Non-invasive TB Triage and Patient Mapping Platform Using Breath Via Low-Cost Titanium Dioxide Nanotube Sensor
Condition: Tuberculosis
MeSH terms: Tuberculosis
Study type: Observational [Patient Registry]

Summary: 
      The purpose of this pilot study is to evaluate the sensitivity and specificity of a
      nanotube-based point-of-care breath-based tuberculosis screening test as compared to the
      current standards of care including sputum microscopy, sputum culture, chest X-ray, and
      GeneXpert (MTB/RIF).

      The primary objective is to determine an initial estimate of the sensitivity and specificity
      of a nano-tube based point-of-care test for the diagnosis and screening of active pulmonary
      tuberculosis.

      Secondary objectives include the collection of user data to test and further develop the
      screening platform based on end-user feedback.
    

Detailed description: 
      TB is an infectious disease caused by various strains of mycobacteria. It typically infects
      the lungs and is spread through the air when an infected patient sneezes, coughs, or spits.
      When this occurs, the TB bacilli are propelled into the air in droplets that can remain
      suspended for long periods of time. An individual simply needs to inhale a small amount of
      bacilli to become infected.

      Conventional methods for TB detection and diagnosis are traditionally performed in
      laboratories or hospitals. For example, the most common method for diagnosis of TB is the
      acid fast staining of a sputum sample which is then followed by a sputum smear microscopy
      test. However a disadvantage with the sputum smear test is its poor sensitivity, which is
      estimated to be at 70%. Additionally, the sensitivity of sputum smear spectroscopy in field
      settings has been shown to be much lower (35%), especially in populations that have high
      rates of TB and HIV coinfection. Culturing of mycobacterium from sputum samples is a more
      sensitive technique. Sputum samples are collected and cultured in either solid media or
      liquid media looking for the presence of the mycobacterium. However this methodology takes
      time to conduct (3-4 weeks for solid cultures, and 10-14 days for liquid cultures), which
      makes it difficult to employ in low resource settings that are typically far from testing
      facilities.

      Recently, other technologies have been developed including fluorescence microscopy for smear
      tests (10% more sensitive than light microscopy), LED fluorescent microscopy for inexpensive
      imaging equipment that can be used in the field without the need for a darkroom, and rapid
      culturing techniques to reduce incubation time. Despite all the improvements that have been
      made in TB diagnosis, no simple inexpensive POC test is currently available. The techniques
      mentioned above either focus on variations of microscopy or culture technique. In either
      case, these methods require lab facilities and highly trained personnel that typically are
      not available in many rural or low resource areas.

      Recent research has shown that various strains of the mycobacteria produce distinct gaseous
      volatile biomarkers that can be used as a methodology for detecting and identifying the
      mycobacterium. Specifically, Syhre and Chambers found that Mycobacterium tuberculosis and
      Mycobacterium bovis cultures give off four specific volatile organic biomarkers (VOBs):
      methyl phenylacetate, methyl p-anisate, methyl nicotinate, and o-phenylanisole. These
      compounds were detectable before the visual appearance of colonies, which could have
      implications in detection of latent TB infection. Syhre et al. were able to detect
      statistically significant differences of methyl nicotinate in the breath of smear positive TB
      patients when compared to healthy (smear negative) subjects. Analyses in these studies were
      done using gas chromatography/mass spectroscopy analysis tools. While they are effective in
      identifying and quantifying complex gas samples, they are expensive, bulky, and not
      appropriate for point of care (POC) diagnostics.

      These challenges associated with the diagnosis of TB are significant as TB is the second
      leading cause of death due to a single infectious organism and is responsible for 1.3 million
      deaths annually (over 3,500 every day), according to the WHO. Overall, an estimated 2 billion
      people are currently infected worldwide with 8.6 million new active infections occurring each
      year.[8] Each of these individuals can transmit the disease to 10 to 15 people per year and
      face a mortality rate of 50% if untreated. The economic burden of TB is staggering as the
      World Bank estimates that high burden countries can lose up to 7% of GDP due to productivity
      losses from TB patients and their caretakers. It is so critical that the World Bank committed
      $100 million to testing for and treating TB in India in 2014 alone.

      Of the 8.6 million new active TB cases that occur annually, the WHO estimates that roughly 3
      million of these patients are 'missed' and do not receive the diagnosis or care they need.
      One of the primary reasons for this gap is delays in accessing TB-related care or long lead
      times for diagnostic tests. As a result, developing new large scale screening tests (also
      known as triage or 'rule out' tests) are particularly needed due to the fact that up to 80%
      of people tested for TB do not have active disease, stretching the limited and valuable
      resources that are devoted for diagnostic testing. As a result, FIND, a world leader in
      guiding and coordinating research and development for diseases such as TB, ranked the
      development of new screening tests as one of the top 3 priorities in the fight against TB.

      This pilot study will be conducted to determine if a newly developed sensing methodology for
      screening TB at the POC based on volatile biomarkers is feasible through the use of a low
      cost solid-state sensor using functionalized 3D TiO2 nanotube arrays that bind the volatile
      biomarkers. If the clinical sensitivity is sufficient, this technology could provide a means
      for identifying many of the 'missed' TB patients and allow testing resources and efforts to
      be focused on those at the highest risk of having the disease.

      Previously, we have tested the breath profile of a small number patients from local TB
      clinics and have confirmed the presence of these biomarkers in their breath (IRB_0065207).
      Larger patients studies are now required to gain an estimate of the sensitivity and
      specificity to determine the potential of using the sensor as a screening test. This study
      will be conducted in Mumbai, India with the University's Research Electronic Data Capture
      (REDCap) system used to securely collect and store the data from this study.

      This study has been reviewed and approved by the Mahatma Gandhi Mission Institute of Health
      Sciences Ethical Committee for Research on Human Subjects and Scientific Advisory Committee.
    

Intervention name(s): Breath Collection
Intervention type(s): Device
Intervention description(s): breath will be collected from patients in breath bag for analysis for observational study.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Study type: Observational feasibility study

          -  Study population: Non-pregnant adults over the age of 18 from the areas around Mumbai,
             India. Based upon records of these clinical sites, about 5% to 7% of the patients
             reporting at these hospitals are suspected to be TB positive.

          -  Endpoint: Estimate of the diagnostic accuracy of a POC TB biomarker breath test
             (sensitivity, specificity).

          -  Phase: Phase I (feasibility or pilot study)

          -  Study sites: Multicenter trial (4 clinical sites in Mumbai, India)

          -  Study groups: 5

          -  Sample Size (approx): 800

          -  Estimated enrollment time: 1 year