A prospective, randomized, phase II study to assess the schemas of retreatment with Lutathera® in patients with new progression of an intestinal, well-differentiated neuroendocrine tumor (ReLUTH).

backgroundAlthough neuroendocrine tumors (NET) are classed as rare, they have a high prevalence and their incidence is increasing. Effective treatment with lutetium

methodsThis will be a multicenter, randomized, controlled, open-label, phase II study in France (ReLUTH). The aim is to evaluate the efficacy of retreatment with Lutathera® in patients with progressive intestinal NET (determined by somatostatin-receptor positive imaging) after previous treatment with two cycles of Lutathera®. Before randomization, all patients will have already received two Lutathera® retreatment cycles (7.4 GBq infusion each, 8 weeks apart). A total of 146 patients will be randomized (1:1) to two additional cycles of Lutathera® (7.4 GBq infusion each, separated by 8 weeks) or to no treatment (active surveillance). PRIMARY

objectiveefficacy of two additional Lutathera® retreatment cycles compared to active surveillance over 6 months. PRIMARY ENDPOINT: disease control rate at 6 months from randomization (defined as Complete Response, Partial Response, and Stable Disease in the Response Evaluation Criteria In Solid Tumours) with an evaluation every 2 months. A secondary objective will be the safety, as well as the PFS, OS, and QoL. It is expected that the efficacy of retreatment will increase after two additional Lutathera® cycles, with no increased safety concerns. DISCUSSION: Our prospective, randomized controlled study may lead to new recommendations for the use of Lutathera® in patients with intestinal progressive NET, and should confirm that four cycles will be more effective than two, with limited adverse impact on safety. Four Lutathera® treatment cycles have the potential to prolong life and improve quality of life in patients.

trial registrationClinicalTrials.gov: NCT04954820.