Inclusion Criteria:

- Patients with histologically or cytologically documented breast cancer

- Patients with progressive breast cancer (advanced breast cancer, locoregional
recurrence not operative, or metastatic breast cancer)

- Patients with hormone receptor (ER and/or PgR) positive or both unknown.

- Postmenopausal patients between ages 20 and 79 years, inclusive

- Patients with a history of adjuvant therapy or advanced breast cancer treated with
anti-estrogens

- Patients with documented measurable or evaluable lesions.

- Patients with sufficient organ function to evaluate the safety

- Patients whose performance status (PS) is 0～2

Exclusion Criteria:

- Patients with diffuse lymphangitis carcinomatosa of the lung or CNS involvement,
liver metastasis occupying more than one third of the liver, or inflammatory breast
cancer

- Patients with other concurrent or previous malignant disease (excluding contralateral
breast cancer, in situ carcinoma of cervix uteri, and adequately treated basal or
squamous cell carcinoma of the skin)

- Patients in whom one of the following is the sole manifestation of disease: hilar
enlargement, pleural effusion and ascites

- Patients with only blastic bone metastases or a mixed blastic and lytic bone
metastases at the same site and no other measurable or evaluable lesions

- Patients with serious current disease such as uncontrolled cardiac diseases and/or
uncontrolled diabetes mellitus by any medications (including a historical serious
cardiac disease)

- Patients with adrenal insufficiency (treated or untreated) or Cushing's syndrome

- Patients with any of the following previous treatments

1. Chemotherapy for metastatic and/or locoregional recurrent disease

2. Previous adjuvant endocrine therapy other than ovariectomy, anti-estrogen
treatment, LH-RH analogues or radiation castration

3. Previous first-line endocrine therapy (e.g., aromatase inhibitors and gastagens)
for the treatment of metastatic and/or locoregional recurrent breast cancer
other than anti-estrogen or LH-RH analogues treatment

4. Patients who have not recovered from toxicity caused by previous therapy

5. For patients on investigational drugs, adequate wash-out periods of at least 7
days in the case of topical investigational drugs and at least 30 days in the
case of systemic

6. Previous bisphosphonate therapy started within 6 months without any other
measurable or evaluable lesions

7. Patients who have not stopped treatment with other anti-estrogen or anti-cancer
drugs (other than bisphosphonates) before starting the trial medication

Other protocol-defined inclusion/exclusion criteria may apply.