BACKGROUND

Sunitinib, a multitarget tyrosine kinase inhibitor, showed encouraging antitumor activity and manageable toxicity in patients with advanced midgut neuroendocrine tumors (NETs) in earlier results from phase I and II trials.

PATIENTS AND METHODS

In this phase II trial, patients with a nonresectable grade 1 or 2 midgut progressive NET and Eastern Cooperative Oncology Group performance status 0-1 were randomly assigned 1:1 to receive 37.5 mg sunitinib or a placebo, combined with 120 mg lanreotide autogel every 28 days. The planned sample size was 104 patients. The primary outcome was investigator-assessed progression-free survival (PFS).

RESULTS

The study was stopped early because of insufficient patient recruitment. Between January 2013 and December 2016, 44 patients were enrolled and received sunitinib ( = 22) or placebo ( = 22). The median age was 63.7 years (1-3 range, 56.6-68.1) and 26 patients (59.1%) were male. The main localization was ileum ( = 37, 84.1%) and the majority were grade 2 ( = 25, 56.8%). The median follow-up was 36.7 months (95% confidence interval (CI) 34.6-48.2). The median PFS was 9.84 months (95% CI 6.8-23.3) with sunitinib and 11.47 months (95% CI 5.4-15.3) with placebo (hazard ratio (HR) = 0.80, 95% CI 0.41-1.56,  = 0.51). There was no difference in overall survival between treatment arms (HR = 0.81, (95% CI 0.32-2.01),  = 0.64). The objective response rate was 9.1% with sunitinib and 0.0% with placebo, and 19 patients (86.4%) had stable disease. Thirty-nine patients (88.6%) completed the baseline QLQ-C30 questionnaire. Baseline health-related quality of life level was similar between treatment arms, except for physical and emotional functioning which were higher ( = 0.089) and lower ( = 0.023) in the sunitinib arm, respectively. Trends toward longer time until a definitive deterioration in favor of the sunitinib arm were observed for 10 out of 15 dimensions (HRs < 1), with a significant result for financial difficulties (HR = 0.31, (90% CI 0.10-0.94)). Twenty-seven patients (61.4%) had at least one adverse event grade ⩾3 (sunitinib: 72.7%, placebo: 50.0%), with only one patient grade 4 for hypertension and vomiting. Eleven deaths non-related to treatment occurred (sunitinib arm:  = 5, placebo arm:  = 6).

CONCLUSION

Our study does not provide enough evidence to conclude the role of sunitinib in advanced midgut NETs, primarily due to a lower-than-expected number of enrolled patients. While we cannot entirely rule out the efficacy of sunitinib, lanreotide alone may play a significant role.

TRIAL REGISTRATION

EudraCT: 2012-001098-94.