This study will evaluate the effect of adding abemaciclib to fulvestrant for the treatment of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer that progressed or recurred after previous treatment with a type of drug known as a CDK4/6 inhibitor and endocrine therapy. Participation could last up to 5 years, depending on how you and your tumor respond.



Eligible Ages
Over 18 Years
Eligible Genders
Accepts Healthy Volunteers

Inclusion Criteria

  • Have a diagnosis of HR+, HER2- locally advanced or metastatic breast cancer - Have radiologic evidence of disease progression or recurrence either - On treatment with a CDK4/6 inhibitor with aromatase inhibitor (AI) as initial therapy for advanced disease, or - On/after treatment with a CDK4/6 inhibitor plus endocrine therapy (ET) administered as adjuvant therapy for early stage breast cancer - Must be deemed appropriate for treatment with ET - If female, have a postmenopausal status by natural or surgical means or by ovarian function suppression - Have Response Evaluable Criteria in Solid Tumors (RECIST) evaluable disease (measurable disease and/or nonmeasurable disease) - Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group scale (Oken et al. 1982) - Have adequate renal, hematologic, and hepatic organ function - Must be able to swallow capsules/tablets

Exclusion Criteria

  • Have visceral crisis, lymphangitic spread, or leptomeningeal carcinomatosis - Have symptomatic or untreated central nervous system metastasis - Have received any systemic therapy between disease recurrence/progression and study screening - Have received more than 1 line of therapy for advanced or metastatic disease. - Have received prior chemotherapy for metastatic breast cancer (MBC) - Have received prior treatment with fulvestrant, any investigational estrogen receptor (ER)-directed therapy (including selective ER degraders [SERDs] and non-SERDs), any phosphatidylinositol 3-kinase (PI3K)-, mammalian target of rapamycin (mTOR)-, or protein kinase B (AKT)-inhibitor

Study Design

Phase 3
Study Type
Intervention Model
Parallel Assignment
Primary Purpose
Double (Participant, Investigator)

Arm Groups

ArmDescriptionAssigned Intervention
Arm A: Abemaciclib plus Fulvestrant
Abemaciclib administered orally in combination with fulvestrant administered intramuscularly (IM).
  • Drug: Abemaciclib
    Administered orally.
  • Drug: Fulvestrant
    Administered IM.
Active Comparator
Arm B: Placebo plus Fulvestrant
Placebo administered orally in combination with fulvestrant administered IM.
  • Drug: Fulvestrant
    Administered IM.
  • Drug: Placebo
    Administered orally.

Recruiting Locations

More Details

Eli Lilly and Company

Study Contact

There may be multiple sites in this clinical trial. 1-877-CTLILLY (1-877-285-4559) or


Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.