Trial of Neoadjuvant Trastuzumab Emtansine in Patients With HER2-Equivocal Breast Cancer

Inclusion Criteria

• •Female gender;
• •Age ≥18 years;
• •Eastern Cooperative Oncology Group performance status of 0-1;
• •Histologically confirmed invasive breast cancer;
• •Primary tumor greater than or equal to 1 cm diameter, as measured by clinical examination and mammography or ultrasound;
• •Any N;
• •No evidence of metastasis (M0) (isolated supra-clavicular node involvement allowed);
• •HER2 low or equivocal status in the invasive component of the primary tumor (confirmed by a central certified laboratory prior to study entry)
• •* HER2 low expression: 1+/2+ by immunohistochemistry and/or HER2/CEP17 ratio \<2.0 with HER2 copy number \<6.0 signals/cell
• •* HER2 equivocal expression: HER2 copy number ≥4.0 and \<6.0 signals/cell;
• •Hematopoietic status:
• •Absolute neutrophil count ≥ 1.0 x 10\^9/L, Platelet count ≥ 100 x 10\^9/L, Hemoglobin at least 9 g/dL;
• •Hepatic status: Serum total bilirubin ≤1 x upper limit of normal (ULN; In the case of known Gilbert's syndrome, a higher serum total bilirubin \[\< 1.5 x ULN\] is allowed), Aspartate aminotransferase and alanine aminotransferase ≤1.5 x ULN, Alkaline phosphatase ≤ 1.5 x ULN;
• •Renal status: Creatinine ≤1.5 mg/dL;
• •International Normalized Ratio ≤1.5 x ULN;
• •Baseline left ventricular ejection fraction ≥50%, as measured by echocardiography or multigated acquisition scan;
• •Negative serum or urine β-human chorionic gonadotropin pregnancy test within 7 days prior study entry for patients of childbearing potential. Women of childbearing potential must use effective contraception (barrier method \[condoms, diaphragm\] in conjunction with spermicidal jelly, or total abstinence. Oral, injectable, and implantable hormonal contraceptives are not allowed) for the duration of the study and for at least 7 months after the last dose of study treatment;
• •Signed informed consent form (ICF);
• •Patient accepts to make available tumor samples for submission to central laboratory to conduct translational studies as part of this protocol.