Background: In pts with metastatic midgut NET, OCT showed antitumor activity and significantly extended time to tumor progression (TTP) vs PBO (PROMID trial, Rinke et al. 2009). We present a post hoc analysis assessing efficacy of OCT (30 mg q28d) in the PBO+ OCT arm of the phase III RADIANT-2 study. Methods: For this post hoc analysis, progression-free survival (PFS by central review, cutoff Apr 2, 2010) and overall survival (OS, cutoff Jun 13, 2013) in the PBO + OCT arm were estimated by prior somatostatin analogue (SSA) use and primary tumor location subgroups using the Kaplan-Meier (KM) method. Results: 213 pts were randomized to PBO + OCT (median age, 60 yrs; male, 58%; WHO PS: 0/1/2 in 66%/29%/5% pts; >80% had well-differentiated disease). Of these, 47 (22%) were SSA naïve (foregut, 32%; midgut, 51%; hindgut, 4%; not classified or missing, 13%) and 166 (78%) had received SSA (foregut, 10%; midgut, 72%; hindgut, 11%; not classified or missing, 7%) prior to study entry. Median PFS (95% CI) for pts who were SSA naïve vs who had received SSA was 13.6 (8.2-22.7) mos vs 11.1 (8.4-14.2) mos. By primary tumor location, median PFS (95% CI) in SSA naïve pts vs who received SSA was 5.7 (2.8-27.8) mos vs 8.7 (2.8-13.9) mos for foregut, 22.2 (8.3-29.5) mos vs 12.0 (8.4-17.7) mos for midgut, and not-reached (NR; 4.7-NR) vs 6.6 (3.0-13.0) mos for hindgut. OS analysis is in table. Conclusions: This post hoc analysis of the PBO + OCT arm of the RADIANT-2 study showed a PFS of 13.6 mos in SSA naïve pts treated with OCT. While the RADIANT-2 study PBO arm differs from PROMID in patient population and method of assessment of tumor progression, the data from this post hoc analysis provide additional evidence of the antiproliferative effect of OCT in NET. Clinical trial information: NCT00412061.