Measuring TB drug levels in the hair in adults and children to monitor drug exposure and outcomes

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International Journal of Tuberculosis and Lung Disease

INTRODUCTION: Testing for anti-TB drugs in small hair samples may serve as a non-invasive tool to measure cumulative drug exposure and/or adherence, as these determine treatment success. We aimed to assess how well hair assays of TB drugs predict TB treatment outcomes.METHODS: A small thatch of hair, ~30 strands, was cut from the occipital region in adults and children from a prospective TB cohort in India. Isoniazid (INH), acetyl-INH and pyrazinamide (PZA) were extracted from the hair samples and quantified using liquid-chromatography-tandem mass spectrometry. The relationship between drug concentrations in hair and time to unfavourable outcomes was assessed using Cox-proportional hazards regression models.RESULTS: A two-fold increase in hair acetyl-INH concentrations in the 264 participants in our cohort with hair assays for TB drugs indicated a lower hazard of unfavourable TB treatment outcomes (aHR 0.67, 95%CI 0.44-1.02) and TB treatment failure (aHR 0.65, 95%CI 0.42-1.01). Higher summed concentrations (a summed measure of INH and acetyl-INH) indicated a lower hazard of treatment failure (aHR 0.69, 95%CI 0.45-1.05)CONCLUSION: Hair levels of INH and its metabolite may predict TB treatment outcomes, indicating the potential utility of this measure to assess and optimise TB treatment outcomes.

Mave V, Kadam D, Gaikwad S, Kinikar A, Aguilar D, Chavan A, Paradkar M, Yogendra SVB, Bharadwaj R, Kagal A, Suryavanshi N, Golub J, Kulkarni V, Dooley KE, Gupta A, Bacchetti P, Gerona R, Gupte N, Gandhi M. Measuring TB drug levels in the hair in adults and children to monitor drug exposure and outcomes. Int J Tuberc Lung Dis. 2021 Jan 1;25(1):52-60. doi: 10.5588/ijtld.20.0574. PMID: 33384045.