Queensland researchers and a US team have developed an antiviral therapy that has killed off the COVID-19 viral load in infected mice by 99.9 per cent.
- Gene-silencing RNA technology is used to destroy the COVID-19 virus genome directly and stops the virus replicating
- The treatment could be available as early as 2023, depending on the next phase of clinical trials
- The research has been published in Molecular Therapy
Lead researcher Professor Nigel McMillan, from Griffith University, called it a “seek and destroy mission” where the therapy genetically targeted the potentially deadly virus.
The international team of scientists from the Menzies Health Institute Queensland and the US research institute City of Hope began their collaborative research last April.
They used a “next-generation” viral approach using gene-silencing RNA technology to attack the virus genome directly, which stops the virus spreading.
“It causes the genome to be destroyed and the virus can’t grow anymore — so we inject the nanoparticles and they go and find the virus and destroy it just like a heat-seeking missile,” Professor McMillan said.
“This is the first time we have been able to package this up as a particle, send it through the blood stream to attack the virus.
Not a cure, but will save lives
Professor McMillan said although it was “not a cure”, it was a therapy that could reduce the amount of virus in the lungs by 99.9 per cent, “so it is almost as good as a cure”.
“It is really for those people who are suffering for example in ICU, where vaccines are too late,” he said.
Professor McMillan said traditional antivirals like zanamivir and remdesivir reduced symptoms and helped people recover earlier.
“Where this therapy actually stops the virus replicating, so the body can repair itself and the recovery will be much quicker,” he said.
“It allows us to treat those people who are suffering from the virus who are very sick, or those who may perhaps be in danger of being exposed to the virus, such as those in hotel quarantine.
“They’d be assured they won’t suffer from the disease itself.”
He said US chief medical adviser Anthony Fauci had said while there were vaccines, there was a lack of direct therapeutics against the virus.
“This is really one of the first cabs off the rank in terms of a direct therapeutic, so we are really excited,” Professor McMillan said.
“It is an injection that would be delivered daily into someone in ICU for four or five days, or as a single injection for someone just exposed.”
He said the treatment could be available as early as 2023, depending on the outcomes of the next phase of clinical trials.
“Remember this virus is not going away — we are going to be living with it forever now,” Professor McMillan said.
Co-lead researcher Professor Kevin Morris said the treatment was designed to work on all betacoronaviruses such as the original SARS virus (SARS-CoV-1) as well as SARS-CoV-2 and MERS.
“And any new variants that may arise in the future because it targets ultra-conserved regions in the virus’s genome,” Professor Morris said.
“We have also shown that these nanoparticles are stable at 4 degrees Celsius 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 siRNA-nanoparticle formulations could be developed as a therapy to treat COVID-19 patients, as well as used for future coronavirus infections by targeting the virus’s 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.”
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