Fighting TB from every angle: New breakthroughs in detection and treatment

OpenForum | July 24, 2009 | 0 Comments

Two new studies suggest promising methods of detecting and treating TB despite discouraging reports about the increasing global prevalence of multi-drug resistant tuberculosis (MDR-TB) and extensively-drug-resistant tuberculosis (XDR-TB). The first study underlines the importance of follow-up visits in detecting TB among immigrants and asylum seekers entering the US. While screening is crucial in preventing the spread of TB, identifying TB-infected persons can be difficult; blood or sputum smear testing can take weeks to complete and has only a 50% accuracy rate. Screening of immigrants and asylum seekers is especially important, as the TB rate in foreign-born persons is 9.7 times higher than in US-born persons. Researchers found that follow-up visits with immigrants after their entry into the US were effective in identifying and reducing the number of TB patients in the US.

The World Health Organization estimated 9.27 million cases of TB in 2007, a significant increase from 6.6 million cases in 1990. The majority of these cases are found in the South-East Asia region, which accounts for 34% of all new cases, and sub-Saharan Africa, which has the highest TB mortality rate in the world. People with health conditions that weaken the immune system like HIV infection, substance abuse, or malnutrition are more susceptible to the disease. A recent study showed that one-fourth of all TB-related deaths were in patients who were also HIV-positive.

No new classes of TB drugs have been created since the 1960s, and few clinical trials have been conducted using modern regulatory standards. To address this need, research groups are focusing on novel approaches to TB therapeutics. The Global Alliance for TB Drug Development (TB Alliance) recently announced four research partnerships that will explore new methods of treating drug-resistant TB. One of these collaborations, led by Anacor Pharmaceuticals, will provide any new compounds developed to the TB Alliance royalty-free.

Another recent study has found that in an eight week exploratory trial with MDR-TB patients in South Africa, the experimental drug TMC207, in combination with the standard MDR-TB drug cocktail, cleared TB bacterial traces in the sputum of 48% of patients, as compared to 9% of patients given only the standard cocktail. The experimental drug appeared to work faster than standard MDR-TB drugs in clearing TB, possibly because of its unique mechanism of action. Current treatment courses last for at least 18 months because MDR-TB drugs take more time to effectively clear the disease. For example, 81% of MDR-TB patients in Peru treated with DOTS-Plus therapy were cured after four months, versus only 40% after two months. Further proof-of-efficacy studies are being conducted with TMC207 now, and will demonstrate if it is effective as a long-term treatment for various types of TB. If approved, this drug could be a significant advance over current treatments, which can be lengthy and toxic.

Comments

Nothing yet.

OpenForum – a blog by the Health and Human Rights community