The purpose of this study is to compare the effectiveness and safety of CAM2029 to octreotide LAR or lanreotide ATG in patients with advanced, well-differentiated GEP-NET. Patients who experience progressive disease in the randomized part of the study may proceed to an open-label extension part with intensified treatment with CAM2029.

Inclusion Criteria:

• Male or female patient ≥18 years old
• Histologically confirmed, advanced (unresectable and/or metastatic), and well-differentiated NET of GEP or presumed GEP origin
• At least 1 measurable, somatostatin receptor-positive lesion according to RECIST 1.1 determined by multiphasic CT or MRI (performed within 28 days before randomization)
• ECOG performance status of 0 to 2

Exclusion Criteria:

• Documented evidence of disease progression while on treatment (including SSAs) for locally advanced unresectable or metastatic disease
• Known central nervous system metastases
• Consecutive treatment with long-acting SSAs for more than 6 months before randomization
• Carcinoid symptoms that are refractory to treatment (according to the Investigator's judgement) with conventional doses of octreotide LAR or lanreotide ATG and/or to treatment with daily doses of ≤600 µg of octreotide IR
• Previous treatment with more than 1 cycle of targeted therapies such as mTOR inhibitors or vascular endothelial growth factor inhibitors, or more than 1 cycle of chemotherapy or interferon for GEP-NET
• Treatment of GEP-NET with trans-arterial chemoembolization or trans-arterial embolization within 12 months before screening
• Previously received radioligand therapy (PRRT) at any time