Table 3.

Implication of gastrointestinal stromal tumors mutations and response to targeted therapy

	Imatinib[23]	Sunitinib[25]	Regorafenib[28]
KIT mutation
Exon 11	OR 63%	CB 34%	Increased sensitivity
Exon 9	OR 37%. Intermediate sensitivity. Higher dose 800 mg more effective in metastatic disease than 400 mg daily	CB 34%	Unknown
Exon 13	OR 40%. Sensitivity as primary mutation. Resistance as secondary mutation	CB 100%	Unknown
Exon 14	Resistance as secondary mutation	Unknown	Unknown
Exon 17	OR 25%. Primary mutation sensitive in vitro. Resistance as secondary mutation	CB 0%	Unknown
PDGFRA mutation
Exon 18	OR 50%	CB 0%	Unknown
Exon 12	Increased sensitivity	CB 0%	Unknown
Exon 14	Increased sensitivity in vitro	Unknown	Unknown
Exon 18 D842V	Decreased sensitivity	Decreased sensitivity	Unknown
BRAF mutation	Resistance	Resistance	Unknown
SDH mutation	Decreased sensitivity	Unknown	Increased sensitivity
No KIT, PDGFRA or BRAF mutation	OR 28%	CB 56%	Some activity

Objective response (OR) is defined as a complete or partial response by Response Evaluation Criteria for Solid Tumors (RECIST) criteria, excludes non-evaluable patients. Clinical benefit (CB) is defined as response or stable disease for 6 mo or more according to RECIST. PDGFRA: Platelet-derived growth factor receptor alpha; SDH: Succinate dehydrogenase.