NETTER-2: ¹⁷⁷Lu-DOTATATE in Higher-Grade GEP-NETs: The Lancet Oncology | August 2026

Introduction:

The Phase III NETTER-2 trial established ¹⁷⁷Lu-DOTATATE plus octreotide as an effective first-line therapy for advanced, well-differentiated, somatostatin receptor (SSTR)-positive higher-grade G2–G3 gastroenteropancreatic neuroendocrine tumors (GEP-NETs). This analysis examined whether benefit remains consistent across tumor grade and primary site.

Why was this study needed?

Higher-grade G2–G3 GEP-NETs have more aggressive biology and limited first-line options.

NETs are heterogeneous according to grade, primary site, and SSTR expression.

It was important to determine whether PRRT benefit extends equally to pancreatic and gastrointestinal NETs and to both G2 and G3 disease.

Results:

Among 226 patients, ¹⁷⁷Lu-DOTATATE markedly reduced progression or death compared with high-dose octreotide, with median PFS in the overall NETTER-2 study of 22.8 vs 8.5 months.

Benefit was consistent across G2 and G3 tumors and across pancreatic and gastrointestinal primary sites.

Objective response rates also consistently favored ¹⁷⁷Lu-DOTATATE across these major subgroups.

Benefit remained evident across different levels of SSTR uptake, reinforcing broad efficacy in appropriately selected SSTR-positive disease.

Clinical Impact:

These findings strengthen the role of ¹⁷⁷Lu-DOTATATE as a first-line treatment option, rather than reserving PRRT only for later lines, in newly diagnosed advanced, well-differentiated, SSTR-positive higher-grade G2–G3 GEP-NETs, particularly when chemotherapy is not considered the preferred initial treatment.

Bottom Line:

NETTER-2 supports moving ¹⁷⁷Lu-DOTATATE earlier in the treatment pathway. Its first-line benefit extends across G2 and G3 disease and both pancreatic and gastrointestinal NETs, establishing PRRT as a major upfront option for appropriately selected SSTR-positive GEP-NETs.