The rest of the chemotherapy will switch between hyper-CVAD and pegylated asparaginase (Courses 3, 5, and 7) and methotrexate,cytarabine (ara-C), vincristine, and pegylated asparaginase (Courses 4, 6, and 8) to complete a total of 8 courses. Participants whose leukemia expresses CD20 will receive a total of 12 doses (2 per each of the first four courses, then one with the last four courses) of rituximab.