Imlunestrant: First Approval

<p dir="ltr"><b>Declarations</b></p><p dir="ltr"><b>Authorship and Conflict of interest</b> During the peer review process the manufacturer of the agent under review was offered an opportunity to comment on the article. Changes resulting from any comments received were made by the authors on the basis of scientific completeness and accuracy. Susan J. Keam is a contracted employee of Adis International Ltd/Springer Nature and declares no relevant conflicts of interest. All authors contributed to this article and are responsible for its content.</p><p dir="ltr"><b>Ethics approval, Consent to participate, Consent to publish, Availability of data and material, Code availability </b>Not applicable.</p><p dir="ltr">Additional information about this Adis Drug Review can be found <a href="http://www.springer.com/gp/adis/products-services/adis-journals-newsletters/adis-drug-reviews" target="_blank"><b>here</b></a>.</p><p dir="ltr"><b>Abstract</b></p><p dir="ltr">Imlunestrant (Inluriyo™), an oral, selective, estrogen receptor (ER) degrader (SERD), is being developed by Eli Lilly and Company for the treatment of ER-positive (ER+), human epidermal growth factor receptor 2 (HER2) negative (HER2-) breast cancer. In September 2025, imlunestrant was approved for the treatment of adults with ER+, HER2-, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy in the USA. This article summarizes the milestones in the development of imlunestrant leading to this first approval for use in patients with ER+, HER2-, ESR1-mutated advanced or metastatic breast cancer.</p><p dir="ltr">© The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025</p>