Multicenter Phase II Trial of Axitinib Monotherapy for Gemcitabine-Based Chemotherapy Refractory Advanced Biliary Tract Cancer (AX-BC Study)

Abstract Lessons Learned Axitinib exhibited marginal activity against gemcitabine-refractory unselected biliary tract cancer. Pretreated soluble vascular endothelial growth factor receptor-2 may be a useful biomarker for axitinib treatment outcome. Ascites should be carefully monitored in patients receiving anti–vascular endothelial growth factor receptor therapy including axitinib in advanced biliary tract cancer. Background There are no clear options for second-line treatment in patients with gemcitabine (GEM)-refractory biliary tract cancer (BTC). We conducted a multicenter, single-arm, phase II trial to confirm the efficacy and safety of axitinib, a potent selective inhibitor of vascular endothelial growth factor receptor (VEGFR)-1/2/3, in patients with GEM-refractory BTC. Methods Patients refractory or intolerant to GEM-based chemotherapy were enrolled. Axitinib was administered orally at an initial dose of 5 mg twice daily. The primary endpoint was progression-free survival (PFS), and the threshold and expected values were set at 2 and 3 months, respectively. The target sample size was 32 patients. Results Nineteen patients were enrolled. The trial was interrupted for a total of 13 months for the evaluation of adverse events. Thirteen patients were previously treated with ≥2 regimens. The median PFS was 2.8 months (95% confidence interval [CI]: 2.1–4.1). The median overall survival was 5.8 months (95% CI: 3.3–9.7). The response rate was 5.3% (95% CI: 0.0–15.3). Grade 3 ascites occurred in two patients. Baseline soluble VEGFR-2 levels were significantly associated with PFS. Conclusion Axitinib exhibited marginal activity against GEM-refractory BTC. Ascites should be carefully monitored in axitinib-treated patients with advanced BTC.