A Study of Abemaciclib (LY2835219) Plus Hormone Therapy in Participants With Early Breast Cancer (eMonarcHER)

eMonarcHER: A Randomized, Double Blind, Placebo-Controlled Phase 3 Study of Abemaciclib Plus Standard Adjuvant Endocrine Therapy in Participants With High-Risk, Node-Positive, HR+, HER2+ Early Breast Cancer Who Have Completed Adjuvant HER2-Targeted Therapy

The main purpose of this study is to measure how well abemaciclib works in participants with early breast cancer who are taking hormone therapy after surgery. Participants must have breast cancer that is hormone receptor positive (HR+) and human epidermal receptor 2 positive (HER2+). Your participation could last up to 10 years depending on how you and your tumor respond.

Study Overview

• Status: Terminated
• Conditions: Breast Neoplasms
• Intervention / Treatment: Drug: Abemaciclib; Drug: Placebo; Drug: Standard Adjuvant ET

• Study Type: Interventional
• Enrollment (Actual): 111
• Phase: Phase 3

Expanded Access

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Contacts and Locations

Study Locations

• Argentina
  • La Rioja, Argentina, F5300COE
    • Fundación CORI para la Investigación y Prevención del Cáncer
  • Salta, Argentina, 4400
    • Sanatorio Parque
  • San Juan, Argentina, 5400
    • Cer San Juan
  • Buenos Aires
    • Mar del Plata, Buenos Aires, Argentina, 7600
      • Instituto de Investigaciones Clínicas Mar del Plata
  • Ciudad Autónoma De Buenos Aires
    • Caba, Ciudad Autónoma De Buenos Aires, Argentina, 1125
      • Fundación Cenit para la Investigación en Neurociencias
  • Córdoba
    • Capital, Córdoba, Argentina, X5008HHW
      • Centro médico privado Cemaic
  • Tucumán
    • San Miguel de Tucumán, Tucumán, Argentina, 4000
      • Centro Médico San Roque
• Australia
  • New South Wales
    • Waratah, New South Wales, Australia, 2298
      • Calvary Mater Newcastle
  • Victoria
    • Melbourne, Victoria, Australia, 3000
      • Peter MacCallum Cancer Centre
• Austria
  • Oberösterreich
    • Linz, Oberösterreich, Austria, 4020
      • Ordensklinikum Linz
  • Wien
    • Vienna, Wien, Austria, 1090
      • Medizinische Universitat Wien
• Belgium
  • Oost-Vlaanderen
    • Gent, Oost-Vlaanderen, Belgium, 9000
      • AZ Maria Middelares
  • Wallonne, Région
    • Ottignies, Wallonne, Région, Belgium, 1340
      • Clinique Saint Pierre
  • West-Vlaanderen
    • Ieper, West-Vlaanderen, Belgium, 8900
      • Jan Yperman Ziekenhuis
    • Kortrijk, West-Vlaanderen, Belgium, 8500
      • AZ Groeninge Campus Kennedylaan
• Brazil
  • Rio de Janeiro, Brazil, 22775-001
    • Instituto de Educação, Pesquisa e Gestão em Saúde
  • São Paulo, Brazil, 04014-002
    • Núcleo de Pesquisa Clínica da Rede São Camilo
  • São Paulo, Brazil, 04543-000
    • Instituto D'Or de Pesquisa e Ensino (IDOR)
  • São Paulo, Brazil, 01229-010
    • NotreDame Intermedica Saude S.A
  • São Paulo, Brazil, 1236030
    • Instituto de Ensino e Pesquisa São Lucas
• China
  • Anhui
    • Bengbu, Anhui, China, 233004
      • Afflilated Hospital of Bengbu Medical College
  • Beijing
    • Beijing, Beijing, China, 100142
      • Beijing Cancer Hospital
    • Beijing, Beijing, China, 100034
      • Peking University People's Hospital
  • Fujian
    • Fuzhou Fujian, Fujian, China, 350001
      • Fujian Medical University Union Hospital-1 Bingfanglou
  • Guangdong
    • Guangzhou, Guangdong, China, 510120
      • Sun Yat-sen Memorial Hospital, Sun Yat-sen University
  • Hainan
    • Haikou, Hainan, China, 570000
      • Hainan Cancer Hospital
  • Hubei
    • Wuhan, Hubei, China, 430079
      • Hubei Cancer Hospital
    • Wuhan, Hubei, China, 430022
      • Tongji Medical College of Huazhong University of Science and Technology
  • Hunan
    • Changsha, Hunan, China, 410013
      • Hunan Cancer Hospital
    • Changsha, Hunan, China, 410008
      • Xiangya Hospital Central South University
  • Jiangsu
    • Nanjing, Jiangsu, China, 210000
      • Nanjing Drum Tower Hospital The Affiliated Hospital of Nanjing University Medical School
  • Jiangxi
    • Nanchang, Jiangxi, China, 330009
      • The Third Hospital of Nanchang
  • Jilin
    • Changchun, Jilin, China
