A Study of Nonsteroidal Aromatase Inhibitors Plus Abemaciclib (LY2835219) in Postmenopausal Women With Breast Cancer

Inclusion Criteria:

- Have a diagnosis of hormone receptor-positive (HR+), human epidermal growth factor
receptor 2-negative (HER2-) breast cancer

- Have locoregionally recurrent disease not amenable to resection or radiation therapy
with curative intent or metastatic disease

- Have postmenopausal status

- Have either measurable disease or nonmeasurable bone-only disease

- Have a performance status ≤1 on the Eastern Cooperative Oncology Group (ECOG) scale

- Have adequate organ function

- Have discontinued previous localized radiotherapy for palliative purposes or for lytic
lesions at risk of fracture prior to randomization and recovered from the acute
effects of therapy

- Are able to swallow capsules

Exclusion Criteria:

- Have visceral crisis, lymphangitic spread, or leptomeningeal carcinomatosis

- Have inflammatory breast cancer

- Have clinical evidence or a history of central nervous system (CNS) metastasis

- Are currently receiving or have previously received endocrine therapy for
locoregionally recurrent or metastatic breast cancer

- Have received prior (neo)adjuvant endocrine therapy with a disease-free interval ≤12
months from completion of treatment

- Are currently receiving or have previously received chemotherapy for locoregionally
recurrent or metastatic breast cancer

- Have received prior treatment with everolimus

- Have received prior treatment with any cyclin-dependent kinase (CDK) 4/6 inhibitor (or
participated in any CDK4/6 inhibitor clinical trial for which treatment assignment is
still blinded)

- Have initiated bisphosphonates or approved receptor activator of nuclear factor
kappa-B ligand (RANK-L) targeted agents <7 days prior to randomization

- Are currently receiving an investigational drug in a clinical trial or participating
in any other type of medical research judged not to be scientifically or medically
compatible with this study

- Have received treatment with a drug that has not received regulatory approval for any
indication within 14 or 21 days of randomization for a nonmyelosuppressive or
myelosuppressive agent, respectively

- Have had major surgery within 14 days prior to randomization