CA 19-9 as a biomarker in advanced pancreatic cancer patients randomised to gemcitabine plus axitinib or gemcitabine alone

BACKGROUND: Response assessment in advanced pancreatic cancer (APC) is difficult and predictive markers are needed. There are insufficient data on the value of carbohydrate antigen 19–9 (CA 19-9) and cytostatic-targeted therapies. Axitinib, a selective vascular endothelial growth factor (VEGF) receptors 1, 2, 3 inhibitor, may increase overall survival (OS) in APC. METHODS: We assessed serum CA 19-9, clinical outcomes and diastolic blood pressure (dBP) in APC patients receiving gemcitabine plus axitinib (Gem+A) or gemcitabine alone. RESULTS: In the total population (N=95), median OS was significantly longer in patients with baseline CA 19-9 values at or below the median than in those with values above it (12.2 months [95% confidence interval (CI), 8.6–16.6%] vs 5.0 months [95% CI, 3.9–5.7%]; P<0.0001). This also reached significance in the Gem+A arm (median OS, 12.5 months [95% CI, 8.6–16.6%] vs 4.9 months [95% CI, 3.6–5.6%]; P<0.0001). Patients with any dBP>90 mmHg had significantly longer OS than those who did not. However, there was no predictive significance of CA 19-9. CONCLUSION: Baseline CA 19-9 levels had prognostic value for OS, but caution is advised in interpreting CA 19-9 as a predictive biomarker for novel cytostatic agents such as VEGF-targeted therapies in phase II studies.