Cocktail found for resistant TB strain

Scientists have successfully tested a new tuberculosis treatment that has the potential to check an epidemic of a deadly, drug-resistant strain of the disease that has been threatening to sweep the globe.

Scientists have successfully tested a new tuberculosis treatment that has the potential to check an epidemic of a deadly, drug-resistant strain of the disease that has been threatening to sweep the globe.

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Results from a groundbreaking trial of three drugs given in combination — one of them completely new and one not yet licensed for this use — killed more than 99% of patients’ TB bacteria after two weeks of treatment. Currently people with TB must take drugs daily for six months and up to two years if they have a drug-resistant strain.

India is one of the countries with the highest burden of drug-resistant TB cases in the world, with more than 99,000 new cases each year. Globally, less than 7% of 440,000 new such cases each year receive treatment, leading to 150,000 deaths annually. In 2010, only 2% of the estimated resistant TB received second-line drug treatment under the national programme.

Drug resistant TB has to be treated longer using very expensive drugs, the cost of which rises every year. Prices for two drugs have shot up by more than 600%, and of a third drug by more than 800% over the last decade, reported the international medical humanitarian organisation Médecins Sans Frontières (MSF) in 2011. Drug-resistant TB treatment needs a two-year-long treatment regimen that can cost up to $9,000 for one patient — 470 times more than the $19 per patient it costs to cure standard TB over six months.

The trial of the new cocktail was carried out in 85 patients in two centres in Africa. A larger trial, using the drugs for two months rather than two weeks, is now underway, but scientists are already excited by the early findings. The disease has been spreading on the back of the HIV epidemic — it is the leading cause of death of people whose immune systems have been weakened by the HIV virus in developing countries.

If the new combination turns out to be as effective as scientists hope, doctors would be able to treat all patients with it no matter what sort of TB they have, said the study’s lead author, Dr Andreas Diacon.

The new combination is also safe to use with patients on HIV treatment, unlike some existing TB drugs.