Cohorts of at least 3 patients are entered at escalating doses of I-3F8. If grade 3 or worse toxicity occurs in 1 or more of 3 patients at a given dose level, then 3 additional patients are accrued at that level. If 2 or more of 6 patients at a given dose level experience grade 3 or worse toxicity, then that dose is declared the maximum tolerated dose (MTD).