This article is more than 5 years old. Information may no longer be current.
Hair, plasma samples were useful indicators of tenofovir exposure
The sensitivity and specificity of detecting tenofovir in hair, plasma and peripheral blood mononuclear cells were greater than 90%, according to findings presented at the 17th Conference on Retroviruses and Opportunistic Infections in San Francisco.
Albert Liu, MD, MPH, director of HIV Prevention Intervention Studies at the HIV Research Section of the San Francisco Department of Public Health, presented the results.
The researchers collected single samples of hair, plasma and peripheral blood mononuclear cells from 89 men uninfected with HIV in the pre-exposure prophylaxis trial. Among these men, 47 were assigned to the active arm and 42 to the placebo arm. The samples were tested for tenofovirin a blinded fashion.
Results indicated that median tenofovir levels were 0.05 ng/mg in hair; 83 ng/mL in plasma; and 40 fmol/million cells in peripheral blood mononuclear cells for the active arm.
Sensitivity analyses indicated that tenofovir detection was 98% for hair and 94% for both plasma and peripheral blood mononuclear cells. Specificity findings indicated that tenofovir detection was 98% for hair and plasma and 92% for peripheral blood mononuclear cells.
“One participant in the placebo arm had detectable tenofovir levels in all three categories of test, suggesting that tenofovir exposure had occurred,” Liu said. “However, it is worth noting that it was the same person, suggesting that he may have been receiving the drug from outside sources.”
Liu said that the Spearman correlation was 0.62 for plasma and peripheral blood mononuclear cell levels, 0.41 for peripheral blood mononuclear cells and hair and 0.21 for plasma and hair.
“Hair, peripheral blood mononuclear cells and plasma may be sensitive and specific for tenofovir exposure in men who have sex with men in this trial,” Liu said. “Indices of long-term drug exposure, afforded with hair and peripheral blood mononuclear cell analysis, are candidate surrogate markers for pre-exposure prophylaxis activity. However, these methods require further validation in efficacy trials.” – by Rob Volansky
Liu A. #86. Presented at: 17th Conference on Retroviruses and Opportunistic Infections; Feb. 16-19, 2010; San Francisco.