The aims of the study are to determine whether single agent imatinib (STI571; Glivec) is more effective as up-front remission induction therapy than conventional multi-agent induction chemotherapy for elderly patients with Philadelphia positive (Ph+)ALL, whether this treatment is better tolerated, and whether subsequent combination therapy with imatinib and chemotherapy of approximately a 1 year duration is tolerable and effective with respect to maintaining remissions.

Inclusion Criteria:

• Male or female patients
• Age > 55 years (biological age)
• Diagnosis of Ph1 chromosome-positive ALL (pre-B, common- or pre-pre-B ALL)
• Newly diagnosed, lymphoid blast crisis of chronic myeloid leukemia
• Only pre-phase chemotherapy prior to study start
• World Health Organization (WHO) status 0, 1 or 2
• Voluntary written informed consent

Exclusion Criteria:

• Creatinine levels more than 2 x the upper limit of normal (ULN)
• Total serum bilirubin more than 1.5 x the ULN
• AST (SGOT) or ALT (SGPT) more than 5 x the ULN
• Any other prior antineoplastic treatment except for pre-phase chemotherapy
• Active central nervous system (CNS) leukemia
• New York Heart Association (NYHA) grade 3/4 cardiac disease
• Active severe infection
• Serious concomitant medical condition
• Patients with a history of non-compliance to medical regimens