Further pre-clinical testing of PharmAust’s (ASX: PAA) monepantel (MPL) and monepantel sulphone (MPLS) drugs continues to demonstrate antiviral activity in cultured cell infection models of SARS-CoV2 – the virus causing the global COVID-19 pandemic.
Following positive earlier results in both primate and non-primate cell cultures, Leiden University Medical Centre has carried out more tests and generated data indicating both MPL and MPLS demonstrate antiviral activity in non-human primates.
This paves the way for the drugs to be tested in human cells.
PharmAust noted the solubility issues with MPL and MPLS were challenging in in vitro systems, however it had addressed this in clinical trials when evaluating the drugs in other diseases. This has been mitigated by developing the MPL in tablet form.
“There are indications for an antiviral effect in these assays, but solubility issues under the conditions required for cell-based screening complicate analysis,” Leiden University Medical Centre associate professor and principal investigator Martin van Hemert explained.
“Additional experiments will now be performed on SARS-CoV-2 infected human lung cell lines,” he added.
PharmAust and Leiden University Medical Centre will continue the antiviral research with human cells to be evaluated in the next stage.
Meanwhile, production of MPL has begun in readiness for clinical trials.
Previous pre-clinical studies
In August, PharmAust revealed particle counts of SARS-CoV-2 could be suppressed between 90-95%.
Melbourne’s Walter and Eliza Hall Institute of Medical Research have been researching MPL and MPLS since April and tested the drugs on human Calu-3 lung adenocarcinoma epithelial cells in culture.
Repeat testing led to PharmAust announcing similar outcomes with MPL and MPLS found to reduce “virus burden regardless of laboratory, cell type, or timing of treatment”.
“MPL and MPLS have provided an antiviral effect against SARS-CoV-2 in every experiment conducted by PharmAust to-date,” PharmAust chief scientific officer Dr Richard Mollard said in September.
“Furthermore, MPL has exerted greater than 90% reduction in SARS-CoV-2 virus burden in five of six experiments in two independent laboratories using both monkey and human cell lines.”
Dr Mollard said it did not appear to matter if the MPL or MPLS were administered pre or post infection.