Geneva/Kuala Lumpur — Results from the largest multi-country implementation of the new rapid tuberculosis (TB) diagnostic test reveal an urgent need to address the growing global crisis of drug-resistant TB (DR-TB), according to the international medical humanitarian organisation Médecins Sans Frontières (MSF).
The data, presented at the 43rd annual Union World Conference on Lung Health in Kuala Lumpur, was collected from 25 MSF projects in 14 countries over a nearly 18-month period. It shows an overall 50 per cent increase in laboratory-based diagnosis of TB using Xpert MTB/RIF compared to the TB test still most commonly used, sputum smear microscopy, with a high variability across projects (increase in lab confirmation ranged from 10 per cent to 115 per cent).
The Xpert MTB/RIF test, which provides results within two hours, also detects whether a person's TB strain is resistant to one of the primary TB drugs, rifampicin. In an MSF project in Zimbabwe, preliminary results showed that the introduction of the test resulted in a near quadrupling of DR-TB cases being diagnosed; and in an MSF project in Swaziland, the delay between the time the patient's sample was collected to starting DR-TB treatment was reduced by 79 per cent, from 65.9 days to 13.9 days.
"This new TB test is helping expose the true size of the drug-resistant TB epidemic and get people on treatment faster," said Dr Helen Bygrave, HIV/TB Specialist with MSF in South Africa. "But patients and doctors alike still struggle with the long and painful treatment for drug-resistant TB that only manages to cure about one in two people."
While data from the implementation of Xpert MTB/RIF using revealed problems with inconclusive test results (the frequency of inconclusive results was higher than 6 per cent in more than half the projects), and a simpler and easier-to-use 'point-of-care' test is still needed, the test clearly represents a significant advance for timely TB and DR-TB diagnosis, and its roll-out should be encouraged.
In addition to making testing more widely available, a major concern is the treatment of DR-TB itself. Patients must undergo two-year treatment with drugs that cause intolerable side effects (ranging from persistent nausea to psychosis and deafness). Results from MSF's cohort of DR-TB patients show a cure rate of only 53 per cent (slightly higher than the global average of 48 per cent). This despite MSF having tailored community-based treatment models that aim to ease the burden on people's lives.
Two new drugs to treat TB-the first to be developed for the disease in almost 50 years-are expected to come to market in 2013 and are both active against drug-resistant forms of the disease. Their introduction represents a critical opportunity to improve DR-TB treatment and every effort should be made to ensure they are used in a way that allows treatment to be shortened and made more tolerable for patients, and made affordable and accessible to patients in developing countries.
"With new medicines for drug-resistant TB at the doorstep for the first time in half a century, the global health community can't afford not to seize the opportunity of a lifetime by stopping drug-resistant TB from spiraling out of control," said Dr Manica Balasegaram, Executive Director of MSF's Access Campaign.