Moreover, BAY 43-9006 inhibited the growth of cells carrying RET V804L (IC50 = 110 nM, 95% confidence interval [CI] = 88 to 133 nM) or RET V804M (IC50 = 147 nM, 95% CI = 123 nM to 170 nM)....BAY 43-9006 is a powerful inhibitor of the RET kinase. Its potential as a therapeutic tool for RET-positive thyroid tumors, including those expressing V804 mutations merits study.