In a major development scientists have identified an existing drug that is effective against Entamoeba histolytica, the parasite responsible for causing amebic dysentery and liver abscesses that is responsible for the death of more than 70,000 people worldwide every year.
Using a high-throughput screen for drugs developed by them, a collaboration of scientists from UC San Diego School of Medicine, UC San Francisco and Wake Forest School of Medicine discovered that auranofin - a drug approved by the US Food and Drug Administration 25 years ago for rheumatoid arthritis - is highly effective in targeting an enzyme that protects amebae from oxygen attack (thus enhancing sensitivity of the amebae to reactive oxygen-mediated killing).
Sharon L. Reed, MD, professor in the UCSD Departments of Pathology and Medicine and James McKerrow, MD, PhD, professor of Pathology in the UCSF Sandler Center for Drug Discovery were lead of the study.
Entamoeba histolytica is a protozoan intestinal parasite which is responsible for causing amebiasis in human and it is world’s fourth leading cause of death from protozoan parasites. It is enlisted in the UK National Institutes of Health as a category B priority biodefense pathogen. Presently the treatment for the drug is based on metronidazole, which comes with its own side effects.
The potential to the drug is also a matter of concern.
"Because auranofin has already been approved by the FDA for use in humans, we can save years of expensive development. In our studies in animal models, auranofin was ten times more potent against this parasite than metronidazole," Reed has been quoted as saying.
In a mouse model of amebic colitis and a hamster model of amebic liver abscess, the medicine significantly reduced the number of parasites, damage from inflammation, and size of liver abscesses.
"This new use of an old drug represents a promising therapy for a major health threat, and highlights how research funded by the National Institutes of Health can benefit people around the world," Reed has been quoted as saying.
The drug has been given “orphan-drug" status (which identifies a significant, newly developed or recognized treatment for a disease which affects fewer than 200,000 persons in the United States) and UC San Diego hopes to conduct clinical trials in the coming days.
The results of this study will be published in the May 20, 2012 issue of Nature Medicine.
--with inputs from ANI