A minimum of three patients will be entered into each dose-level cohort for five weeks. Escalation to the next cohort will occur when three patients have received at least one infusion at the highest scheduled dose level, and at least one patient has completed the entire five week dosing schedule. Cohorts will be enrolled at a maximal dose level of 3, 4, 6, or 8 mg/kg/week. Initial therapy will last for 5 weeks. Responding patients will receive additional infusions every two weeks x 4 at the maximal dose for each specific cohort.