OUTLINE: All patients receive PSC 833 by mouth every 6 hours for a total of 12 doses. Paclitaxel is infused over 3 hours, after the 5th dose of PSC 833. Treatment is repeated every 3 weeks in stable and responding patients. PSC 833 must not be mixed with grapefruit juice. Growth factors may be used at the discretion of the investigator. Patients are followed every 3 months for the first two years, then every 6 months for years 2-5, and then annually thereafter.