Pregnant women with drug-resistant TB can be safely treated, says new study

Expectant mothers with drug-resistant tuberculosis (TB) can be safely treated with bedaquiline, a treatment not previously evaluated in pregnant women

This is the main finding of a study published last week in Clinical Infectious Diseases. The research, led by the South African Medical Research Council and the Department of Infectious Disease at Imperial, represents one of the first investigations into the effects of newer TB treatments in pregnant women.

Treading new ground in TB treatment

Drug-resistant TB, a type of disease which occurs when TB-causing bacteria develop resistance to one or more first-line medications, is a major global health issue with an estimated 558,000 new cases recorded in 2017. The World Health Organization (WHO) recommends that pregnant women with TB should be treated in the same way as non-pregnant adults. However, guidance on how to treat the drug-resistant form of disease in pregnancy is less clear-cut. This is because pregnant women and their newborns are typically excluded from taking part in clinical trials for new treatments, meaning there are limited data around which medications are safe and effective to use in these groups. This is particularly problematic as drug-resistant TB is most prevalent among women of reproductive age (15-45 years).

The researchers behind the current study set out to find out whether a relatively new drug, called bedaquiline, might be suitable for use in pregnant women with drug-resistant TB. The study team assessed pregnant women starting treatment for drug-resistant TB at King Dinuzulu Hospital in KwaZulu-Natal, South Africa over a five-year period. Drawing on data routinely collected by healthcare workers, the findings show that 67% of the 108 pregnant women who were treated with bedaquiline had favourable treatment outcomes for drug-resistant TB, a figure which is comparable to that seen in non-pregnant adults.

The study also found that babies who were exposed to bedaquiline had a slightly lower birthweight (approximately 200g) compared to those who were not. However, of the 86 children evaluated at 12 months, 88% of babies exposed to bedaquiline were thriving and developing normally compared to 82% of the babies not exposed.

Challenges and next steps

"Currently, pregnant women with TB are hugely neglected, both from the perspective of clinical care, as well as in research and development of new drugs and treatments" Dr James Seddon Senior author

Although the study is the largest to date to document drug-resistant TB treatment outcomes in pregnant women and their babies, its relatively small size means that more data from different locations need to be gathered to further clarify the findings.

Significantly, however, the results suggest that bedaquiline can be considered safe to use in pregnancy and that pregnant women should be included in treatment studies of new TB drugs.

Explaining the challenges of the study, Dr James Seddon, Clinical Senior Lecturer in Paediatric Infectious Diseases at Imperial and senior author of the paper, said: “Given that we used routine data and that this is a retrospective study, the data are not as complete as we would have liked.”

“We tried to overcome these challenges by searching extensively for data from multiple sources and using complex statistical methods to overcome missing data. As women were frequently receiving multiple medications, it was difficult to disentangle the effects of individual drugs. Finally, the study was only done in one region of South Africa, so caution should be exercised when drawing conclusions in other contexts.”

Commenting on the wider significance of the work, Dr Seddon added: “Pregnancy is a time of high risk for TB, and so many pregnant women develop the disease each year, including drug-resistant forms. Currently, these women are hugely neglected, both from the perspective of clinical care, as well as in research and development of new drugs and treatments. We hope that this neglected population will be included more often in studies to evaluate new treatments in the future.”

‘Maternal and infant outcomes among pregnant women treated for multidrug/rifampicin-resistant tuberculosis in South Africa’ by Marian Loveday et al. is published in Clinical Infectious Diseases