Trastuzumab (Herceptin and Biosimilars)
Trastuzumab (brand name Herceptin, with biosimilars such as Kanjinti, Herzuma, etc.) is a targeted cancer therapy known as a monoclonal antibody. It is used to treat cancers that are HER2-positive.
How It Works
Trastuzumab targets the HER2 protein found in high amounts on certain cancer cells. It works by:
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Blocking signals that cause cancer cells to grow and divide
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Preventing HER2 receptors from activating growth pathways
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Activating the immune system to destroy cancer cells (ADCC)
Indications
Trastuzumab is approved for HER2-positive cancers, including:
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Breast cancer (early-stage and metastatic)
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Stomach and gastroesophageal junction cancer (advanced or metastatic)
HER2 testing (IHC 3+ or FISH positive) is required before treatment.
Administration
Given by a healthcare professional:
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IV infusion into a vein (30–90 minutes)
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Subcutaneous injection under the skin (breast cancer only)
Treatment is usually given weekly or every 3 weeks, depending on the condition.
Key Side Effects & Monitoring
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Heart problems: Risk of heart failure; regular heart monitoring is required
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Infusion reactions: Fever, chills, breathing difficulty may occur
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Pregnancy risk: Can harm the fetus; contraception required during treatment and for 7 months after
Common side effects include fever, headache, nausea, diarrhea, and muscle or joint pain.
