Determined to become one of the first companies to develop an active treatment for COVID-19, oncology company PharmAust (ASX: PAA) has reported it has successfully repeated a second round of in-vitro anti-viral confirmatory testing, demonstrating anti-SARS-CoV-2 activity of both its monepantel (MPL) and monepantel sulfone (MPLS) drug candidates.
In August, PharmAust published positive early results showing that MPL can inhibit the progression of SARS-CoV-2, according to research conducted by the Walter and Eliza Hall Institute of Medical Research in Melbourne, Australia.
The study used MPL and MPLS on human Calu-3 lung adenocarcinoma epithelial cells in culture and showed virus particle counts of SARS-CoV-2 were suppressed by between 90% and 95%.
Currently, there is a significant dearth of options for treating COVID-19. To date, Remdesivir is the only drug approved by the US Food and Drug Administration (FDA) for the treatment of COVID-19 infections.
The FDA approval for the clinical use of Remdesivir is under emergency-use authorisation, corroborated by a study demonstrating the capacity of the drug to reduce COVID-19 infection recovery time from 15 to 11 days.
However, as a worrying development for public healthcare officials, recently completed research involving 105 hospitals in the US, Europe and Asia concluded that Remdesivir had “scant benefit” in patients with moderate COVID-19 infections.
The revelation means there is a wide scope for effective drugs to be developed over the coming years to fill the supply gap – a gap PharmAust wants to fill by conducting a full set of Phase 1-3 trials with Phase 1 human trial set to commence shortly.
Moreover, Remdesivir can only be administered intravenously in a hospital setting, whereas MPL has been developed in a tablet form for oral ingestion prior to intensive care.
“This means patients could be treated earlier when they first test positive, rather than when they reach hospital in serious condition,” PharmAust executive chairman Dr Roger Aston told Small Caps.
In a statement to the market this morning, PharmAust said tests demonstrated that MPL and MPLS “reduced SARS-CoV-2”, the causative agent of COVID-19.
The news raises hope that PharmAust can repurpose MPL and MPLS as effective drugs against coronavirus given their proven ability to reduce “virus burden” regardless of laboratory, cell type or treatment timing, whether it be prior or post-infection.
More specifically, PharmAust said its experiments, conducted at 360biolabs, showed MPL and MPLS inhibited virus burden by up to 99% and 75%, respectively. The data for MPL was notably similar to the 100% inhibition demonstrated for Remdesivir used as a positive control, although at differing concentrations of the drug, the company said.
“MPL and MPLS have provided an anti-viral effect against SARS-CoV-2 in every experiment conducted to date,” Dr Mollard said.
“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. It does not appear to matter if MPL or MPLS are added pre or post virus infection,” he added.
According to PharmAust, MPL may have a distinct advantage over many other drugs currently being developed or repurposed by other pharmaceutical companies, given its previous use in human clinical trials and its strong safety profile.
Ultimately, the potential benefit of MPL and MPLS needs to be determined in Phase 2 and Phase 3 trials – a step PharmAust is now preparing to take via a clinical trial program in humans.
Vet partner withdraws from drug development option
In a separate announcement on Wednesday, PharmAust advised the market that US veterinary pharmaceutical company Elanco US Inc has chosen not to proceed with exercising its option to develop MPL as a cancer treatment for dogs.
This is disappointing news for the company as a deal with US$9 billion NASDAQ-listed Elanco had been on the cards since 2018 and said the market expected that positive outcomes from a Phase 2 canine trial would trigger Elanco to exercise the exclusive licensing option.
PharmAust did not disclose a reason for Elanco’s withdrawal, noting that MPL is a novel, potent and safe inhibitor of the mTOR pathway – a key driver of cancer – and had been evaluated in human and dogs trials as a well-tolerated drug that produced a significant reduction in key prognostic biomarkers.
However even if Elanco did want to exercise, the parties may have not reached agreement on upfront payment and royalty level. Elanco is also busy bedding down its Bayer animal health brand acquisition.
Chairman Dr Aston said there were some positives to take from the news.
“We are now free to talk to multiple potential cancer partners. Monepantel is potent in multiple uses and will find a place,” Dr Aston added.