Auranofin ‘Promising’ to Treat Amoebic Dysentery

Auranofin, a common and cheap drug currently used for arthritis, could help fight against parasitic organisms responsible for amoebic dysentery, according to US researchers.

Amoebic dysentery is caused by Entamoeba histolytica, which infects the bowels.  It results in severe diarrhoea as well as bloody stools.  More than 70,000 people globally are believed to die from the infection every year, most of which are in developing countries.

US scientists tested 910 drugs, a number of which had previously been demonstrated to be safe for human use, on amoebas in the laboratory.

Studies on animals demonstrated that Auranofin was 10 times more effective than the existing treatment, metronidazole, at killing Entamoeba histolytica.  Additional research will be required on humans, but researchers noted that it looks promising.

Auranofin (ridaura) contains a medical form of gold and fights rheumatoid arthritis by reducing inflammation.  The new trials demonstrate that it could be used to treat amoebic dysentery and possibly Giardia.  Both infections cause dysentery symptoms which include stomach cramps and severe diarrhoea.

Quicker to develop

Auranofin has been prescribed to patients with rheumatoid arthritis since 1985.  The fact that the drug has already been confirmed to be safe will reduce the timeline and the cost required to develop it as a dysentery treatment.

Prof James McKerrow, one of the researchers from the Sandler Center for Drug Discovery at the University of California, San Francisco, mentioned that when they are “looking for new treatments for the developing world, we start with drugs that have already been approved.  If we can find an approved drug that happens to kill these organisms, we’ve leapfrogged the development process that goes into assessing whether they are safe, which also makes them affordable throughout the world.”

Lead researcher, Prof Sharon Reed, from the University of California, San Diego added that “this new use of an old drug represents a promising therapy for a major health threat.”

Dr Graham Clark, a reader in molecular parasitology at the London School of Hygiene & Tropical Medicine, observed that although metronidazole was very effective, it had side effects and was not always effective.

He added “the work presented in this paper is particularly useful as it identifies an existing drug, auranofin that has already been tested and approved for use in humans, which seems to be at least as effective as metronidazole.”

“Although auranofin has to date only been tested in animal models of amoebic disease, this means that there is now a potential alternative treatment for individual cases where metronidazole fails to cure the infection or in the event resistance to metronidazole emerge as a clinical problem in the future,” he concluded.

Links:
www.bbc.co.uk
www.nature.com

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