Preliminary clinical work by PharmAust (ASX: PAA) on the effects of its lead candidate monepantel and monepantel sulfone on cells infected with COVID-19 has demonstrated potential suppression of the virus by up to 95%.
In vitro experiments conducted by Melbourne’s Walter and Eliza Hall Institute of Medical Research using COVID-19 viral infections of African green monkey vero cells aimed to test the total amount of virus released from cells into the culture media and measure the infectivity of newly-released virus during treatment with compounds.
Routine assays called median tissue culture infectious dose (TCID50) and quantitative polymerase chain reaction (qPCR) were used.
The former measures how a virus’ life cycle has been inhibited, while qPCR can determine whether a virus is getting made and released but cannot tell if that virus is capable of infecting new targets.
Virologists were able to show the infectivity and replication of COVID-19 particles can be suppressed by between 50% and 95% in tissue cell cultures.
They demonstrated that monepantel and monepantel sulfone can reduce the capacity of the virus to replicate and mature into infectious virus particles.
Of note, relatively low concentrations of monepantel were found to block the infectious capacity of the virus in tissue culture.
Phase 1 success
Monepantel is a novel, potent and safe inhibitor of the mTOR pathway which is a key driver of cancer.
Phase 1 clinical trials last year found the drug to be well-tolerated in humans and dogs, producing a significant reduction in key prognostic biomarkers.
Based on the latest findings, PharmAust has made moves to broaden and extend its intellectual property in the area of anti-viral activity through the filing of a patent application specifically covering monepantel in the treatment of the virus.
PharmAust and the Walter and Eliza Hall Institute signed a materials transfer agreement in April whereby PharmAust would supply quantities of monepantel and monepantel sulfone for the COVID-19 study.
Under the agreement, PharmAust will own all intellectual property results and rights generated from the study, and will pay the institute a nominal fee for its work.
PharmAust chief scientific officer Dr Richard Mollard said the early signs demonstrating that monepantel can block virus infectivity in vitro were encouraging.
“We are excited by this early data set and looking forward to continuing this project with the Walter and Eliza Hall Institute,” he said.
“Continuation will involve repetition of these experiments for validation and comparisons with other mTOR inhibitors and treatments currently in the clinic.”