Sequential Everolimus and Sunitinib Treatment in Pancreatic Metastatic Well-Differentiated Neuroendocrine Tumours Resistant to Prior Treatments

Abstract

Objective: Alternating treatment with sunitinib and everolimus has been shown to be efficacious in renal cell carcinoma. However, no data currently exist for the role of alternate sequence administration of these agents in well-differentiated pancreatic neuroendocrine tumours (pNETs). Methods: Thirty-one patients were administered one compound and upon progression were switched to the other. All patients had grade 1 or 2 tumours and stage IV disease with similar metastatic load. The primary end point included estimation of the median overall progression-free survival (mPFS) along with each drug's mPFS as a first-line (mPFS1) and a second-line treatment (mPFS2); tolerability and serious adverse events were also evaluated. Secondary end points included overall survival (OS), 2-year mortality rate, and incidence of disease progression. Results: Overall, mPFS did not differ between the everolimus to sunitinib group (36.5 months) and the sunitinib to everolimus group (31.6 months) with a hazard ratio of 0.94 ([95% CI, 0.45-1.97], p = 0.7). Although mPFS1 after first-line everolimus was longer (16.3 months) compared to sunitinib (9 months), this was not statistically significant (p = 0.15). Sequential second-line treatment showed no difference in the mPFS2 (p = 0.3). No difference in OS between the 2 groups was observed. Tolerability was better for everolimus compared to sunitinib. Conclusions: Treatment with sequential molecular target agents was well tolerated and associated with similar overall mPFS in both schemes of administration. Larger prospective studies are required to investigate the long-term efficacy and sequence of administration of alternate therapy with molecular targeting agents in metastatic pNETs and their effect on OS.