Background: Adj chemo has been shown to improve absolute survival after resection of early stage NSCLC by 5-15%. Encouraging results with B on E4599 in advanced stage NSCLC led to trial development of B with adj chemo. Methods: E1505 aims to enroll 1500 pts with resected stage IB (>/= 4 cm) – IIIA (by AJCC 6) NSCLC. All pts receive 4 x 3 wk cycles of doublet chemo with cisplatin (C) plus vinorelbine (V), docetaxel (D), gemcitabine (G) or pemetrexed (P). P option was added in 2009. Pts are randomized 1:1 to chemo alone or chemo + B (B continued up to 1 yr). Inclusion criteria for this interim toxicity analysis included randomization at least one year prior to the data pull (Jan 5, 2011). Fisher's exact test was used to test for differences in categorical data; Wilcoxon rank sum test was used to test for differences in continuous variables. Toxicities were graded using CTCAE v 3.0. Results: Included here are 557 pts (enrolled Aug 2007-Jan 5, 2010) (282 Chemo/275 Chemo+B) median age 61 (range 36-86 yo), 340 (61%) ECOG PS 0, 291 (52%) women, 490 (88%) white, 302 (54%) adenocarcinoma, 172 (31%) squamous histology. Stages enrolled were: 129 (23%) IB, 244 (43%) II, 158 (29%) IIIA-N2, 22 (4%) IIIA-T3N1 and only a minority had had a pneumonectomy 73 (13%). All demographic features were well balanced. Adj chemo was CV- 155 (28%), CD 186 (34%), CG 145 (26%), CP 69 (12%), balanced by arm. There is a significant increase in risk of grades 3/4 hypertension (0.7 vs. 19.7%, p<0.001), proteinuria (0.7 vs. 3.4%, p=0.03), abdomen pain (0.4 vs. 4.6%, p=0.001), and overall grade 3/4 toxicity (68.5% vs. 83.4%, p<0.001) associated with B. Grade 5 toxicity rates were not significantly different at 2.5% vs 3.8% -/+ B, p=0.46. Only 1 case each of fatal hemoptysis and non-fatal bronchopleural fistula have been seen in pts receiving B. Conclusions: This report provides interim demographic safety data for E1505, revealing no unexpected toxicities. Enrollment challenges include lack of adequate lymph node sampling in otherwise eligible pts. The study remains open to accrual with projected enrollment completion in 2013.