in a phase ii study of patients with nonresectable neuroendocrine tumors, 91% of patients responded to sunitinib (9% partial response + 82% stable disease). sunitinib was found to protect jimt-1 breast cancer cells against natural killer cell-mediated cytotoxicity, which was claimed to block the anticancer immune response. if sunitinib were to be paired with anticancer immunotherapies, this finding might need to be taken into account. leukemia sunitinib was used to treat the leukemia of a washington university in st. louis leukemia researcher who developed the disease himself. his team used genetic sequencing and noticed that the flt3 gene was hyperactive in his leukemia cells and used sunitinib as a treatment. unsuccessful trials between april 2009 and may 2011, pfizer has reported unsuccessful late-stage trials in breast cancer, metastatic colorectal cancer, advanced non-small-cell lung cancer, and castration-resistant prostate cancer.