II. Indications
-
Breast Cancer (HER2 Positive)
- Trastuzumab
- Ado-Trastuzumab Emtansine
- Pertuzamab
-
Gastric Cancer (metastatic, HER2 Positive)
- Trastuzumab
III. Mechanism
- Human Epidermal Growth Factor Receptor 2 (HER2, HER2/neu, erbB-2 Receptor, CD340 Antigen)
- HER2/neu is a EGFR related Tyrosine Kinase important in Breast Cancer
- HER2 is overexpressed by many adenocarcinomas (esp. Breast adenocarcinoma)
- Overexpression of HER2/neu may predict worse prognosis and cancer recurrence
-
Epidermal Growth Factor Receptor (EGFR, HER1, ErbB1)
- EGFR is a Tyrosine Kinase that is activated by specific Ligands
- Triggers cascade that leads to cell proliferation, invasion and migration
- Anti-HER2 Monoclonal Antibody
- Recombinant human Monoclonal Antibody directed against the HER2 cell surface receptor
- Binds HER2 and triggers a cell-mediated cytotoxic immune response
- Targeted most significantly against tumor cells overexpressing HER2
IV. Medications: Anti-HER2
- Trastuzumab (Herceptin)
- Used in Breast Cancer (where HER2-neu is overexpressed) and metastatic HER2+ Gastric Cancer
- Trastuzumab has been very effective in HER2 positive Breast Cancer
- Risk of infusion reactions, pneumonitis, Cardiomyopathy, cytopenias
- Trastuzumab Biosimilar agents
- Trastuzumab-ANNS (Kanjinti)
- Trastuzumab-DTTB (Ontruzant)
- Trastuzumab-PKRB (Herzuma)
- Trastuzumab-QYYP (Trazimera)
- Pertuzamab (Perjeta)
- Risk of infusion reactions, Cardiomyopathy, cytopenias
V. Medications: Anti-HER2 with Cytotoxic Conjugates
- Ado-Trastuzumab Emtansine (Kadcyla)
- Trastuzumab is conjugated to the cytotoxic agent emtansine (DM1), a microtubule inhibitor
- Delivers cytotoxic DM1 to HER2 positive cells (e.g. Breast Cancer)
- Risk of Trastuzumab adverse effects, as well as hepatotoxicity, bleeding
VI. Dosing
- See other references for disease specific dosing protocols
VII. Adverse Effects
- Infusion Reaction (Trastuzumab, Pertuzamab)
- Cardiomyopathy (box warning, Trastuzumab, Pertuzamab)
-
Lung Toxicity (box warning, Trastuzumab)
- Interstitial pneumonitis
- Acute Respiratory Distress Syndrome
- Cytopenia (Trastuzumab)
- Hepatotoxicity (Ado-Trastuzumab Emtansine)
- Major Bleeding (Ado-Trastuzumab Emtansine)
- Other common adverse effects
VIII. Safety
- Avoid in Lactation
- Avoid in pregnancy (all trimesters, Pregnancy category X)
- Risk of pulmonary hypoplasia, oligohydramnios, neonatal death
- Use reliable Contraception
- Monitoring