RET mutations occur in 70% of medullary thyroid cancers, and RET fusions occur rarely in other thyroid cancers. In patients with RET-altered thyroid cancers, the efficacy and safety of selective RET inhibition are unknown.

RET fusions are oncogenic drivers in 1 to 2% of non–small-cell lung cancers (NSCLCs). In patients with RET fusion–positive NSCLC, the efficacy and safety of selective RET inhibition are unknown.