The oral-administered Pimitespib (TAS-116, tablets 40 mg), also an N-terminal inhibitor of both Hsp90 isoforms by Taiho Pharmaceutical (Japan), was approved by Japan’s Ministry of Health, Labor and Welfare for treatment of advanced GIST, after the tumors have progressed and no longer respond to previously US FDA-approved protein tyrosine kinase inhibitor drugs (imatinib, sunitinib, and regorafenib) in 2022.13 The gene discussed is HSP90AA1; the disease is gastrointestinal stromal tumor.