FDA Grants Full Approval to Inluriyo Plus Verzenio for ESR1-Mutated Breast Cancer

The US Food and Drug Administration (FDA) has granted full approval to Inluriyo (imlunestrant) in combination with Verzenio (abemaciclib) for adults with estrogen receptor-positive, HER2-negative, ESR1-mutated breast cancer that has progressed after at least one line of endocrine therapy. The decision, announced by Eli Lilly on 18 September 2026, rests on the Phase 3 EMBER-3 trial, in which the combination doubled median progression-free survival compared with Inluriyo alone.

The all-oral regimen pairs an estrogen receptor antagonist with a CDK4/6 inhibitor, targeting the two central drivers of ER-positive disease. It is Lilly’s second approval for Inluriyo in under a year, following the September 2025 monotherapy clearance for the same ESR1-mutated population.

ESR1-mutated breast cancer: the EMBER-3 trial

The analysis covered 159 patients: 92 received Inluriyo alone and 67 received the combination after prior treatment with an aromatase inhibitor, with or without a CDK4/6 inhibitor. The combination produced a median progression-free survival of 11.1 months versus 5.5 months for Inluriyo alone, for a hazard ratio of 0.53 (95% CI, 0.35-0.80).

“In less than a year since its approval, Inluriyo is the leading treatment option for people with ER+, HER2- ESR1m metastatic breast cancer, now reaching over half of all patients starting an oral SERD,” said Jacob Van Naarden, executive vice president and president of Lilly Oncology.

Targeting two drivers of tumor growth

About half of people with ER-positive, HER2-negative metastatic breast cancer develop an ESR1 mutation during or after treatment with an aromatase inhibitor. The change makes the estrogen receptor overactive and fuels tumor growth. Inluriyo degrades mutated estrogen receptors and cuts off the growth signal, while Verzenio slows the rate at which cancer cells divide.

Because both drugs are oral tablets, the regimen adds no new monitoring beyond what Verzenio already requires. Lilly argues this avoids early exposure to additional side effects and spares patients the anxiety of unnecessary testing, while lowering avoidable costs to the healthcare system.

Switching both therapies at clinical progression

Lilly points to evidence that switching both endocrine therapy and CDK4/6 inhibition when the disease progresses improves outcomes more than switching earlier. The EMBER-3 design, which moved most patients to imlunestrant plus abemaciclib at progression, mirrors that practice.

“In EMBER-3, switching both the endocrine therapy and CDK4/6 inhibitor, for the majority of patients, to imlunestrant plus abemaciclib at disease progression achieved a median progression-free survival of 11.1 months and a safety profile consistent with that of each medicine individually,” said Komal Jhaveri, MD, principal investigator for the EMBER-3 and EMBER-4 trials at Memorial Sloan Kettering Cancer Center.

A second approval, and the adjuvant trial ahead

Inluriyo follows Camizestrant, another oral SERD cleared for ESR1-mutated breast cancer in combination with a CDK4/6 inhibitor in September 2026, but that clearance came through the accelerated approval pathway. Inluriyo’s full approval is not contingent on confirmatory trial results.

Lilly is also studying Inluriyo in the adjuvant setting through the Phase 3 EMBER-4 trial (NCT05514054), the largest oral SERD study with more than 8,000 patients across 650-plus sites in 30-plus countries. Initial results are expected in 2027.

Source: Eli Lilly press release