• Progression-free survival [ Designated as safety issue: No ]
• Overall survival [ Designated as safety issue: No ]
• Toxicity [ Designated as safety issue: Yes ]

• Progression-free survival
• Overall survival
• Toxicity

RATIONALE: Monoclonal antibodies, such as rituximab, can locate cancer cells and either kill them or deliver cancer-killing substances to them without harming normal cells.

PURPOSE: Phase II trial to study the effectiveness of rituximab in treating patients who have refractory or relapsed primary CNS lymphoma.

OBJECTIVES:

Primary

• Determine the radiographic response proportion in patients with refractory or recurrent primary CNS lymphoma treated with rituximab.

Secondary

• Determine the progression-free and overall survival of patients treated with this drug.
• Determine the toxicity profile of this drug in these patients.

OUTLINE: This is a multicenter study.

Patients receive rituximab IV on days 1, 8, 15, and 22. Treatment repeats every 28 days for 2 courses in the absence of disease progression or unacceptable toxicity. Patients may receive additional courses of rituximab off study at the discretion of the treating physician.

Patients are followed every 2 months.

PROJECTED ACCRUAL: A total of 15-25 patients will be accrued for this study within 5-9 months.

DISEASE CHARACTERISTICS:

• Histologically confirmed primary CNS lymphoma based on 1 of the following:

  • Histologically confirmed non-Hodgkin's B-cell lymphoma by brain biopsy or resection
  • Positive cerebrospinal fluid (CSF) cytology or immunohistochemical diagnosis of CSF monoclonality with or without measurable intracranial disease
  • Histologically confirmed vitreal lymphoma with measurable intracranial tumor
• CD20 positive by brain biopsy
• Measurable (greater than 1 cm in diameter) tumor by CT scan or MRI
• Progressed during first-line chemotherapy and/or radiotherapy OR relapsed after initial successful treatment
• No systemic lymphoma by CT scan of the chest, abdomen, and pelvis with contrast
• No leptomeningeal lymphoma by lumbar puncture for CNS cytology/flow cytometry
• No ocular lymphoma by slit lamp examination

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• Karnofsky 60-100%

Life expectancy

• Not specified

Hematopoietic

• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3
• Hemoglobin at least 9.0 g/dL

Hepatic

• Bilirubin less than 1.5 mg/dL
• Transaminases less than 4 times upper limit of normal

Renal

• Creatinine less than 1.5 mg/dL

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 1 year after study participation
• HIV negative
• Mini mental status examination score at least 15
• No concurrent serious infection
• No other medical illness that would preclude study treatment
• No other malignancy within the past 5 years except curatively treated basal cell or squamous cell skin cancer or carcinoma in situ

PRIOR CONCURRENT THERAPY:

Biologic therapy

• More than 90 days since prior biologic therapy
• No prior rituximab
• No concurrent prophylactic growth factors (e.g., filgrastim [G-CSF] or sargramostim [GM-CSF])

Chemotherapy

• See Disease Characteristics
• At least 3 weeks since prior chemotherapy (6 weeks for nitrosoureas)

Endocrine therapy

• Not specified

Radiotherapy

• See Disease Characteristics
• At least 3 months since prior radiotherapy

Surgery

• Not specified

Other

• Recovered from prior therapy
• More than 90 days since prior investigational drugs
• More than 90 days since prior use of a therapeutic device