As monotherapy, imlunestrant significantly reduced the risk of progression or death by 38% compared to standard endocrine therapy (ET) in patients with ESR1 mutations
As combination therapy, imlunestrant plus Verzenio significantly reduced the risk of progression or death by 43%, compared to imlunestrant alone, in all patients, regardless of ESR1 mutation status
These data were published simultaneously in the New England Journal of Medicine and will be presented today at the 2024 San Antonio Breast Cancer Symposium
INDIANAPOLIS, IN, USA I December 11, 2024 I Eli Lilly and Company (NYSE: LLY) today announced results from the Phase 3 EMBER-3 study of imlunestrant, an investigational, oral selective estrogen receptor degrader (SERD), in patients with estrogen receptor positive (ER+), human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer (ABC), whose disease progressed on a prior aromatase inhibitor (AI), with or without a CDK4/6 inhibitor. Imlunestrant demonstrated a statistically significant and clinically meaningful improvement in progression-free survival (PFS) as monotherapy in patients with an ESR1 mutation versus standard of care endocrine therapy (SOC ET), reducing the risk of disease progression or death by 38%. Imlunestrant in combination with Verzenio (abemaciclib; CDK4/6 inhibitor) reduced the risk of progression or death by 43% versus imlunestrant alone, in all patients.
These results were published in The New England Journal of Medicine and will be shared in a late-breaking oral presentation at the San Antonio Breast Cancer Symposium (SABCS) today, Wednesday, December 11 at 9:15 AM CT/10:15 AM ET. These data are being submitted to regulatory health authorities globally.
“The median progression free survival observed in EMBER-3 is among the most compelling we’ve seen in CDK4/6 pre-treated ER+, HER2- advanced breast cancer patients and indicates a potential shift in the therapy options we provide for these patients, which are currently very limited,” said Komal Jhaveri, M.D., section head, endocrine therapy research and clinical director, early drug development at Memorial Sloan Kettering Cancer Center, and one of the study’s principal investigators. “The benefit and safety profile of the imlunestrant and abemaciclib combination signal a potential new all-oral option for patients.”
In the EMBER-3 study, patients were randomized 1:1:1 to receive imlunestrant alone, SOC ET, or the imlunestrant-abemaciclib combination. Randomization was stratified by prior CDK4/6 inhibitor use, the presence of visceral metastases and geographic region. Patients enrolled as first line (1L) treatment for ABC (32%), following disease recurrence on or within 12 months of completing adjuvant AI, with or without CDK4/6 inhibitor for early breast cancer (EBC), or as second line (2L) treatment for ABC (64%), following progression on AI, with or without CDK4/6 inhibitor as initial therapy for ABC. Primary endpoints were investigator-assessed PFS of imlunestrant versus SOC ET therapy in patients with ESR1 mutations, imlunestrant versus SOC ET in all patients, and imlunestrant-abemaciclib versus imlunestrant in all patients.
Imlunestrant versus standard of care endocrine therapy
Imlunestrant significantly improved PFS versus SOC ET in patients with an ESR1 mutation. In patients with an ESR1 mutation, median PFS was 5.5 months with imlunestrant versus 3.8 months with SOC ET [HR=0.62 (95% CI 0.46-0.82); p-value<0.001]. The overall response rate (ORR) with imlunestrant was 14% compared to 8% with SOC ET in patients with an ESR1 mutation. In all patients, the median PFS was 5.6 months with imlunestrant versus 5.5 months with SOC ET [HR=0.87 (95% CI 0.72-1.04); p-value 0.12] and did not reach statistical significance.
Consistent with preclinical data demonstrating central nervous system (CNS) penetrance and CNS-activity of imlunestrant, CNS progression rates from a post-hoc analysis were lower with imlunestrant in all patients (HR=0.47; 95% CI, 0.16-1.38), as well as patients with an ESR1 mutation (HR=0.18; 95% CI, 0.04-0.90), however, these analyses are limited by low event numbers and lack of mandated serial asymptomatic CNS imaging in all patients.
Imlunestrant in combination with abemaciclib versus imlunestrant alone
Imlunestrant-abemaciclib significantly improved PFS compared to imlunestrant in all patients, regardless of ESR1 mutation status, with median PFS of 9.4 months for imlunestrant-abemaciclib versus 5.5 months for imlunestrant alone [HR=0.57 (95% CI 0.44-0.73); p-value <0.001]. The PFS benefit of the combination was consistent across subgroups, regardless of ESR1 mutation, or PI3K pathway mutation status, and including in patients who had previously received CDK4/6 inhibitor treatment. In all patients, the ORR with imlunestrant-abemaciclib was 27% compared to 12% with imlunestrant alone.
