Methotrexate, Mannitol, Rituximab, and Carboplatin in Treating Patients With Newly Diagnosed Primary Central Nervous System Lymphoma

PRIMARY OBJECTIVES: I. To evaluate the safety and toxicities of a treatment regimen consisting of rituximab (intravenously \[IV\]) the day prior to methotrexate (intra-arterially \[IA\]), and carboplatin (IA) in conjunction with blood-brain barrier disruption (BBBD) and delayed sodium thiosulfate (IV). II. To demonstrate, adding a monoclonal antibody and carboplatin to methotrexate BBBD, that a 45% rate of complete response (CR) within the first 3 months of treatment is achieved, while excluding a CR rate as low as 30%. SECONDARY OBJECTIVE: I. To estimate the response rate (counting all CRs), the two-year overall survival and the two-year event-free survival, as baselines for subsequent trials. OUTLINE: Patients receive rituximab IV over 5 hours on day 1, mannitol IA, methotrexate IA over 10 minutes, and carboplatin IA over 10 minutes on days 2 and 3. Patients then receive sodium thiosulfate IV over 15 minutes at 4 and 8 hours after carboplatin. Treatment repeats monthly for up to 12 courses in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 2 months, then every 2 months for 2 years, every 6 months for 1 year, and then annually for at least 2 years.