Assessing PrEP Adherence/Exposure Using Hair Samples
Assessing PrEP Adherence/Exposure Using Hair Samples
This study demonstrates a number of novel findings, notably that monitoring concentrations of TFV/FTC in hair in the HIV prevention setting was feasible, acceptable, and correlated strongly with MEMS-caps measures and drug concentrations in other biomatrices. The lack of strong correlations between pharmacologic measures of exposure and self-reported pill-taking in this study adds to the growing evidence that self-reported adherence in HIV prevention trials performs poorly. The strong correlation between pharmacologic measures and behavior as assessed by electronic monitoring of bottle openings suggests a role for combining modalities of measuring adherence or exposure to PrEP. Given the urgent need for developing feasible, low-cost, and objective measures of adherence and exposure monitoring in PrEP, these findings pave the way for further exploration of hair concentrations as an exposure monitoring tool in PrEP investigational and implementation projects.
Conclusions
This study demonstrates a number of novel findings, notably that monitoring concentrations of TFV/FTC in hair in the HIV prevention setting was feasible, acceptable, and correlated strongly with MEMS-caps measures and drug concentrations in other biomatrices. The lack of strong correlations between pharmacologic measures of exposure and self-reported pill-taking in this study adds to the growing evidence that self-reported adherence in HIV prevention trials performs poorly. The strong correlation between pharmacologic measures and behavior as assessed by electronic monitoring of bottle openings suggests a role for combining modalities of measuring adherence or exposure to PrEP. Given the urgent need for developing feasible, low-cost, and objective measures of adherence and exposure monitoring in PrEP, these findings pave the way for further exploration of hair concentrations as an exposure monitoring tool in PrEP investigational and implementation projects.