Safety in the imlunestrant-abemaciclib arm was consistent with the known safety profile of fulvestrant in combination with abemaciclib, with mostly low-grade adverse events including diarrhea (86%), nausea (49%), neutropenia (48%) and anemia (44%), and had a low discontinuation rate (6.3%).1,2
Overall survival (OS) results for EMBER-3 were immature at the time of analysis. The trial will continue to assess OS as a secondary endpoint.
“EMBER-3 is the first Phase 3 trial to show benefit of combining an oral SERD with a CDK4/6 inhibitor for a patient population where an all-oral regimen would represent a meaningful advance,” said David Hyman, M.D., Chief Medical Officer, Lilly. “We’re highly encouraged by these data for both imlunestrant as monotherapy and in combination with Verzenio, as well as the safety and tolerability profile, which demonstrate the potential for imlunestrant to be a meaningful new oral endocrine therapy option for patients. We look forward to sharing these results with the oncology community and completing regulatory submissions to global health authorities.”
An estimated 70 to 80% of hormone receptor positive breast cancers are ER+ and after progression on initial endocrine therapy, are predominantly treated with fulvestrant, which is administered by intramuscular injection in a doctor’s office.3,4 According to patient-reported outcomes data from EMBER-3, 72% of patients receiving fulvestrant in the standard ET group reported injection site pain, swelling, or redness. Imlunestrant is an orally administered, brain penetrant, pure ER antagonist that delivers continuous ER target inhibition.
Imlunestrant is also being investigated in the adjuvant setting in people with ER+, HER2- early breast cancer (EBC) with an increased risk of recurrence. This Phase 3 trial, EMBER-4, is expected to enroll 6,000 EBC patients worldwide.
About EMBER-3
EMBER-3 is a Phase 3, randomized, open-label study of imlunestrant, investigator’s choice of endocrine therapy, and imlunestrant in combination with abemaciclib in patients with estrogen receptor positive (ER+), human epidermal growth factor receptor 2 negative (HER2-) locally advanced or metastatic breast cancer whose disease has recurred or progressed during or following an aromatase inhibitor (AI) therapy with or without a CDK 4/6 inhibitor. The trial enrolled 874 adult patients, 32% of which enrolled from the adjuvant setting into first-line treatment of ABC and 64% as second line treatment following progression on initial therapy for ABC. Enrolled trial participants were randomized between imlunestrant, investigator’s choice of fulvestrant or exemestane, or imlunestrant plus abemaciclib. More information on the EMBER-3 study can be found on clinicaltrials.gov.
About Metastatic/Advanced Breast Cancer
Metastatic/advanced breast cancer (ABC) is a cancer that has spread from the breast tissue to other parts of the body. Locally advanced breast cancer means the cancer has grown outside the organ where it started but has not yet spread to other parts of the body.1 Of all high risk early-stage breast cancer cases diagnosed in the U.S., approximately 30% will become metastatic5 and an estimated 6-10% of all new breast cancer cases are initially diagnosed as being metastatic.6 Survival is lower among women with a more advanced stage of disease at diagnosis: five-year relative survival is 99% for localized disease, 86% for regional/locally advanced disease, and 30% for metastatic/advanced disease.7 Other factors, such as tumor size, also impact five-year survival estimates.7
About Breast Cancer
Breast cancer is the second most commonly diagnosed cancer worldwide (following lung cancer), according to GLOBOCAN. The estimated 2.3 million new cases indicate that close to 1 in every 4 cancers diagnosed in 2022 is breast cancer. With approximately 666,000 deaths in 2022, breast cancer is the fourth-leading cause of cancer death worldwide.8 In the U.S., it is estimated that there will be more than 310,000 new cases of breast cancer diagnosed in 2024. Breast cancer is the second leading cause of cancer death in women in the U.S.9
About Imlunestrant
Imlunestrant is a brain-penetrant, oral selective estrogen receptor degrader (SERD), that delivers continuous ER inhibition, including in ESR1-mutant cancers. The estrogen receptor (ER) is the key therapeutic target for patients with estrogen receptor positive (ER+), human epidermal growth factor receptor 2 negative (HER2-) breast cancer. Novel degraders of ER may overcome endocrine therapy resistance while providing consistent oral pharmacology and convenience of administration. Imlunestrant is currently being studied as a treatment for advanced breast cancer and as an adjuvant treatment in early breast cancer, including: NCT04975308, NCT05514054, NCT04188548, NCT05307705.
