LBA7511 Background: INFORM (a phase III, randomized, multicenter, parallel group study; NCT00770588 ) investigated the efficacy, safety and tolerability of gefitinib (G) vs. placebo (P) as maintenance therapy in pts with locally advanced/metastatic NSCLC following standard first-line platinum based chemotherapy. Methods: Pts (≥18 years, with stage IIIB/IV NSCLC and WHO performance status 0-2) had completed 4 cycles of first-line platinum based doublet chemotherapy without progression/unacceptable toxicity. Pts were randomized 1:1 to G 250mg/day or P on discontinuation of first-line therapy. Progression-free survival (PFS; primary endpoint) was assessed in the intent to treat population (Cox proportional hazards adjusted for histology [adenocarcinoma vs. non-adenocarcinoma], smoking status [never-smoker vs. smoker], EGFR mutation status [positive vs. negative vs. unknown] and best response to first-line chemotherapy [complete response/partial response vs. stable disease]). PFS was considered superior with gefitinib if the G:P hazard ratio (HR) upper confidence interval (CI) was <1.00. Secondary endpoints included overall survival (OS), objective response rate, disease control rate, symptom improvement and tolerability. Results: 296 pts (n=148 G, n=148 P) were randomized (27 centers in china; 26 September 2008-10 August 2009). PFS data cutoff on 24 January 2011. Median duration of follow-up was 16.8 months: 91% pts progressed; 59% deaths. Demography was balanced between treatments; overall, 54.1% pts were never-smokers, 70.6% had adenocarcinoma, and 40.9% were female. For G vs. P, PFS HR=0.42; 95% CI 0.32-0.54; p<0.0001; median PFS 4.8 vs. 2.6 months. Most common AEs (any grade) with G were rash (49.7%), diarrhea (25.2%), and ALT increase (21.1%) which were generally mild/moderate. Overall incidence of serious AEs: G (6.8%); P (3.4%). Other secondary endpoint data (including OS and biomarkers) will be presented. Conclusions: PFS was significantly longer with G compared with P as maintenance therapy in Chinese patients with locally advanced NSCLC.