South African drug trials lead to TB breakthrough

Thu, Jul 26, 2012, 01:00

A NEW drug combination being tested for the first time in South Africa on people suffering from tuberculosis has proved to be effective in killing 99 per cent of the bacteria within two weeks, early results have shown.

The development has been hailed as “very promising” by the trial’s principal investigator, Stellenbosch University’s Dr Andreas Diacon, but he has cautioned that the three-drug cocktail still has many trials to go through before it becomes widely available.

“We only tested the drug for two weeks and that is not really long enough for any TB treatment to work,” he warned.

Nevertheless, scientists published their test results in medical journal The Lancet this week and presented them at an international Aids conference in Washington DC on Monday.

The drug trial, which was funded by the non-profit Global Alliance for TB Drug Development, involved 85 patients. It tested several drugs simultaneously, in different combinations, on those involved.

Fifteen members of the test group were put on the new PaMZ combination, which includes a new drug, an established antibiotic and the existing TB drug, pyrazinamide.

The breakthrough, if verified, could potentially address a disease that is one of the biggest killers in the developing world. In 2010, TB, a disease that primarily targets a person’s lungs, infected 8.8 million people worldwide, according to the World Health Organisation.

In addition, there have been concerns among health officials about the emergence of a drug-resistant strain of the bacteria that has proven difficult to treat using traditional medication.

South Africa is one of the four countries in the world – the others are China, Russia and India – with the largest concentration of TB sufferers with diagnosed drug-resistant strains of the disease. In 2010, there were 7,386 recorded cases in the country.

Treating the disease in South Africa is further complicated by its close links with the HIV virus, which attacks a person’s immune system and makes them more susceptible to contracting other diseases.

At least 60 per cent of the estimated six million people in South Africa who suffer from HIV/Aids have TB – and the current regime of medicines for the latter adversely affects the antiretroviral drugs used to control the former, say experts.

According to the South African National Tuberculosis Association, TB is the leading cause of death among people who are HIV-positive. Approximately one third of all HIV-related deaths worldwide are caused by TB.

A follow-up trial for the PaMZ combination involving 230 patients is already under way, and will be carried out for a period of eight weeks. If this proves successful, the drug will move into a longer, third phase trial involving thousands of participants on three continents.

After this phase, the drug will undergo a final round of tests before its registration with regulatory authorities such as the US Food and Drug Administration and the South African Medicines Control Council can take place.

Dr Diacon told local reporters on Monday that the approach to testing the new drug – in combination with other drugs rather than alone – could make it possible to produce a new treatment within five years instead of decades.

“From a doctor’s perspective, that’s amazing progress. Before, I was anticipating it could take decades for a new TB drug regimen but now it looks like it will take years,” he said.