Masavibart (ZRC3308-A7) is an Anti-SARS-CoV-2 IgG1 Monoclonal Antibody

SARS-COV-2 is a positive-sense single-stranded RNA coronavirus. This virus can cause severe acute respiratory syndrome and spreads between people through aerosols and respiratory droplets. It broke out in early 2020, causing a massive epidemic contagious disease, called COVID-19 (Coronavirus disease 2019). The symptoms of COVID-19 are fever, cough, headache, and even loss of smell and taste. Sadly, this disease has disrupted the rhythm of life for most people around the world. Because of its high infectivity, kinds of variants have emerged, including alpha, beta, gamma delta, and omicron. Therefore, the inhibitors and vaccines for the virus have been studied and developed broadly. However, due to the inequitable access to vaccines and the emergence of new variants with immune escape properties, there remains an unfulfilled need for therapeutic agents to restrict morbidity and mortality.

Masavibart is an anti-SARS-CoV-2 IgG1 monoclonal antibody and shows a good effect on COVID-19 animal models.

From: Min L, Sun Q. Front Mol Biosci. 2021;8:671633.

It shows good binding affinity to a non-competing epitope on the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein. Masavibart in combination with ZRC3308-B10 (at a ratio of 1:1) is effective for the prevention of COVID-19 and the early stage of COVID-19 before the development of the severe disease.

Following the experiments in vitro, Masavibart (0-5×105 ng/mL) in combination with ZRC3308-B10 exhibits virus-neutralizing activity in VeroE6/Vero CCL81 (SARS-CoV-2 infection model), with an IC50 value of 0.1527 ng/mL. Moreover, Masavibart neutralizes SARS-CoV-2 variants B.1.1.7, B.1.351, B.1.617.2, and B.1.617.2 AY.1 when in combination with ZRC3308-B10.

In vivo, Masavibart (0.5-25 mg/kg, i.p., 48 h prior to the SARS-CoV-2 infection) is effective in preventing SARS-CoV-2 in Syrian hamsters when combined with ZRC3308-B10. In addition, Masavibart (0.5-25 mg/kg, i.p., single) serum concentrations remain unchanged for up to 7 days without much decrease (in Syrian hamsters).

All in all, Masavibart is a potent anti-SARS-CoV-2 antibody and exhibits a more effective antiviral activity when combine with ZRC3308-B10.


1. Yadav PD, et al. Viruses. 2021 Dec 3;13(12):2424.