Rapid, Quantitative Point-of-Care Measurement of Tuberculosis Treatment Adherence

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Project Summary/Abstract Tuberculosis (TB) continues to be a major health concern worldwide and is the leading cause of death worldwide from a single infectious agent. Globally, an estimated 10 million people fell ill with TB in 2018, and there were an estimated 1.2 million TB deaths among HIV- negative people in 2018 and an additional 251,000 deaths among HIV positive people. In the U.S. there were 9,029 new TB confirmed by the CDC’s national surveillance program in 2018, the lowest on record, yet there are an estimated 13 million in the U.S. living with latent TB infection, and an estimated 290,000 new cases each year in the Americas indicating a significant remaining regional burden. The emergence of drug resistant strains of TB is considered a global threat to the control of TB. Despite this threat, TB is a curable disease if treatment is received quickly and appropriately. Thus, rapid and accurate diagnosis and the use of effective anti-TB treatments not only minimize morbidity and mortality, but also mitigate the spread of TB among the population. Nevertheless, TB patients who are not cured or non-adherent to their treatment pose a serious risk both for individuals and their community. Non-adherence to anti-TB treatment may result in the emergence of multidrug resistant TB (MDR-TB), prolonged infectiousness and poor TB treatment outcomes. Even in the U.S., adherence to treatment through to completion is poor and challenging due to a number of factors – the duration of treatment is long (usually six months or longer), combination therapy is required, and side effects may be unpleasant. Cost of medications (even relatively small copays or deductibles) can be a serious barrier to adherence if not covered by the public health system. Furthermore, patients often experience rapid improvement in symptoms, which may obfuscate the importance of continuing prolonged treatment with drugs that may be perceived as unnecessary. Worldwide, there are often even more obstacles to adherence including: access to transportation for directly observed therapy (DOT), lack of knowledge on the benefits of completing a treatment course, running out of drugs at home, distance to the health facility, HIV seropositivity, alcohol abuse, and use of herbal medication. Non-adherence was also significantly associated with drug side effects, being in the continuation phases of chemotherapy, pill burden, lack of adequate communication with health professionals and lack of family support. Finally, there is wide variability in absorption and metabolism of the anti-TB drugs, and low drug concentrations in blood are associated with inferior TB treatment outcomes, including treatment failure and relapse. Pharmacokinetic variability has been identified as a key mediator of the rate of sterilizing effect and the emergence of new drug resistance mutations during anti-TB therapy. In summary, there is still a desperate need for rapid, quantitative assessment of TB drug dosing and adherence to treatment, preferably at the point of care. In this SBIR project, we will develop a new sensor platform that can be used to quickly measure the primary TB drugs in urine. The system will resemble a personal glucose meter for diabetics in that there is a small handheld reader and a test strip (screen-printed electrode). DNA aptamers will be immobilized on the electrode in order to provide specific molecular recognition in a sensitive format that we have already proven for other analytes in urine. This approach has the promise to educate clinicians on proper dosing and monitor patient adherence to treatment which remains a significant hurdle to ultimately eradicating TB.