Data reveals urgent need to scale up treatment Results from the largest multi-country implementation of a new rapid tuberculosis (TB) diagnostic test reveal an urgent need to address the growing global crisis of drug-resistant tuberculosis (DR-TB).
The data, presented by Médecins Sans Frontières (MSF) at the 43rd annual Union World Conference on Lung Health in Kuala Lumpur, was collected from 25 MSF projects in 14 countries over approximately 18 months. It shows an overall increase of 41 per cent in laboratory-based diagnosis of tuberculosis using the new test, known as Xpert MTB/RIF. This was in comparison to the TB test still most commonly used, sputum smear microscopy, that had a high variability across projects – the increase in lab confirmation ranged from 23 per cent to 109 per cent. The Xpert MTB/RIF test, which provides results within two hours, also detects whether a person’s tuberculosis strain is resistant to rifampicin, one of the primary drugs used in treatment. 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. In an MSF project in Swaziland, the time between when a patient’s sample was collected to when they started 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,” says Helen Bygrave, a physican and 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.”
Data from the implementation of Xpert MTB/RIF did reveal problems with inconclusive test results (the frequency of inconclusive results was higher than six per cent in more than half the projects). As well, a simpler and easier-to-use ‘point-of-care’ test is still needed. However, 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 group of DR-TB patients show a cure rate of only 53 per cent (slightly higher than the global average of 48 per cent). This is despite MSF having tailored community-based treatment models that aim to ease the burden on people’s lives. Two new drugs to treat tuberculosis – 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 people who need them, and made affordable and accessible to patients in developing countries.