A deadly strain of tuberculosis kills 70% of those who are infected, but there is a new treatment which, according to the director of Johns Hopkins University Center for Tuberculosis Research, “may represent an enormous breakthrough.” (JHUC TR was not involved in these tests.)
XDR TB
Xdr Tb is shorthand for extensively drug-resistant tuberculosis, one of several strains of TB which don't respond to traditional treatment modalities. They are usually found in HIV patients but could develop in anyone with a weakened immunity system such as the elderly.
There are treatments which can be effective in more than the current 30% of patients who survive, but even at the risk of death patients often won’t follow the very long and difficult (due to the high toxicity of the drugs) treatments.
A recent clinical trial in South Africa involved 34 people with XDR and a novel treatment with three antibiotics which had never been used against TB before. After six months there was no sign of the infection in any of the 34 patients which is a remarkably positive result for any experimental treatment modality.
The three-drug cocktail consists of bedaquiline, pretomanid, and linezolid. Of these, bedaquiline, was originally developed to treat TB patients but hasn’t been used in many patients since it was introduced in 2012.
Pretomanid is also a TB drug but is still in the experimental stage so it can’t be used by most doctors - it isn’t approved in the US. The most unusual of the three drugs is linezolid which is normally used for dermal (skin) infections or to treat some strains of pneumonia.
The study was conducted by Francesca Conradie of the University of the Witwatersrand in Johannesburg, South Africa, who said, I didn’t in my wildest dreams expect the results to be this successful.”
Some of the patients continued taking the drugs but 20 of the 34 stopped.
Of those 20 only one has relapsed indicating that this is possibly a cure for this form of tuberculosis.
How many people get this disease?
The World Health Organization estimated in 2015 that there are almost a half million new cases of multiple drug resistant TB (MDR TB) each year and, of those, 7234 are known to have the even more dangerous XDR TB infection.
The standard treatment lasts two and one-half years and usually requires hospitalization.
As with some chemotherapies for cancer patients often find the side effects of the treatment are so terrible that they just stop.
Nix-TB, as the new treatment is being called, involves pills rather than painful injections and, if it develops in future clinical trials that low doses of the toxic linezolid work the Nix-TB regimen may be applied to people with the MDR TB strain also.
Cost is, as always a consideration and the entire treatment course for Nix-TB costs $30,000 in advanced countries - Janssen Therapeutics (New Jersey) is donating 30,000 doses of their bedaquiline to poor countries and is selling it to other third-world countries at a price of only $900 for 6-months.
President Trump has spoken out against the slow approval of life-saving drugs which could be given to the terminally ill so perhaps this drug cocktail will become available quickly in the US.
