Emerging Treatment Options for Gastroenteropancreatic Neuroendocrine Tumors

Treatment options for neuroendocrine tumors (NETs) and carcinomas (NECs) are expanding. Early-phase studies have shown preliminary evidence of the antitumor activity of alpha-emitting peptide receptor radionuclide therapy (PRRT), and novel radiopeptides incorporating somatostatin receptor antagonists (rather than agonists) have been developed. Several tyrosine kinase inhibitors (TKIs) with antiangiogenic potential have been evaluated in patients with NETs, including lenvatinib, axitinib, cabozantinib and pazopanib. Recently, two phase 3 clinical trials have demonstrated the efficacy and safety of surufatinib, an inhibitor of vascular endothelial growth factor receptor (VEGFR)-1, -2, -3, fibroblast growth factor receptor (FGFR)-1 and colony stimulating factor-1 receptor (CSF-1R), in patients with pancreatic and extra-pancreatic NETs. Multiple clinical trials of combination immunotherapy have been recently completed, but interpretation of the results is hampered by small samples sizes and discordant outcomes. This review summarizes recent data on emerging treatments for neuroendocrine neoplasms.