NETTER-1 phase III: Efficacy and safety results in patients with midgut neuroendocrine tumors treated with 177Lu-DOTATATE.

4005Background: There are limited therapeutic options for patients with advanced midgut NETs progressing on first-line somatostatin analog therapy. The purpose of this phase III trial was to evaluate the efficacy and safety of 177Lu-DOTA0-Tyr3-Octreotate (Lutathera) in patients with advanced, progressive sstr positive midgut NETs. Methods: 230 patients with grade 1-2 metastatic midgut NETs were randomized to Lutathera, 7.4 GBq every 8 weeks (x 4 administrations) vs Octreotide LAR 60 mg every 4 weeks. Primary endpoint was PFS (RECIST 1.1) with tumor assessment every 12 weeks. Secondary objectives included ORR, OS, toxicity and QoL. Results: In the intent-to-treat population (ITT), the median PFS was not reached for Lutathera and was 8.4 months with control (p u003c 0.0001, HR 0.21). There were 23 centrally confirmed disease progressions or deaths in the Lutathera arm and 67 in the Octreotide LAR 60 mg arm. The objective radiographic response rate (ORR) was 18% with Lutathera and 3% with control (p = 0.0008). B...