Participants received chemotherapy (gemcitabine) with a starting dose of 1000 mg/m^2 IV on Day 1, 8, and 15 of every 28 day cycle up to a maximum of 12 cycles. If 0 out of 3 or <2 out of 6 participants in the CP-870893 0.1 mg/kg cohort experienced a dose limiting toxicity in Cycle 1, subsequent participants were enrolled in the 0.2 mg/kg dose cohort and received CP-870893 0.2 mg/kg IV on Day 3 of every 28 day cycle (0.2 mg/kg escalation cohort) for up to a maximum of 12 cycles.