An international team of scientists has developed an experimental antiviral therapy to treat COVID-19 which has been shown to reduce the viral load by 99.9 per cent and improve the rate of survival in mice.
Developed by researchers from the Menzies Health Institute Queensland (MHIQ) at Griffith University and the Beckman Research Institute in Los Angeles, the next-generation approach to antiviral therapy has been designed to treat the original virus that causes COVID-19 and any new variants that may arise in the future.
It builds on existing antiviral treatments like Tamiflu, zanamivir and remdesivir that reduce symptoms of COVID-19 and help people recover earlier.
The therapy uses gene-silencing RNA technology called siRNA (small-interfering RNA) to attack the virus' genome directly, which stops the virus from replicating, as well as lipid nanoparticles designed at Griffith and the Beckman Research Institute's City of Hope centre to deliver the siRNA to the lungs - the critical site of infection.
"Treatment with virus-specific siRNA reduces viral load by 99.9 per cent. These stealth nanoparticles can be delivered to a wide range of lung cells and silence viral genes,'' MHIQ co-lead researcher Professor Nigel McMillan said about the team's research published in scientific journal Molecular Therapy.
"Treatment with the therapy in SARS-Cov-2 infected mice improved survival and loss of disease. Remarkably, in treated survivors, no virus could be detected in the lungs.''
Co-lead researcher from both City of Hope and Griffith University Professor Kevin Morris said the experimental treatment is able to adapt to new COVID-19 variants and can be stored at room temperature.
"This treatment is designed to work on all betacoronaviruses such as the original SARS virus (SARS-CoV-1) as well as SARS-CoV-2 and any new variants that may arise in the future because it targets ultra-conserved regions in the virus' genome," Professor Morris said.
"We have also shown that these nanoparticles are stable at 4°C for 12 months and at room temperature for greater than one month, meaning this agent could be used in low-resource settings to treat infected patients."
The results suggest that siRNA-nanoparticle formulations can be developed as a therapy to treat COVID-19 patients, as well as used for future coronavirus infections by targeting the virus' genome directly.
"These nanoparticles are scalable and relatively cost-effective to produce in bulk," Professor Morris said.
"This work was funded as an urgent call by Medical Research Futures Fund and is the type of RNA medicine that can be manufactured locally in Australia."
Updated at 12.20pm AEST on 18 May 2021.
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