Axitinib and Long-Acting Octreotide in Advanced Extrapancreatic Neuroendocrine Tumors: A Randomized, Double-Blind, Placebo-Controlled, Phase III Clinical Trial (AXINET, GETNE 1107)

Abstract

PURPOSE Angiogenesis plays an essential role in neuroendocrine tumors (NETs). This study evaluates efficacy and safety of axitinib in extrapancreatic (ep)-NETs. PATIENTS AND METHODS AXINET was an international, randomized, double-blind, placebo-controlled, phase II/III trial including patients age 18 years and older, with unresectable/metastatic G1-2 epNETs and up to two previous treatment lines. Patients were randomly assigned (1:1) to axitinib 5 mg or placebo, both orally twice a day, in combination with intramuscular octreotide long-acting release 30 mg once every 28 days until disease progression or unacceptable toxicity. Randomization was stratified by primary tumor site, Ki-67 index (≤5% or >5%), and time from diagnosis (> or ≤12 months). The primary end point was investigator-assessed progression-free survival (PFS). Efficacy was also assessed by a blinded independent central review (BICR). RESULTS From October 2011 to May 2019, 256 patients were assigned to axitinib (n = 126) or placebo (n = 130). Investigator-assessed median PFS was 17.2 months (95% CI, 13.6 to 24.7) versus 13.1 months (95% CI, 10.9 to 18.6) in the axitinib and placebo groups, respectively (hazard ratio [HR], 0.86 [95% CI, 0.65 to 1.15]). The median BICR PFS was 16.6 months (95% CI, 13.5 to 24.2) versus 9.9 months (95% CI, 8.2 to 13.9) in the axitinib and placebo groups, respectively (HR, 0.71 [95% CI, 0.54 to 0.94], P = .017). Objective response rate (ORR) was significantly greater for axitinib per investigator assessment (17.5% v 4.6%; P = .001) and BICR (12.8% v 3.2%; P = .005). Most common grade ≥3 toxicities were hypertension (24.0% v 9.2%) and diarrhea (13.6% v 1.5%). CONCLUSION Axitinib significantly increased PFS per BICR assessment and ORR both per investigator and BICR assessment compared with placebo, although the primary study end point was not met. Toxicity profile was manageable with no new safety concerns.