Finding New Uses For Old Leprosy Drugs

The leprosy drug clofazimine can block SARS-CoV-2 replication and even prevent the cytokine storm often seen in COVID-19 patients.

AsianScientist (Mar. 17, 2021) – While you can’t teach an old dog new tricks, old drugs can certainly be repurposed for new applications. Indeed, researchers have found that the leprosy drug clofazimine shows promise as an at-home treatment for COVID-19. Their findings were published in Nature.

Having plagued humanity for millenia, the bacterial skin disease leprosy was finally eliminated as a public health problem in 2000. This remarkable feat was achieved with the help of drugs like clofazimine, which binds to bacterial DNA and blocks further replication. Given its potency against leprosy, clofazimine is listed as an essential medicine by the World Health Organization.

It turns out there’s more to clofazimine than meets the eye, found researchers from the University of Hong Kong (HKU) and Sanford Burnham Prebys Medical Discovery Institute. After screening over 12,000 compounds from the ReFRAME library—one of the world’s most comprehensive collections of known drugs—clofazimine was singled by out by the team for its ability to block the replication of the SARS-CoV-2 virus in cell culture.

In hamster models of COVID-19, the drug managed to lower the amount of virus in the lungs, reduce lung damage and even prevented the infamous “cytokine storm”—an immune system overreaction with potentially lethal consequences. Clofazimine stops SARS-CoV-2 in its track in two ways: not only does it block viral entry into cells, but it also disrupts the replication of the virus’ genetic material.

Interestingly, clofazimine’s effects also extend to other coronaviruses. In human lung tissue, the drug reduced the replication of MERS-CoV, the coronavirus that causes Middle East Respiratory Syndrome.

The authors also found that clofazimine also worked synergistically with remdesivir, the current standard-of-care treatment for hospitalized COVID-19 patients. Given remdesivir’s limited availability and high cost, their findings suggest that clofazimine can be used hand-in-hand with other repurposed COVID-19 drugs.

Given these findings, the team hopes to soon test clofazimine in a Phase 2 clinical trial for COVID-19 outpatients. Currently, there is no available outpatient treatment for these individuals, making clofazimine a promising candidate as a convenient and affordable COVID-19 drug in the near future.

“Clofazimine appears to have pan-coronavirus activity, indicating it could be an important weapon against future pandemics,” said co-author Dr. Yuen Kwok-Yung from HKU, who first discovered the coronavirus causing severe acute respiratory syndrome (SARS). “Our study suggests that we should consider creating a stockpile of ready-made clofazimine that could be deployed immediately if another novel coronavirus emerges.”

The article can be found at: Yuan et al. (2021) Clofazimine broadly inhibits coronaviruses including SARS-CoV-2.


Source: University of Hong Kong; Photo: Shutterstock.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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