New drug candidates from Australia could prevent Covid infection, stop disease in its tracks

Drugs have been developed by QIMR Berghofer Medical Research Institute. Researchers have detailed findings in a study published in Nature Cell Discovery on 24 May.

A medical worker collects a sample for Covid-19 testing in New Delhi | Representational Image | Photo: Suraj Singh Bisht | ThePrint

New Delhi: A team of scientists from Australia has developed two new drug candidates that promise to prevent SARS-CoV-2 infection, as well as stop the disease from taking on a more severe form in Covid patients. 

Both drugs target how human cells respond to SARS-CoV-2, instead of the virus itself, researchers at the QIMR Berghofer Medical Research Institute have said. The development of the drug candidates was made possible by the discovery of a previously unknown mode of entry that the virus exploits to invade cells and cause Covid-19, the researchers noted in their study, published in the journal Nature Cell Discovery on 24 May. 

The team designed two types of peptides that block this pathway.

Peptides are short chains of amino acids, which are also building blocks for proteins. Peptides are easier for the body to absorb than proteins.  

So far, the research has been conducted on Covid-19 patient blood and human cells. The drug candidates are now being tested in hamsters at the Infectious Disease Models and Innovative Therapies (IDMIT) in France. Researchers said these tests are showing promising early results that the drugs are not toxic and have few side effects.

The drugs, the researchers added, are stable at room temperature, which would make them easier to store and distribute.

If found to be effective in human trials, the first candidate — a combination of peptides known as ACE2-01 and ACE2-02 — would be taken as a preventive measure, ie, before exposure to the virus, while the second — NACE2i — would stop the spread of the virus in infected cells.

Sudha Rao, head of QIMR Berghofer’s Gene Regulation and Translational Medicine Group and one of the authors of the study, said the group was able to develop the drug candidates after discovering that some people have a “chemical tag” that acts like a padlock on the ACE2 receptor.

“The tag can either keep the receptor locked or open — controlling infection. This means people who have the ‘padlock-like’ tag on their ACE2 receptors will be less susceptible to SARS-CoV-2 and those without the tag are more vulnerable to infection,” Rao said in a statement.

“Our drugs stop the tag from being removed and also protect the untagged ACE2 receptors from being infected… Our new peptide-based drugs can keep the padlock closed and prevent infection taking hold.”

Why they could be important

Laboratory tests, the researchers said, show the first drug reduces infection by cloaking the ACE2 receptor protein on human cells. The virus then latches onto the cloaking peptides, which they mistake for human cells — preventing infection.

If the virus finds its way into cells, lab tests show that the second peptide drug can block how the virus hijacks the host cell and replicates. It also boosts the immune system’s ability to recognise the virus.

“We hope, if the clinical trials are successful, that the first drug could be given as a therapy alongside vaccination to prevent the virus binding to cells and taking hold, while the second peptide could be used to stop the virus replicating in already-infected patients,” Rao said.

Nabila Seddiki, who is testing the drugs in animal models at IDMIT, said these “drugs could also be very important because they may provide the protection we need for emerging variants and be used to protect the small group of people who cannot be vaccinated”. 

The peptide-based drugs have been patented.

(Edited by Sunanda Ranjan)