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Tuberculosis cures

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Patients in a TB isolation ward in impoverished Bihar state, which has one of India’s highest infection rates.

Time magazine reported in February 2013:

India’s urgent battle against tuberculosis is almost invisible, until you start to look for it. Then you will find it everywhere: in the hospital down the street, in the corner pharmacy, in labs, offices, and schools. With some two million new cases each year, India has more TB patients than any other single country. The government is fighting this ancient, airborne bacteria in both small, far-flung villages and the some of the biggest cities in the world.

And so when news hit in late 2011 that there were patients in India who had cases of TB that weren’t responding to any known drug, the alarm bells went off — loudly. The government has been providing free supervised drugs for TB across the country since 2006. But a TB sufferer can also walk into any number of pharmacies around the country and pick up a prescription to treat his or her own disease.

A recent report from WSJ filled in the numbers:

More than 1.5 million people currently receive free drugs at 13,000 Indian government centers nationwide. Tuberculosis kills more than 300,000 people in India every year, out of about 990,000 who died from TB globally in 2011, excluding those who were also infected with HIV.

The report went on to say:

India faces a potential shortage of a critical medication for drug-resistant tuberculosis that could deepen an already acute drug- shortfall-problem in the country with the highest burden of the deadly contagious disease.

Tuberculosis officials in several Indian states said this week that their stocks of kanamycin, an injectable antibiotic commonly used to treat drug-resistant TB, are running low, and an Indian government official acknowledged that the country has only a three-month supply left.

The potential shortage would be the latest of several that India is facing with its TB drugs, and is particularly worrying because sporadic supplies of medications for drug-resistant forms of the disease can actually fuel further drug resistance. If a patient who is ill with TB starts and then stops taking a TB drug, even if it isn’t for long, the bacteria that cause it can quickly become resistant to it.

In the short term there can only be administrative solutions to this problem. However, there is possibly hope in the future for those with drug-resistant TB, reports an article in Nature:

Electron micrograph of Mycobacterium tuberculosis

A new drug candidate has shown promising signs in treating tuberculosis. The synthetic molecule is effective in mice and bears no similarity to existing TB drugs, many of which have become inadequate as drug-resistant bacterial strains have developed. If it is shown to be safe and effective in humans, it could help to combat a disease that killed 1.4 million people in 2011.

[A team led by Kevin Pethe, a microbiologist at the Pasteur Institute Korea near Seoul] showed that the synthetic antibacterial compound has a novel mechanism of action: it inhibits the synthesis of ATP, the chemical that is used as a source of energy by most of the cell’s enzymes, and thereby blocks M. tuberculosis growth.

Subsequent tests showed the compound to be successful at treating TB in mice. The molecule belongs to a new class of synthetic chemicals with no similarities to existing drugs. This factor could make it tougher for the bacteria to develop resistance to it.

Success at this stage does not guarantee that the compound will lead to an effective treatment in humans. Pethe says that the candidate drug will move on to phase I clinical trials next year to assess its safety and tolerability in a small group of healthy human volunteers. But only 5% of drugs that make it to phase I in all disease areas ultimately end up as marketed pharmaceuticals.

Getting the drug through the next two phases of clinical trials would also need substantial investment. Typically, state-funded institutions such as the Pasteur Institute Korea have focused on drug discovery, with the onus for drug development placed on the pharmaceutical industry.

But the TB market does not have the financial incentives to attract large investment from big pharma, experts say. Pethe’s team aims to bridge the gap with support from the Korean government and a company spun off by his institute, called Qurient. “Our goal is conflate research and the product — a model not yet established in the world,” says Pethe.


Written by Arhopala Bazaloides

August 5, 2013 at 6:50 pm

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