A repeat preliminary evaluation of PharmAust’s (ASX: PAA) lead cancer drug monepantel and monepantel sulfone has found it can reduce transmission in cells infected with the current SARS-CoV-2 strain of coronavirus.
Replication of an in vitro virus infectivity experiment carried out earlier this month has used the same median tissue culture infectious dose (TCID50) method and confirmed initial findings.
The repeat experiments were conducted by virologists at Melbourne’s Walter and Eliza Hall Institute of Medical Research and again demonstrated that infectivity of SARS-CoV-2 virus particles can be suppressed by up to 95% in cell cultures treated with either monepantel or monepantel sulfone.
Moves are now being made to further explore the significance of the experiments, including comparing monepantel or monepantel sulfone with other mTOR pathway inhibitors such as rapamycin.
Comparisons will also be made with current anti-viral treatments such as remdesivir which have been authorised by the US Food and Drug Administration for emergency use to treat COVID-19.
PharmAust chief scientific officer Dr Richard Mollard said the repeat results validate the initial test, forming strong grounds for progressing the drug to the next step.
“Demonstrating twice that infectivity of SARS-CoV-2 virus particles can be suppressed by up to approximately 95% in cell cultures is a remarkable outcome,” he said.
“The reproducible nature of this work in vitro paves a propitious pathway for continued evaluation and we are looking forward to building on these experiments.”
PharmAust is now planning a phase I trial of monepantel and monepantel sulfone on a small number of human patients with COVID-19.
Oral monepantel has previously been evaluated in human patients with treatment-resistant cancer tumours.
A phase 1 clinical trial in 2015 showed the drug could suppress or reduce tumours in patients where first line therapy had failed, giving PharmAust confidence that it could act against markers which have been correlated with aggressive cancer characteristics such as growth, invasion and metastasis.
Monepantel also demonstrated a robust safety profile when compared with other established anti-cancer drugs but a series of adverse events on the test group including nausea, vomiting, diarrhoea and decreased appetite pointed to its poor palatability and PharmAust worked on a reformulation to make it more commercially attractive.
The company subsequently appointed UK-based Juniper Pharma Services and Canada’s BRI Pharmaceutical Research to reformulate monepantel for further studies.
In 2019, PharmAust signed an agreement with a major US-based research organisation to commence phase I clinical trials of the newly-formulated tablet.
At midday, shares in PharmAust were trading 31.82% higher at $0.145.