Citrovorum factor (leucovorin), an antidote for side effects of methotrexate, will be given by vein or by mouth for 2-3 days (Day 2 and on). Pegfilgrastim will be given as in Course 1 (24-72 hours after the chemotherapy is finished). The treatment to protect the brain inside the spinal fluid will be given as in Course 1 on Days 2 and 7.