapy as consolidation and maintenance.