Several parallel studies across the world are busy finding a cure or a vaccine against the deadly COVID-19. While some scientists are seeking out new options, others are falling back on existing drugs to find the ideal candidate to tackle the new coronavirus. Researchers from Georgia State University seem to have found one in a common arthritis drug, Auranofin.

In a new study, researchers have demonstrated that the US Food & Drug Administration (FDA) approved drug to treat rheumatoid arthritis was successful in inhibiting the SARS-CoV-2 virus. The study was carried out as a part of a bigger project aimed at identifying FDA-approved drugs to counter the coronavirus.

"Drug repurposing is the fastest way to get a treatment for SARS-CoV-2 because it's already been established that these medicines are safe to use in humans," said Mukesh Kumar, lead author of the study, in a statement. The study has been submitted for peer review.

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What is Auranofin?

It is a gold salt—a chemical compound containing gold particles. Auranofin was approved by the FDA in 1985 for the treatment of rheumatoid arthritis. Gold compounds are known for their medicinal properties, including anti-inflammatory ones. Salts of Gold such as Auranofin have been found effective against diseases such as cancer, HIV, parasitic and bacterial infections, and neurodegenerative disorders.

Inhibiting replication

For the preliminary study, Auranofin was used to treat human cells infected by the coronavirus. What the scientists found next was astounding. The amount of virus in the cells fell by 95 percent within only 48 hours after being treated with the drug.

Despite being a potent coronavirus, the SARS-CoV-2 is still bound by the biological limitations of all viruses—it cannot reproduce on its own. It requires proteins within a host cell to multiply. By inhibiting this process, Auranofin was able to prevent the virus from making copies of itself. A significant decrease in the inflammation caused by the pathogen was also observed.

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"Effective drugs need to interfere with this replication process, shutting down the virus's ability to proliferate inside the host," said Hussin Rothan, co-author of the study.

Mitigating erratic cytokine expression

A common cause of death among patients infected with COVID-19 is a sudden immunological aberration known as a 'cytokine storm'. Cytokines are signaling proteins that regulate the immune system by drawing immune cells to the site of infection.

In the case of coronavirus-afflicted individuals, this signaling process is impaired and a haywire response of the immune system or a 'cytokine storm', damages healthy tissues. This causes lung damage and organ failure. Auranofin was found to significantly suppress the erratic expression of these proteins.

"This shows that the drug not only could inhibit replication of SARS-CoV-2, mitigating the infection, but also reduce the associated lung damage that often leads to severe respiratory distress and even death," highlighted Kumar. The team intends to test the drug in animal models, through which they seek to learn more about its effect on the infection and illness, and whether it can be effective in treating COVID-19.

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Repurposing existing drugs to fight COVID-19

Auranofin joins the list of hopeful candidates of existing drugs that could turn the tide against the disease. A recent study, by researchers from Peter Doherty Institute of Infection and Immunity (Doherty Institute), and Monash University's Biomedicine Discovery Institute (BDI), found that Ivermectin, a drug used to treat conditions such as scabies and head lice, could effectively wipe out the SARS-CoV-2 virus' genetic material in 48 hours.

Remdesivir, a broad-spectrum antiviral drug originally developed against Ebola, has shown promise against COVID-19. According to the latest reports, a trial conducted by the University of Chicago Medicine, patients affected by the coronavirus were found to respond to treatment using the antiviral.

Other drugs being looked into for treating the coronavirus infection include Kaletra, a combination of two antiretroviral drugs — lopinavir and ritonavir—used to treat HIV, and Hydroxychloroquine, an antimalarial.