Experimental TB compound might make effective drug

WASHINGTON (Reuters) - Researchers who have been trying to design new drugs to fight tuberculosis said on Thursday they think they have a winner -- a new compound that stops the TB bacillus from building cell walls.

Tests in mice showed the compound could kill off the bacterial infection with no apparent side-effects, the New Medicines for Tuberculosis Consortium reported in the journal Science.

They hope to take the compound, called BTZ043, into further testing. It takes years to bring new compounds into human tests, and then years of human testing to show they can produce safe and effective drugs.

But TB experts agree new drugs are needed to fight tuberculosis, which infects up to a third of the world's population and kills 1.7 million people a year.

Tuberculosis can be cured with a cocktail of drugs that patients usually must take for months. The current standard regimen requires four antibiotics -- all more than 40 years old -- taken for six to nine months.

Drug-resistant forms of TB take as long as two years to treat with second-line drugs, which can cause severe side-effects. And a new strain called extensively drug-resistant TB or XDR TB sometimes cannot be cured with any existing antibiotics.

Vadim Makarov of the Bakh Institute of Biochemistry in Moscow and colleagues at the TB consortium noted that sulfur was common in the drugs that do work against TB.

In the study, they synthesized several sulfur-containing compounds, tested them against bacteria and fungi, and narrowed their search down to a class called nitro-benzothiazinones.

One of them, BTZ043, killed the Mycobacterium tuberculosis bacteria in test tubes and reduced levels in the lungs and spleens of infected mice, with no side-effects, after one month of treatment.

The compound appears to stop the bacterium from building cell walls, they reported in Science. "BTZ is a candidate for development into a sterilizing TB drug," they wrote.

(Reporting by Maggie Fox; editing by Todd Eastham)