E-DRUG: Study 'proves' efficacy of drug for Chagas disease
[Copied as fair use from SciDev. KM]
Study 'proves' Chagas drug efficacy
6 May 2008
Research shows that the main drug treatment for Chagas disease can
completely rid chronically infected hosts of the disease-causing
The researchers say this provides the first evidence that the drug can
be so effective. The study also suggests a new way of assessing the
efficacy of drugs for the disease.
Current therapies are limited in their use due to potentially severe
side effects and doubts surrounding their effectiveness. Some drug
treatments are thought to be effective in less than 50 per cent of
But the new study found that benznidazole - the principle drug used to
treat Chagas disease - can completely clear Trypanosoma cruzi parasites
in a mouse model.
"I would hope that the proof of efficacy reported in our study will
prompt wider use of the available drugs to treat chronically infected
individuals," says Rick Tarleton, lead author of the study from the
US-based University of Georgia.
The study also measured the population of CD8 T cells - a type of immune
cell - specific to the parasite in the blood. The researchers found that
successful treatment of the parasite led to the emergence of a stable
population of T. cruzi-specific T cells. These were able to mount an
effective immune response against re-infection.
The researchers suggest that monitoring CD8 T cells could be a useful
marker to evaluate the efficacy of new Chagas drugs in humans - a marker
which they say is lacking in current Chagas drug development. If a
treatment works, T cells specific to T. cruzi would be detected.
"Our work shows that we have an experimental model and a 'gold standard'
treatment [beznidazole] against which to compare other new drugs. If
they do not work as well as benznidazole, they probably should not be
pursued in human trials," says Tarleton.
The research was published in the online edition of the journal Nature
Chagas disease affects 16-18 million people throughout Latin America.