['breast cancer']
['abemaciclib', 'anastrozole', 'letrozole', 'placebo']

        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
      