RATIONALE: Drugs used in chemotherapy use different ways to stop cancer cells from dividing so they stop growing or die. Peripheral stem cell transplantation may allow the doctor to give higher doses of chemotherapy drugs and kill more cancer cells. Monoclonal antibodies such as rituximab can locate cancer cells and either kill them or deliver cancer-killing substances to them without harming normal cells. It is not yet known if combination chemotherapy plus peripheral stem cell transplantation is more effective with or without rituximab for non-Hodgkin's lymphoma.

PURPOSE: This randomized phase III trial is studying giving combination chemotherapy and peripheral stem cell transplantation together with rituximab to see how well it works compared to combination chemotherapy and peripheral stem cell transplantation alone in treating patients with relapsed non-Hodgkin's lymphoma.

OBJECTIVES:

• Determine the effects of in vivo rituximab purging and maintenance on progression-free survival in patients with relapsed or resistant follicular non-Hodgkin's lymphoma undergoing high-dose chemotherapy.
• Determine the effects of this regimen on response rate and overall survival in this patient population.
• Determine the effects of in vivo purging with rituximab on molecular remission rates in the hematopoietic product and the patients.
• Determine the safety of rituximab in the transplant setting.

OUTLINE: This is a randomized, open-label, multicenter study. Patients are stratified according to type of remission (complete vs good partial) and which remission (second vs third). Patients are randomized to one of four treatment arms.

All patients receive induction chemotherapy comprising cyclophosphamide IV over 3-4 hours on day 0 or a standard induction chemotherapy regimen. Filgrastim (G-CSF) is administered subcutaneously daily beginning on day 1.

Patients are then randomized to receive either in vivo rituximab purging or no purging following restaging after completion of induction. For those patients receiving purging (arms I and II), rituximab is administered IV once weekly for 4 weeks.

Peripheral blood stem cells (PBSC) are collected between days 8 and 12 post induction chemotherapy. Within 4 weeks of PBSC collection, patients receive carmustine IV over 2 hours on day -6, etoposide IV over 2 hours on days -5 to -2, cytarabine IV over 5 minutes twice daily on days -5 to -2, and melphalan IV over 10-15 minutes on day -1. (Alternatively, high dose cyclophosphamide and total body irradiation beginning 2-4 weeks after cyclophosphamide or standard induction chemotherapy priming is also allowed.) PBSC are reinfused on day 0.

Patients are further randomized to receive either rituximab maintenance or observation only. For those patients receiving maintenance (arms I and III), rituximab is administered IV once every 2 months for 4 doses beginning 30 days after PBSC reinfusion.

Patients are followed at 30 days, 3, 6, 9, and 12 months after PBSC transplant, every 6 months for 2 years, and then annually thereafter.

PROJECTED ACCRUAL: A total of 460 patients (115 per treatment arm) will be accrued for this study within 5 years.

DISEASE CHARACTERISTICS:

• Relapsed or resistant follicular non-Hodgkin's lymphoma (NHL)

  • No evidence of transformation to high grade or diffuse large B-cell NHL

• CD20 positive with no evidence of transformation

• Achievement of complete remission (CR) or very good partial remission (VGPR) following reinduction chemotherapy with any standard regimen

  • Includes patients who fail to respond to first-line chemotherapy but who achieve CR or VGPR after proceeding directly to second-line chemotherapy

• Platelet count greater than 100,000/mm^3 after induction chemotherapy and before randomization

• No CNS involvement

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• WHO 0-1

Life expectancy:

• Not specified

Hematopoietic:

• See Disease Characteristics

Hepatic:

• Bilirubin normal
• ALT no greater than 2 times upper limit of normal (ULN)
• Alkaline phosphatase no greater than 2 times ULN
• Hepatitis B negative
• Hepatitis C negative

Renal:

• Creatinine no greater than 2 times ULN
• BUN no greater than 2 times ULN

Cardiovascular:

• No inadequate cardiac function

Pulmonary:

• No inadequate pulmonary function

Other:

• Not pregnant or nursing
• HIV negative
• No other uncontrolled serious medical conditions
• No other malignancy within the past 5 years except nonmelanoma skin tumors or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• More than 12 months since prior CD20 therapy, including rituximab
• No prior peripheral blood stem cell transplantation

Chemotherapy:

• See Disease Characteristics
• No more than 3 prior chemotherapy regimens for NHL

Endocrine therapy:

• Not specified

Radiotherapy:

• No prior radiotherapy to greater than 30% of bone marrow

Surgery:

• Not specified