Ontruzant
Ontruzant is a brand-name biosimilar medication referencing trastuzumab, a monoclonal antibody designed to target and inhibit HER2 (Human Epidermal Growth Factor Factor Receptor 2) proteins. It is primarily used to treat certain HER2-positive cancers, including specific types of breast and gastric cancers.
Ontruzant is a HER2-targeted therapy used to treat HER2-positive breast and gastric cancers.
Key facts at a glance
- RxNorm
- 2289228
- Generic
- Ontruzant
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Treatment of HER2-positive breast cancer (both early-stage and metastatic) and HER2-positive gastric or gastroesophageal junction adenocarcinoma. Patients must have confirmed HER2 overexpression or gene amplification before treatment.
As a biosimilar to trastuzumab, Ontruzant is a monoclonal antibody that binds specifically to the HER2 receptor on cancer cells, inhibiting the signals that promote tumor cell growth and survival. It may also engage the immune system to help destroy cancer cells.
Administered as an intravenous infusion by healthcare professionals. Requires HER2 testing prior to treatment initiation. May cause cardiotoxicity, so cardiac monitoring is recommended during therapy. Can cause infusion-related reactions. Should only be used under the supervision of qualified oncology specialists. Patient should inform their doctor about all medications and health conditions before starting treatment.
Official drug label
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This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy