A Randomized Phase II Study to Determine the Effect of 2 Different Doses of Aflibercept in Patients With Metastatic Renal Cell Carcinoma (ECOG-ACRIN [E4805])

Micro-Abstract Vascular endothelial growth factor (VEGF) represents a major target for therapeutic interventions in metastatic renal cell carcinoma. In this randomized phase II study we evaluated the safety and efficacy of the VEGF blocker AVE0005 (VEGF Trap), or aflibercept, in previously treated renal cell carcinoma patients. Aflibercept at a dose of 4 mg was safe and had favorable clinical activity. These results provide the rationale for further investigation of aflibercept in rational combination strategies for renal cell carcinoma patients. Background Aflibercept is a recombinantly produced fusion protein that has potent anti-vascular endothelial growth factor (VEGF) activity. We tested whether aflibercept has clinical activity in clear-cell renal cell carcinoma (ccRCC). The recommended phase II dose was 4 mg/kg but several patients (pts) treated at 1 mg/kg showed prolonged progression-free survival. We therefore tested both doses in a parallel group randomized trial. Patients and Methods Eligible pts had histologically confirmed advanced or metastatic ccRCC and previous treatments included exposure to a VEGF receptor tyrosine kinase inhibitor. Pts received aflibercept (either 1 mg/kg or 4 mg/kg) on day 1 of a 14-day cycle until disease progression. Pts randomized to 1 mg/kg could crossover to 4 mg/kg at the time of disease progression. The primary end point was proportion alive and progression-free at 8 weeks. A Simon 2-stage design was used for each arm with 33 and 24 eligible pts per arm enrolled in stages 1 and 2. Results Ninety-four pts were enrolled, 59 and 35 to 4 mg and 1 mg doses, respectively. Seventy-two percent had 1 previous treatment most commonly sunitinib. Sixteen eligible pts crossed over at the time of disease progression to the 4-mg dose. Most common adverse events were hypertension, proteinuria, and fatigue. Only 4 pts reported Grade 4 or higher toxicity. With 36 of 59 pts (61%) progression-free at 8 weeks, the 4-mg/kg dose met protocol-specified efficacy criteria. Conclusion Aflibercept is active in previously treated ccRCC and might be worthy of further study.