New
Test Can Rapidly Diagnose Multidrug-resistant Tuberculosis By
Liz Highleyman  | | Experts
discussed multiple-drug-resistant tuberculosis at a news conference Monday in
Geneva. Dr. Mario C. Raviglione, second from right, of the W.H.O., said a new
test was “revolutionary.” |
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Tuberculosis
(TB) is among the leading causes of death among people with HIV worldwide. In
recent years, several countries have seen outbreaks of multidrug-resistant TB
(MDR-TB) and even extensively
drug-resistant TB (XDR-TB) in HIV patients. On
June 30, the World Health Organization (WHO), Stop TB Partnership, UNITAID (an
international drug purchase facility), and the Foundation for Innovative New Diagnostics
(FIND) announced that they would jointly distribute a new diagnostic test for
MDR-TB that can quickly detect resistance to isoniazid and rifampicin, 2 of the
antibiotics most often used to treat the disease. Experts estimate that about
5% of all TB cases worldwide are resistant to these drugs. The
new line probe assay, which detects resistance-associated mutations in TB genetic
material (similar to how an HIV genotypic resistance test works) can produce results
in 2 days, compared with the several weeks or months it can take to incubate and
expose bacteria to various drugs (similar to how an HIV phenotype resistance test
works). 
More
rapid identification of drug-resistant TB strains will reduced delays in establishing
appropriate treatment, and in turn decrease transmission of resistant bacteria
and emergence of further resistance due to inadequate treatment. The
test, produced by Hain Lifescience and Innogenetics, is ineffective for patients
who cannot produce a sputum sample and cannot yet diagnose XDR-TB, though the
company is working to develop a version of the test that will do so. The
new test is expected to cost less than the older standard assay. It will be distributed
initially in Africa, then in several Central, South, and Southeast Asian countries
over the next few years. In addition to the test, the Stop TB Partnership also
plans to expand distribution of anti-TB drugs, in an effort to increase the percentage
of MDR-TB cases that are properly diagnosed and treated from 2% to 15%. Below
is the text of the WHO's recent press release describing the new test: New
Rapid Tests for Drug-Resistant TB for Developing Countries Geneva,
30 June 2008 -- People in low-resource countries who are ill with multidrug-resistant
TB (MDR-TB) will get a faster diagnosis -- in two days, not the standard two to
three months -- and appropriate treatment thanks to two new initiatives unveiled
today by WHO, the Stop TB Partnership, UNITAID, and the Foundation for Innovative
New Diagnostics (FIND).
MDR-TB is a form of TB that responds poorly to
standard treatment because of resistance to the first-line drugs isoniazid and
rifampicin. At present it is estimated that only 2% of MDR-TB cases worldwide
are being diagnosed and treated appropriately, mainly because of inadequate laboratory
services. The initiatives announced today should increase that proportion at least
seven-fold over the next four years, to 15% or more.
"I am delighted
that this initiative will improve both the technology needed to diagnose TB quickly,
and increase the availability of drugs to treat highly resistant TB," said
British Prime Minister Gordon Brown, who helped launch the Stop TB Partnership's
Global Plan to Stop TB in 2006 and whose government is a founding member of UNITAID.
"The UK is committed to stopping TB around the world, from our funding of
TB prevention programmes in poor countries, to our support of cutting edge research
to develop new drugs."
In developing countries most TB patients are
tested for MDR-TB only after they fail to respond to standard treatments. Even
then, it takes two months or more to confirm the diagnosis. Patients have to wait
for the test results before they can receive life-saving second-line drugs. During
this period, they can spread the multidrug-resistant disease to others. Often
the patients die before results are known, especially if they are HIV-infected
in addition to having MDR-TB.
The initiative comes just one week after
WHO recommended "line probe assays" for rapid MDR-TB diagnosis worldwide.
This policy change was driven by data from recent studies, including a large field
trial -- conducted by FIND together with South Africa's Medical Research Council
and National Health Laboratory Services -- which produced evidence for the reliability
and feasibility of using line probe assays under routine conditions.
"Five
months ago, WHO renewed its call to make MDR-TB an urgent public health priority,"
said WHO Director-General Dr Margaret Chan, "and today we have evidence to
guide our response. Based on that evidence, we are launching these promising initiatives."
Two
Projects
The
new initiative consists of two projects. The first, made possible through US$
26.1 million in funding from UNITAID, will introduce a molecular method to diagnose
MDR-TB that until now was used exclusively in research settings. These rapid,
new molecular tests, known as line probe assays, produce an answer in less than
two days.
Over the next four years -- as lab staff are trained, lab facilities
enhanced and new equipment delivered -- 16 countries will begin using rapid methods
to diagnose MDR-TB, including the molecular tests. The countries will receive
the tests through the Stop TB Partnership's Global Drug Facility, which provides
countries with both drugs and diagnostic supplies.
As part of the project,
WHO's Global Laboratory Initiative and FIND will help countries prepare for installation
and use of the new rapid diagnostic tests, ensuring necessary technical standards
for biosafety and the capacity to accurately perform DNA-based tests. One country,
Lesotho, is already equipped to start using these tests; Ethiopia is expected
to be ready by the end of 2008. The tests will be phased in during 2009-2011 in
the remaining 14 countries.
Under a second, complementary agreement with
UNITAID for US$ 33.7 million, the Global Drug Facility will boost the supply of
drugs needed to treat MDR-TB in 54 countries, including those receiving the new
diagnostic tests. This project is also expected to achieve price reductions of
up to 20% for second-line anti-TB drugs by 2010. All the countries receiving this
assistance have met WHO's technical standards for managing MDR-TB and already
have treatment programmes in place. Some will use grants from the Global Fund
against AIDS, Tuberculosis and Malaria to purchase the drugs.
"Through
the US$ 60-million support provided by UNITAID, these projects are expected to
produce significant results in diagnosing and treating patients as well as reducing
drug prices and the costs of diagnosis. These efforts illustrate the way in which
innovative financing can be deployed for health and development," said Philippe
Douste-Blazy, Chairman of UNITAID's Executive Board. |
7/08/08
Sources World
Health Organization. New rapid tests for drug-resistant TB for developing countries.
Press release. June 30, 2008. LK
Altman. Officials
Praise New Test for Drug-Resistant TB. New York Times. July 1, 2008.
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