Drug Detail:Margetuximab (Margetuximab [ mar-je-tux-i-mab ])
Drug Class: HER2 inhibitors
Usual Adult Dose for Breast Cancer
15 mg/kg IV every 3 weeks
Comment:
- Infuse initial dose over 120 minutes and subsequent doses over 30 minutes.
- This drug may be administered immediately after the completion of chemotherapy.
- Continue treatment until disease progression or unacceptable toxicity.
- All therapeutic proteins, including this drug, have the potential to produce an immune response.
Use: In combination with chemotherapy, for the treatment of adult patients with metastatic HER2-positive breast cancer who have received two or more prior anti-HER2 regimens, at least one of which was for metastatic disease
Renal Dose Adjustments
Data not available
Liver Dose Adjustments
Data not available
Dose Adjustments
LEFT VENTRICULAR EJECTION FRACTION (LVEF):
Withhold dosing for at least 4 weeks for any of the following:
- If 16% or greater absolute decrease in LVEF from pretreatment values.
- LVEF below institutional limits of normal or 50% if no limits are available.
- If 10% or greater absolute decrease in LVEF from pretreatment values
- The dosing may be resumed if, within 8 weeks, LVEF returns to normal limits, and a total reduction from baseline is 15% or less.
- Permanently discontinue if LVEF decline persists for greater than 8 weeks or if dosing is interrupted on greater than 3 occasions for LVEF decline.
INFUSION-RELATED REACTIONS (IRRs):
- For mild or moderate IRRs, decrease the rate of infusion.
- For dyspnea or clinically significant hypotension, interrupt the infusion.
- For patients with severe or life-threatening IRRs, permanently discontinue treatment.
Precautions
US BOXED WARNINGS:
- LEFT VENTRICULAR DYSFUNCTION: This drug may lead to reductions in left ventricular ejection fraction (LVEF). Evaluate cardiac function prior to and during treatment. Discontinue treatment for a confirmed a clinically significant decrease in left ventricular function.
- EMBRYO-FETAL TOXICITY: Exposure to this drug during pregnancy can cause embryofetal harm. Advise patients of the risk and need for effective contraception.
CONTRAINDICATIONS:
- None
Safety and efficacy have not been established in patients younger than 18 years.
Consult WARNINGS section for additional precautions.
Dialysis
Data not available
Other Comments
Administration advice:
- Administer as an IV infusion after dilution.
- Infuse initial dose over 120 minutes and subsequent doses over 30 minutes.
- This drug may be administered immediately after the completion of chemotherapy.
- Do not administer as an IV push or bolus.
- Do not mix this drug with other drugs.
- Do not co-administer other drugs through the same infusion line.
- If a patient misses a dose, administer the scheduled dose as soon as possible, and then adjust the administration schedule to maintain a 3-week interval between doses.
Storage Requirements:
- Store vials refrigerated at 2C to 8C (36F to 46F) in the original carton to protect from light.
- Do not freeze.
- Do not shake.
Reconstitution/preparation techniques:
- The manufacturer product information should be consulted.
Monitoring:
- Cardiovascular: Left ventricular dysfunction by echocardiogram or MUGA scan.
- Immunologic: Monitor or sign and symptoms for infusion-related reactions.
- Pregnancy: Monitor females who received this drug for oligohydramnios during pregnancy or within 4 months prior to conception.
Patient advice:
- Advise pregnant women and females of reproductive potential that exposure to this drug during pregnancy or within 4 months prior to conception can result in fetal harm.
- Advise females of reproductive potential to use effective contraception during treatment and 4 months after the last dose.
- Advise female patients to contact their healthcare provider with a known or suspected pregnancy.
- Advise patients to report immediately any new onset or worsening shortness of breath, cough, swelling of the ankles/legs, swelling of the face, palpitations, weight gain of more than 5 pounds in 24 hours, dizziness, or loss of consciousness.