Trofinetide: First Approval.

Trofinetide (DAYBUE™), an oral, small molecule, synthetic analog of glycine-proline-glutamate [GPE; the N-terminal tripeptide derivative of insulin like growth factor-1 (IGF-1)], is being developed by Neuren Pharmaceuticals and Acadia Pharmaceuticals for the treatment of rare childhood neurodevelopmental disorders. Trofinetide was approved in March 2023 in the USA for the treatment of Rett syndrome in adult and pediatric patients 2 years of age and older. This article summarizes the milestones in the development of trofinetide leading to this first approval for Rett syndrome.