Neuroendocrine tumors (NETs) are characterized by their expression of vascular endothelial growth factor (VEGF). This trial investigated the activity of Ziv-aflibercept, a recombinant protein that binds to and inhibits the activity of VEGF, in patients with advanced NETs (NCT01782443).A single-arm, phase II trial enrolling patients with advanced, progressive extrapancreatic NET. Patients were treated with Ziv-aflibercept 4 mg/kg intravenously on day 1 and 15 of a 28-day cycle; the starting dose was reduced to 2 mg/kg on days 1 and 15 of a 28-day cycle because of hypertension-related events. The primary end point was progression-free survival.The trial enrolled 19 patients (13 male:6 female). Patients received a median of 7 cycles (range, 1-18 cycles). The median progression free survival was 11.8 months (95% confidence interval, 3.2-16.1 months), and the median overall survival was 36.4 months (95% confidence interval, 16.1-not reached). Best responses by Response Evaluation Criteria in Solid Tumors 1.1 are as follows: 1 (5%) partial response, 13 (68%) stable disease, 2 (10%) with progressive disease, and 3 (15%) unevaluable. Hypertension occurred in 18 patients (95%), including grade 3-4 hypertension in 12 patients (63%).Although the progression free survival is similar to other VEGF inhibitors in NET, toxicity may preclude further investigation.