Bevacizumab in non small cell lung cancer: development, current status and issues

Bevacizumab is a monoclonal antibody directed against Vascular Endothelial Growth Factor (VEGF). Evidence about its efficacy in addition to first-line chemotherapy in non-small-cell-lung-cancer (NSCLC) has been produced by two large randomized phase III clinical trials (ECOG 4599 and AVAiL), conducted in a clinically selected population with non-squamous histology and without major risk factors for bleeding. In the ECOG 4599 trial, the addition of bevacizumab (15 mg/kg) to carboplatin plus paclitaxel produced a statistically significant and clinically relevant improvement in overall survival (OS), that was the primary endpoint of the trial (12.3 months vs 10.3 months, HR 0.79; p=0.003). Furthermore, patients receiving bevacizumab showed a significant improvement in progression-free survival (PFS) and in objective response rates. Treatment with bevacizumab was well tolerated by the majority of patients, but was still associated with increased risk of clinically significant bleeding (4.4% vs 0.7%, p0.001). In the AVAiL trial the addition of bevacizumab (at the dose of 7.5 and 15 mg/kg) to cisplatin plus gemcitabine produced a small improvement in PFS, but no differences in OS. Information from retrospective analysis and two large observational studies (SAIL and ARIES) have confirmed the safety profile of first-line bevacizumab with a wide range of chemotherapy partners, but whether its efficacy is comparable when combined with the different regimens is still unknown. The identification of predictive factors of efficacy would be relevant for the optimal use of the drug, but to date we have no conclusive data in this direction.