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

Invasive breast cancer-free survival (IBCFS)

Timeframe: Up to 10 years

IBCFS is defined as time from randomisation until date of first occurrence of: * Invasive ipsilateral breast tumour recurrence (invasive IBTR) * Locoregional invasive breast cancer recurrence * Distant recurrence * Invasive contralateral breast cancer * Death attributable to any cause.

Invasive disease-free survival (IDFS)

Timeframe: Up to 10 years

IDFS is defined as time from randomisation until date of first occurrence of one of the following events: * Invasive ipsilateral breast tumor recurrence (invasive IBTR) * Locoregional invasive breast cancer recurrence * Distant recurrence * Invasive contralateral breast cancer * Second primary non-breast invasive cancer * Death attributable to any cause.

Distant relapse-free survival (DRFS)

Timeframe: Up to 10 years

DRFS is defined as time from randomisation until date of first distant recurrence or death from any cause, whichever occurs first.

Overall survival (OS)

Timeframe: Up to 10 years

OS is defined as time from randomisation until death from any cause.

Incidence and Severity of Adverse Events, with Severity Determined According to National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0 (NCI-CTCAE v5.0)

Timeframe: Until 28 days after the final dose of study treatment (up to 5 years)

Absolute and percent change from baseline in Clinical Laboratory Parameters

Timeframe: Until 28 days after the final dose of study treatment (up to 5 years)

Absolute and percent change from baseline in Vital Sign Parameters

Timeframe: Until 28 days after the final dose of study treatment (up to 5 years)

Change from baseline of arthralgia as measured by the EORTC-IL-194 (European Organisation for Research and Treatment of Cancer) item 10. EORTC-IL-194 uses 0 - 4 scale (higher score is worse)

Timeframe: Until 28 days after the final dose of study treatment (up to 5 years)

Change from baseline of hot flush as measured by the EORTC-IL-194 item 4. EORTC-IL-194 uses 0 - 4 scale (higher score is worse)

Timeframe: Until 28 days after the final dose of study treatment (up to 5 years)

Change from baseline of vaginal dryness as measured by the EORTC-IL-194 item 15. EORTC-IL-194 uses 0 - 4 scale (higher score is worse)

Timeframe: Until 28 days after the final dose of study treatment (up to 5 years)

Proportion of patients experiencing each level of symptomatic AEs of arthralgia as measured by the EORTC-IL-194 item 10. EORTC-IL-194 uses 0 - 4 scale (higher score is worse)

Timeframe: Until 28 days after the final dose of study treatment (up to 5 years)

Proportion of patients experiencing each level of symptomatic AEs of hot flush as measured by the EORTC-IL-194 item 4. EORTC-IL-194 uses 0 - 4 scale (higher score is worse)

Timeframe: Until 28 days after the final dose of study treatment (up to 5 years)

Proportion of patients experiencing each level of symptomatic AEs of vaginal dryness as measured by the EORTC-IL-194 item 15. EORTC-IL-194 uses 0 - 4 scale (higher score is worse)

Timeframe: Until 28 days after the final dose of study treatment (up to 5 years)

Change from baseline and TTD (time to deterioration ) of health-related QoL (quality of life) as measured by the 2 global QoL items from the EORTC-QLQ-C30 items 11 and 12. EORTC-QLQ-C30 uses 0 - 4 scale (higher score is worse)

Timeframe: Until 28 days after the final dose of study treatment (up to 5 years)

Pharmacokinetics (PK)

Timeframe: Until 6 months from treatment start

• Plasma concentrations of camizestrant pre-dose (Ctrough)( trough concentration)