KIT and gastrointestinal stromal tumor: Consistent with these in vitro results in GIST cells, evaluations of primary and secondary KIT mutants transfected in Chinese Hamster Ovarian (CHO) cells showed that sunitinib was more active than regorafenib against the KIT exon 13 V654A ATP-binding pocket mutant, whereas regorafenib was more active than sunitinib against KIT exon 17 activation loop mutants (Supplementary Figure 1).