In a groundbreaking development recently, the United States Food and Drug Administration approved a three-drug regimen against the most lethal form of multi-drug-resistant tuberculosis, known as the XDR (extensively drug-resistant) strain.
Essentially, this strain of TB is resistant to some of the most potent anti-TB drugs, making it difficult for patients suffering from this strain to be cured. A trial in the US, which enrolled 109 patients with the XDR strain, was able to cure 90 per cent of them.
Cases of XDR TB are much fewer than those of the other drug-resistant strain, MDR/RR TB, and have been reported from 117 countries until 2017, a World Health Organization (WHO) report said. Out of 10,800 cases worldwide, India accounted for 2,650 cases, or almost one-fourth.
As per WHO, two-thirds of cases of the XDR-strain are in China, India and Russia. These countries also share 47 per cent of the burden for MDR/RR TB. The average success rates for drugs to treat the XDR strain has been 34 percent globally.
WHO explains that XDR can be contracted in two ways. It may develop in a patient who is already receiving treatment for TB and misuses the anti-TB drugs, or it can be contracted from a person who already has the disease.
The risk of transmission for XDR remains the same as the risk of transmission of other strains of TB. Often, XDR TB may go undiagnosed since lower-middle-income countries lack the infrastructure to detect it.
Worldwide, TB has surpassed HIV-AIDS as the leading cause of death due to infectious diseases. In 2017, over 13 lakh people died of the disease.