Potential cure for deadliest form of TB
Usually a death sentence, extensively drug-resistant tuberculosis (XDR-TB) can potentially be cured with a new drug combination.
Interim results from the Nix-TB trial, which were presented at the Conference on Retroviruses and Opportunistic Infections in Seattle, are extremely promising and point to new hope for people diagnosed with XDR-TB.
“In South Africa, up to 75 percent of XDR-TB patients die within five years after treatment – that’s a higher death rate than metastatic [advanced] breast cancer,” said Dr Pauline Howell, from the Clinical HIV Research Unit at Wits University and co-author for the study.
According to the TB Alliance, the organisation conducting the trial, the “vast majority” of patients with XDR-TB in the study were “clinically well” and “able to go home to their families” after completing just six months of treatment with a new drug regimen.
Novel drugs for XDR-TB
XDR-TB is a strain of TB resistant to four commonly used anti-TB drugs. Because there have been no new TB drugs for decades there is no regulatory-approved regimen for curing XDR-TB.
But the new anti-TB drugs bedaquiline and pretomanid together with another drug linezolid, have been found to have the potential to drastically increase survival rates of people with XDR-TB.
Speaking to Health-e News at the Union Conference on Lung Health last year, lead investigator of the trial Dr Francesca Conradie said that up until now there have been so few options available to treat these patients, physicians have to use a “kitchen sink” approach where every possible drug is given in the hope that some will have an effect on the disease.
But, she said, “more drugs for more time means more side-effects”.
Due to toxic and often ineffective drugs, only 28 percent of patients with XDR-TB are cured even after two years or more of gruelling treatment, according to the World Health Organisation.
The Nix-TB drug regimen is an oral combination and takes a quarter of the time to complete compared to current treatment – six months. This is the same amount of time it takes to treat ‘standard’ or drug sensitive TB.
As of February 1, 2017: 69 patients have enrolled in the trial, which is being conducted at two sites in South Africa (Sizwe Hospital and Brooklyn Chest Hospital), and 40 have completed treatment and have no sign of the bacteria in their sputum.
“XDR-TB reminds me of the early days of HIV where nearly everybody who got the condition died. Now we have treatment but this is still in the early stages,” said Conradie.
Co-author for the study, Dr Christo van Niekerk said that these results are “exciting news”, especially for patients who would no longer have to endure painful daily injections, which can also cause serious side-effects like permanent deafness.
Howell, who treats XDR-TB patients at Sizwe Hospital, said that XDR-TB is becoming a bigger problem because infectious patients often remain in communities, because of the ineffective treatment, and spread the illness.
“It’s no longer just a situation of patients not taking their medication properly and then developing resistance to it. In Johannesburg 81 percent of XDR patients contracted the resistant bug and had never had TB before,” she said.
The Nix-TB study is still ongoing, however, and aims to enrol at least 200 patients. But the TB Alliance has said regulatory bodies might consider approving its use before that point, based on smaller numbers, because the results are so promising – and because XDR-TB, currently, is so deadly.
Said Howell: “Nix-TB is a breakthrough – there are five tablets a day instead of the current 30, no injections and minimal side-effects. If I contracted XDR-TB now I would do everything I could to get access to this treatment.” – Health-e News.
An edited version of this story was published on Health24.com