The experimental therapy is the product of a consortium of non-profit organisations, US government agencies and two drug makers who have come together to beat a disease that disproportionately afflicts people in developing countries.

Led by the New York-based Global Alliance for TB Drug Development, the group announced on Tuesday that it has begun testing 53 healthy volunteers at a clinic in Lincoln, Nebraska, to determine whether the drug is safe.

Researchers hope to have the drug approved for mass distribution within six years, said Dr Mel Spigelman, head of the alliance's research and development.

Antibiotics can cure tuberculosis, but treatment involves a regimen of up to four drugs administered for six months.

Resistant strains

Many strains of tuberculosis have become resistant to current drugs.

"It has the promise to be active against these bugs that are resistant"

Dr Mel Spigelman, head of Global Alliance's R&D

"It has the promise to be active against these bugs that are resistant," Spigelman said.

The experimental drug, dubbed PA-824, is owned by the biotechnology company Chiron Corporation.

Chiron sold rights to the drug for a "modest fee" to Global Alliance in 2002 and agreed to allow the non-profit alliance to distribute it for free in developing countries.

Chiron retains commercial rights to the drug in developed countries.