AlternativeHerceptin
Trastuzumab
Anti-HER2 monoclonal antibody
Backbone of HER2-positive breast cancer — cardiotoxic.
IV / SC
First-line for
- HER2-positive breast cancer (adjuvant, neoadjuvant, metastatic)
Mechanism
Binds HER2 extracellular domain → ADCC + blocks HER2 signalling.
"HER2 → heart"
- Baseline LVEF then 3-monthly
- Reversible cardiomyopathy
- Combine with pertuzumab in HER2+
Dosing
- Loading
- 8 mg/kg IV, then 6 mg/kg IV q3-weekly (or 600 mg SC q3-weekly)
Contraindications
- AbsolutePregnancy, severe LV dysfunction
- CautionPrior anthracyclines, HTN
Side effects
- Cardiotoxicity (reversible)
- Infusion reactions
- Diarrhoea
- Rash
Fetal & maternal notes
- • Category D — oligohydramnios/anhydramnios if used in 2nd/3rd trimester; contraception during and 7 months after
Key interactions
Anthracyclines
AvoidAdditive cardiotoxicity — avoid concurrent
Clinical pearls
- 💡 LVEF monitoring pre-treatment then every 3 months
- 💡 Consider fertility preservation before starting
Content last reviewed: REPLACE_ME (e.g. 2026-07)
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