OUTLINE: This is an open label, dose escalation, multicenter study. Patients receive IV combretastatin A4 phosphate over 10 minutes once a week for 3 weeks. Patients not experiencing unacceptable toxic effects begin individual dose escalation, receiving a maximum of 3 dose levels with 2 weeks of rest between each dose level. Dose escalation stops when 2 patients have experienced dose limiting toxicity (DLT) at a particular dose level. Once DLT is established, at least 6 patients are treated at a lower dose to determine the maximum tolerated dose. Patients may receive up to 6 courses of 3 infusions each. Patients are followed for 4 weeks.