Queensland researchers have identified a key cause of severe COVID-19, paving the way for a potential new treatment.
Unlike antiviral treatments, Mater Research biochemist Katharina Ronacher said the experimental medication would not attack SARS-CoV-2, the virus that causes COVID-19, but was designed instead to target the immune system.
Dr Ronacher said she would approach pharmaceutical company Novartis, which owns the patent to the drug, dubbed NIBR189, to discuss the potential for human trials.
She said studies in mice, infected with SARS-CoV-2, found it lessened the severity of the disease.
The animal studies are based on previous work by Dr Ronacher and her team comparing cells in the lungs of healthy volunteers with patients who have moderate or severe COVID-19.
They found patients with severe COVID-19 produce enzymes that lead to the creation of cholesterols in the lungs.
"These cholesterol molecules actually are a signal for immune cells in the blood to leave the bloodstream and to migrate to the site of infection … the lungs," Dr Ronacher said.
"While we know we need immune cells at the site of infection to fight the infection, and to control the virus, what we observed in severe COVID-19 patients is that they have excessive infiltration of immune cells and, particularly, of a type of immune cell called macrophage.
"These macrophages cause a lot of inflammation and tissue damage in the lung."
Dr Ronacher said NIBR189 worked by blocking cholesterol receptors on immune cells, thereby stopping the signal for macrophages, a type of white blood cell, to leave the bloodstream.
She said in studies of mice with SARS-CoV-2, the researchers compared animals treated with the drug and others given a placebo. Those given NIBR189 had significantly reduced inflammation in the lungs, and less viral load.
'Other medications really important'
Human trials will depend on funding and getting the support of Novartis, with Dr Ronacher planning to start negotiations in the New Year.
Novartis originally developed NIBR189 as a treatment for blood cancers, but that research was discontinued, and the drug has never been marketed.
If NIBR89 is successful as a COVID-19 drug in human trials, which would take years, it would form a completely new class of drug that could have benefits beyond treating COVID-19.
"For instance, in transplant medicine … one of the main problems is that macrophages infiltrate the new transplant, and that can often contribute to rejection," Dr Ronacher said.
The research, conducted in collaboration with the University of Queensland and the University of Copenhagen, is published in the European Respiratory Journal.
It was funded by the Mater Foundation, the Australian Infectious Disease Research Centre, the Australian Respiratory Council and Diabetes Australia.
Infectious diseases director at Mater Health Services and physician Paul Griffin said while the research was "really exciting", much more work was needed to develop the drug before it could be added to a doctor's COVID-19 arsenal.
"To get from promising animal studies to human trials will take some years," Dr Griffin said.
"Success in animals doesn't necessarily correlate with success in humans."
However, Dr Griffin, who was not involved in the research, said it was important to improve the tools doctors had to combat the virus.
"The big thing about COVID … is it's very clear that it's not going to go away," he said.
Dr Griffin said while resistance to COVID-19 antiviral drugs had been raised as a possibility as the virus mutated, this was a "theoretical concern" at this stage.
"We're always worried about changes in viruses that are going to impact how the antivirals work," he said.
"We're not really seeing that yet based mainly on the mechanism of the main antivirals we're using but it would be foolish to get complacent and just assume that that's not going to be a big issue.
"Other medications … are going to be really important."
