The NETTER-1 clinical trial compared peptide receptor radionuclide therapy (PRRT) with [177Lu]Lu-DOTA-TATE (Lutathera®) every eight weeks (4 doses) plus 30 mg octreotide LAR every 4 weeks with high dose (60 mg) of octreotide LAR every 4 weeks in patients with progressive and unresectable midgut neuroendocrine well differentiated (G1, G2) tumors (NETs) with somatostatin-receptor positive imaging (SSTRi+). Lutathera® improves both median progression free survival (PFS) (28.4 months vs 8.5 months) and median overall survival (OS) (not reached vs 27.4 months) with a follow-up of 42 months. Lutathera® also has an impact on quality of life. Therefore, this treatment was approved by the European Medicines Agency and is now reimbursed in France in that specific indication. Despite these promising results, progression will occur in most of patients within a variable time with limited treatment options left. Retreatment with additional cycles of Lutathera® may be an option. Van der Zwan et al. showed in a large retrospective cohort (the ROTTERDAM cohort) a median PFS of 14.6 months after retreatment with two additional cycles of PRRT with [177Lu]Lu-DOTA-TATE and a significant longer OS than in the non-randomized control group. Interestingly, the safety was similar in salvage group than in initial PRRT: no grade (G) 3/4 renal toxicity occurred and hematological toxicities were similar to the group of patients who received the initial treatment (4 cycles). In a smaller cohort of 15 patients, Yordanova et al. showed that 8 or more cycles of [177Lu]Lu-DOTA-TATE were well tolerated and led to a survival improvement. In this study, each salvage therapy consisted of 2 or 3 cycles. No severe (G3, G4) renal toxicity or G4 adverse event occurred. In France, since the reimbursement of Lutathera®, this treatment is allowed for retreatment if patients still fulfill the criteria of its indication and 4 news cycles could be proposed. However, clinical practices are heterogeneous regarding the number of new cycles and most teams perform only two additional cycles (every 8 weeks). Therefore, the coordinator propose to evaluate the efficacy of two additional cycle of Lutathera® versus active surveillance in patients already retreated with two cycles Lutathera® for a new progression of intestinal neuroendocrine tumor and who previously received the 4 cycles of treatment with a clinical benefit.
In France, since the reimbursement of Lutathera®, this treatment is allowed for retreatment if patients still fulfill the criteria of its indication and 4 news cycles could be proposed. However, clinical practices are heterogeneous regarding the number of new cycles and most teams perform only two additional cycles (every 8 weeks). Therefore, the coordinator propose to evaluate the efficacy of two additional cycle of Lutathera® versus active surveillance in patients already retreated with two cycles Lutathera® for a new progression of intestinal neuroendocrine tumor and who previously received the 4 cycles of treatment with a clinical benefit.