Health

The Spread of Drug Resistant Tuberculosis

The developed world is getting worried about Tuberculosis. About time.

TB killed an estimated 1.7 million people in 2004 (see WHO factsheet). An estimated third of the world’s population is suspected to be currently infected, with new infections every second. But if the numbers weren’t worrying enough, the fact that medicines no longer are working should be.

50 years ago, there were no medicines to cure TB. Over the past decade, however, even as widespread use of medicines has stabilized the incidence of TB worldwide, TB itself has become resistant to medicines. Every country has strains resistant to individual medicines.

The new threat, which is worrying the global healthcare community is TB resistant to multiple drugs. An estimated 18% of TB cases worldwide are considered Multi-Drug Resistant TB (MDR-TB cases are resistant to 2 main line TB drugs). Going even further, parts of Central Asia and the former Soviet Union also have Extensive Drug Resistance TB (XDR-TB cases are also resistant to three of the 2nd line treatments). XDR-TB is considered virtually untreatable.
Earlier this month, the WHO expressed concern over the rise of MDR and XDR-TB, and its implications on their Stop TB strategy. And today, the Red Cross and WHO together warned that the areas with the highest incidence of drug resistant TB border the EU, in Eastern Europe and Central Asia.

Finally, the problem becomes even bigger if one considers the investment being done in research for TB medicines. As previously pointed out, of the approved New Chemical Entities in USA and Europe between 1979-99, only 3 (0.2%) targeted TB.

What this means is that not only is TB becoming resistant to existing drugs, we have few if any drugs in development to tackle the disease. This is another, and excellent example of the 10/90 health gap – the lack of investment in a disease that places a significant health burden, but selectively on the developed world.

There is a silver lining here, and a catch for the developed world. With the EU expanding, many of these Eastern European and Baltic nations that are seeing MDR TB, will enter the EU over the next decade. The risk of the disease migrating to more affluent regions in Europe and eventually the USA will increase. And with that will come a potential market for big pharma, leading to the attendant investments to develop effective new cures.