Inclusion Criteria:

- Female patients must be postmenopausal.

- ER+, Human epidermal growth factor receptor 2 (Her2) negative metastatic breast
cancer.

- Disease must have been sensitive to anastrozole or letrozole therapy prior to disease
progression.

- No more than two prior lines of therapy in the metastatic setting, of which no more
than one was chemotherapy.

- Eastern Cooperative Oncology Group (ECOG) performance status score of <=1.

- Patients with disease confined only to bone may be included, but patients with purely
sclerotic lesions may not participate in the study.

Exclusion Criteria:

- Prior treatment with exemestane, ketoconazole, aminoglutethimide, or a CYP17
inhibitor. Prior treatment with ketoconazole for <= 7 days is permitted and topical
formulations of ketoconazole are permitted.

- Potential patients must not have taken anastrozole, letrozole, fulvestrant, or any
chemotherapy for at least 2 weeks (bevacizumab for at least 3 weeks) before
randomization.

- Anticancer immunotherapy or investigational agent within 4 weeks before
randomization, or anticancer radiotherapy (except palliative) or anticancer endocrine
therapy within 2 weeks before randomization.

- Serious or uncontrolled nonmalignant disease, including active or uncontrolled
infection.

- Clinical or biochemical evidence of hyperaldosteronism or hypopituitarism.

- Any condition that, in the opinion of the investigator, would compromise the
well-being of the patient or that could prevent, limit, or confound the
protocol-specified assessments.