Scientists are making progress on TB—again.
For a disease that scientists conquered 40 years ago, tuberculosis has made an astonishing comeback. Today relatively recent strains of TB that resist antibiotics have driven the death toll from the disease to 2 million people a year. TB is also responsible for the deaths of a third of HIV/AIDS sufferers worldwide, according to the New York-based Global Alliance for TB Drug Development, because HIV often acts as a catalyst for latent TB infections. "What we need to do is work with completely new drugs," says Maria Freire, the Alliance's CEO.
The urgency of the problem has sent researchers back to the lab, and now they're starting to come up with leads. Last week Belgian scientist Koen Andries at Johnson & Johnson in Belgium announced in the journal Science that he and his colleagues had come across a promising compound that could be effective against resistant strains of TB. The new compound—christened R207910—attacks Mycobacterium tuberculosis, the bacterium that causes TB, in a new way: by neutralizing an enzyme responsible for supplying energy to the bacterium.
What's especially promising about R207910 is that it could potentially reduce treatment time. Current antibiotic regimens require patients to pop pills for as long as eight months. That's partly why TB has developed resistance to the drugs—patients begin to feel better and stop their course of treatment too soon, giving the bugs a chance to breed resistant strains. When tested on mice, R207910 seemed to cut treatment time by half. Clinical trials on humans are just getting under way, though the company wouldn't say where the compound was being tested or when the tests would be done.
There are other efforts afoot to come up with more TB drugs as well. The Global Alliance and the drug company Novartis are working on a family of compounds known as PA-824, which had already been identified as a possible component for cancer treatment. New research shows that it could also be successful at undermining M. tuberculosis by targeting its protective cell wall. Since the compound uses a new mechanism to attack cells, scientists think it will work against resistant strains of TB. "And hopefully we can find new regimens that, in all likelihood, will work together as combination therapy and treatments that will last two months or less," says Freire. She's cautiously optimistic that a new drug could be out of clinical trials in five years. After that, it will be a matter of making the new drugs affordable and accessible for TB sufferers. And that's a task for the politicians, not the scientists.