OUTLINE: This is a dose escalation study of humanized monoclonal antibody A33 (MOAB A33). Patients receive humanized MOAB A33 IV once a week for 14 weeks. Chemotherapy begins on day 29 and consists of carmustine IV on days 29-33, fluorouracil IV on days 29-33 and 64-68, vincristine IV on days 29 and 64, and streptozocin IV every 7 days, beginning on day 29, for 10 doses. Courses repeat every 14 weeks in the absence of disease progression or unacceptable toxicity. Cohorts of 3-6 patients receive escalating doses of humanized MOAB A33. The maximum tolerated dose is defined as the dose at which no more than 2 of 6 patients experience dose limiting toxicity.