Phase I patients on cohorts 1-4 received the following: cohort 1: 2 mg/kg over 60 minutes intravenously on days 1 and 2; cohort 2: 4 mg/kg over 90 minutes intravenously on day 1, single dose; cohort 3: 6 mg/kg over 90 minutes intravenously on day 1, single dose; and cohort 4: 8 mg/kg over 90 minutes intravenously on day 1, single dose.