Lutetium 177Lu-Edotreotide Versus Best Standard of Care in Well-differentiated Aggressive Grade-2 and Grade-3 GastroEnteroPancreatic NeuroEndocrine Tumors (GEP-NETs) - COMPOSE

Inclusion Criteria:

• Patients aged ≥ 18 years.

• Histologically confirmed diagnosis of unresectable, well-differentiatedGastroEnteroPancreatic NeuroEndocrine Tumors (GEP-NETs). measurable site of diseaseper RECIST v1.1 (Response evaluation criteria in solid tumors) using contrastcomputed tomography (CT) / magnetic resonance imaging (MRI).

• Somatostatin receptor-positive (SSTR+) disease.

Exclusion Criteria:

• Known hypersensitivity to Lutetium 177Lu, edotreotide, DOTA (dodecane tetraaceticacid), any of the comparators, or any excipient or derivative (e.g. rapamycin).

• Prior (Peptide Receptor Radionuclide Therapy) PRRT.

• Any major surgery within 4 weeks prior to randomization in the trial.

• Therapy with an investigational compound and/or medical device within 30 days or 7half-life periods (whichever is longer) prior to randomization.

• Other known malignancies.

• Serious non-malignant disease.

• Renal, hepatic, cardiovascular, or hematological organ dysfunction, potentiallyinterfering with the safety of the trial treatments.

• Pregnant or breastfeeding women.

• Patients not able to declare meaningful informed consent on their own or any othervulnerable population to that.