E6201
DrugE6201 Part A (Dose Escalation): Intravenous (IV) infusion administered over 30 minutes once weekly for 3 weeks (Days 1, 8, and 15). The first 3 to 6 subjects of the first cohort will receive 20 mg/m^2/week for a cycle of 3 weeks followed by a 1-week rest period. Subsequent dose escalations may increase at increments of 100% until two Grade 2 toxicities or 1 dose-limiting toxicity (DLT) are observed in a dose group. Thereafter, doses will be increased in increments of 50% or less until the maximum tolerated dose (MTD) is determined. Part B (MTD Expansion): After the MTD is determined in Part A, 15 additional subjects will continue to receive cycles at the MTD.