If you are found to be eligible to take part in this study, you will receive methotrexate through a needle in your vein on Days 1 and 15 (+/- 2 days) over 2 hours. You will receive vincristine by vein on Days 1, 8 and 15 (+/- 2 days) over 30 minutes. You will receive pegylated-L-asparaginase by vein on Days 2 and 16 (+/- 2 days) over about 2 hours. You will receive dexamethasone by vein over about 30 minutes or by mouth on Days 1-4 and 15-18 (+/- 2 days). If leukemia cells have a protein called cluster of differentiation antigen 20 (CD20), you will also receive rituximab by vein on Days 1 and 15 of Cycles 1-4 (+/- 2 days) over about 2-8 hours.