Conditions: Breast Cancer
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 991
Healthy volunteers: no

Brief summary:
This is a Phase III, randomized, multicenter, international, 2-arm, open-label clinical trial designed to compare the safety and efficacy of trastuzumab emtansine (T-DM1) with that of capecitabine + lapatinib in participants with human epidermal growth factor receptor 2 (HER2)-positive locally advanced or metastatic breast cancer. Participants will be treated until disease progression (PD), unmanageable toxicity, or study termination. Once disease progression is reported, all participants will be followed for survival every 3 months until death, loss to follow-up, withdrawal of consent, or study termination.

Detailed description:

Arms:
arm 1: Participants will receive trastuzumab emtansine 3.6 milligrams per kilogram (mg/kg) intravenous (IV) infusion over 30-90 minutes on Day 1 of each 21-day treatment cycle until disease progression (PD) (as assessed by the investigator), unmanageable toxicity, or study termination. arm 2: Participants will receive lapatinib 1250 mg (five 250 mg tablets) orally once daily during each 21-day cycle + capecitabine 1000 milligrams per square meter (mg/m\^2) orally twice daily on Days 1-14 of each 21-day treatment cycle until PD (as assessed by the investigator), unmanageable toxicity, or study termination. Eligible participants will cross over to receive trastuzumab emtansine if second interim analysis demonstrates statistically significant overall survival benefit in favor of trastuzumab emtansine.

Interventions: intervention 1: Trastuzumab emtansine intervention 2: Lapatinib intervention 3: Capecitabine
Intervention descriptions: intervention 1: Trastuzumab emtansine 3.6 mg/kg IV infusion over 30-90 minutes on Day 1 of each 21-day treatment cycle. intervention 2: Lapatinib 1250 mg (five 250 mg tablets) orally once daily during each 21-day cycle. intervention 3: Capecitabine 1000 mg/m\^2 orally twice daily on Days 1-14 of each 21-day treatment cycle.

Protocol document: