Selpercatinib (RETEVMO™) is a receptor tyrosine kinase RET (rearranged during 
transfection) inhibitor being developed by Loxo Oncology for the treatment of 
cancers harbouring RET alterations. Based on results from the phase I/II 
LIBRETTO-001 trial, selpercatinib was recently approved by the US FDA for the 
treatment of RET fusion-positive non-small-cell lung cancer, RET fusion-positive 
thyroid cancer and RET-mutant medullary thyroid cancer. This article summarizes 
the milestones in the development of selpercatinib leading to this first 
approval.