Cohorts of 3-6 patients receive escalating doses of UCN-01 and then gemcitabine until the maximum tolerated dose (MTD) of the combination is determined. The MTD is defined as the dose preceding that at which at least 2 of 3 or 2 of 6 patients experience dose-limiting toxicity. Once the MTD is determined, at least 6 patients are treated at the recommended phase II dose.