Efficacy and Safety of Onartuzumab in Combination With First-Line Bevacizumab- or Pemetrexed-Based Chemotherapy Regimens in Advanced Non-Squamous Non-Small-Cell Lung Cancer

Abstract Background Onartuzumab is a monovalent monoclonal antibody that binds with the extracellular domain of the MET receptor. Given the role of MET in non–small-cell lung cancer (NSCLC), we investigated whether onartuzumab added to first-line chemotherapy efficacy in non-squamous NSCLC. Methods Patients with untreated stage IIIB/IV non-squamous NSCLC, stratified by MET diagnostic status, were randomized to receive onartuzumab (15 mg/kg intravenously every 3 weeks) or placebo in combination with either paclitaxel/platinum/bevacizumab (bevacizumab cohort), or in combination with platinum/pemetrexed (pemetrexed cohort) with maintenance bevacizumab or pemetrexed and onartuzumab/placebo as appropriate. Co-primary endpoints of this phase II study were progression-free survival (PFS) in all patients and in MET+ patients (2+/3+), defined by the Ventana immunohistochemistry assay; secondary endpoints included overall survival (OS), objective response rate (ORR), safety, and pharmacokinetics. Results Efficacy data were available for 139 and 120 patients in the bevacizumab and pemetrexed cohorts, respectively. No benefit was seen in the PFS endpoint in the intent-to treat population of either cohort, but was numerically worse in the onartuzumab arm of the MET+ subgroup of the bevacizumab cohort. The onartuzumab and placebo arms had similar ORR and OS results in both cohorts. A higher incidence of some adverse events was observed with onartuzumab versus placebo, including peripheral edema (30% vs. 3%, bevacizumab cohort; 48% vs. 14%, pemetrexed cohort) and venous thromboembolic events (bevacizumab cohort only, 15% vs. 6%). Conclusion Onartuzumab does not appear to provide any additional clinical benefit when given in combination with current first-line standard-of-care chemotherapy for non-squamous NSCLC.