Inclusion Criteria:

• Written informed consent prior to beginning specific protocol procedures, including expected cooperation of the patients for the treatment and follow-up, must be obtained and documented according to the local regulatory requirements.
• Histologically confirmed invasive adenocarcinoma of the breast.
• Primary tumour or metastasis negative or positive (≥ 10% positive stained cells) for oestrogen and/or progesterone receptor detected by immunohistochemistry.
• Single or multiple bone metastasis (x-ray, CT or MRI) as only metastatic site.
• Hormone receptor positive patients should have received an aromatase inhibitor in any given previous breast cancer therapy. Endocrine pre-treatment for metastatic bone disease is allowed. Previous treatment with bisphosphonates is allowed.
• Up to one previous chemotherapy for metastatic disease is allowed
• Patients must have either measurable or non-measurable target lesions according to the WHO criteria.
• At least 1 target lesion must be completely outside the radiation portal or there must be pathologic proof of progressive disease.
• At least 2 weeks since major surgery with full recovery.
• Complete staging within 4 weeks prior to registration.
• Karnofsky performance status evaluation > 60%.
• Age >18 years.
• Absolute neutrophil count >1,500 cells/µl, platelet count >100,000 cells/µl.
• Bilirubin >1.5x the upper normal limit for the institution (UNL); elevation of transaminases, alkaline phosphatase < 2.5x UNL and serum albumin < 30g/l. Normal renal function (creatinine >1.5x upper normal limit)
• If of childbearing potential, negative pregnancy test. In addition the patient has to agree to use an effective method to avoid pregnancy for the duration of the study.

Exclusion Criteria:

• Known hypersensitivity reaction to the compounds or incorporated substances (e.g. everolimus or sirolimus [rapamycin] or lactose).
• Concurrent immunotherapy or hormonal therapy (antihormonal, contraceptive and/or replacement therapy).
• Need for chemotherapy or irradiation of bone metastasis during study treatment.
• HER2 positive primary tumour and/or lesion.
• Evidence of metastasis in other organs
• Uncompensated diabetes mellitus; fasting value of blood sugar of >120 (mg/dl)
• Corrected (adjusted for serum albumin) serum calcium concentration < 8.0 mg/dl (2.00 mmol/l) or > 12.0 mg/dl (3.00 mmol/l)
• Abnormal renal function as evidenced by a calculated creatinine clearance < 30 ml/minute.
• Life expectancy of less than 3 months.
• Serious intercurrent medical or psychiatric illness that may interfere with the planned treatment (including AIDS and serious active infection).
• History of other malignancy within the last 5 years which could affect the diagnosis or assessment of metastatic breast cancer.
• Concurrent treatment with other experimental drugs. Participation in another clinical trial with any investigational not marketed drug within 30 days prior to study entry.
• Patients being treated with drugs recognized as being strong inhibitors or inducers of the isoenzyme CYP3A (e.g. rifabutin, rifampicin, clarithromycin, ketoconazole, itraconazole, ritonavir, telithromycin, erythromycin, verapamil, dilitazem) within the last 5 days or the expected need for these treatments during study participation.
• Pregnant or nursing women.
• The patient is not accessible for treatment and follow-up. Patients registered on this trial must be treated and followed at the participating centre which could be the Principal or Co-Investigator's site.