New line of defence

Wed, Aug 21, 2019

In a landmark decision, the Food and Drugs Administration (FDA) approved a new oral three-drug regimen on August 14 to treat drug resistant tuberculosis. Comprising of bedaquiline, linezolid and the novel compound pretomanid, the rigorous new regimen is together called BPaL. The regimen was developed to help patients fight non-responsive Multidrug-Resistant TB (MDR-TB) and Extensively Drug Resistant TB (XDR-TB) prevalent in huge numbers globally.
Developing new treatment is the need of the hour since tuberculosis is the leading cause of death worldwide from a single infectious agent, surpassing HIV/AIDS, according to the World Health Organization (WHO).  
This medical discovery provides hope to millions of people globally diagnosed every year since the drug will be made available in high income markets as well as non-exclusive middle-income and low-income countries. Only 25 percent of the estimated 558,000 people who developed Multi-Drug Resistant TB (MDR-TB) and Rifampicin-Drug Resistant TB (RR-TB) in 2017 received the second-line regimen. According to the Global Tuberculosis Report 2018, the success rate of the treatment was low at just 55 percent for MDR-TB and 34 percent for XDR-TB globally. India and China make up for 40 percent of the global gap in treatment and detection. The number of MDR/RR-TB cases detected and notified worldwide rose from 153/119 in 2016 to 160/684 in 2017. However, there has been some progress since Bangladesh, Ethiopia, Kazakhstan, Myanmar and Vietnam are some of the countries with a success rate of above 70 percent.
The anti-tuberculosis drug pretomanid will be a game changer for treating people with extensively drug-resistant TB (XDR-TB) and those who do not tolerate or respond to now available multidrug-resistant TB (MDR-TB) drugs. That pretomanid is only the third drug in the last 40 years to get FDA approval highlights the scarcity of new drugs to treat TB bacteria that are rapidly developing resistance against most available drugs. The all-oral, three-drug regimen of bedaquiline, pretomanid, and linezolid (BPaL) had a 90% cure rate in a phase III trial in South Africa involving 109 participants. In contrast, the current treatment success rate for XDR-TB and MDR-TB is about 34% and 55%, respectively. Importantly, the regimen was found to be safe and effective in curing TB in people living with HIV.
According to WHO, in 2017, there were an estimated 4.5 lakh people across the world with MDR-TB, of which India accounted for 24%, and about 37,500 with XDR-TB. With only a low percentage of MDR-TB cases being treated, the actual number of people who do not tolerate or respond to available MDR-TB drugs and so will be eligible to receive the BPaL regimen is unknown. Though the total number of people who will require the new drug may not be high, these are people who have very little alternative treatment options that are safe and efficacious. Also, the number of those who would need a pretomanid-based regimen is increasing due to rising drug resistance.
While the availability of a potent drug is welcome news, it remains to be seen if it would be made affordable, particularly in the developing countries where the burden of XDR-TB and MDR-TB is the highest. Making the drug affordable to those with extreme form of drug resistance will be highly commendable and a desperately needed model to be followed. After all, there is a compulsion to keep the prices low and increase treatment uptake to stop the spread of highly drug-resistant TB bacteria.

Area: 7096 Sq Km
Altitude: 5,840 ft
Population: 6.10 Lakhs
Topography: Hilly terrain elevation from 600 ft. to over 28,509 ft above sea level
Summer: Max- 21°C ; Min – 13°C
Winter: Max -13°C ; Min – 0.48°C
Rainfall: 325 cm per annum
Language Spoken: Nepali, Bhutia, Lepcha, Tibetan, English, Hindi