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Joining the fight against tuberculosis

The World Health Organisation estimates around 10 million people across the world acquired tuberculosis (TB) in 2017.

These infections led to 1.3 million deaths, making TB the leading cause of death from infectious disease.[1]

A key area in the fight against tuberculosis is to improve the diagnosis of the disease. The difficulty of providing diagnostics means that tuberculosis often goes undetected, unmonitored and untreated. This means people living with active TB will pass the infection onto others.

Quantifying tuberculosis bacteria

Healthcare workers confirm a diagnosis of TB by counting the number of live Mycobacterium tuberculosis (MTB) cultured from a sample of sputum. But the bacterial culture for TB is very slow, so the results are not usually available until several weeks after the patient has been to a clinic.

In addition, the test conditions require expensive containment facilities and staff training, both of which are often beyond the means of health facilities in regions where the disease is common. Simplifying treatment decisions and reducing the cost for health services would help save lives.

Novel approach to TB testing

In 2010, The University of St Andrews Infection Group, headed by Professor Stephen Gillespie, started developing a new biomarker test for TB, subsequently progressing a molecular bacterial load assay (TB-MBLA) based on the RT-qPCR enumeration of Mycobacterium tuberculosis 16S rRNA from viable tubercle bacilli. It works by amplifying the 16S ribosomal RNA of MTB in a PCR reaction. The TB-MBLA offers the potential to be used to diagnose a patient’s bacillary load of MTB in real time, quantifying live TB in hours rather than weeks.

Moving the academic work towards a standardised test was the next crucial step for the TB-MBLA and in August 2018, St Andrews joined forces with LifeArc to take the TB-MBLA to that next stage in becoming a diagnostic tool.

Michael Dalrymple, Executive Director, Diagnostics & Science Foresight at LifeArc said: “The aim was to progress the assay from research use to a stage where more patients can benefit from its application. Millions of people contract TB every year. With an appropriate diagnostic, patient treatment and recovery should be much improved.”

Progressing the diagnostic

LifeArc scientists at our Centre for Diagnostics Development evaluated, standardised, and improved the diagnostic from St. Andrews to make it fit for purpose as a tool in its intended use setting. A key part of the collaboration was to verify results generated using the assay against those from conventional testing methodologies.

The diagnostic will be a research-only tool initially, with the goal of collecting clinical evidence of its suitability to monitor treatment in limited resource settings.

Next steps

1. Development

  • Optimisation of reagents and extraction protocol
  • Prototype & design transfer documentation in collaboration with contract manufacturer

2. Transfer to manufacturing

  • Process validation, shelf-life studies, transport studies, RUO launch
  • Gathering clinical evidence in collaboration with a consortium of clinical sites

3. Submission / partnering

  • In future, the TB-MBLA tool could replace the microscope and culture test to provide faster treatment detection and monitoring of tuberculosis, allowing doctors and health care workers to diagnose tuberculosis, or monitor the response to treatment, in a single assay.

For further information on collaborating with LifeArc on diagnostics, please get in touch with TB-MBLA@lifearc.org

[1] WHO Global tuberculosis report 2018

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