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  • Combination drug therapy could end TB's deadly grip

Researchers have developed a tuberculosis (TB) combination therapy that could be considerably more effective than existing treatments.

In phase II clinical trials, the therapy, PaMZ — which consists of the novel TB drug candidate PA-824, the antibiotic moxifloxacin, and pyrazinamide, an existing TB drug — killed more than 99 per cent of people's TB bacteria within just 14 days.

The findings, from the Global Alliance for TB Drug Development, were presented this week (23 July) at the 2012 International AIDS Conference, in Washington DC, United States.

The trial — called NC-001 or New Combination 1 — took place over a period of two weeks, at two locations in South Africa. A second trial, NC-002, was launched earlier this year, and is being conducted at eight sites in Brazil, South Africa and Tanzania.

As well as successfully eradicating regular TB, PaMZ can also treat forms of drug-resistant TB within four months. Current treatment methods for these strains take 18–24 months, are very expensive, and involve injections, making treatment access and adherence hugely challenging.  

Melvin K Spigelman, president of the alliance, and an author of the study, told SciDev.Net: "The study shows that the regimen is potentially suitable for treating drug-sensitive and multidrug-resistant tuberculosis".

"What's really exciting is that this trial took a whole new approach to TB drug development. By testing new combinations together early in development, we can dramatically reduce the time needed to develop new anti-tuberculosis regimens," Spigelman said.  

The next study, NC-002, which tests the PaMZ regimen over eight weeks, has been enrolling patients since March this year.  

The new therapy will also bring benefits to HIV-positive people. TB is the biggest killer of people living with HIV/AIDS, and HIV-positive people infected with the bacteria causing TB are up to 34 times more likely than HIV-negative groups to develop TB. In 2010, 1.1 million people living with HIV developed TB, 82 per cent of them in Africa.  

"[It is hoped] the new drug combination will be easier to use with other drugs such as anti-HIV drugs," says Andreas H Diacon, a professor at Stellenbosch University, South Africa, and the trial's principal investigator.

Mario Raviglione, director of the Stop TB Partnership at the WHO said: "I estimate that if this regimen is confirmed to be efficacious in the longer study, then we will gain many years and have the regimen available in about five years' time".  

An affordable, safe, fast, easy regimen, which can be used for drug-susceptible and simple multidrug-resistant TB (MDR-TB), will constitute a revolution in the way TB care is delivered, Raviglione said.

TB kills almost two million people every year, and is the world's second biggest killer of adults after HIV/AIDS.