They usually do not respond to IM treatment but may have a response to sunitinib or regorafenib and may be candidates for various clinical trials.25, 124Sunitinib has activity against in SDH-deficient tumors, possibly owing to inhibitory activity against VEGFR.7The toxicity profile of sunitinib includes diarrhea, fatigue, hypertension and cardiac toxic effects, hypothyroidism, and hand–foot syndrome.7, 125With the combination of BGJ398 and sunitinib, SDH-GIST patients may get better outcomes.126. This evidence concerns the gene SDHB and hypothyroidism.