On December 16, 2020, the US Food and Drug Administration approved margetuximab-cmkb (MARGENZA), 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. MARGENZA is a chimeric IgG1 monoclonal antibody that binds to HER2. The antibody’s modified Fc region increases binding to the activating Fc receptor CD16A and decreases binding to the inhibitory Fc receptor CD32B,  which leads to greater in vitro antibody-dependent cell-mediated cytotoxicity and natural killer cell activation.

FDA’s approval was based on safety and efficacy results from the pivotal Phase 3 SOPHIA trial, which showed a statistically significant 24% reduction in the risk of disease progression or death with MARGENZA plus chemotherapy compared with trastuzumab plus chemotherapy (hazard ratio [HR]=0.76; 95% CI, 0.59-0.98; P=0.033; median PFS 5.8 vs 4.9 months). The objective response rate  for MARGENZA plus chemotherapy was 22% vs 16% for trastuzumab plus chemotherapy.

MARGENZA is the 11th antibody therapeutic to be granted a first approval in the US or EU during 2020.

The Antibody Society maintains a comprehensive table of approved monoclonal antibody therapeutics and those in regulatory review in the EU or US. The table, which is located in the Web Resources section of the Society’s website, can be downloaded in Excel format.

On October 14, 2020, FDA approved the triple antibody cocktail of atoltivimab, maftivimab, and odesivimab-ebgn (Inmazeb) for the treatment for Zaire ebolavirus (Ebola virus) infection in adult and pediatric patients. Atoltivimab, maftivimab, and odesivimab are IgG1 antibodies that bind glycoprotein on the surface of Ebola virus, thereby blocking attachment and entry of the virus into cells. FDA granted the atoltivimab, maftivimab, and odesivimab cocktail Breakthrough Therapy and Orphan Drug designations for the approved indication. Inmazeb was developed by Regeneron.

The effects of Inmazeb were evaluated in adult and pediatric patients with confirmed infections that occurred during an Ebola virus outbreak in the Democratic Republic of the Congo in 2018 and 2019. In the Pamoja Tulinde Maisha (PALM) study (NCT03719586), a 4-arm trial evaluating investigational therapies for Ebola virus infection initiated in November 2018, 154 patients received Inmazeb  as a single IV infusion of 50 mg of each monoclonal antibody. The primary efficacy endpoint was 28-day mortality. At this timepoint, 33% of those who received Inmazeb had died vs 51% of those who received a control. Inmazeb was also made available in an expanded access program, which included an additional 228 patients who received Inmazeb. The PALM study was sponsored by the US National Institute of Allergy and Infectious Diseases, with collaborators from Institut National de Recherche Biomédicale (Democratic Republic of Congo); the Alliance for International Medical Action (Senegal); International Medical Corps, Los Angeles (US); Epicentre, Médecins sans Frontières, (France); and the World Health Organization (Switzerland).

Inmazeb is the 9th antibody therapeutic to be granted a first approval in the US or EU in 2020.

The Antibody Society maintains a comprehensive table of approved monoclonal antibody therapeutics and those in regulatory review in the EU or US. The table, which is located in the Web Resources section of the Society’s website, can be downloaded in Excel format.