e18007 Background: Erlotinib was approved in Japan in 2007 for recurrent/advanced NSCLC after failure of at least one prior chemotherapy regimen. Previous Phase I/II studies highlighted interstitial lung disease (ILD) as an adverse drug reaction (ADR) of particular concern in Japanese pts. To investigate the safety and efficacy of erlotinib, including ILD incidence and risk factors in Japanese pts, large scale surveillance has been implemented. Methods: From Dec 2007 to Oct 2009, all pts with recurrent/advanced NSCLC treated with erlotinib, were enrolled into the study. The observation period was 12 months, all adverse events (AEs) were collected and ADRs were defined as AEs where causality to erlotinib could not be ruled out. All ILD-like events were assessed by an independent ILD review committee. Overall survival (OS) and progression-free survival (PFS) were also assessed. Interim data were analyzed for pts registered prior to 30 Jun 2008. Results: By Oct 2009, a total of 10,708 pts were enrolled. We analyzed 3,743 pts enrolled by 30 Jun 2008, and data were available for 3,488, excluding 255 pts who were not treated with erlotinib, not available for CRF, or registered more than once. The overall incidence of ADRs was 81.8% (mostly grade 1/2), the most common were skin disorders (68.5%), including rash (63.0%), and gastrointestinal disorders (32%), including diarrhea (23.5%). Physician-assessed ‘ILD-like’ events were reported in 189 pts. Of these, the independent ILD review committee confirmed ILD (all grades) in 158 pts (4.5% of population) with a mortality rate of 1.6%. As risk factors for ILD, multivariate analysis identified smoking status (hazard ratio [HR]: 3.0), history of ILD (HR: 4.1), history of lung infection (HR: 2.0) and ECOG PS 2–4 (HR: 1.6). Median OS and PFS were 260 days and 64 days, respectively. Further data collection and analyses are ongoing and will be reported. Conclusions: Results of this primary analysis from a large surveillance study in unselected pts support the clinical benefits of erlotinib and provide evidence about ILD risk with erlotinib in Japan. No new safety signals were identified. The risk/benefit balance for use of erlotinib in pts with recurrent/advanced NSCLC remains favorable.