About Verzenio® (abemaciclib)
Verzenio® (abemaciclib) is approved to treat people with certain HR+, HER2- breast cancers in the adjuvant and advanced or metastatic setting. Verzenio is the first CDK4/6 inhibitor approved to treat node-positive, high risk early breast cancer (EBC) patients.10 For HR+, HER2- breast cancer, The National Comprehensive Cancer Network® (NCCN®) recommends consideration of two years of abemaciclib (Verzenio) added to endocrine therapy as a Category 1 treatment option in the adjuvant setting.11 NCCN® also includes Verzenio plus endocrine therapy as a preferred treatment option for HR+, HER2- metastatic breast cancer.11
The collective results of Lilly’s clinical development program continue to differentiate Verzenio as a CDK4/6 inhibitor. In high risk EBC, Verzenio has shown a persistent and deepening benefit beyond the two-year treatment period in the monarchE trial, an adjuvant study designed specifically to investigate a CDK4/6 inhibitor in a node-positive, high risk EBC population.12 In metastatic breast cancer, Verzenio has demonstrated statistically significant OS in the Phase 3 MONARCH 2 study.13 Verzenio has shown a consistent and generally manageable safety profile across clinical trials.
Verzenio is an oral tablet taken twice daily and available in strengths of 50 mg, 100 mg, 150 mg, and 200 mg. Discovered and developed by Lilly researchers, Verzenio was first approved in 2017 and is currently authorized for use in more than 90 counties around the world. For full details on indicated uses of Verzenio in HR+, HER2- breast cancer, please see full Prescribing Information, available at www.Verzenio.com.
INDICATIONS FOR VERZENIO®
VERZENIO® is a kinase inhibitor indicated:
- in combination with endocrine therapy (tamoxifen or an aromatase inhibitor) for the adjuvant treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, node-positive, early breast cancer at high risk of recurrence.
- in combination with an aromatase inhibitor as initial endocrine-based therapy for the treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer.
- in combination with fulvestrant for the treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer with disease progression following endocrine therapy.
- as monotherapy for the treatment of adult patients with HR-positive, HER2-negative advanced or metastatic breast cancer with disease progression following endocrine therapy and prior chemotherapy in the metastatic setting.
About Lilly
Lilly is a medicine company turning science into healing to make life better for people around the world. We’ve been pioneering life-changing discoveries for nearly 150 years, and today our medicines help tens of millions of people across the globe. Harnessing the power of biotechnology, chemistry and genetic medicine, our scientists are urgently advancing new discoveries to solve some of the world’s most significant health challenges: redefining diabetes care; treating obesity and curtailing its most devastating long-term effects; advancing the fight against Alzheimer’s disease; providing solutions to some of the most debilitating immune system disorders; and transforming the most difficult-to-treat cancers into manageable diseases. With each step toward a healthier world, we’re motivated by one thing: making life better for millions more people. That includes delivering innovative clinical trials that reflect the diversity of our world and working to ensure our medicines are accessible and affordable. To learn more, visit Lilly.com and Lilly.com/news, or follow us on Facebook, Instagram, and LinkedIn. P-LLY
References
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6 Metastatic Breast Cancer Network. 13 Facts about Metastatic Breast Cancer. http://www.mbcn.org/13-facts-about-metastatic-breast-cancer/. Accessed July 9, 2024.
7 American Cancer Society. Breast Cancer Facts & Figures 2022-2024. Atlanta: American Cancer Society, Inc. 2022. https://www.cancer.org/content/dam/cancer-org/research/cancer-facts-and-statistics/breast-cancer-facts-and-figures/2022-2024-breast-cancer-fact-figures-acs.pdf. Accessed July 9, 2024.
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10 Verzenio. Prescribing information. Lilly USA, LLC.
11 Referenced with permission from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Breast Cancer V.2.2024. © National Comprehensive Cancer Network, Inc. 2024. All rights reserved. Accessed May 9, 2024. To view the most recent and complete version of the guidelines, go online to NCCN.org. NCCN makes no warranties of any kind whatsoever regarding their content, use or application and disclaims any responsibility for their application or use in any way.
12 Johnston SRD, Toi M, O’Shaughnessy J, Rastogi P, et al. Abemaciclib plus endocrine therapy for hormone receptor-positive, HER2-negative, node-positive, high-risk early breast cancer (monarchE): results from a preplanned interim analysis of a randomized, open-label, phase 3 trial. Lancet Oncol. 2023 Jan;24(1):77-90.
13 Sledge GW Jr, Toi M, Neven P, et al. The effect of abemaciclib plus fulvestrant on overall survival in hormone receptor-positive, ERBB2–negative breast cancer that progressed on endocrine therapy—MONARCH 2: a randomized clinical trial. JAMA Oncol. 2020;6(1):116-124. doi:10.1001/jamaoncol. 2019.4782.
SOURCE: Eli Lilly