Study: NCT05306340

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Giredestrant
Description: Participants will receive treatment with giredestrant 30 milligrams (mg) orally once a day (QD) on Days 1-28 of each 28-day cycle until unacceptable toxicity or disease progression as determined by the investigator according to Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST v1.1).

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Exemestane
Description: If exemestane is chosen as the physician's choice of endocrine therapy, the participant will receive exemestane at a dose of 25 mg orally once a day (QD) on Days 1-28 of each 28-day cycle or as per local label, until unacceptable toxicity or disease progression as determined by investigator according to RECIST v1.1.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Fulvestrant
Description: If fulvestrant is chosen as the physician's choice of endocrine therapy, the participant will receive fulvestrant in the clinic at a dose of 500 mg intramuscularly on Day 1 and Day 15 of Cycle 1, then Day 1 of each cycle thereafter (1 cycle is 28 days) or as per local prescribing information, until unacceptable toxicity or disease progression as determined by investigator according to RECIST v1.1.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Tamoxifen
Description: If tamoxifen is chosen as the physician's choice of endocrine therapy, the participant will receive tamoxifen at a dose of 20 mg orally QD on Days 1-28 of each 28-day cycle or as per local prescribing information, until unacceptable toxicity or disease progression as determined by investigator according to RECIST v1.1.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Everolimus
Description: Participants will receive treatment with everolimus 10 mg orally QD during each 28-day cycle until unacceptable toxicity or disease progression as determined by the investigator according to RECIST v1.1.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Everolimus
Description: Participants will receive treatment with everolimus 10 mg orally QD during each 28-day cycle until unacceptable toxicity or disease progression as determined by the investigator according to RECIST v1.1.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: LHRH Agonist
Description: Only premenopausal/perimenopausal female participants and male participants will receive a luteinizing hormone-releasing hormone (LHRH) agonist on Day 1 of each 28-day treatment cycle. The investigator will determine and supply the appropriate LHRH agonist locally approved for use in breast cancer.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: LHRH Agonist
Description: Only premenopausal/perimenopausal female participants and male participants will receive a luteinizing hormone-releasing hormone (LHRH) agonist on Day 1 of each 28-day treatment cycle. The investigator will determine and supply the appropriate LHRH agonist locally approved for use in breast cancer.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Dexamethasone Mouth Rinse
Description: A compounded alcohol-free mouthwash of dexamethasone (0.5 mg in 5 mL) will be supplied, where feasible. It is strongly recommended for prophylaxis or treatment of stomatitis/mucositis. Participants should use the alcohol-free mouthwash of dexamethasone four times QD for 8 weeks started concurrently with study treatment, and use it reactively thereafter with the first appearance of symptoms.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Dexamethasone Mouth Rinse
Description: A compounded alcohol-free mouthwash of dexamethasone (0.5 mg in 5 mL) will be supplied, where feasible. It is strongly recommended for prophylaxis or treatment of stomatitis/mucositis. Participants should use the alcohol-free mouthwash of dexamethasone four times QD for 8 weeks started concurrently with study treatment, and use it reactively thereafter with the first appearance of symptoms.