Kinase Genotyping of Gastrointestinal Stromal Tumors (GIST) From Patients Enrolled in the A6181112 Phase IIIb Trial at Participating U.S. and Ex-U.S. Medical Centers
In this companion study, we will analyze the genomic DNA from the GIST tumor specimens of
patients enrolled in the in the A6181112 phase IIIb trial at participating U.S. and ex-U.S.
medical centers. Specifically, GIST samples will be screened for mutations in KIT gene exons
9, 11, 13 and 17, and PDGFRA gene exons 12, 14 and 18, to determine the primary kinase
genotype. Subset analyses will be performed and compared with the overall PFS rates observed
in patients with primary and secondary imatinib resistance. Based on data from a previous
phase I/II trial, our hypothesis is that patients with either primary or secondary imatinib
resistance having a KIT exon 9-mutant or WT GIST will have a longer PFS when treated with
sunitinib than patients with exon 11-mutant GIST. We further hypothesize that this
difference will be observed among patients treated with high-dose imatinib.
Observational Model: Case Control, Time Perspective: Prospective
Christopher L Corless, MD, PhD
Oregon Health and Science University
United States: Institutional Review Board
Pfizer GIST Genotyping Study