15. For patients with ER positive breast cancer in Cohorts A, B and C: EITHER postmenopausal, as defined by at least one of the following criteria: Age >60 years; Age <60 years and cessation of regular menses for at least 12 consecutive months with no alternative pathological or physiological cause; and serum estradiol and follicle stimulating hormone (FSH) level within the laboratory's reference range for postmenopausal females; Documented bilateral oophorectomy; medically confirmed ovarian failure. OR Pre-/peri-menopausal (i.e. not meeting the criteria for being postmenopausal) if being treated with an LHRH agonist that was commenced at least 4 weeks prior to Cycle 1 Day 1, and continues on the LHRH agonist throughout the trial period.