Taking on TB: On new anti-tuberculosis drug

Context

  • The anti-tuberculosis drug pretomanid was recently approved by the US FDA.
  • It will be a game-changer for treating people with extensively drug-resistant TB (XDR-TB) and those not tolerating multidrug-resistant TB (MDR-TB) drugs available at present.

TB scenario

  • 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. 

Background of the new drug

Pretomanid is only the third drug in the last 40 years to get FDA approval.

    1. Simpler regime – It is an all-oral, three-drug regimen of bedaquiline, pretomanid, and linezolid (BPaL).
    2. High success rate – It had a 90% cure rate in a phase III trial in South Africa; against the current treatment success rate for XDR-TB and MDR-TB at 34% and 55%, respectively.
    3. HIV – It was found to be safe and effective in curing TB in people living with HIV. 
    4. Shorter duration – Unlike 18-24 months needed to treat highly-resistant TB using nearly 20 drugs, the BPaL regimen took just six months.
    5. Effective and better tolerated – It was better tolerated and more potent in clearing the bacteria. The shorter duration is more likely to increase adherence to therapy and improve treatment outcomes. 
  • The need of the hour – The number of those who would need a pretomanid-based regimen is increasing due to rising drug resistance.

Challenges

  • There are only a low percentage of MDR-TB cases being treated and the actual number of people who do not tolerate or respond to available MDR-TB drugs is unknown.
  • It remains to be seen if it would be made affordable, in the developing countries where the burden of XDR-TB and MDR-TB is the highest. Bdaquiline’s prohibitive cost has severely restricted access in developing countries.

Pricing the new drug

  1. TB Alliance, a New York-based international NGO, which developed and tested the drug, has signed an exclusive licensing agreement with a generic-drug manufacturer for high-income markets.
  2. The drug will be licensed to multiple manufacturers in about 140 low- and middle-income countries, including India.

Source:TH