Patients were stratified according to a minimisation algorithm by Eastern Cooperative Oncology Group performance status , smoking history , centre , and masked pretreatment serum protein test classification , and randomly assigned centrally in a 1:1 ratio to receive erlotinib ( 150 mg/day , orally ) or chemotherapy ( pemetrexed 500 mg/m ( 2 ) , intravenously , every 21 days , or docetaxel 75 mg/m ( 2 ) , intravenously , every 21 days ) .