A Study of Camizestrant in ER+/HER2- Early Breast Cancer After at Least 2 Years of Standard Adjuvant Endocrine Therapy

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 high or intermediate risk of recurrence, based on clinical-pathological risk features, 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
Completed at least 2 years but no more than 5 years (+3 months) of adjuvant ET
Prior adjuvant therapy with CDK4/6 inhibitors for 2 years is allowed
Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1
Adequate organ and 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 at 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 >470 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