OUTLINE: This is a dose escalation study. Patients receive DX-8951f IV over 30 minutes daily for 5 days. Treatment continues every 3 weeks for at least 2 courses in the absence of disease progression or unacceptable toxicity. Cohorts of 3-6 patients receive escalating doses of DX-8951f until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which at least 2 of 6 patients experience dose limiting toxicity. Patients are followed every 3 months until death.