Background: Surufatinib is a small-molecule inhibitor of VEGFR1, 2, & 3, FGFR1, and CSF-1R. Surufatinib demonstrated prolonged PFS and tolerable safety in two phase 3 studies in advanced neuroendocrine tumors (NETs) of pancreatic (SANET-p; NCT02589821) and extrapancreatic (SANET-ep; NCT02588170) origin (Xu, 2020 Lancet Oncology). Detailed outcomes on safety from these 2 studies are reported here as a pooled analysis. Methods: Data is pooled from SANET-p and SANET-ep studies which have similar designs including a 2:1 randomization of surufatinib to placebo in patients ≥18 years with advanced, well differentiated NETs, progressing on or after ≤2 prior therapies. Surufatinib 300 mg or placebo, was administered once daily until disease progression or unacceptable toxicity. Safety outcomes for each pooled treatment group are reported as treatment-emergent adverse events (TEAE) assessed by NCI-CTC 4.03. Patients were included if they had received study treatment during the double-blinded phase of the studies. Results: As of 30^th June 2020, 396 patients were assigned to the surufatinib (n = 263) and placebo (n = 133) groups. Median treatment duration was longer with surufatinib 7.4 months (range 0.1–41.4) compared with placebo 4.6 months (range 0.1–39.9). 29% of patients reached more than 12 months of treatment with surufatinib group compared to 11% with placebo. The mean relative dose intensity was 87.56% in the surufatinib group and 97.01% in the placebo group. Most common TEAEs (surufatinib vs placebo) were proteinuria 68.8% vs 54.9%, hypertension 68.4% vs 27.1%, and diarrhea 49% vs 22.6%. Most common grade ≥3 TEAE were hypertension 38.8% vs 13.5%, proteinuria 14.8% vs 0.8% and hypertriglyceridaemia 5.3% vs 0%. Deaths due to TEAEs were comparable between groups 2.7% vs 2.3%. TEAEs led to dose reductions in 43.0% vs 6.8% of patients and dose interruptions in 47.1% vs 29.3% of patients. The majority of patients (83.3% vs 93.2%) were managed without discontinuation because of TEAE. Median onset of proteinuria and hypertension were < 1 month in both groups. Median (range) onset was 0.95 months (0.16–30.36) vs 0.95 months (0.23–16.95) for proteinuria and 0.49 months (0.03–31.18) vs 0.89 months (0.03–14.75) for hypertension. Among patients with hypertension, 59% (n = 111) vs 28% (n = 11) received antihypertensive medication. Conclusions: Surufatinib was generally well tolerated in this pooled analysis and the safety profile was consistent with its previously reported data. The monitoring and management of hypertension and proteinuria are important for patients receiving surufatinib. Clinical trial information: NCT02589821; NCT02588170.