An Adjuvant Endocrine-Based Therapy Study of Camizestrant (AZD9833) in ER+/HER2- Early Breast Cancer

Inclusion Criteria: - Women and Men; ≥18 years at the time of screening (or per national guidelines) - Histologically confirmed ER+/HER2- early-stage resected invasive breast cancer with absence of any evidence of metastatic disease as defined in the protocol. - Completed adequate (definitive) locoregional therapy (surgery with or without radiotherapy) for the primary breast tumour(s), with or without (neo)adjuvant chemotherapy. - Patients must be randomised within 12 months of definitive breast surgery. - Patients may have received up to 12 weeks of endocrine therapy prior to randomisation. - Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1 - Adequate organ and bone marrow function Exclusion Criteria: - Inoperable locally advanced or metastatic breast cancer - Pathological complete response following treatment with neoadjuvant therapy - History of any other cancer (except non-melanoma skin cancer or carcinoma in situ of the cervix or considered a very low risk of recurrence per investigator judgement) unless in complete remission with no therapy for a minimum of 5 years from the date of randomisation - Any evidence of severe or uncontrolled systemic diseases which, in the investigator's opinion precludes participation in the study or compliance " - Known LVEF <50% with heart failure NYHA Grade ≥2. - Mean resting QTcF interval > 480 ms at screening - Concurrent exogenous reproductive hormone therapy or non topical hormonal therapy for non-cancer-related conditions - Any concurrent anti-cancer treatment not specified in the protocol with the exception of bisphosphonates (e.g. zoledronic acid) or RANKL inhibitors ( eg, denosumab) - Previous treatment with camizestrant, investigational SERDs/investigational ER targeting agents, or fulvestrant - Currently pregnant (confirmed with positive serum pregnancy test) or breastfeeding. - Patients with known hypersensitivity to active or inactive excipients of camizestrant or drugs with a similar chemical structure or class to camizestrant. In pre-/peri-menopausal female and male patients, known hypersensitivity or intolerance to LHRH agonists that would preclude the patient from receiving any LHRH agonist.