Conditions: Breast Cancer
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 258
Healthy volunteers: no

Brief summary:
This randomized, open-label, two-arm, multi-center, Phase II study will evaluate the efficacy and safety of pertuzumab in combination with trastuzumab plus an aromatase inhibitor (AI) in first-line participants with HER2-positive and hormone receptor-positive advanced breast cancer. Participants will be randomized to one of two treatment arms; Arm A (pertuzumab in combination with trastuzumab plus an AI) or Arm B (trastuzumab plus an AI). Participants may also receive induction chemotherapy (a taxane, either docetaxel or paclitaxel) at the investigator's discretion in combination with the assigned treatment arm. The anticipated time on study treatment is until disease progression, unacceptable toxicity, withdrawal of consent, or death whichever occurs first.

Detailed description:

Arms:
arm 1: Participants will receive pertuzumab in combination with trastuzumab plus aromatase inhibitor (AI) until pre-defined study end, disease progression, unacceptable toxicity, withdrawal of consent or death, whichever occurs first.

Participants may also receive induction chemotherapy (docetaxel every 3 weeks or paclitaxel weekly) up to the first 18-24 weeks of the treatment period at the investigator's discretion. arm 2: Participants will receive trastuzumab plus aromatase inhibitor (AI) until predefined study end, disease progression, unacceptable toxicity, withdrawal of consent or death, whichever occurs first.

Participants may also receive induction chemotherapy (docetaxel every 3 weeks or paclitaxel weekly) up to the first 18-24 weeks of the treatment period at the investigator's discretion.

Interventions: intervention 1: Pertuzumab intervention 2: Trastuzumab intervention 3: Aromatase Inhibitor intervention 4: Induction Chemotherapy
Intervention descriptions: intervention 1: Participants will receive a loading dose of 840 milligrams (mg) as an intravenous infusion on Day 1 of first treatment cycle, followed by 420 mg on Day 1 or Day 2 of each subsequent 3-week cycle until disease progression or unacceptable toxicity. intervention 2: Participants will receive a loading dose of 8 milligrams per kilogram (mg/kg) as an intravenous infusion on Day 1 or 2 of first treatment cycle, followed by 6 mg/kg on Day 1 or Day 2 of each subsequent treatment 3-week cycles until disease progression or unacceptable toxicity. intervention 3: Participants will receive 1 mg anastrozole or 2.5 mg letrozole orally once daily. intervention 4: Participants receiving induction chemotherapy up to the first 18-24 weeks of the treatment period will receive a taxane (docetaxel every 3 weeks or paclitaxel weekly), administered in line with the respective pertuzumab and/or trastuzumab infusions at the investigator's discretion.

Protocol document: