While gemcitabine (GEM) is widely accepted for the treatment of advanced pancreatic cancer, capecitabine (CAP) has shown single agent activity and promising efficacy in combination with GEM. This phase II study was conducted to evaluate the efficacy and toxicity of GEM combined with dose escalated 14-day CAP as first-line chemotherapy for advanced pancreatic cancer. In addition, we also analyzed the correlation between CA19-9 response and clinical outcomes. Patients had advanced pancreatic adenocarcinoma, no prior systemic chemotherapy other than that given concurrently with radiation therapy, at lease one measurable disease, and adequate organ functions. The patients were treated with GEM 1,000 mg/m2 IV on days 1, 8 and CAP 1,000 mg/m2 twice a day PO on days 1-14, in 21-day cycles. The objective RR among 45 patients was 40.0% (95% CI; 25.1-54.9), including 1CR (2.2%). The median TTP and OS were 5.4 months (95% CI; 1.8-9.0) and 10.4 months (95% CI; 6.2-14.5), respectively. Patients with >or=25% decline of serum CA19-9 had significantly better outcomes in terms of TTP and OS than those who did not (P < 0.03). The most frequent, grade 3-4, non-hematologic toxicity was hand-foot syndrome (6.7%). The combination of GEM with dose escalated 14-day CAP is well tolerated and offers encouraging activity in the treatment of advanced pancreatic cancer. In addition, CA19-9 response correlates well with clinical outcomes in this population.