PRIOR CONCURRENT THERAPY: Biologic therapy: At least 3 weeks since prior biologic therapy Chemotherapy: At least 3 weeks since prior chemotherapy and recovered No prior gemcitabine No more than 1 prior chemotherapy regimen (single agent or combination therapy) Endocrine therapy: At least 3 weeks since prior endocrine therapy Radiotherapy: At least 3 weeks since prior radiotherapy and recovered Surgery: At least 3 weeks since prior surgery and recovered