FDA Approves Eli Lilly's Inluriyo for Advanced Breast Cancer Treatment

On September 25, 2025, the U.S. Food and Drug Administration (FDA) approved Eli Lilly's oral selective estrogen receptor degrader (SERD), Inluriyo (imlunestrant), for the treatment of adult patients with estrogen receptor-positive (ER+), HER2-negative, ESR1-mutated advanced or metastatic breast cancer. This approval specifically targets patients whose disease has progressed after at least one line of endocrine therapy.

FiercePharmaFDA Approves Lilly’s Inluriyo Oral Therapy for ESR1-Mutated Metastatic Breast CancerFDA Approves Imlunestrant for ER+ and HER2-Negative Breast CancerBioPharmaDive

The approval was based on results from the Phase 3 EMBER-3 trial, which demonstrated that Inluriyo reduced the risk of disease progression or death by 38% compared to standard endocrine therapies. Patients treated with Inluriyo experienced a median progression-free survival (PFS) of 5.5 months, compared to 3.8 months for those receiving standard treatments. The trial included 874 participants, with a significant focus on those with ESR1 mutations, which are present in nearly half of patients who have undergone hormone therapies.

FDA Approves Lilly’s Inluriyo Oral Therapy for ESR1-Mutated Metastatic Breast CancerFiercePharmaBioPharmaDive

Inluriyo is designed to target and degrade overactive estrogen receptors, which can drive cancer progression when mutated. This oral therapy offers a more convenient alternative to traditional injectable therapies, potentially improving patient adherence and quality of life. The drug is administered as a once-daily oral dose of 400 mg.

FDA Approves Lilly’s Inluriyo Oral Therapy for ESR1-Mutated Metastatic Breast Cancer

While Inluriyo has shown promising efficacy, it is associated with certain adverse events. Common side effects include fatigue, diarrhea, and nausea. In the EMBER-3 trial, 83% of patients in the Inluriyo group experienced treatment-emergent adverse events, with 17% reporting grade 3 or higher events. Notably, the combination of Inluriyo with Eli Lilly's abemaciclib (Verzenio) resulted in a higher incidence of adverse events, with 48.6% of patients experiencing significant side effects.

FDA Approves Lilly’s Inluriyo Oral Therapy for ESR1-Mutated Metastatic Breast Cancer

Jacob Van Naarden, executive vice president and president of Lilly Oncology, emphasized the significance of this approval, stating, “This therapy reflects our commitment to developing treatments that improve outcomes for people with breast cancer and represents an important step toward advancing innovative, all-oral treatment approaches.” Komal Jhaveri, MD, a principal investigator of the EMBER-3 trial, noted that Inluriyo provides a meaningful alternative for patients with ESR1-mutated metastatic breast cancer, particularly as these mutations often contribute to treatment resistance.

FDA Approves Lilly’s Inluriyo Oral Therapy for ESR1-Mutated Metastatic Breast CancerBioPharmaDive

Despite the positive reception, some experts have raised concerns regarding the long-term impact of Inluriyo and similar oral SERDs on cancer care. Critics point out that the efficacy of these drugs in patients without ESR1 mutations remains unclear, and there are uncertainties regarding the overall market potential for these therapies. Additionally, the high list price of $22,500 per 28-day supply may limit accessibility for some patients.

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Eli Lilly is currently exploring the use of Inluriyo in adjuvant therapy for early-stage breast cancer, with initial results expected in 2027. The ongoing research aims to further establish the drug's role in preventing relapses in breast cancer patients.

ReutersBioPharmaDiveFDA Approves Lilly’s Inluriyo Oral Therapy for ESR1-Mutated Metastatic Breast Cancer

• “This therapy reflects our commitment to developing treatments that improve outcomes for people with breast cancer and represents an important step toward advancing innovative, all-oral treatment approaches,” — Jacob Van Naarden, Executive Vice President, Lilly Oncology

FDA Approves Imlunestrant for ER+ and HER2-Negative Breast Cancer

• “This represents an important advancement for patients with ESR1-mutated metastatic breast cancer, a mutation found in nearly half of patients who have taken hormone therapies, often contributing to treatment resistance,” — Komal Jhaveri, MD, Memorial Sloan Kettering Cancer Center

FDA Approves Lilly’s Inluriyo Oral Therapy for ESR1-Mutated Metastatic Breast Cancer