HER2+ Breast Cancer (see Breast Cancer, [[Breast Cancer]])
Adjuvant Therapy for HER-2+ Breast Cancer
Neoadjuvant Therapy for Early-Stage Locally Advanced, or Inflammatory HER-2+ Breast Cancer: off-label
Metastatic HER2+ Breast Cancer: alone or in combination with paclitaxel
Metastatic HER2+ Gastric Cancer (see Gastric Cancer, [[Gastric Cancer]]): in combination with cisplatin and either capecitabine or 5-fluorouracil
Contraindications
Pregnancy (see Pregnancy, [[Pregnancy]]): due to risk of oligohydramnios and oligohydramnios sequence (pulmonary hypoplasia, skeletal malformations, and neonatal death)
Pharmacology
Monoclonal Antibody Binds to the Extracellular Domain of the HER2: it mediates antibody-dependent cellular cytotoxicity by inhibiting proliferation of cells which overexpress the HER2 protein
Background on ErbB Family of Receptors
General Comments: this is a family of closely-related epidermal growth factor receptor tyrosine kinases
Human Epidermal Growth Factor Receptor = HER
Family Members
Epidermal Growth Factor Receptor (EGFR): also called HER1 or ErbB-1
HER2/neu: also called ErbB-2 or CD340
HER3: also called ErbB-3
HER4: also called ErbB-4
Metabolism
Washout: in most cases, trastuzumab concentrations will decrease to approximately 3% (approximately 97% washout) by 7 mo after discontinuation
Risk of heart failure in breast cancer patients after anthracycline and trastuzumab treatment: a retrospective cohort study. J Natl Cancer Inst. 2012;104(17):1293-1305 [MEDLINE]
Trastuzumab-Associated Cardiac Events at 8 Years of Median Follow-Up in the Herceptin Adjuvant Trial (BIG 1-01). J Clin Oncol. 2014;32(20):2159-2165 [MEDLINE]