An Efficacy Study of Trabectedin in the Treatment of Participants With Specific Subtypes of Metastatic Breast Cancer

Phase II, Multicenter, Open-label, Clinical Trial of Trabectedin (Yondelis) in Metastatic Breast Cancer Patients With Triple Negative Profile (ER-, PR-, HER2-), HER2 Overexpressing Tumors and BRCA1 or BRCA2 Mutation Carriers

The purpose of this study is to evaluate the effectiveness and safety of trabectedin in 3 subpopulations of participants with previously treated progressive metastatic ( spread of a cancer from one organ or part to another non-adjacent organ or part) breast cancer (abnormal tissue that grows and spreads in the body until it kills) participants.

This is an open-label (all people know the identity of the intervention), prospective (study following participants forward in time), multi-center (when more than 1 hospital or medical school team work on a medical research study) study evaluating the effectiveness and safety of trabectedin in 3 subpopulations of breast cancer participants: Group A: triple negative profile for estrogen receptor, progesterone receptor and human estrogen receptor, Group B: human epidermal growth factor receptor-2 overexpressing tumors (HER-2+) and Group C: familial breast cancer gene 1 (BRCA1) or breast cancer gene 2 (BRCA2) mutation carrier. Participants will receive trabectedin 1.3 milligram per square meter (mg/m^2) intravenous infusion (a fluid or a medicine delivered into a vein by way of a needle) over 3-hour every 3 weeks, on Day 1 of each cycle. Each cycle length will be 3 weeks. Treatment will be continued until disease progression, unmanageable toxicity, participant refusal or treatment delay no longer than 3 weeks due to toxicity. Efficacy will be primarily evaluated by percentage of participants with confirmed objective response by independent external review and Investigators assessment. Participants' safety will be monitored throughout the study.

Inclusion Criteria:

• Participants with histologically proven diagnosis of progressive metastatic breast cancer
• Participants with measurable disease as per the Response Evaluation Criteria In Solid Tumors (RECIST) guidelines
• Participants with bone metastases currently receiving bisphosphonates for palliation will be eligible if other sites of measurable disease are present
• Participants with Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) 0 or 1 and adequately recovered from the acute toxicity of any prior treatment
• Participants with serum creatinine less than or equal to 1.5 milligram per deciliter (mg/dl) or creatinine clearance greater than or equal to 30 milliliter per minute (ml/min)

Exclusion Criteria:

• Participants with previous exposure to trabectedin
• Participants with more than 3 previous chemotherapy regimens for metastatic disease and known hypersensitivity to components of trabectedin intravenous formulation or dexamethasone
• Pregnant or lactating women or any women of childbearing potential who is not employing adequate contraception
• Completion of previous therapy : Less than 2 weeks from radiation therapy or last dose of hormonal therapy, less than 3 weeks from previous biological therapy or chemotherapy
• Participants with known leptomeningeal disease and other serious illnesses like congestive heart failure or angina pectoris; myocardial infarction within 1 year before enrolment; uncontrolled arterial hypertension or arrhythmias or active infection or psychiatric disorder or active viral hepatitis