      • The Second Hospital of Jilin University
  • Shandong
    • Linyi, Shandong, China, 276000
      • LinYi Cancer Hospital
  • Shanghai
    • Shanghai, Shanghai, China, 200032
      • Fudan University Shanghai Cancer Center
  • Sichuan
    • Cheng Du, Sichuan, China, 610041
      • West China Hospital of Sichuan University
    • Chengdu, Sichuan, China, 610042
      • Sichuan Cancer Hospital
  • Tianjin
    • Tianjin, Tianjin, China
      • Tianjin Medical University Cancer Institute and Hospital
  • Xinjiang
    • Urumqi, Xinjiang, China, 830011
      • Xinjiang Medical University Cancer Hospital - Urumqi
  • Zhejiang
    • Hangzhou, Zhejiang, China, 310003
      • The First Affiliated Hospital, Zhejiang University
    • Hangzhou, Zhejiang, China, 310006
      • The First People's Hospital of Hangzhou
• France
  • Doubs
    • Besançon, Doubs, France, 25000
      • CHU Besançon
  • Meurthe-et-Moselle
    • Vandoeuvre-lès-Nancy, Meurthe-et-Moselle, France, 54519
      • Institut de Cancérologie de Lorraine Alexis Vautrin
  • Nord
    • Lille, Nord, France, 59020
      • Centre Oscar Lambret
  • Pays-de-la-Loire
    • Le Mans, Pays-de-la-Loire, France, 72000
      • Clinique Victor Hugo Le Mans
• Germany
  • Baden-Württemberg
    • Ludwigsburg, Baden-Württemberg, Germany, 71640
      • Klinikum Ludwigsburg
    • Mannheim, Baden-Württemberg, Germany, 68135
      • Universitätsmedizin Mannheim
    • Ulm, Baden-Württemberg, Germany, 89075
      • Universitaetsklinikum Ulm
  • Nordrhein-Westfalen
    • Paderborn, Nordrhein-Westfalen, Germany, 33098
      • St. Vincenz-Krankenhaus Frauen- und Kinderklinik
• Greece
  • Thessaloniki, Greece, 570 01
    • European Interbalkan Medical Center
  • Attikí
    • Athina, Attikí, Greece, 115 28
      • Alexandra Hospital
    • Nea Kifissia, Attikí, Greece, 14564
      • General Oncology Hospital of Kifissia "Agioi Anargiroi"
  • Thessaloníki
    • Thessaloniki, Thessaloníki, Greece, 546 45
      • EUROMEDICA General Clinic of Thessaloniki
• Hungary
  • Győr-Moson-Sopron
    • Gyor, Győr-Moson-Sopron, Hungary, 9024
      • Petz Aladar Egyetemi Oktato Korhaz
• Israel
  • Tell Abīb
    • Tel Aviv, Tell Abīb, Israel, 6423906
      • Sourasky Medical Center
• Italy
  • Macerata, Italy, 62100
    • Ospedale Generale Provinciale Macerata
  • Taranto
    • Statte, Taranto, Italy, 74100
      • Ospedale San Giovanni Moscati
  • Verona
    • Legnago, Verona, Italy, 37045
      • Ospedale Mater Salutis
• Japan
  • Fukuoka, Japan, 811-1395
    • National Hospital Organization Kyushu Cancer Center
  • Hiroshima, Japan, 734-8551
    • Hiroshima University Hospital
  • Kagoshima, Japan, 892-0833
    • Sagara Hospital
  • Kumamoto, Japan, 862-8655
    • Kumamoto Shinto General Hospital
  • Osaka, Japan, 541-8567
    • Osaka International Cancer Institute
  • Osaka, Japan, 540-0006
    • National Hospital Organization Osaka Medical Center
  • Shizuoka, Japan, 420-8527
    • Shizuoka General Hospital
  • Tokyo, Japan, 104-8560
    • St. Luke's International Hospital
  • Aichi
    • Nagoya, Aichi, Japan, 467-8602
      • Nagoya City University Hospital
  • Chiba
    • Chiba-shi, Chiba, Japan, 260-8717
      • Chiba Cancer Center
  • Ehime
    • Matsuyama, Ehime, Japan, 791-0280
      • National Hospital Organization Shikoku Cancer Center
  • Gunma
    • Ota, Gunma, Japan, 373-0828
      • Gunma Prefectural Cancer Center
  • Ibaraki
    • Tsukuba, Ibaraki, Japan, 305-8576
      • Tsukuba University Hospital
  • Ishikawa
    • Kanazawa, Ishikawa, Japan, 920-8201
      • Ishikawa Prefectural Central Hospital
  • Kanagawa
    • Kawasaki, Kanagawa, Japan, 216-8511
      • St. Marianna University Hospital
  • Tokyo
    • Bunkyo-ku, Tokyo, Japan, 113-8431
      • Juntendo University Hospital
    • Chuo-ku, Tokyo, Japan, 104-0045
      • National Cancer Center Hospital
    • Koto, Tokyo, Japan, 135-8550
      • Japanese Foundation for Cancer Research
    • Shinagawa, Tokyo, Japan, 142-8555
      • Showa University Hospital
• Korea, Republic of
  • Incheon-gwangyeoksi [Incheon]
    • Incheon, Incheon-gwangyeoksi [Incheon], Korea, Republic of, 22332
      • Inha University Hospital
  • Kyǒnggi-do
    • Seongnam, Kyǒnggi-do, Korea, Republic of, 13620
      • Seoul National University Bundang Hospital
    • Seongnam-si, Kyǒnggi-do, Korea, Republic of, 13496
      • Cha Bundang Medical Center, Cha University
  • Seoul-teukbyeolsi [Seoul]
    • Seoul, Seoul-teukbyeolsi [Seoul], Korea, Republic of, 3722
      • Severance Hospital, Yonsei University Health System
    • Seoul, Seoul-teukbyeolsi [Seoul], Korea, Republic of, 2841
      • Korea University Anam Hospital
• Mexico
  • Distrito Federal
    • Mexico City, Distrito Federal, Mexico, 3310
      • Grupo Medico Camino SC
  • Jalisco
    • Guadalajara, Jalisco, Mexico, 45647
      • Centro Oncológico Internacional (COI)
• Spain
  • Madrid, Spain, 28040
    • Hospital Clinico San Carlos
  • Valencia, Spain, 46010
    • Hospital Quironsalud Valencia
  • A Coruña [La Coruña]
    • A Coruña, A Coruña [La Coruña], Spain, 15006
      • CHUAC-Hospital Teresa Herrera
  • Madrid, Comunidad De
    • Madrid, Madrid, Comunidad De, Spain, 28041
      • Hospital Universitario 12 de Octubre
  • Málaga
    • Malaga, Málaga, Spain, 29011
      • H.R.U Málaga - Hospital Materno-infantil
  • Santa Cruz De Tenerife
    • San Cristobal de La laguna, Santa Cruz De Tenerife, Spain, 38320
      • Hospital Universitario de Canarias
• Switzerland
  • Sankt Gallen
    • St.Gallen, Sankt Gallen, Switzerland, 9016
      • Brustzentrum Ostschweiz
  • Zürich
    • Winterthur, Zürich, Switzerland, 8401
      • Kantonsspital Winterthur
• Taiwan
  • Taipei, Taiwan, 10002
    • National Taiwan University Hospital
  • Taipei, Taiwan, 112
    • Koo Foundation Sun Yat-Sen Cancer Center
  • Taoyuan, Taiwan, 333
    • Chang Gung Medical Foundation-Linkou Branch
• United Kingdom
  • Manchester, United Kingdom, M20 4BX
    • The Christie
  • Bristol, City Of
    • Bristol, Bristol, City Of, United Kingdom, BS2 8ED
      • Bristol Haematology and Oncology Centre
  • Essex
    • Colchester, Essex, United Kingdom, CO4 5JL
      • Colchester General Hospital
  • Hammersmith And Fulham
    • London, Hammersmith And Fulham, United Kingdom, W6 8RF
      • Charing Cross Hospital
  • London
    • Chelsea, London, United Kingdom, SW3 6JJ
      • Royal Marsden Hospital
  • Suffolk
    • Ipswich, Suffolk, United Kingdom, IP4 5PD
      • Ipswich Hospital
  • Sutton
    • London, Sutton, United Kingdom, SM2 5PT
      • Royal Marsden Hospital (Sutton)
• United States
  • Arizona
    • Glendale, Arizona, United States, 85304
      • Palo Verde Cancer Specialists
  • California
    • Los Angeles, California, United States, 90024
      • TRIO-US (Translational Research in Oncology-US)
  • Florida
    • Hollywood, Florida, United States, 33024
      • Millennium Oncology - Hollywood
    • Saint Petersburg, Florida, United States, 33705
      • Florida Cancer Specialists - North
  • Illinois
    • Chicago, Illinois, United States, 60608
      • Mt. Sinai Hospital PRiSMS
  • Missouri
    • Joplin, Missouri, United States, 64804
      • Cornell-Beshore Cancer Institute
  • New Jersey
    • Ridgewood, New Jersey, United States, 07450
      • The Valley Hospital
  • Tennessee
    • Nashville, Tennessee, United States, 37203
      • Sarah Cannon Research Institute SCRI
  • Texas
    • Dallas, Texas, United States, 75230
      • Texas Oncology - Medical City Dallas
    • The Woodlands, Texas, United States, 77380
      • US Oncology
    • The Woodlands, Texas, United States, 77380
      • Northwest Cancer Specialists PC
    • The Woodlands, Texas, United States, 77380
      • Texas Oncology - Medical City Dallas
    • The Woodlands, Texas, United States, 77380
      • USO-Southern Cancer Center, P.C.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Have confirmed HR+, HER2+ early invasive breast cancer without evidence of disease recurrence or distant metastases
• Have undergone definitive surgery of the primary breast tumor(s)
• Have tumor tissue from breast (preferred) or lymph node
• Have received a minimum of four cycles of chemotherapy in either the neoadjuvant or adjuvant setting per standard of care
• Have completed approximately nine to 20 months of standard HER2-targeted therapy (neoadjuvant/adjuvant combined duration)

• Have received one of the following eligible HER2-targeted adjuvant regimens AND be randomized within 12 weeks of completing the regimen:

  • For participants treated with neoadjuvant therapy and HER2-targeted therapy: A minimum of 4 cycles of T-DM1 in the adjuvant setting. NOTE: Participants may have received up to approximately 6 cycles of adjuvant trastuzumab prior to initiation of T-DM1. Additionally, participants may have switched to trastuzumab-based therapy (monotherapy or in combination with other HER2-targeted therapies) after 4 cycles of T-DM1
  • For participants who had definitive surgery prior to systemic therapy, a minimum of 4 cycles of adjuvant pertuzumab with trastuzumab.

• Have high risk disease, defined by one of the following criteria:

  • Those who received neoadjuvant chemotherapy along with HER2-targeted treatment must have:

    • residual disease in at least one axillary lymph node, or
    • a residual tumor ≥ 5 cm, or
    • a residual tumor of any size that has direct extension to the chest wall and/or skin (ulceration or skin nodules).

  • Those who had definitive surgery prior to systemic therapy and completed adjuvant chemotherapy along with HER2-targeted therapies (trastuzumab and pertuzumab) must have

    • tumor involvement in ≥4 ipsilateral axillary lymph nodes, or
    • tumor involvement in 1 to 3 ipsilateral axillary lymph node(s) and histological Grade 3, or
    • primary invasive tumor size of ≥ 5 cm on pathological evaluation.

Exclusion Criteria:

• Have breast cancer with any of the following features:

  • Disease recurrence or distant metastatic disease (including contralateral axillary lymph nodes)
  • Pathological complete response from any prior early breast cancer treatments. Participants are required to have residual primary tumor and/or lymph node disease at the time of definitive surgery as indicated in inclusion criteria.
  • Inflammatory breast cancer

• Have other medical conditions including:

  • Previous breast cancer (Exceptions: Ipsilateral ductal carcinoma in situ [DCIS] treated by locoregional therapy alone ≥5 years ago; contralateral DCIS treated by locoregional therapy at any time)
  • Other cancer being treated and/or not in complete remission within the last 5 years (Exceptions: Appropriately treated non-melanomatous skin cancer or carcinoma in situ of cervix, bladder, or colon)
  • Females who are pregnant or lactating
  • History of venous thromboembolism
  • Other serious medical conditions

• Have previously received treatment with:

