Tuberculosis Drug Combo Cut Treatment Time in Study

An experimental combination of medicines killed both the regular and drug-resistant strains of tuberculosis, suggesting it may be a simpler and cheaper way to combat the deadly disease, a study found.

In a test comparing five treatment regimens, a three-drug combination called PaMZ was the most effective, eliminating more than 99 percent of the bacteria within two weeks, researchers from Stellenbosch University in Cape Town wrote in The Lancet medical journal today.

Because the combination doesn’t contain isoniazid or rifampicin, the two main medicines used against TB, it also may provide a much-needed weapon against strains that fail to succumb to those drugs and are spreading, the researchers wrote. The new combination may shorten the time to treat TB by more than two years, while being 90 percent cheaper than current treatments for multi-drug-resistant tuberculosis, they said.

“We may have a major solution here for drug-sensitive TB and drug-resistant TB,” Mario Raviglione, director of the World Health Organization’s Stop TB Partnership, said on a call with reporters last week before the results were published. “This will change policies worldwide.”

The 85-person mid-stage study was funded by The Global Alliance for TB Drug Development, a New York-based non-profit organization supported by the Bill and Melinda Gates Foundation. The group is recruiting patients for a follow-up study in South Africa, Tanzania and Brazil.

Deadly Bacteria

About 1.4 million people died from TB in 2010, making the airborne bacteria the second-deadliest infectious disease globally after AIDS, according to the World Health Organization. TB is the biggest killer of people with HIV, and the drugs used to treat the bacterial disease can interfere with AIDS medicines.

There were about 650,000 cases of multi-drug-resistant tuberculosis worldwide in 2010, and the number is increasing, according to the Geneva-based WHO. In Belarus, about one in three new cases of TB is multi-drug resistant, Raviglione said.

“We have been losing our tools to combat this epidemic,” Andreas Diacon, the university researcher who led the trial. The results mean doctors may have a new treatment against both regular and drug-resistant TB within five years, instead of 10 to 20 years if each medicine in the mix was tested separately, Diacon said on the call.

A study published in the New England Journal of Medicine last month showed an antibiotic developed by Otsuka Holdings Co. called delamanid helped fight tuberculosis strains not stopped by other medications, suggesting the Tokyo-based drugmaker may be close to having the first approved TB treatment in 40 years.

While that result is promising, the bacteria are more likely to develop resistance to a single treatment than to combinations, according to the TB Alliance.

PaMZ consists of PA-824, a new drug; moxifloxacin, an approved antibiotic being developed for use as a first-line TB treatment; and an existing TB drug called pyrazinamide.

The results of the study are scheduled to be presented at the International AIDS Conference in Washington today.

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