Conditions: Breast Cancer
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 602
Healthy volunteers: no

Brief summary:
This randomized, multicenter, 2-arm, open-label study (TH3RESA) will evaluate the efficacy and safety of trastuzumab emtansine (T-DM1) in comparison with treatment of the physician's choice in participants with metastatic or unresectable locally advanced/recurrent human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Eligible participants will be randomized to receive either trastuzumab emtansine 3.6 mg/kg intravenously every 21 days or treatment of the physician's choice. Participants continue to receive study treatment until disease progression or unacceptable toxicity occurs. This study is also known under Roche study protocol number BO25734.

Detailed description:

Arms:
arm 1: Trastuzumab emtansine 3.6 mg/kg intravenously every 3 weeks until disease progression (as assessed by the investigator) or unmanageable toxicity. arm 2: Treatment of physician's choice until disease progression (as assessed by the investigator) or unmanageable toxicity. The treatments included single-agent chemotherapy, single-agent or dual-agent hormonal therapy for hormone receptor positive-disease, and HER2-directed therapy.

Interventions: intervention 1: Trastuzumab emtansine intervention 2: Treatment of physician's choice
Intervention descriptions: intervention 1: The dose was calculated based on the patient's Baseline weight on Day 1 of each 3-week treatment cycle. The same dose was administered in subsequent cycles if the patient's weight stayed within 10% of the Baseline weight. If there was a weight change \> 10%, the dose was adjusted accordingly and the recorded weight became the new Baseline weight. Trastuzumab emtansine was provided as a single-use lyophilized formulation. intervention 2: The treatment of physician's choice (TPC) was a protocol-specified approved or standard of care therapy or combination of therapies, based on frequently used regimens for late-line HER2-positive metastatic breast cancer treatment after receipt of both trastuzumab- and lapatinib-containing regimens. The therapies included single-agent chemotherapy, single-agent (e.g., tamoxifen or aromatase inhibitor) or dual-agent (e.g., aromatase inhibitor with luteinizing hormone releasing hormone \[LHRH\] agonist) hormonal therapy for hormone receptor positive-disease, and HER2-directed therapy.

Participants who had documented progressive disease (PD) were eligible to switch treatment to receive trastuzumab emtansine 3.6 mg/kg. Participants who switched treatment remained on trastuzumab emtansine treatment until another PD event or unmanageable toxicity.

The formulation, storage, and preparation of all TPC were as per the appropriate package insert or national prescribing information.

Protocol document: