4030 Background: Octreotide LAR (O) compared to placebo (P) lengthens significantly time to tumor progression (TTP) in patients with metastatic midgut neuroendocrine tumors (Rinke et al. 2009). The antiproliferative response was more pronounced in patients with low (≤ 10%) hepatic tumor load (HL). To investigate whether this beneficial effect also affects overall survival (OS), patients included in the PROMID trial were followed until January 2013 at least once a year. Methods: Between July 2001 and January 2008, 42 and 43 patients were randomly assigned to receive O or P. Post study treatment was at the discretion of the local investigator. Data on cause of death and on post study treatment were documented. OS was analyzed using the Kaplan-Meier method. Treatment groups (O vs. P; HL at study entry ≤ 10% vs. >10%) were compared using the log rank test and hazard ratios were estimated with the use of the Cox proportional hazards model. Results: 41 of 85 patients died until January 2013. 19 in the octreotide and 22 in the placebo arm. Median OS for all 85 patients was 85 months, “not reached” in the O arm and 84 months in the P arm (p=0.59, HR=0.85 [CI 0.46; 1.56]). Cause of death was unrelated to the tumor disease in 8 patients. 26 of 64 patients (10 in the O vs. 16 in the P arm) died in the HL ≤ 10% subgroup and 15 of 21 patients (9 in the O vs. 6 in the P arm) in the HL > 10 % (p=0.002, HR=2.7). Median OS in the HL ≤ 10% subgroup was “not reached” (octreotide) vs 80.5 months (placebo) (p=0.14, HR=0.56 [CI 0.25; 1.23]). In the HL > 10% subgroup the respective numbers were 35 vs. 84 months (p=0.14, HR=2.18 [CI 0.75; 6.33]). Post study treatment in the O and P groups included octreotide LAR (29 vs. 38 patients), hepatic CHE (5 vs. 12 patients), PRRT (13 vs. 13 patients) and CHT (4 vs. 5 patients). Conclusions: Octreotide LAR not only prolongs TTP but also extends OS in the subgroup of patients with metastatic midgut NETs and a low HL (≤ 10% at study entry) but not in the high (HL > 10%) subgroup. Almost all patients who were randomized at study entry in the P group received octreotide LAR after disease progression, but these experienced a less favourable OS in the low HL subgroup. Clinical trial information: NCT00171873.