FDA approves Lilly breast-cancer pill combo for ESR1 tumors

FDA approved Eli Lilly’s Inluriyo with Verzenio on Sept. 18 after a trial subgroup showed 11.1 months of median progression-free survival, Healthline News reported.

Evidence grade: Moderate (consistent observational data or small trials). In the 159-participant ESR1 subgroup of EMBER-3, median progression-free survival, meaning time before cancer worsened or death, was 11.1 months with the combination versus 5.5 months with Inluriyo alone, according to the FDA.

The approval applies to adults whose cancer is locally advanced or metastatic, estrogen receptor-positive, HER2-negative and confirmed by an FDA-authorized test to carry an ESR1 mutation. The cancer must also have grown after at least one prior round of hormone therapy, also called endocrine therapy.

Inluriyo, also called imlunestrant, blocks estrogen signaling in certain breast cancer cells and helps break down the receptor that receives that signal, according to its FDA-approved prescribing information. Verzenio, also called abemaciclib, blocks CDK4 and CDK6, proteins that can help cancer cells grow and divide, according to its prescribing information.

Neil Iyengar, a breast medical oncologist at Winship Cancer Institute of Emory University, told Healthline that “the individual treatments are not necessarily new, but the combination is a new concept.” Verzenio first received FDA approval in 2017, and Inluriyo was approved as a stand-alone treatment in September 2025.

Komal Jhaveri, a breast medical oncologist at Memorial Sloan Kettering Cancer Center and lead researcher on the trial, told Healthline that some cancer specialists had already prescribed the drugs together. “Now FDA has backed that with an official approval, so more patients can receive it without having any issues,” Jhaveri said.

ESR1 mutations affect the estrogen receptor. Hope Rugo, chief of breast medical oncology for City of Hope, told Healthline the mutation “makes it stay turned on.” Iyengar said the mutation can develop during hormone therapy and can make the cancer resistant to that treatment.

ESR1 mutations appear in about 1% of breast tumors at diagnosis but in 10% to 50% of metastatic cancers that have stopped responding to hormone therapy, according to the College of American Pathologists, as cited by Healthline. The FDA said a blood test can show whether breast cancer has an ESR1 mutation.

EMBER-3 included 874 adults, according to the FDA, and Eli Lilly funded the clinical trial. The FDA approval was based on a 159-person cohort with ESR1-mutated tumors, where tumors shrank in 35% of people taking the combination and 15% of people taking Inluriyo alone.

The study cannot show whether the combination helps people live longer. The FDA said the survival data were not mature at the time of review, and Rugo told Healthline: “There isn’t any survival data from any of these trials. The trials weren’t powered to look at survival.”

Safety remains a practical limit. In EMBER-3, 86% of people taking Verzenio with Inluriyo had diarrhea, and 9% had severe cases, according to Verzenio’s prescribing information cited by Healthline. A 2026 analysis of EMBER-3 in npj Breast Cancer reported that about 6% of people taking the combination stopped treatment because of side effects.

Source: Healthline News article, Sept. 23, 2026.

Atlas360 reports health research and does not provide medical advice.