Margetuximab-cmkb in Combination With Chemotherapy Approved by FDA for Metastatic Breast Cancer

Margetuximab-cmkb in Combination With Chemotherapy Approved by FDA for Metastatic Breast Cancer

By: JNCCN 360 Staff
Posted: Friday, December 18, 2020

The U.S. Food and Drug Administration (FDA) recently approved the HER2-targeted monoclonal antibody margetuximab-cmkb (Margenza) in combination with chemotherapy for the treatment of adults with metastatic HER2-positive breast cancer who have received at least two prior anti-HER2 regimens (one of which was for metastatic disease), according to MacroGenics, the developer of this agent.

The approval is based, in part, on data from the phase III SOPHIA trial. The trial included 536 patients randomly assigned 1:1 to receive margetuximab (n = 266) or trastuzumab (n = 270) in combination with one of four chemotherapy agents: capecitabine, eribulin, gemcitabine, or vinorelbine. As previously reported, data from that trial showed the combination of margetuximab plus chemotherapy led to a significant 24% reduction in the risk for disease progression or death compared with trastuzumab plus chemotherapy. Researchers reported objective response rates of 22% with the margetuximab combination and 16% with the trastuzumab combination. Overall survival data are expected later in 2021.

Adverse events associated with the margetuximab combination included fatigue/asthenia (57%), nausea (33%), diarrhea (25%), and vomiting (21%). Infusion-related reactions occurred in 13% of patients receiving margetuximab, with 1.5% being grade 3.

The product label for margetuximab includes a boxed warning for left ventricular dysfunction and embryofetal toxicity.

“As the only HER2-targeted agent to have shown a progression-free survival improvement versus trastuzumab in a head-to-head phase III clinical trial, margetuximab with chemotherapy represents the newest treatment option for patients who have progressed on available HER2-directed therapies,” commented SOPHIA researcher Hope S. Rugo, MD, of the University of California, San Francisco, in a press release.

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U.S. Food and Drug Administration