New hope for patients as ‘gruelling’ treatment for drug resistant TB could be cut to six months

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An 18-month-old boy suffering TB in Sudan - EPA/NIC BOTHMA
An 18-month-old boy suffering TB in Sudan - EPA/NIC BOTHMA

A “gruelling” two year treatment plan for drug resistant tuberculosis could be cut to just six months, after a clinical trial identified a new drug combination that is shorter, safer and more effective.

TB remains one of the world’s most deadly infectious diseases, killing roughly 1.5 million people a year, and drug resistant infections are a mounting challenge. In 2018, the World Health Organization estimated that, of the 10 million new cases detected, 500,000 were resistant to the antibiotics most commonly used to treat the pathogen.

But drug resistant TB (DR-TB) infections are notoriously complicated to tackle. Currently patients undergo up to 20 months of treatment, which can include painful injections and some 20 pills a day.

The cocktail of several drugs can cause severe side-effects - including nausea, headaches, loss of hearing and psychosis - and many patients drop out. Even at the end of the course, only around half of people are cured.

However results from a trial - called Practecal and led by Médecins Sans Frontières - could herald a new chapter in treatment, with a “drastically shorter, effective, safer and kinder” drug regimen.

The study, which is yet to be peer-reviewed, focused on treatment options for TB infections resistant to rifampicin, one of the most commonly used first line antibiotics to treat the disease.

Researchers compared a six-month schedule combining four drugs - bedaquiline, pretomanid, linezolid and moxifloxacin - against the standard treatment package in Belarus, South Africa and Uzbekistan.

The phase two/three clinical trial, which enrolled 552 patients, found that 89 per cent of those on the shorter regimen were cured. In the standard care group, this figure was just 52 per cent - and four patients died during the study. More patients in the six-month schedule also avoided major side effects - 80 per cent, compared to 40 per cent in the control group.

“The trial has led to a new all oral six-month treatment regimen that is easier to take, safer and much more effective against the disease,” said Bern-Thomas Nyang’wa, MSF’s medical director and chief investigator of the Practecal, adding that the results offer “hope for the future” for patients and the medics who treat them.

MSF is optimistic that the results could inform a change in the recommended treatment package for TB as soon as early 2022, when the World Health Organization (WHO) is set to update guidelines. MSF has already shared the data with the UN health agency as part of a rolling review process.

Pandemic could 'unravel years of progress' in tackling TB

The results, unveiled at the Union World Conference on Lung Health this week, come after a bleak WHO report earlier this month warned that the pandemic is on track to “unravel years of progress” against the ancient killer.

In 2020, deaths rose for the first time in more than a decade - from 1.4m in 2019 to 1.5m - and the number of people being newly diagnosed with the disease plummeted by 18 per cent - from 7.1m in 2019 to 5.8m in 2020 - due to “severe disruptions” triggered by Covid-19.

But a flurry of research presented at the virtual Union conference this week has offered some hope for the future fight against TB.

One study from the University of Cape Town has upended centuries of medical dogma. It found coughing - which was thought to be the main means of spreading TB - might not be the primary driver of transmission. Instead, up to 90 per cent of TB bacteria released from an infected person may be spreading in tiny droplets, called aerosols, when a person breathes.

Experts involved in the study said this could help to explain why certain crowded settings - for instance prisons - see such high rates of TB transmission, and provide critical clues about how to stem the bacteria’s spread.

Dr Ryan Dinkele, lead author of the paper, said the findings suggest that screening people who already have TB symptoms may be less useful in halting the spread of disease.

“The current approach, which relies on the testing and treatment of passively identified individuals, may not be a reliable response to preventing transmission, as it depends on people feeling sick enough to seek treatment,” he said. “It may also shed light onto why constructing transmission chains is so challenging in high TB burden settings.”

Researchers also unveiled a new fingerstick blood test that would detect a TB infection in less than an hour, and the results of a study from Imperial College that used genome sequencing to predict which strains of TB are likely to become drug resistant. Scientists said this work could help prevent the amplification of resistance in people, by targeting certain bacteria.

Meanwhile, a separate paper by the Comprehensive Resistance Prediction for Tuberculosis International Consortium (CRYPTIC) - an international collaboration that has been working to create a faster process to identify drug resistant TB strains - identified almost all the genomic variation that gives people resistance to 13 of the most common antibiotics.

The team analysed more than 15,000 samples from patients in 27 countries, and said the results can help target DR-TB as medics will be able to better identify which drugs will and won’t work against a particular infection.

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