Biologic
RCSB PDB 6OGE
Trastuzumab
Herceptin
- Mechanism of action
- HER2 receptor antagonist (mAb)
- In plain language
- A lab-made antibody that latches onto HER2, a protein some breast and stomach cancer cells overproduce, both blocking their growth signal and flagging the cells for destruction by the immune system.
- How it works
- Trastuzumab is a humanized IgG1 monoclonal antibody that binds the extracellular domain of the HER2 (ErbB2) receptor on tumor cells that overexpress this protein. By binding HER2, it inhibits proliferation of HER2-overexpressing tumor cells, interrupting the growth signaling that the amplified receptor normally drives. In parallel, the antibody's Fc region recruits immune effector cells, mediating antibody-dependent cellular cytotoxicity (ADCC) that is preferentially directed at HER2-overexpressing cells over normal cells. This dual action — direct growth-signal blockade plus immune-mediated tumor cell killing — underlies its clinical activity, and patient selection requires FDA-authorized testing confirming HER2 protein overexpression or gene amplification.
- Therapeutic applications
- Herceptin is indicated for adult patients with HER2-overexpressing breast cancer, both in the adjuvant setting (node-positive or node-negative disease, in combination with chemotherapy regimens containing doxorubicin, cyclophosphamide, and a taxane, or as monotherapy following anthracycline-based therapy) and in the metastatic setting (first-line in combination with paclitaxel, or as monotherapy after prior chemotherapy for metastatic disease). It is also indicated, in combination with cisplatin and capecitabine or 5-fluorouracil, for previously untreated HER2-overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma. All indications require confirmation of HER2 protein overexpression or gene amplification via FDA-authorized testing prior to treatment.
- Class
- Monoclonal antibody
- Therapeutic area
- Oncology
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