Purpose The phase III OAM4971g study (METLung) examined the efficacy and safety 
of onartuzumab plus erlotinib in patients with locally advanced or metastatic 
non-small-cell lung cancer selected by MET immunohistochemistry whose disease 
had progressed after treatment with a platinum-based chemotherapy regimen. 
Patients and Methods Patients were randomly assigned at a one-to-one ratio to 
receive onartuzumab (15 mg/kg intravenously on day 1 of each 21-day cycle) plus 
daily oral erlotinib 150 mg or intravenous placebo plus daily oral erlotinib 150 
mg. The primary end point was overall survival (OS) in the intent-to-treat 
population. Secondary end points included median progression-free survival, 
overall response rate, biomarker analysis, and safety. Results A total of 499 
patients were enrolled (onartuzumab, n = 250; placebo, n = 249). Median OS was 
6.8 versus 9.1 months for onartuzumab versus placebo (stratified hazard ratio 
[HR], 1.27; 95% CI, 0.98 to 1.65; P = .067), with a greater number of deaths in 
the onartuzumab arm (130 [52%] v 114 [46%]). Median progression-free survival 
was 2.7 versus 2.6 months (stratified HR, 0.99; 95% CI, 0.81 to 1.20; P = .92), 
and overall response rate was 8.4% and 9.6% for onartuzumab versus placebo, 
respectively. Exploratory analyses using MET fluorescence in situ hybridization 
status and gene expression showed no benefit for onartuzumab; patients with EGFR 
mutations showed a trend toward shorter OS with onartuzumab treatment (HR, 4.68; 
95% CI, 0.97 to 22.63). Grade 3 to 5 adverse events were reported by 56.0% and 
51.2% of patients, with serious AEs in 33.9% and 30.7%, for experimental versus 
control arms, respectively. Conclusion Onartuzumab plus erlotinib did not 
improve clinical outcomes, with shorter OS in the onartuzumab arm, compared with 
erlotinib in patients with MET-positive non-small-cell lung cancer.