New treatment for drug resistant TB hailed
A milestone in the fight against TB was reached this month when the first tuberculosis drug to be approved in 50 years became available in South Africa.
Bedaquiline (Sirturo), the first TB drug to be licensed since 1967, was approved by the US Food and Drug Administration (FDA) this month.
“This heralds a new era in TB treatment and research,” said Dr Alex Pym, principal investigator at the KwaZulu-Natal Research Institute for TB and HIV.
While the drug is now available in the country through a compassionate use programme, Pym said it still needed to be approved by the South African Medicines Control Council (MCC) before it can be more widely used.
A phase III study is due to start shortly in Durban and other sites around the world.
Pym, who was the lead investigator for the Durban site of the multi-centre international drug trial, said the approval came after lengthy clinical development.
He said the company that developed the drug, Janssen Pharmaceuticals, initially had a programme to develop new antibiotics against drug-resistant bacteria.
It was only an after-thought to develop a non-pathogenic variety for mycobacteria that led to the development of a new TB drug.
The first patients to be treated with the new drug were in Cape Town and Durban.
“That study started in 2005. However, this was a very short study conducted over only one week with a small group of patients who had a drug susceptible version of TB. The results showed a very small effect,” said Pym.
Despite the weak result, Pym said the company had the courage to go ahead and do another study to see if the drug would work in drug-resistant TB. Pym describes this as an innovative step, as there had never been a drug tested for drug-resistant TB before.
The second trial started in 2007 and the final results only became available last year.
“Again, most patients for this study were South African and part of the trial was conducted here in Durban. What the trial showed was that if you treat MDR-TB patients for six months with this drug, you have a greater chance of clearing the bug from the sputum than with the standard drug alone,” he said.
“As a landmark, this is really exciting,” said Pym, “but it also has many challenges.”
So far, only a few hundred patients had been treated with the drug, Pym said.
“Another challenge is that this drug has only been approved for use in MDR patients. While KZN and South Africa have a high burden of MDR-TB, this is still a small proportion of the total population affected by TB, so we need new studies to see if it can improve treatment of ordinary TB,” he said.