Phase II Trial of Bevacizumab Monotherapy in Pancreatic Neuroendocrine Tumors

Systemic therapies for pancreatic neuroendocrine tumors (PNETs) are limited. The combination of bevacizumab and temsirolimus showed significant antitumor activity, but the single-agent activity of bevacizumab was unknown. We conducted a single-arm, phase II trial to evaluate the efficacy of bevacizumab in PNETs.

Patients with progressive disease by the Response Evaluation Criteria in Solid Tumors version 1.1 within 7 months of enrollment were eligible for bevacizumab 10 mg/kg every 2 weeks. Adverse events were assessed according to the Common Terminology Criteria for Adverse Events version 3.0. The primary end point was response rate (RR).

Twenty-four patients were enrolled and followed up for a median duration of 36.1 months. Confirmed RR was 12.5%; 75.0% of patients had stable disease at 6 months. Median progression-free survival was 18.0 months; median overall survival was not reached. Common grade 3 adverse events were hypertension (45.8%) and proteinuria (8.3%). No grade 4 adverse events were observed.

Bevacizumab demonstrated promising antitumor activity in progressive PNETs comparable to standard targeted therapy. Although this study failed to reject the null hypothesis (RR, 10%), bevacizumab seems a reasonable monotherapy and a potential component of combination therapies given clinical activity and low rates of adverse events.