Inclusion Criteria:

          -  Provision of signed and dated written informed consent prior to any study specific
             procedures, sampling analysis

          -  Aged at least 18

          -  At least one lesion (measurable and/or non-measurable) that can be accurately assessed
             at baseline by computerised tomography (CT) magnetic resonance imaging (MRI) or plain
             X-ray and is suitable for repeated assessment

          -  Histological or cytological confirmation of an ER+ advanced metastatic breast cancer
             tumour that is eligible for treatment with fulvestrant

          -  Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

          -  Patients must have evidence of non-child-bearing potential.

        Exclusion Criteria:

          -  Prior chemotherapy, biological therapy, radiation therapy, androgens, thalidomide,
             immunotherapy, other anticancer agents, and any investigational agents within 14 days
             of starting study treatment (not including palliative radiotherapy at focal sites)

          -  Major surgery within 4 weeks prior to entry to the study (excluding placement of
             vascular access), or minor surgery within 2 weeks of entry into the study.

          -  Patients with severe cardiac condition of ischemia, impaired ventricular function and
             arrhythmias, evidence of severe or uncontrolled systemic or current unstable or
             uncompensated respiratory or cardiac conditions.

          -  Patients with diabetes type 1 or uncontrolled type II (HbA1c > 8% assessed locally)