OUTLINE: This is a randomized, double blind, placebo controlled, multicenter study. Patients are stratified according to performance status and are randomized to one of two treatment arms. Arm I: Patients receive CI-994 orally on days 1-21 and gemcitabine IV over 30 minutes on days 1, 8, and 15. Arm II: Patients receive placebo capsules orally on days 1-21 and gemcitabine as in arm I. Treatment repeats every 28 days as long as medically appropriate (absence of disease progression or unacceptable toxicity).