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Inluriyo ™ (imlunestrant) tablets
200 mg
This information is provided in response to your request. Resources may contain information about doses, uses, formulations and populations different from product labeling. See Prescribing Information above, if applicable.
What is the mechanism of action of Inluriyo® (imlunestrant)?
Imlunestrant is an orally bioavailable selective estrogen receptor degrader with antagonistic properties resulting in inhibition of estrogen receptor-dependent gene transcription and cell growth.
Imlunestrant is an estrogen receptor (ER) antagonist that binds to ERα. In vitro, imlunestrant induced degradation of ERα, leading to inhibition of ER-dependent gene transcription and cellular proliferation in ER+ breast cancer cells. Imlunestrant demonstrated in vitro and in vivo anti-tumor activity in ER+ breast cancer xenograft models, including models with estrogen receptor 1 (ESR1) mutations.1
In cell proliferation assays, imlunestrant inhibited the proliferation of ER+ breast cancer cell lines in both wild-type and mutant ESR1 cell lines. 2-6
In in vivo target inhibition studies, imlunestrant inhibited the expression of progesterone receptor (PgR), a transcriptional target of ERα and pharmacodynamic biomarker, in both ESR1 wild-type and ESR1 (Y537S)-mutant xenograft and patient-derived xenograft (PDX) mouse tumor models.2-6
Figure 1. Imlunestrant ER Pathway3,5,7-10
Figure
1 description: The selective estrogen receptor degradation mechanism
of action of imlunestrant is illustrated. Imlunestrant has
demonstrated inhibition of estrogen-dependent signaling and
subsequent inhibition of cell proliferation in estrogen receptor
wild-type and mutant expressing tumor models.
Abbreviation:
ER = estrogen receptor.
Enclosed Prescribing Information
INLURIYO® (imlunestrant) tablets, for oral use, Lilly
References
The published references below are available by contacting 1-800-LillyRx (1-800-545-5979).
Inluriyo [package insert]. Indianapolis, IN: Eli Lilly and Company; 2026.
Bhagwat SV, Mur C, Vandekopple M, et al. Imlunestrant Is an Oral, Brain-Penetrant Selective Estrogen Receptor Degrader with Potent Antitumor Activity in ESR1 Wild-Type and Mutant Breast Cancer. Cancer Res. 2025;85(4):777-790. https://doi.org/10.1158/0008-5472.CAN-24-2608
Bhagwat SV, Zhao B, Shen W, et al. Preclinical characterization of LY3484356, a novel, potent and orally bioavailable selective estrogen receptor degrader (SERD). Cancer Res. 2021;81(13 suppl):1236. American Association for Cancer Research abstract 1236. https://doi.org/10.1158/1538-7445.AM2021-1236
Bhagwat SV, Zhao B, Shen W, et al. Preclinical characterization of LY3484356, a novel, potent and orally bioavailable selective estrogen receptor degrader (SERD). Poster presented at: 112th Annual Meeting of the American Association for Cancer Research (AACR Virtual); April 10-15, May 17-21, 2021.
Vandekopple M, Mur C, Shen W, et al. Preclinical characterization of imlunestrant, an oral brain-penetrant selective estrogen receptor degrader with activity in a brain metastasis (BM) model. ESMO Open. 2023;8(1 suppl 4):101265. European Society for Medical Oncology abstract 41P. https://doi.org/10.1016/j.esmoop.2023.101265
Vandekopple M, Mur C, Shen W, et al. Preclinical characterization of imlunestrant, an oral brain-penetrant selective estrogen receptor degrader with activity in a brain metastasis (BM) model. Poster presented at: 5th European Society for Medical Oncology Breast Cancer (ESMO-BC) Congress; May 11-13, 2023; Berlin, Germany. Accessed October 11, 2023. https://cslide.ctimeetingtech.com/breast23hybrid/public/download_uploaded_media/pdf/125
Clusan L, Ferrière F, Flouriot G, Pakdel F. A Basic Review on Estrogen Receptor Signaling Pathways in Breast Cancer. Int J Mol Sci. 2023;24(7):6834. Published 2023 Apr 6. https://doi.org/10.3390/ijms24076834
Dustin D, Gu G, Fuqua SAW. ESR1 mutations in breast cancer. Cancer. 2019;125(21):3714-3728. https://doi.org/10.1002/cncr.32345
Jhaveri KL, Neven P, Casalnuovo ML, et al. Imlunestrant with or without Abemaciclib in Advanced Breast Cancer. N Engl J Med. 2025;392(12):1189-1202. https://doi.org/10.1056/NEJMoa2410858
Sherman S, Sandusky ZM, Russo D, et al. Imlunestrant a next-generation oral SERD overcomes ESR1 mutant resistance in estrogen receptor-positive breast cancer. JCI Insight. 2025;10(12):e188051. Published 2025 May 6. https://doi.org/10.1172/jci.insight.188051
Date of Last Review: August 24, 2026