Researchers identify potential tuberculosis drug

An experimental drug shows promise in fighting tuberculosis at a time when TB is becoming increasingly resistant to existing antibiotics, especially in poor countries, researchers said Wednesday.

If tests are successful and the compound, PA-824, is approved, it will be the first new TB-specific drug on the market in 30 years, said C. Kendall Stover, a scientist at PathoGenesis Corp., where it was developed.

Stover said it kills all of the drug-resistant forms of TB that have been tested to date, including the strains resistant to more than one drug.

Tests on mice and guinea pigs indicate PA-824 is at least as potent as today's first-line anti-tuberculosis drug, isoniazid, he said.

It also hits different molecular targets, affecting the bacteria's fatty cell wall and shutting down protein synthesis.

''This drug is sort of a Trojan horse,'' Stover said. ''The bacteria actually activates it and turns it into something that hits these targets and kills the bacteria.''

The findings were published in Thursday's issue of the journal Nature.

Tuberculosis can be contracted by inhaling droplets from an infected person's sneeze or cough.

TB, a major killer in the 19th and early 20th centuries, was once thought to be on the verge of eradication with the advent of powerful antibiotics in the 1940s. But it re-emerged in the 1980s in the aftermath of AIDS.

Today, it kills an estimated 2 million people a year. If treated correctly over a course of six months or more, most cases are curable. But if the patient stops treatment, the bacteria can grow resistant.

Lee Reichman, executive director of the New Jersey Medical School National Tuberculosis Center, said the new drug has the potential to kill TB even before symptoms appear.

If PathoGenesis decides to pursue the research, PA-824 could be ready for tests on people in two years.

On the Net: Nature: http://www.nature.com

PathoGenesis Corp.: http://www.pathogenesis.com