Dosage: 37.5 mg, qd, continuous. This usage differs from the other two indications, which are a 50 mg, qd, 4/2 (with 4 weeks off for 2 weeks) dosing regimen. The latter two indications are: gastrointestinal mesenchymal tumors (GIST) that have failed or are intolerant to treatment with imatinib mesylate; and inoperable advanced renal cell carcinoma (RCC). Because of the greater adverse effects of the 50 mg, qd, 4/2 (with 4 weeks off for 2 weeks) dosing regimen, the clinical use for the latter two indications has also been changed to 37.5 mg, qd, continuous. Special considerations: Based on premarketing studies and postmarketing reports, potentially serious adverse reactions include left ventricular dysfunction, prolonged QT interval, hemorrhage, hypertension, impaired adrenal function, decreased thyroid function, and hepatotoxicity. Hepatotoxic reactions have been observed in patients in clinical studies conducted and in clinical applications approved for marketing, and hepatotoxicity may be severe, with reported cases of fatalities. Special attention to hepatotoxicity is required. Storage: Store at 25°C; allowable temperature range is 15-30°C. We have found in our work that some patients are stored in the refrigerator. Molecular Marker Testing: Molecular targets for sunitinib include PDGFRα, PDGFRβ, VEGFR1, VEGFR2, VEGFR3, KIT, FLT3, colony-stimulating factor receptor type 1 (CSF-1R), and RET. many physicians do not value individualized molecular testing prior to sotanib administration.