Margetuximab
Margetuximab is a monoclonal antibody designed to target the human epidermal growth factor receptor 2 (HER2) protein found on certain cancer cells. It is used to treat HER2-positive metastatic breast cancer, working by binding to HER2 on tumor cells to inhibit their growth and proliferation. The medication is administered intravenously and is typically used in patients who have previously received anti-HER2 therapy for metastatic disease.
Margetuximab is a HER2-targeting monoclonal antibody used to treat HER2-positive metastatic breast cancer by inhibiting tumor cell growth.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- L01FD06
- RxNorm
- 2473851
- Generic
- Margetuximab
- Class
- atc-l01
- Brands
- Margenza
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- injection
- 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.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
10 groupspregnancy
first trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks; discuss with healthcare provider
regular fetal monitoring and ultrasound assessments
Use with caution and monitor for adverse effects.
pregnancy
second trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks
regular fetal monitoring and ultrasound assessments
Use with caution and monitor for adverse effects.
pregnancy
third trimesteravoid if possible
avoid use during pregnancy; consider timing of last dose before delivery
regular fetal monitoring and assessment of fetal growth
Use with caution and monitor for adverse effects.
lactation
breastfeedingno adjustment recommended
discontinue breastfeeding during treatment and for at least 4 months after last dose
no specific monitoring required
pediatric_age
children adolescentsnot established
not recommended for use in patients under 18 years; safety and efficacy not established
not applicable
geriatric
elderly 65 and olderno specific adjustment required
use with caution; monitor for increased adverse effects; no dose reduction required but careful monitoring recommended
regular assessment of cardiac function and general condition
Use with caution and monitor for adverse effects.
renal_impairment
mild to moderateno adjustment required
no dose adjustment needed for mild to moderate renal impairment; monitor renal function
routine renal function monitoring
renal_impairment
severeno specific adjustment established
use with caution; limited data available for severe renal impairment
close monitoring of renal function
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateno specific adjustment established
use with caution; limited clinical data in hepatic impairment
monitor liver function tests regularly
Use with caution and monitor for adverse effects.
hepatic_impairment
severenot established
use with caution; not recommended unless benefits outweigh risks
close monitoring of liver function and clinical status
Use with caution and monitor for adverse effects.
Statistics and clinical data
FDA approval year
Initial FDA approval date for Margetuximab (Margenza)
Drug class
Therapeutic classification of Margetuximab
Indication
FDA-approved therapeutic indication
Mechanism of action
Pharmacological mechanism of action
Treatment of adult patients with HER2-positive metastatic breast cancer who have received two or more prior anti-HER2 regimens in the metastatic setting.
Margetuximab binds to the extracellular domain of HER2 on tumor cells, inhibiting tumor cell proliferation, reducing shedding of the HER2 extracellular domain, and mediating antibody-dependent cellular cytotoxicity (ADCC).
As a monoclonal antibody, it is administered by intravenous infusion. Common side effects may include fatigue, nausea, and infusion-related reactions. Patients should be monitored for cardiac function during treatment, similar to other HER2-targeted therapies.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
WellAlly may earn a referral fee from linked resources at no extra cost to you. Editorial content is never influenced by commercial relationships.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
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