About GIST (Gastrointestinal Stromal Tumor)
GIST develops in the walls of the gastrointestinal tract (frequently in the stomach and small intestine and rarely in the large intestine and esophagus) and is a type of malignant tumor (sarcoma) that causes metastasis and relapses. It has different characteristics than gastric and colorectal cancers that develop from mucous membrane.*2 The incidence in Japan is estimated to be roughly 1,500 to 2,500 patients per year (calculated based on the annual incidence rate reported in different countries),*3 making it a rare cancer. In many cases of GIST, there are mutations in the KIT and PDGFRA genes, which are involved in the growth and survival of cancer. All GIST treatments approved by the three regulatory authorities of Japan’s Ministry of Health, Labour and Welfare, the U.S. Food and Drug Administration (FDA), and the European Medicines Agency (EMA) have as their main mechanism of action the inhibition of receptor tyrosine kinases KIT and PDGFRA. There is an unmet medical need for a therapeutic agent to treat GIST that remains after treatment with the drugs currently approved.