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

This is a Phase III open-label study to assess if camizestrant improves outcomes compared to standard endocrine therapy in patients with ER+/HER2 - early breast cancer who completed definitive locoregional therapy (with or without chemotherapy) and standard adjuvant endocrine therapy (ET) for at least 2 years and up to 5 years. The planned duration of treatment in either arm of the study is 60 months. The eligible patients must have intermediate or high risk of recurrence, as defined by specified clinical and biologic criteria. Prior use of CDK4/6 inhibitors is permitted. The primary endpoint of the study is Invasive breast cancer-free survival (IBCFS) and main secondary endpoints include Invasive disease-free survival (IDFS), Distant relapse-free survival (DRFS), Overall survival (OS), Safety and Clinical Outcome Assessments (COAs). Patients will be followed for 10 years from randomization of the last patient.