Cohorts of 3-6 patients receive escalating doses of BMS-247550 until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 6 patients experience dose-limiting toxicity. Once the MTD is determined, additional patients are treated at that dose level. Patients treated at the MTD receive treatment once weekly on weeks 1-3 of each 4-week course.