7557 Background: Concurrent chemoradiotherapy (CRT) is standard treatment for stage III NSCLC, although the management of resectable patients (pts) remains controversial. We report an open-label phase I/II trial of the epidermal growth factor receptor inhibitor E added to perioperative CRT for resectable stage III NSCLC pts, followed by maintenance (m) E. Methods: Eligible pts had stage IIIA/B NSCLC, PS 0–1, and were resectable as determined by a thoracic surgeon. Pts received weekly P (50 mg/m2), and C (AUC 2) with daily oral E for 28 days concurrent with twice daily thoracic radiation (1.5 Gy/fraction) to 30 Gy, followed by restaging. Non-progressors underwent resection followed by the same CRT regimen and 2 years of mE (150mg). The primary endpoint of the phase I portion was the maximum tolerated dose (MTD) of E given with CRT; and for the phase II was safety and tolerability. Secondary endpoints were pathologic complete response (pCR) rate, pathologic downstaging of mediastinal nodes, progression free survival (PFS), and overall survival (OS). Results: 9 pts were enrolled in the phase I trial. The MTD of E was150mg, which was the phase II dose used. 25 pts were treated in the phase II component: median age 60, 92% stage IIIA, 64% female, 72% PS 0, 64% adenocarcinoma, and 16% never smokers. The median duration of mE was 5.5 months, with the most common reason for discontinuation being pt preference. There was no grade 4 toxicity. Grade 3 toxicity seen in >5% of pts: rash (12%), diarrhea (9%), nausea (9%), and encephalopathy (6%). The most common toxicities during mE: grade 1/2 diarrhea (72%), rash (61%), fatigue (56%), nausea (22%), and dry eyes (17%).1 pt (4%) had a pCR after neoadjuvant CRT, and 46% were downstaged to pN0–1 at surgery. At a median follow-up of 36.5 mos the median PFS is 41.8 mos (95% CI 9.3-not yet reached). The median OS has not been reached. 3 year survival is 69%. Pts downstaged to pN0–1 vs those with persistent pN2–3 had a median PFS of 41.8 vs 18.1 mos (p=0.11). Conclusions: Perioperative P, C, and E given concurrently with HFRT was well tolerated and showed promising efficacy, while compliance was poor with maintenance E. [Table: see text]