- Phase I: Patients undergo osmotic blood-brain barrier disruption (BBBD) comprising mannitol by transfemoral catheterization followed by methotrexate intra-arterially (IA) over 10 minutes and carboplatin IA over 10 minutes on days 1 and 2. Patients also receive sodium thiosulfate IV over 15 minutes at 4 and 8 hours after each dose of carboplatin; leucovorin calcium IV or orally every 6 hours on days 3-9; and pegfilgrastim subcutaneously (SC) on day 4 or filgrastim (G-CSF) SC beginning on day 4 and continuing until blood counts recover (7-10 days). Patients with HER-2 positive disease receive trastuzumab (Herceptin®) IV over 90 minutes within 48 hours prior to BBBD and then weekly for 3 weeks (between BBBD therapy sessions). Treatment repeats every 4 weeks for up to 12 months in the absence of disease progression or unacceptable toxicity.