3 Background: Bevacizumab (BEV) is a monoclonal antibody that inhibits tumor angiogenesis by targeting VEGF. In relapsed RCC, BEV improved time to progression compared with placebo (2.5 vs. 4.8 months). A phase III trial was conducted to evaluate the efficacy and safety of BEV in combination with interferon (IFN)-a2a as first-line treatment in metastatic (m) RCC. The final analysis of progression-free survival (PFS) and interim analysis of overall survival (OS) are presented. Methods: Nephrectomized patients with clear cell mRCC, KPS of =70%, no CNS metastases and adequate organ function received IFN- a2a (x3/week at a recommended dose of 9 MIU for up to 1 year) plus BEV (10mg/kg q2w) or placebo until disease progression. Tumor assessments were performed every 8 weeks until week 32 and 12 weekly thereafter. Patients were stratified according to country and Motzer score. Results: Between June 2004 and October 2006, 649 patients were randomized (641 treated) at 101 centers in 18 countries. The treatment arm...