  • Any cyclin-dependent kinase (CDK)4 and CDK6 inhibitor
  • Prior adjuvant treatment with immunotherapy, tucatinib, neratinib, any investigational HER2 directed therapy, or T-DXd (DS8201) for treatment of breast cancer
  • Endocrine therapy (ET) (i.e., tamoxifen, raloxifene or aromatase inhibitor) for breast cancer prevention (without diagnosis of breast cancer)
  • Additional chemotherapy, anti-cancer ET, or HER2-targeted therapy beyond standard of care at study enrollment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 150 mg Abemaciclib + Endocrine Therapy (ET); Participants received 150 milligrams (mg) of abemaciclib administered twice daily (BID) orally along with standard adjuvant endocrine therapy (ET).	Drug: Abemaciclib; Administered orally.; Other Names: LY2835219; Drug: Standard Adjuvant ET; Administered according to label instructions.
Active Comparator: Placebo + ET; Participants received placebo administered BID orally along with standard adjuvant ET.	Drug: Placebo; Administered orally.; Drug: Standard Adjuvant ET; Administered according to label instructions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Invasive Disease Free Survival (IDFS)	IDFS, as defined by the STEEP System, is measured from the date of randomization to the date of first occurrence of one of the following events: ipsilateral invasive breast tumor recurrence, regional invasive breast cancer recurrence, distant recurrence, contralateral invasive breast cancer, second primary non-breast invasive cancer, death attributable to any cause. Study was terminated early. Data was not collected for this outcome and outcome measures were not assessed.	Randomization to Recurrence or Death from Any Cause (up to 890 days)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Overall Survival (OS)	OS is defined as the time from randomization until death from any cause. Study was terminated early. Data was not collected for this outcome and outcome measures were not assessed.	Randomization to Death from Any Cause (up to 890 days)
Distant Relapse-Free Survival (DRFS)	DRFS is defined as the time from randomization to distant recurrence or death from any cause, whichever occurs first. Study was terminated early. Data was not collected for this outcome and outcome measures were not assessed.	Randomization to Distant Recurrence or Death from Any Cause (up to 890 days)
Percentage of Participants With Central Nervous System (CNS) Metastases as First Site of Disease Recurrence	Study was terminated early. Data was not collected for this outcome and outcome measures were not assessed.	Randomization to Distant Recurrence or Death from Any Cause (up to 890 days)
Change From Baseline in the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) Scale Score	The EORTC QLQ-C30 (v. 3.0) is a self-administered, cancer-specific questionnaire with multidimensional scales assessing 15 domains (5 functional domains, 9 symptoms, and global health status). A linear transformation will be applied to standardize the raw scores to range between 0 and 100 per developer guidelines. For the functional domains and global health status scale, higher scores represent a better level of functioning. For symptom scales, higher scores represent a greater degree of symptoms. Study was terminated early. Data was not collected for this outcome and outcome measures were not assessed.	Cycle 1 up to 390 days
Change From Baseline in the EuroQOL 5 Dimension 5 Level (EQ-5D 5L) Index Score	The EQ-5D-5L is a standardized instrument for use as a measure of self-reported health status. Participants completed the 5-level (no problem, slight problem, moderate problem, severe problem, and inability or extreme problem), 5-dimension (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression) questionnaire concerning their current health state. Five dimensions of health status are each assessed with 5 response options and scored as a composite index which are anchored on a scale of 0 to 1 with a higher score representing better health status. Study was terminated early. Data was not collected for this outcome and outcome measures were not assessed.	Cycle 1 up to 390 days
Pharmacokinetics (PK): Mean Steady State Concentrations of Abemaciclib	Study was terminated early. Data was not collected for this outcome and outcome measures were not assessed.	Day 1 of Cycles 1-3 (Cycle = 28 days)

Collaborators and Investigators

• Sponsor: Eli Lilly and Company
• Investigators: Study Director: Call 1-877-CTLILLY (1-877-285-4559) or 1-317-615-4559 Mon - Fri 9 AM - 5 PM Eastern time (UTC/GMT - 5 hours, EST), Eli Lilly and Company

Publications and helpful links

Helpful Links

• A Study of Abemaciclib (LY2835219) Plus Hormone Therapy in Participants With Early Breast Cancer (eMonarcHER)

Study record dates

Study Major Dates

• Study Start (Actual): May 10, 2021
• Primary Completion (Actual): June 26, 2024
• Study Completion (Actual): June 26, 2024

Study Registration Dates

• First Submitted: February 11, 2021
• First Submitted That Met QC Criteria: February 11, 2021
• First Posted (Actual): February 12, 2021

Study Record Updates

• Last Update Posted (Actual): July 15, 2025
• Last Update Submitted That Met QC Criteria: June 26, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Breast Neoplasms
• Other Study ID Numbers: 17384; I3Y-MC-JPCW (Other Identifier: Eli Lilly and Company); 2020-004035-24 (EudraCT Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Anonymized individual patient level data will be provided in a secure access environment upon approval of a research proposal and a signed data sharing agreement.
• IPD Sharing Time Frame: Data are available 6 months after the primary publication and approval of the indication studied in the US and EU, whichever is later. Data will be indefinitely available for requesting.
• IPD Sharing Access Criteria: A research proposal must be approved by an independent review panel and researchers must sign a data sharing agreement.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No