Conditions: Breast Cancer
Allocation: NON_RANDOMIZED | Intervention model: PARALLEL
Enrollment: 98
Healthy volunteers: no

Brief summary:
This is an open-label, multi-center, non-randomized study of the safety and tolerability of the combination of T-DM1 plus docetaxel for the treatment of participants with metastatic breast cancer (MBC) and of T-DM1 plus docetaxel with or without pertuzumab, for the treatment of participants with locally advanced breast cancer (LABC). The study comprises an initial dose finding (feasibility) part to determine the maximum tolerated dose (MTD) of T-DM1 and docetaxel, followed by an extension part aiming to consolidate the safety and efficacy of the recommended docetaxel/T-DM1 combination regimen.

Detailed description:

Arms:
arm 1: Participants with human epidermal growth factor receptor 2 (HER2)-positive MBC will receive docetaxel (Doc) 75 milligrams per square meter (mg/m\^2) intravenous (IV) infusion on Day 1 and T-DM1 2.4 milligrams per kilogram (mg/kg) IV infusion on Day 2 of Cycle 1 followed by T-DM1 75 mg/m\^2 and docetaxel 2.4 mg/kg IV infusion on Day 1 of each 3-week cycle for a minimum of 6 cycles. After 6 cycles, docetaxel 75 mg/m\^2 will be stopped and T-DM1 2.4 mg/kg will be continued until confirmed evidence of disease progression, unacceptable toxicity, or withdrawal of participant consent. arm 2: Participants with HER2-positive MBC will receive docetaxel 60 mg/m\^2 IV infusion on Day 1 and T-DM1 2.4 mg/kg IV infusion on Day 2 of Cycle 1 followed by T-DM1 60 mg/m\^2 and docetaxel 2.4 mg/kg IV infusion on Day 1 of each 3-week cycle for a minimum of 6 cycles. After 6 cycles, docetaxel 60 mg/m\^2 will be stopped and T-DM1 2.4 mg/kg will be continued until confirmed evidence of disease progression, unacceptable toxicity, or withdrawal of participant consent. arm 3: Participants with HER2-positive MBC will receive docetaxel 60 mg/m\^2 IV infusion and T-DM1 2.4 mg/kg IV infusion on Day 1 of each 3-week cycle for a minimum of 6 cycles. After 6 cycles, docetaxel 60 mg/m\^2 will be stopped and T-DM1 2.4 mg/kg will be continued until confirmed evidence of disease progression, unacceptable toxicity, or withdrawal of participant consent. arm 4: Participants with HER2-positive MBC will receive docetaxel 60 mg/m\^2 IV infusion and T-DM1 3.6 mg/kg IV infusion on Day 1 of each 3-week cycle for a minimum of 6 cycles. After 6 cycles, docetaxel 60 mg/m\^2 will be stopped and T-DM1 3.6 mg/kg will be continued until confirmed evidence of disease progression, unacceptable toxicity, or withdrawal of participant consent. arm 5: Participants with HER2-positive LABC will receive T-DM1 3.6 mg/kg IV infusion and docetaxel 60/75/100 mg/m\^2 IV infusion on Day 1 of each 3-week cycle, for 6 cycles. Study treatment will be administered for up to 6 cycles or until unacceptable toxicity, and prior to surgery. arm 6: Participants with HER2-positive LABC will receive T-DM1 3.6 mg/kg Iv infusion, docetaxel 60/75 mg/m\^2 IV infusion, and pertuzumab 840 mg (for Cycle 1) or 420 mg (for remaining cycles) IV infusion on Day 1 of each 3-week cycle, for 6 cycles. Study treatment will be administered for up to 6 cycles or until unacceptable toxicity, and prior to surgery.

Interventions: intervention 1: Docetaxel intervention 2: Pertuzumab intervention 3: Trastuzumab emtansine
Intervention descriptions: intervention 1: Docetaxel will be administered on Day 1 of each 3-week cycle at a dose specified in the respective arms (as per summary of product characteristics \[SmPC\]). intervention 2: Pertuzumab at a loading dose of 840 mg IV infusion on Day 1 of Cycle 1 followed by maintenance dose of 420 mg IV infusion on Day 1 of each 3-week cycle. intervention 3: T-DM1 will be administered on Day 1 or Day 2 of each 3-week cycle at a dose specified in the respective arms.

Protocol document: