Summary: Clinical response and mutational status
Phase II	Correlation of radiographic response and median OS with mutational status: 86% and 63 months for KIT exon 11, 48% and 44 months with exon 9, and 0% and 26 months for WT or other mutations (US-Finnish). EORTC reported similar outcomes, but patients with exon 9 and wild-type mutations had slightly better outcomes.
Phase III	EORTC study reported response rates of 69% for KIT exon 11, 34% with exon 9, and 25% with WT genotypes. SWOG reported response rates, median TTP, and OS as follows: exon 11 (71%, 24.7 mo and 60 mo), exon 9 (44%, 16.7 mo and 38.4 mo), and WT (45%, 12.8 mo and 49 mo).
Meta-GIST	A 4-month increase in median PFS in the high-dose arm but benefit diminished after 2 years. RR, PFS, and OS are as follows: KIT exon 11 mutations (80%, 26 months, 60 months) when compared to KIT exon 9 (40%, 13, 31 months), wild-type KIT (16, 43 months), and other mutations (11, 34 months).
Meta-analysis	KIT exon 9 mutations treated with imatinib 800 mg daily had better response rates and prolongs PFS, but not OS.
Summary: Prognostic factors that predict PFS and OS with IM therapy
High granulocyte count (strongest), poor performance status (strongest), advanced age (OS), low albumin level at entry (OS), prior chemotherapy, large tumor size (OS), and male gender (OS and PFS). Tumor site was not prognostic.