Sandra Cuellar, PharmD, BCOP, FASHP, on Cardiotoxicity With Margetuximab for HER2+ Metastatic Breast Cancer

An oncology pharmacist speaks about the occurance of left ventricular dysfunction noted with margetuximab in the treatment of HER2-positive metastatic breast cancer.

For the latest installment of the “Product Profile”, ONCOLOGY® spoke with Sandra Cuellar, PharmD, BCOP, FASHP, about margetuximab (Margenza) as therapy for patients with HER2-positive metastatic breast cancer. Here, she discusses cardiotoxicity that is frequently experienced by patients receiving monoclonal antibodies that target the HER2 receptor.


[Speaking specifically about] left ventricular dysfunction, just knowing the mechanism of action [of this agent and] that it targets the HER2 receptor, we know that there will be, just from the mechanistic perspective, some level of cardiotoxicity, given our [experience with] previous agents. Again, margetuximab had about 3% of cardiotoxicity, primarily manifesting as decrease in ejection fraction, [which was] asymptomatic and reversible. The management is [similar to what] we do with trastuzumab. If it’s greater than or equal to a 16% drop from pretreatment ejection fractions, you’re going to hold [the drug] and at that point, you should consult a cardiooncologist. Once it recovers, you can restart.


1. Rugo HS, Im SA, Cardoso F, et al. Efficacy of Margetuximab vs Trastuzumab in Patients With Pretreated ERBB2-Positive Advanced Breast Cancer: A Phase 3 Randomized Clinical Trial. JAMA Oncol. 2021;7(4):573-584. doi:10.1001/jamaoncol.2020.7932

2. Margetuximab. Prescribing information. Macrogenics; 2020. Accessed August 23, 2021.

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