Study: NCT02947685

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: palbociclib
Description: o Starting dose: 125 mg capsule taken orally once per day for 21 days followed by 7 days off to complete 28 day cycle. Dose reductions: 100 mg, 75 mg. allowed. Number of Cycles: until progression or unacceptable toxicity develops

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: trastuzumab
Description: Patients must have received a minimum of 4 and maximum of 8 cycles of induction therapy prior to randomization to Arm A or B, at which point they will continue on antiHER2 therapy and endocrine therapy, with or without palbociclib. Trastuzumab dosing will be determined based on a loading dose of 8mg trastuzumab/kg body weight for Q3WK dosing schedules or a maintenance dose of 6mg/kg trastuzumab/kg dosing weight for Q3WK dosing schedules. Loading dose will be administered on Cycle 1, Day 1.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: pertuzumab
Description: Patients must have received a minimum of 4 and maximum of 8 cycles of induction therapy prior to randomization to Arm A or B, at which point they will continue on antiHER2 therapy and endocrine therapy, with or without palbociclib.Pertuzumab will be administered at a loading dose of 840 mg infusion and then at a maintenance dose of 420 mg q3wks. If patient is within 5 weeks of receiving loading dose at Cycle 1, Day 1, patient may start with maintenance dose of 420 mg.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: pertuzumab
Description: Patients must have received a minimum of 4 and maximum of 8 cycles of induction therapy prior to randomization to Arm A or B, at which point they will continue on antiHER2 therapy and endocrine therapy, with or without palbociclib.Pertuzumab will be administered at a loading dose of 840 mg infusion and then at a maintenance dose of 420 mg q3wks. If patient is within 5 weeks of receiving loading dose at Cycle 1, Day 1, patient may start with maintenance dose of 420 mg.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: letrozole
Description: There are several allowed endocrine treatment agents for Arm A and Arm B of this study. Administration is performed on an outpatient, self-administration basis according to local requirements and local standard practice. Endocrine treatment may have started before the patient enters the study. Agents will be administered at the discretion of principal investigator as well as according to standard institutional or regional practice. Recommended dosing regimen for letrozole oral therapy is 2.5 mg orally, once a day.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: letrozole
Description: There are several allowed endocrine treatment agents for Arm A and Arm B of this study. Administration is performed on an outpatient, self-administration basis according to local requirements and local standard practice. Endocrine treatment may have started before the patient enters the study. Agents will be administered at the discretion of principal investigator as well as according to standard institutional or regional practice. Recommended dosing regimen for letrozole oral therapy is 2.5 mg orally, once a day.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Anastrozole
Description: There are several allowed endocrine treatment agents for Arm A and Arm B of this study. Administration is performed on an outpatient, self-administration basis according to local requirements and local standard practice. Endocrine treatment may have started before the patient enters the study. Agents will be administered at the discretion of principal investigator as well as according to standard institutional or regional practice. Recommended dosing regimen for anastrozole is 1 mg orally, once a day.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Anastrozole
Description: There are several allowed endocrine treatment agents for Arm A and Arm B of this study. Administration is performed on an outpatient, self-administration basis according to local requirements and local standard practice. Endocrine treatment may have started before the patient enters the study. Agents will be administered at the discretion of principal investigator as well as according to standard institutional or regional practice. Recommended dosing regimen for anastrozole is 1 mg orally, once a day.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Exemestane
Description: There are several allowed endocrine treatment agents for Arm A and Arm B of this study. Administration is performed on an outpatient, self-administration basis according to local requirements and local standard practice. Endocrine treatment may have started before the patient enters the study. Agents will be administered at the discretion of principal investigator as well as according to standard institutional or regional practice. Recommended dosing regimen for exemestane is 25 mg orally, once a day.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Exemestane
Description: There are several allowed endocrine treatment agents for Arm A and Arm B of this study. Administration is performed on an outpatient, self-administration basis according to local requirements and local standard practice. Endocrine treatment may have started before the patient enters the study. Agents will be administered at the discretion of principal investigator as well as according to standard institutional or regional practice. Recommended dosing regimen for exemestane is 25 mg orally, once a day.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Fulvestrant
Description: There are several allowed endocrine treatment agents for Arm A and Arm B of this study. Administration is performed on an outpatient, self-administration basis according to local requirements and local standard practice. Endocrine treatment may have started before the patient enters the study. Agents will be administered at the discretion of principal investigator as well as according to standard institutional or regional practice. Recommended dosing regimen for Fulvestrant is 250 mg injections on Day 1 and Day 15 of Cycle 1, and q4weeks thereafter.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Fulvestrant
Description: There are several allowed endocrine treatment agents for Arm A and Arm B of this study. Administration is performed on an outpatient, self-administration basis according to local requirements and local standard practice. Endocrine treatment may have started before the patient enters the study. Agents will be administered at the discretion of principal investigator as well as according to standard institutional or regional practice. Recommended dosing regimen for Fulvestrant is 250 mg injections on Day 1 and Day 15 of Cycle 1, and q4weeks thereafter.