Phase II study of aflibercept (VEGF-Trap) in patients with recurrent or metastatic urothelial cancer, a california cancer consortium trial

OBJECTIVES: To determine whether aflibercept, a recombinant fusion protein that binds and neutralizes multiple vascular endothelial growth factor isoforms, is effective in the treatment of urothelial cancer. The efficacy of systemic therapies for advanced urothelial cancer after failure of front-line platinum-based chemotherapy is limited. Evidence has shown that vascular endothelial growth factor is important in the pathophysiology of urothelial cancer. METHODS: Patients with measurable, metastatic, or locally advanced urothelial cancer previously treated with 1 platinum-containing regimen were enrolled. Aflibercept was administered at 4 mg/kg intravenously every 2 weeks. The response rate (RR) and progression-free survival (PFS) were assessed in a 2-stage accrual design (22 + 18). A maximum of 40 patients were to be accrued to rule out a null hypothesis RR of 4% and PFS of 3 months versus an alternative RR of 15% and PFS of 5.4 months, with α = 0.12 and β = 0.19. RESULTS: A total of 22 patients were accrued. One partial response (4.5% RR, 95% confidence interval 0.1%-22.8%) was seen. The median PFS was 2.79 months (95% confidence interval 1.74-3.88). Attributable Grade 3 toxicities included fatigue, hypertension, proteinuria, pulmonary hemorrhage, pain, hyponatremia, anorexia, and lymphopenia. No treatment-related Grade 4 or greater toxicities occurred. CONCLUSIONS: Aflibercept was well tolerated, with toxicity similar to those seen with other vascular endothelial growth factor pathway inhibitors; however, it had limited single-agent activity in patients with urothelial carcinoma previously treated with platinum-containing chemotherapy.