AB Science announces that a new independent publication confirms that masitinib has anti-vital activity against the SARS-CoV-2 virus in vitro and is a promising candidate for treating Covid-19

NEW INDEPENDENT PUBLICATION CONFIRMS THAT MASITINIB HAS ANTI-VIRAL ACTIVITY AGAINST THE SARS-COV-2 VIRUS IN VITRO AND IS A PROMISING CANDIDATE FOR TREATING COVID-19

Paris, 25 January 2021, 8.30am CET

AB Science SA (NYSE Euronext - FR0010557264 - AB) today announced the publication of preclinical study results with masitinib in COVID-19. Research led by scientists from the Institute of Human Virology (Guangzhou, China) has been published in the peer-reviewed journal mBIO (a journal of the American Society for Microbiology). The article, entitled ‘Engineering a reliable and convenient SARS-CoV-2 replicon system for analysis of viral RNA synthesis and screening of antiviral inhibitors’,[1] is freely accessible online from the mBio journal site https://mbio.asm.org/content/mbio/12/1/e02754-20.full.pdf

This article reports results of an independent study led by Professor Yuewen Luo and colleagues from the Institute of Human Virology (Guangzhou, China), describing development of a replicon system that has been used for high-throughput screening of antiviral drugs. Replicon systems permit convenient and safe simulation of virus replication to analyze the effects of various SARS-CoV-2 genes, the effects of pandemic SARS-CoV-2 gene variants, and the antiviral activities of small compounds.

Starting from a library of 1,680 clinically approved drugs, masitinib was one of just 5 candidate drugs selected for further study due to its potent inhibitory effect upon the replicon system and also its ability to block viral replication of authentic SARS-CoV-2 viruses. In both the replicon system and the authentic SARS-CoV-2 virus, masitinib demonstrated a submicromolar IC₅₀ equal to 0.6 µM (this being a quantitative measure of how much of a particular inhibitory substance is needed to inhibit, in vitro, viral replication by 50%). This value is equivalent to that of masitinib-dependent SARS-CoV-2 replication inhibition in a model of Human Airway Epithelial cells. Importantly, such active concentration (0.6 µM) is reached in human patients at therapeutic dosing (6 mg/kg/day). The authors concluded that their findings supported a hypothesis that the RNA synthesis of SARS-CoV-2 could be directly dependent on a kind of phosphorylation regulation pathway or indirectly dependent on certain receptor tyrosine kinase pathways. These new results show that masitinib, in addition to be a direct antiviral drug blocking the 3CLPro, as was previously shown by research from the University of Chicago [2], could also probably indirectly block virus replication through inhibition of cellular kinases. Thus, masitinib, as an antiviral and an anti-inflammatory drug, might be used at all stages of the COVID-19 disease, alone or in combination with other drugs, including anti-viral drugs and/or dexamethasone.