Improved cure for TB

Combination drug can treat both TB and resistant TB

By Arpita Bhagat
Published: Saturday 15 September 2012


TUBERCULOSIS is one of the largest killer diseases in the world. It claimed around 1.4 million lives in 2010 alone. What is worse, the disease is increasingly becoming drug-resistant. In January this year, India became the third country after Italy and Iran to confirm the presence of a totally drug resistant strain of TB (TDR-TB). The number of suspected cases of TDR-TB worldwide jumped from 29,000 in 2008 to 53,000 in 2010.

But now there is hope of a cure. Scientists have found a new combination of drugs that has been shown to kill more than 99 per cent of both drug susceptible and drug-resistant TB bacteria—Mycobacterium tuberculosis—within two weeks. Normally, two drugs—isoniazid and rifampicin—are given to TB patients. The new combination tentatively called PaMZ, consists of PA-824, a new drug discovered in 2008; moxifloxacin, an improved antibiotic being used as a first-line TB treatment; and an existing TB drug called pyrazinamide.

To test the drug’s efficacy, 85 patients with pulmonary TB were administered the new drug for two weeks. The result was assessed on the basis of daily decline in number of the bacterial colonies per millilitre of sputum. It was found that the bacterial count decreased significantly for both drug susceptible and drug resistant pathogens. The study was published in Lancet on July 23.

“Treating TB and TDR-TB with the same regimen can simplify the delivery of treatment worldwide,” says lead author Andreas Diacon from University of Stellenbosch in Cape Town. Virander S Chauhan, director of International Centre for Genetic Engineering and Biotechnology in New Delhi, concurs. “However, more trials will need to be done for proper assessment. I strongly feel that we in India should gear up for such trials considering the burden of the disease,” he adds.

Meanwhile, Giovanni Battista Migliori, director of the WHO Collaborating Centre for Tuberculosis and Lung Diseases’, cautions that the new drug regimen needs to be used carefully to avoid past mistakes of overuse of TB drugs, which had led to resistance.

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