e19583 Background: PF is commonly concomitant disorder with lung cancer. Because PF sometimes deteriorates and results unfavorable clinical course, patients with PF are excluded from most cancer clinical trials. S-1 is a novel active oral fluoropyrimidine anticancer agent consisting of tegafur, gimeracil and oteracil potassium. Although most anti-cancer agent have pulmonary toxicity, post marketing surveillance reported S-1 has lower pulmonary toxicity incidence. We have conducted feasibility study of S-1 and carboplatin combination for patients with advanced or ineligible for other treatment modality of NSCLC patients. Methods: Patients with histologically or cytologically confirmed NSCLC, clinically diagnosed pulmonary fibrosis, aged 80 years old or younger, performance status 0-2 and chemo naive were eligible for the study. Carboplatin (AUC 5) was administered on day 1 and S-1 (80mg/m2/day) on day 1 to 14 for four to six cycles. Endpoints were response rate, common safety profiles and effect to PF. Results: From March 2009 to December 2011, 21 pts (19 males/ 2 females, median age 67 years old, ranged 55 to 77, 10 adenocarcinoma, 10 squamous, 1 adenosquamous, stage IIA: 1, IIIA: 3, IIIB: 9, IV: 4, recurrence: 4) were enrolled. All patients had moderate or severe PF. Treatment delivery; 1 cycle: 3pts, 2: 3pts, 3: 3pts, 4: 10pts, 5; 1pts, 6: 1pts. Partial responses were observed in 7 patients (RR; 33%). The median progression free survival duration was 4.0 months and the median overall survival duration in 10.4 months. During the treatment, 2 patient experienced moderate deterioration of pulmonary fibrosis, 1 experienced infectious pneumonia, all three patients recovered from the event. There was no treatment related death. Besides pulmonary toxicity, most common adverse events were myelotoxicities. Conclusions: This is the first trial of S-1 and carboplatin combination for patients with PF and NSCLC. The study revealed S-1 and carboplatin combination was feasible and active even in patients with PF and NSCLC who are usually excluded from cancer clinical trials.