Margenza

Margenza (margetuximab-cmkb) is a HER2/neureceptor antagonist indicated, in combination with chemotherapy, to treat 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.

WARNING

LEFT VENTRICULAR DYSFUNCTION AND EMBRYO-FETAL TOXICITY

Left Ventricular Dysfunction: Margenza may lead to reductions in left ventricular ejection fraction (LVEF). Evaluate cardiac function prior to and during treatment. Discontinue Margenza treatment for a confirmed clinically significant decrease in left ventricular function.

Embryo-Fetal Toxicity: Exposure to Margenza during pregnancy can cause embryofetal harm. Advise patients of the risk and need for effective contraception.

Side effects of Margenza in combination with chemotherapy include:

• fatigue,
• weakness,
• nausea,
• diarrhea,
• vomiting,
• constipation,
• headache,
• fever,
• hair loss,
• abdominal pain,
• numbness and tingling in extremities,
• joint or muscle pain,
• cough,
• decreased appetite,
• shortness of breath,
• infusion-related reactions,
• hand-foot syndrome (palmar-plantar erythrodysesthesia), and
• extremity pain

Recommended Doses and Schedules

• The recommended dose of Margenza is 15 mg/kg, administered as an intravenous infusion every 3 weeks (21-day cycle) until disease progression or unacceptable toxicity.
• Administer Margenza as an intravenous infusion at 15 mg/kg over 120 minutes for the initial dose, then over a minimum of 30 minutes every 3 weeks for all subsequent doses.
• On days when both Margenza and chemotherapy are to be administered, Margenza may be administered immediately after chemotherapy completion.
• Refer to the respective Prescribing Information for each therapeutic agent administered in combination with Margenza for the recommended dosage information, as appropriate.

Dose Modification or Important Dosing Considerations

• If a patient misses a dose of Margenza, administer the scheduled dose as soon as possible. Adjust the administration schedule to maintain a 3-week interval between doses.

Left Ventricular Dysfunction

Assess left ventricular ejection fraction (LVEF) before starting Margenza and regularly during treatment. Withhold Margenza dosing for at least 4 weeks for any of the following:

• ≥ 16% absolute decrease in LVEF from pre-treatment values
• LVEF below institutional limits of normal (or 50% if no limits are available) and ≥ 10% absolute decrease in LVEF from pretreatment values.

Margenza dosing may be resumed if, within 8 weeks, LVEF returns to normal limits and absolute decrease from baseline is ≤ 15%. Permanently discontinue Margenza 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

• Decrease the rate of infusion for mild or moderate infusion-related reactions (IRRs). Interrupt the infusion for dyspnea or clinically significant hypotension.
• Permanently discontinue Margenza dosing in patients with severe or life-threatening IRRs.

Preparation for Administration

Administer as an intravenous infusion after dilution.

Preparation for Intravenous Infusion

Prepare solution for infusion, using aseptic technique, as follows:

• Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. The solution is clear to slightly opalescent, colorless to pale yellow or pale brown. Some visible, translucent, inherent proteinaceous particles may be present.
• Swirl the vial(s) gently. Do not shake the vial(s).
• Calculate the required volume of Margenza needed to obtain the appropriate dose according to patient’s body weight. The calculated total dose volume should be rounded to the nearest 0.1 mL.
• Withdraw appropriate volume of Margenza solution from the vial(s) using a syringe.
• Transfer Margenza into an intravenous bag containing 100 mL or 250 mL 0.9% Sodium Chloride Injection, USP. Polyvinyl chloride (PVC) intravenous bags or intravenous bags made with polyolefins (polyethylene and polypropylene) and polyamide or polyolefins only or copolymer of olefins may be used. Do not use 5% Dextrose Injection, USP solution.
• The final concentration of the diluted solution should be between 0.5 mg/mL to 7.2 mg/mL.
• Gently invert the intravenous bag to mix the diluted solution. Do not shake the intravenous bag.
• Discard any unused portion left in the vial(s).
• Do not administer as an intravenous push or bolus. Do not mix Margenza with other drugs.

Storage of Diluted Solution

• The product does not contain a preservative. If diluted infusion solution is not used immediately, it can be stored at room temperature up to 4 hours or stored refrigerated at 2°C to 8°C (36°F to 46°F) up to 24 hours. If refrigerated, allow the diluted solution to come to room temperature prior to administration. Do not freeze.

Administration

• Administer diluted infusion solution intravenously over 120 minutes for the initial dose, then over a minimum of 30 minutes every 3 weeks for all subsequent doses. Administer through an intravenous line containing a sterile, non-pyrogenic, lowprotein binding polyethersulfone (PES) 0.2 micron in-line or add-on filter.
• Do not co-administer other drugs through the same infusion line.

Anthracyclines

• Patients who receive anthracyclines less than 4 months after stopping Margenza may be at increased risk of cardiac dysfunction.
• While this interaction has not been studied with Margenza, clinical data from other HER2-directed antibodies warrants consideration.
• Avoid anthracycline-based therapy for up to 4 months after stopping Margenza.
• If concomitant use is unavoidable, closely monitor patient's cardiac function.

• Based on findings in animals and mechanism of action, Margenza can cause fetal harm when administered to a pregnant woman.
• There are no available data on use of Margenza in pregnant women to inform the drug-associated risk.
• In postmarketing reports, use of a HER2- directed antibody during pregnancy resulted in cases of oligohydramnios and oligohydramnios sequence manifesting as pulmonary hypoplasia, skeletal abnormalities, and neonatal death.
• There is no information regarding presence of Margenza in human milk, effects on the breastfed child, or effects on milk production.
• Published data suggest human IgG is present in human milk but does not enter neonatal or infant circulation in substantial amounts.
• Consider developmental and health benefits of breastfeeding along with the mother's clinical need for Margenza treatment and any potential adverse effects on the breastfed child from Margenza or from the underlying maternal condition. This consideration should also take into account the Margenza washout period of 4 months.