The US Food and Drug Administration (FDA) has approved new oral three-drug regimen for the extensively-drug resistant tuberculosis (XDR-TB) estimate to have a mortality rate of 60%.





According to the FDA the treatment involves pretomanid tablets in combination with bedaquiline and linezolid, collectively refer as the BPal, regimen. And it has an efficacy rate of 90%.

Previously available drugs had a success rate only 34% for XDR-TB and 55% for multi-drug resistant TB (MDR-TB) cases, according to the World Health Organization (WHO). They also had severe side-effects like deafness, numbness, joint pain, renal failure hormonal imbalance, vertigo, among others.









Pretomanid is only the third new anti-TB drug approved for use by FDA in more than 40 years.

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Tuberculosis burden around the world

Tuberculosis is not a past disease, it has high burden in present.





India is known as TB Capital of the world as most of the cases of Tuberculosis remain undiagnosed, and lack of data helps the bacteria in spreading more.





Though due to constant efforts of WHO and governments, cases have been reduced.

The new target set in the End TB strategy includes a 90 percent reduction in TB deaths and an 80 percent reduction in TB incidents by 2030, compared to 2015.

Tuberculosis is of the top 10 cause of death worldwide. In 2017, 10 million people fell ill with TB, and 1.6 million died from diseases including 0.3 among people with HIV. TB is a leading killer of HIV-positive people.





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In 2017, an estimate 1 million children became ill with TVB and 230,000 children died of TB.

Multidrug-resistant TB MDR-TB) remains a public health crisis and a health security threat. WHO estimates that there were 559 000 new cases with resistance to rifampicin- the most effective first-line drug, of which- 82% had MDR-TB.

Globally, TB incidence is falling at about 2% per year. This needs to accelerate to a 4-5% annual decline to reach the 2020 milestone of the End TB strategy.

Ending the TB epidemic by 2030 is among the health targets of the sustainable Development goals.









How does it spread and what are the causes?

Tuberculosis (TB) is causes by bacteria (Mycobacterium tuberculosis) that most often affect the lungs Tuberculosis is curable and preventable.

TB is spread from person to person through the air when people with lung TB cough, sneeze or spit, they propel the TB germs into the air. A person needs to inhale only a few these germs to become infected.

When a person develops active TB disease, the symptoms (such as cough, fever, night sweats, or weigh loss) may be mild for many months. This can lead to delays in seeking care, and results in transmission of the bacteria to others. People with active TB can infect 10-15 other people through close contact over the course of a year.

Is it treatable?

TB is treatable and curable diseases. Active, drug-susceptible Tb disease is treated with a standard 6 month course of 4 antimicrobial drugs that are provided with information, supervision and support to the patient by a health worker or trained volunteer. Without such support, treatment adherence can be difficult and the disease can spread. The vast majority of TB cases can be cured when medicine are provided and taken properly.

Between 2000 and 2017, and estimate 54 million lives were saved through TB diagnosis and treatment.

Why this new TB drug-resistant medicine promising?

The drug was developed and tested in clinical trials by new York-based non-profit organisation TB Alliance. TB Alliance has granted a licence to Pennsylvania-based Mylan to manufacture and commercialise the drug.

Pretomanid drug is expected to be available in the U.S by the end of this year. TB Alliance has submitted pretomanid as part of the three-drug regimen for drug approval by the European Medicines Agency (EMA). It has also provided data to the World Health Organisation (WHO) for consideration of inclusion in treatment guidelines for highly drug-resistant TB.

According to the WHO, the treatment success in MDR-TB patients is about 54% while it’s just 30% in the case of XDR-TB patients. Most drugs are ineffective in people with XDR-TB and so a combination of eight drugs for more than a year is need for XDR-TB treatment.

Treatment success in XDR-TB patients depends on many other factors- the extent of the drug resistance, the severity of the disease, whether the patient’s immune system is weakened, and adherence to treatment.

Drugs used for treating MDR-TB and XDR-TB can cause serious adverse effects such as deafness. The drugs are highly toxic thus reducing adherence to treatment.









How safe this drug is for clinical use?

The new regime was tested on 109 patients with XDR-TB and MDR-TB from South Africa in 2015-2017. After six-month trial, 95 patients were successfully treated. A follow-up of six months was also done.

The FDA has approved the drug based on limited clinical safety and efficacy data, and so should the drug should be restricted to specific population of patients. Safety and effectiveness of the drug has been studied and established only when used in combination with bedaquiline and linezolid.

The drug has not been tested in pregnant women. Similarly safety and effectiveness of the drug has not been established in children.



TB burden in India

India has 26,966 MDR-TB patients, the highest in the world, while there are 2,130 XDR-TB patents in the country.

Of the total MDR-TB patients worldwide, 6.2% are likely to become XDR-TB, thereby meaning the number if XDR-TB cases may very well be more than 9,000 in India.





Conclusion

The success rate of treatment for XDR-TB in India is merely 23% while for MDR-TB it is 46%.

Thus, the new drug regimen is important for countries like India, which has the second-highest burden to XDR-TB patients in the world, after Russia.

However, what remains the concern is the cost of the treatment. In case of the drug-resistant TB, the treatment gets stretched for much longer period.





Bhim _UPI - 526683880@icici







