The repurposing of an old drug once used to treat a bladder condition now means there’s a treatment option for people with muscle and joint pain associated with arboviruses such as Ross River virus.
The intramuscular injection pentosan polysulfate sodium (PPS) (Zilosul) is now available under the TGA’s Special Access Scheme for the treatment of Ross River virus infection, ahead of Phase 2 clinical trials due to start in Queensland later in the year.
Researcher Dr Lara Herrero, from Griffith University’s Institute for Glycomics, told the limbic the special access acknowledged the robust safety profile of PPS in humans and the lack of treatment options for debilitating Ross River virus infections.
“PPS has been used safely in humans for decades, with an oral formulation of the drug available in Australia to treat interstitial cystitis,” she said.
“Our pre-clinical studies have shown that PPS can significantly reduce inflammation and alleviate symptoms in Ross River infections but that the most efficient delivery method is by IM injection.”
Dr Herrero said she believed the drug would be effective in acute, sub-acute and chronic stages of the infection.
“PPS is not an antiviral drug – it doesn’t stop replication of the virus – so we’re not really targeting the viraemic phase of the infection. What we’re interested in is the immunomodulatory effects of these viruses,” said Dr Herrero who became interested in alphaviruses after becoming infected with Ross River virus in 2004.
Histological studies in animals have shown extensive joint inflammation, pannus-like formation, thinning of articular cartilage, and other features similar to those seen in rheumatoid arthritis.
PPS reduced the infiltration of immune cells in muscles and joints, reduced pro-inflammatory factors and increased anti-inflammatory cytokines such as interleukin- 10. It also significantly reduced clinical disease scores.
Dr Herrero said PPS had also been shown effective against Chikungunya virus infections in the laboratory and would most likely be effective against Barmah Forest virus.
While Chikungunya was not yet endemic in Australia, the emerging disease has spread rapidly in Africa, Asia, Europe, the US, Indian and Pacific Ocean islands.
Griffith University and Paradigm Biopharmaceuticals have entered into a commercialisation agreement under which Paradigm will fund and undertake the necessary clinical trials. If the trials are successful Griffith University will receive a royalty on Paradigm’s sale of the drug to treat viral arthritis.