margetuximab

Concurrent anthracycline (daunorubicin, doxorubicin, or idarubicin) therapy may ↑ risk of cardiotoxicity; avoid anthracycline therapy for ≥4 mo after discontinuing margetuximab.

Route/Dosage ⬆ ⬇

IV (Adults ): 15 mg/kg every 3 wk (on days when administered with chemotherapy, give margetuximab immediately after chemotherapy). Continue until disease progression or unacceptable toxicity.

Availability ⬆ ⬇

Assessment ⬆ ⬇

Monitor cardiac function before and during treatment. Obtain baseline ECG 4 wk before start of therapy and every 3 mo during treatment or as clinically indicated. May cause ↓ in left ventricular ejection fraction (LVEF). If ≥16% absolute ↓ in LVEF from pretreatment values, or LVEF below institutional limits of normal (or <50% if no limits are available) and ≥10% absolute ↓ in LVEF from pretreatment values, hold therapy for >4 wk; resume if LVEF returns to normal limits and absolute ↓ from baseline ≤15% within 8 wk. Permanently discontinue if LVEF ↓ persists for >8 wk or if dosing is interrupted for LVEF ↓ on >3 occasions.
Assess for infusion-related reactions (fever, chills, arthralgia, cough, dyspnea, dizziness, fatigue, nausea, vomiting, headache, diaphoresis, tachycardia, hypotension, pruritus, rash, urticaria). If mild or moderate reactions occur,↓ infusion rate. Consider premedications (antihistamines, corticosteroids, antipyretics) with future cycles. If dyspnea or clinically significant hypotension occurs,interrupt infusion. If severe or life-threatening reaction occurs, permanently discontinue margetuximab. Implement medical therapy intervention with epinephrine, corticosteroids, diphenhydramine, bronchodilators, or oxygen if indicated.

Lab Test Considerations:

Verify negative pregnancy status before starting treatment.
HER2 protein overexpression is used to determine whether treatment with margetuximab is indicated. HER2 protein overexpression is detected by HercepTest (IHC assay) and PathVysion (FISH assay).
Obtain baseline troponin and B-type natriuretic peptide.
Obtain hepatitis B virus screening with hepatitis B surface antigen, hepatitis B core antibody, total Ig or IgG, and antibody to hepatitis B surface antigen before starting therapy.
Monitor CBC regularly during therapy. May ↓ WBC, neutrophils, lymphocytes, and hemoglobin.
May ↑ serum creatinine, AST, ALT, lipase, and alkaline phosphatase.
May ↑ aPTT and INR.

Implementation ⬆ ⬇

Consider premedications (antihistamines, corticosteroids, and antipyretics) if a mild to moderate infusion reaction occurs.
If administering on the same day with chemotherapy, administer chemotherapy first, followed by margetuximab immediately after chemotherapy.

IV Administration:

Patient/Family Teaching ⬆ ⬇

Explain purpose and side effects of medication to patient. Advise patient to read Patient Information before starting therapy. If a dose is missed, administer the scheduled dose as soon as possible and adjust the administration schedule to maintain a 3-wk interval between doses.
Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care professional before taking other medications.
Advise patient to notify health care professional if cough or shortness of breath that is new or worse, swelling of the ankles or legs, a heartbeat that does not feel normal, weight gain of >5 pounds in 24 hr, dizziness, or passing out occurs.
Advise patient to notify health care professional if signs of infection develop (fever, chills, sore throat).
Rep: May cause fetal harm. Advise women of reproductive potential to notify health care professional if pregnancy is planned or expected or if breastfeeding. Patients who may become pregnant should use effective contraception during treatment and for 4 mo after the last dose.