Point-of-care semi-quantitative test for adherence to tenofovir alafenamide or tenofovir disoproxil fumarate.

Derin Sevenler, Xin Niu, Sandy Dossantos, Mehmet Toner, Tim R Cressey, Rebecca D Sandlin, Paul K Drain

The Journal of antimicrobial chemotherapy 2022 Mar 31

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Objective measurement of antiretrovirals may aid clinical interventions for improving adherence to HIV prevention or treatment regimens. A point-of-care urine test could provide real-time information about recent adherence to regimens containing tenofovir disoproxil fumarate or tenofovir alafenamide. We developed a lateral flow immunoassay (LFA) and ELISA for urinary tenofovir. The intensity of the LFA test line was quantified using an optical reader and visually scored 0-5 by two independent people, using a reference card. The sensitivity and specificity of both the ELISA and LFA were determined for two different tenofovir concentration cut-offs for tenofovir disoproxil fumarate and tenofovir alafenamide adherence-1500 and 150 ng/mL, respectively. To validate the assays, we measured 586 urine samples from 28 individuals collected as part of a study of tenofovir pharmacokinetics in adults, which were also measured by MS for reference. Both the LFA signal and ELISA signal were each strongly correlated with drug concentrations (0.91 and 0.92, respectively). The LFA signal and ELISA were highly sensitive and specific at both thresholds (LFA sensitivity/specificity: tenofovir disoproxil fumarate, 89%/96%; and tenofovir alafenamide, 90%/96%) (ELISA sensitivity/specificity: tenofovir disoproxil fumarate, 94%/94%; and tenofovir alafenamide, 92%/84%). Visual scoring of the LFA was also highly sensitive and specific at both the tenofovir disoproxil fumarate threshold and the tenofovir alafenamide threshold (sensitivity/specificity: tenofovir disoproxil fumarate, 91%/94%; and tenofovir alafenamide, 87%/90%). Our rapid semi-quantitative test can measure tenofovir concentrations relevant to both tenofovir alafenamide and tenofovir disoproxil fumarate adherence, which may support adherence-promoting interventions across a range of HIV care settings. © The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Citation

Derin Sevenler, Xin Niu, Sandy Dossantos, Mehmet Toner, Tim R Cressey, Rebecca D Sandlin, Paul K Drain. Point-of-care semi-quantitative test for adherence to tenofovir alafenamide or tenofovir disoproxil fumarate. The Journal of antimicrobial chemotherapy. 2022 Mar 31;77(4):996-999