OUTLINE: This is a dose escalation study. Patients receive 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP) IV over 2 hours on days 1-5. Treatment repeats every 4 weeks in the absence of disease progression or unacceptable toxicity. Cohorts of 1-6 patients receive escalating doses of 3-AP 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. Patients are followed for 4 weeks or until recovered.