Combination Chemotherapy Plus Rituximab in Treating Patients With Relapsed Non-Hodgkin's Lymphoma

OBJECTIVES: * Determine response rate to cisplatin, cytarabine, and dexamethasone (DHAP) plus rituximab in patients with relapsed CD20+ B-cell non-Hodgkin's lymphoma. * Determine the percentage of patients able to proceed to transplant after two courses of this treatment regimen. * Determine the duration of response and overall survival of the patients not proceeding to transplant after two courses of this treatment regimen. OUTLINE: Patients receive rituximab IV on days 1, 8, 15, and 22 for the first course only. Patients receive dexamethasone orally or IV on days 1-4, cisplatin IV continuously for 24 hours on day 1, cytarabine IV over 3 hours every 12 hours for 2 doses on day 2, and sargramostim (GM-CSF) subcutaneously on days 3-12 or until blood counts recover. Chemotherapy repeats every 21 days for 2 courses in the absence of disease progression or unacceptable toxicity. Patients are followed every 3 months for 1 year, every 4 months for 1 year, and then every 6 months for 3 years. PROJECTED ACCRUAL: A total of 17-50 patients will be accrued for this study within 11 months.