RATIONALE: Drugs used in chemotherapy use different ways to stop cancer cells from dividing so they stop growing or die. Monoclonal antibodies, such as rituximab, can locate cancer cells and either kill them or deliver cancer-killing substances to them without harming normal cells. Combining combination chemotherapy with monoclonal antibody therapy may kill more cancer cells.

PURPOSE: Phase II trial to study the effectiveness of combination chemotherapy plus rituximab in treating patients who have 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.

DISEASE CHARACTERISTICS:

• Histologically confirmed CD20+ B-cell non-Hodgkin's lymphoma

  • Relapsed following chemotherapy and eligible for platinum-containing regimen

• Measurable disease

  • Must be at least 1.5 x 1.5 cm

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2

Hematopoietic:

• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 75,000/mm^3

Hepatic:

• Bilirubin no greater than 2.0 mg/dL

Renal:

• Creatinine no greater than 1.5 times upper limit of normal

Cardiovascular:

• No uncontrolled hypertension

Other:

• HIV negative
• No other active malignancy
• No uncontrolled diabetes mellitus
• No uncontrolled peptic ulcer disease
• No uncontrolled infection
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception