Three-year study searches for new biological markers to measure parasite clearance in Chagas’ disease
22 November 2012
Chagas' disease infects approximately 8 million people worldwide and is the leading parasitic killer in the Americas, where it causes more deaths than malaria. Although treatments are available to kill the parasite, their efficacy is inconsistent, and they have to be taken for many years because of the chronic nature of the disease.
Patients and doctors are often sceptical regarding the benefits, particularly since there is currently no easy and reliable test to measure whether treatment has successfully rid the patient of the parasite. A robust test to assess disease burden is therefore urgently needed to help expand treatment, as well as to provide a valuable tool for accelerating the evaluation of new drugs in clinical trials.
The funding from the Wellcome Trust will be used to conduct the first large-scale study involving treatment of non-human primates (macaques) who were naturally infected with the parasite that causes Chagas' disease while living in an outdoor environment.
The animals will be treated with three different drug regimens compared with placebo and tested for clearance of the parasite over a period of 12 months after treatment using a range of blood tests. The primary goal of the study is to see whether these tests can accurately measure parasitological cure.
"We need to be able to tell patients whether their treatment has worked," said Dr Graeme Bilbe, Research and Development Director for DNDi. "The results of this study could encourage treating more patients now, with what we have, and facilitate future clinical trials of new treatments for chronic Chagas' disease patients."
The study will begin within months and will be coordinated by DNDi with partners at the Texas Biomedical Research Institute and the Center for Tropical and Emerging Global Diseases at the University of Georgia. Texas Biomed will conduct the experimental protocols with the animals and conduct biomarker analysis, and the University of Georgia will also perform biomarker analysis. The biological samples collected in the study will be stored and made available to other researchers to facilitate future biomarker discovery efforts.
Chagas' disease is a chronic, systemic, parasitic infection caused by the parasite Trypanosoma cruzi. It is potentially fatal and a leading cause of heart failure in Latin America, resulting in frequent and prolonged hospitalisation, the use of pacemakers and defibrillators, and heart transplants.
The disease causes loss of productivity among tens of thousands of working-age adults across Latin America, with over a billion US dollars in estimated economic losses annually. As a result of worldwide population flow, Chagas' disease is no longer confined to Latin America, and patient numbers are growing in the USA, Europe, Australia and Japan.
Image: A trypanosome (yellow) among host red blood cells. Credit: Gull Lab, Sir William Dunn School of Pathology/Wellcome Images.