Patients receive filgrastim (G-CSF) subcutaneously (SQ) or IV beginning on day -5 and continuing through at least day 3. Peripheral blood stem cells (PBSC) are collected on days 0, 2, and 4. Patients then receive oral temozolomide daily for 5 consecutive days. PBSC collections are reinfused 1 day after the last dose of temozolomide. Patients also receive G-CSF beginning at the time of transplant and continuing until blood counts recover. Treatment continues in the absence of disease progression or unacceptable toxicity.