This study will be conducted in different centres and will study adult patients with Philadelphia chromosome-negative (Ph-) acute lymphoblastic leukemia (ALL). The study treatment will include a induction/consolidation therapy incorporating pegylated Asparaginase (Peg-ASP) and lineage-targeted high-dose methotrexate plus other antileukemic drugs, for the achievement of an early negative minimal residual disease (MRD) status. The MRD study supports a risk/MRD-oriented final consolidation phase.

The aim of this clinical study in adult ALL is to improve , by risk category, the overall disease-free survival in relation to the achievement of an early MRD negative status and following induction/consolidation with Peg-ASP, lineage-targeted methotrexate infusions and other disease-specific therapeutic elements, with or without the application of allogeneic or autologous SCT depending on risk class and MRD study results. A survey of severe infections occurring along the entire chemotherapy and stem cell transplant program and until 2 years from the achievement of CR will be performed with the aim to increase the knowledge of these complications and to evaluate their impact on the antileukemic program and on the long term outcome of the underlying malignancy. The prospective survey of severe infections will be performed as an ancillary observational objective of the present study.

Inclusion Criteria:

• Signed written informed consent according to ICH/EU/GCP and national local laws.
• Age 18-65 years.
• A diagnosis of untreated Ph- ALL or LL is required, either de novo or secondary to chemo-radiotherapy for other cancer. Pretreatment with low-dose corticosteroids in patients presenting with hyperleukocytosis is allowed. All diagnostic procedures need to be performed on freshly obtained bone marrow (BM) and peripheral blood (PB) samples. The diagnosis must be one of: de novo ALL, secondary ALL, B-/T-cell LL Full cytological, cytochemical, cytogenetic and immunobiological disease characterization according to EGIL and WHO classifications. Bone marrow and peripheral blood sampling (ALL) or biopsy specimen (LL) are required for MRD study. Detailed indications on patient registration, storage of representative diagnostic material and diagnostic work-up, including the forwarding of samples for MRD study are given in Appendix B.
• Bone marrow and peripheral blood sampling (ALL) or biopsy specimen (LL) for MRD study.
• ECOG performance status 0-2, unless a performance of 3 is unequivocally caused by the disease itself and not by preexisting comorbidity, and is considered and/or documented to be reversible following the application of antileukemic therapy and appropriate supportive measures.

Exclusion Criteria:

• Diagnosis of Burkitt's leukemia or lymphoma.
• Down's syndrome
• Pre-existing, uncontrolled pathology such as heart failure (congestive/ischemic, acute myocardial infarction within the past 3 months, untreatable arrhythmias, NYHA classes III and IV), severe liver disease with serum bilirubin >3 mg/dL and/or ALT >3 x upper normal limit (unless attributable to ALL), kidney function impairment with serum creatinine >2 mg/dL (unless attributable to ALL), and severe neuropsychiatric disorder that impairs the patient's ability to understand and sign the informed consent, or to cope with the intended treatment plan. N.B. For altered liver and kidney function tests, eligibility criteria can be reassessed at 24-96 hours, following the institution of adequate supportive measures.
• Pre-existing HIV positive serology (i.e. already known before enrolment). If HIV positivity is detected after enrolment, the patient is sent off study.
• A history of cancer that is not in a remission phase following surgery and/or radiotherapy and/or chemotherapy, with life expectancy <1 year.
• Pregnancy declared by the patient herself, unless a decision is taken with the patient to induce a therapeutic abortion in order to carry on with ALL therapy. A pregnancy test is performed at diagnosis but does not preclude the enrolment into study. Fertile patients will be advised to adopt contraceptive methods while on treatment.