Signs and symptoms associated with selpercatinib-induced hypersensitivity reactions were generally tolerable (i.e., maculopapular rash, fever, or arthralgias/myalgias associated with thrombocytopenia, increased AST or ALT, hypotension, tachycardia, or increased creatinine) and occurred more frequently in patients with RET fusion-positive NSCLC previously treated with ICI therapy. The gene discussed is RET; the disease is Thrombocytopenia.