FDA Approves Lilly’s Inluriyo Plus Verzenio for ESR1-Mutated Breast Cancer
The all-oral combination doubled median progression-free survival in a key trial subgroup. Here’s how it works, who it’s for, and what side effects to know.
If you or someone you love has ER-positive, HER2-negative advanced or metastatic breast cancer that progressed after hormone therapy, there’s a new treatment option approved this week, and it comes with real tradeoffs worth understanding before you talk to your oncologist.
The FDA granted full approval on Friday, September 18, 2026, to Eli Lilly’s combination of Inluriyo (imlunestrant) and Verzenio (abemaciclib) for adults with ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer, as detected by an FDA-authorized test, whose disease progressed after at least one line of endocrine therapy. The approval is based on the Phase 3 EMBER-3 trial’s ESR1-mutated subgroup, which included 159 patients: 92 who received Inluriyo alone and 67 who received Inluriyo plus Verzenio, following treatment with an aromatase inhibitor. Patients who received the combination went a median of 11.1 months without their cancer progressing, compared with 5.5 months for patients on Inluriyo alone. This is the second FDA approval for Inluriyo in under a year; it was first approved as a standalone treatment in September 2025. The combination is now available in the United States.
At a Glance
If you have this specific cancer subtype and your disease progressed after endocrine therapy, ask your oncologist whether you’ve been tested for an ESR1 mutation using an FDA-authorized test and whether this combination fits your case. In the relevant trial subgroup, the combination roughly doubled median progression-free survival compared with Inluriyo alone, but it also carries real side-effect risks. In the trial, 86% of patients on the combination had diarrhea, with 9% experiencing Grade 3 or 4 cases, and 86% had a drop in neutrophils, infection-fighting white blood cells, with 21% experiencing Grade 3 or 4 decreases. Interstitial lung disease or pneumonitis occurred in 2.9% of patients, and venous thromboembolism, blood clots, occurred in 4.8%. Talk through monitoring and side-effect management with your care team before starting treatment.
How the Two Drugs Work Together
EMBER-3 Trial Results (ESR1-Mutated Subgroup)
In the ESR1-mutated subgroup of the Phase 3 EMBER-3 trial, the combination reduced the risk of disease progression or death by 47% compared with Inluriyo alone (HR 0.53; 95% CI: 0.35, 0.80). Objective response rate was 35% for the combination versus 15% for monotherapy. This is a full FDA approval, not an accelerated one. Full approval is not contingent on confirmatory trial results, unlike accelerated approval, which the FDA grants based on a surrogate endpoint reasonably likely to predict clinical benefit and requires confirmatory trials afterward.
Key Side Effects (Inluriyo + Verzenio Arm, EMBER-3)
The majority of adverse events with the combination were Grade 1-2, according to the Lilly investor release. The most common (≥10%) adverse reactions included decreased neutrophils, diarrhea, decreased hemoglobin, nausea, fatigue, and infections. Permanent discontinuation of Inluriyo due to adverse reactions was low.
What the Trial Investigators Said
“We have an urgent need for effective and safe treatment options for patients with disease progression on adjuvant or first-line therapy. Combining therapies that work on two distinct drivers of tumor growth—the estrogen receptor and CDK4/6—is an important strategy to help address treatment resistance.”
— Dr. Komal Jhaveri, Memorial Sloan Kettering Cancer Center, Principal Investigator for EMBER-3 and EMBER-4
Dr. Jhaveri has said switching both the endocrine therapy and the CDK4/6 inhibitor at disease progression achieved a median progression-free survival of 11.1 months with a safety profile consistent with each medicine individually. Lilly’s Jacob Van Naarden, executive vice president and president of Lilly Oncology, said the available evidence suggests switching therapy at clinical progression, rather than combining drugs earlier, improves outcomes, spares patients from earlier side effects, reduces unnecessary testing and anxiety, and avoids added costs to the healthcare system.
What’s Next: EMBER-4 Trial
Lilly is also running a larger trial called EMBER-4, enrolling more than 8,000 patients at over 650 sites across 30-plus countries, to test whether using Inluriyo earlier, after surgery, can prevent recurrence in people with early-stage, high-risk breast cancer. Initial results are anticipated in 2027. This approval follows another targeted breast-cancer pill that doubles time before progression, and is part of a broader trend in FDA approvals for targeted cancer treatments in 2026.
What is an ESR1 mutation in breast cancer?
In about half of patients with ER-positive, HER2-negative metastatic breast cancer, tumors develop an ESR1 mutation during or after treatment with aromatase inhibitors. The mutation can make estrogen receptors stay active even without estrogen, driving continued tumor growth. Inluriyo works by binding to the receptor and promoting its breakdown.
Frequently Asked Questions
The FDA has approved Inluriyo plus Verzenio for ESR1-mutated, ER-positive, HER2-negative advanced or metastatic breast cancer that progressed on hormone therapy, roughly doubling median progression-free survival in the relevant trial subgroup, though with side effects worth discussing with your doctor. A larger trial testing the therapy earlier, called EMBER-4, is expected to report initial results in 2027 — worth checking back on if you or a family member is tracking treatment options for this cancer type. For related coverage, see our report on the NHS-approved breast cancer pill and our FDA approval coverage for daraxonrasib.
