Cohen EEW et al. - This study reports that axitinib is a selective inhibitor of vascular endothelial growth factor receptors (VEGFR) with compelling antitumor activity in all histologic subtypes of advanced thyroid cancer. Methods
Study to assess the activity and safety of axitinib, an oral, potent, and selective inhibitor of VEGFR 1, 2, and 3 in pts with advanced thyroid cancer
Pts with thyroid cancer (n=60) resistant or not appropriate for 131I were enrolled to receive axitinib orally (starting dose, 5 mgx2/d)
ORR was the primary end point
Secondary end points included duration of response, PFS, OS, safety, and modulation of soluble (s) VEGFR
Results
Partial responses were observed in 18 pts, yielding an ORR of 30%
SD lasting ≥16 wks was reported in another 38% of pts
Objective responses were noted in all histologic subtypes
Median PFS was 18.1 mos
Axitinib was generally well tolerated, with the most common grade ≥3 treatment-related AEs being hypertension (12%)
13% of pts discontinued treatment because of AEs
Axitinib selectively decreased sVEGFR-2 and sVEGFR-3 plasma concs vs sKIT, demonstrating its targeting of VEGFR