Streptozotocin plus 5-fluorouracil followed by everolimus or the reverse sequence in patients with advanced pancreatic neuroendocrine tumors (SEQTOR-GETNE phase III study): a randomized clinical trial

Background: Everolimus or streptozotocin plus 5-fluorouracil (STZ/5-FU) are approved treatments for patients with pancreatic neuroendocrine tumors (panNETs). The SEQTOR trial aimed to assess the optimal treatment sequence. Patients and methods: SEQTOR was an international, open-label, randomized, crossover, phase III trial that recruited adults with unresectable or metastatic, advanced, well-differentiated panNET. Patients received 10 mg/day of everolimus followed upon progression by STZ/5-FU; or the reverse sequence. The primary endpoint was the 35-month progression-free survival (PFS) rate after first- and second-line treatment; however, due to slow accrual and longer survival, it was changed to the 12-month PFS rate following first-line treatment (12-mPFS<inf>1</inf>). Results: Patients were randomized to everolimus (n = 72) or STZ/5-FU (n = 69) first. The 12-mPFS<inf>1</inf> was 71.4% [95% confidence interval (CI) 59.4% to 81.6%] and 61.8% (95% CI 49.2% to 73.3%) (odds ratio 0.65, 95% CI 0.32-1.32) with a median PFS<inf>1</inf> of 19.4 versus 22.7 months for everolimus and STZ/5-FU, respectively. STZ/5-FU achieved a significantly higher overall response rate in first-line (11.6% versus 30.3%, P = 0.012) and second-line (30.6% versus 9.1%, P = 0.072) treatments. No differences were shown in overall survival (median 61.7 versus 50.6 months in everolimus first and STZ/5-FU first, respectively; hazard ratio 1.43, 95% CI 0.86-2.37). Discontinuations of everolimus were more frequent. Conclusion: STZ/5-FU and everolimus were not statistically different in PFS rates, but STZ/5-FU achieved higher response rates.