Abemaciclib (LY2835219) Plus Fulvestrant Compared to Placebo Plus Fulvestrant in Previously Treated Breast Cancer

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 initialtherapy 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 ovarianfunction 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 studyscreening

• 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 estrogenreceptor (ER)-directed therapy (including selective ER degraders [SERDs] andnon-SERDs), any phosphatidylinositol 3-kinase (PI3K)-, mammalian target of rapamycin (mTOR)-, or protein kinase B (AKT)-inhibitor