 PHASE I: Patients receive flavopiridol IV over 412 hours on days 1, 8, 15, and 22. Treatment repeats every 6 weeks for up to 6 courses in the absence of disease progression or unacceptable toxicity. Cohorts of 3-6 patients receive escalating doses of flavopiridol until the maximum tolerated dose MTD is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose-limiting toxicity. 