Journal of the International Association of Providers of AIDS Care (Nov 2019)

Moderately High Tenofovir Diphosphate in Dried Blood Spots Indicates Drug Resistance in Viremic Persons Living with HIV

  • Jenna Lynn Yager PharmD,
  • Ryan Patrick Coyle BA,
  • Stacey Summer Coleman BS, BSN,
  • Lucas Ellison BS,
  • Jia-Hua Zheng PhD,
  • Lane Bushman BChem,
  • Edward Michael Gardner MD,
  • Mary Morrow MS,
  • Samantha MaWhinney ScD,
  • Peter L. Anderson PharmD,
  • Jennifer Justice Kiser PharmD, PhD,
  • Jose Ramon Castillo-Mancilla MD

DOI
https://doi.org/10.1177/2325958219888457
Journal volume & issue
Vol. 18

Abstract

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Background: Tenofovir diphosphate (TFV-DP) in dried blood spots (DBS) is a strong predictor of viral suppression in persons living with HIV (PLWH). Its association with antiretroviral therapy (ART) resistance remains unknown. Methods: Blood was collected in PLWH receiving TDF-containing ART enrolled in a 48-week study. Tenofovir diphosphate/emtricitabine triphosphate (FTC-TP) were quantified from the same sample as HIV viral load (VL) in PLWH who developed resistance within ≤12 months. Results: The study enrolled 807 participants, of whom 10 had new resistance-conferring mutations. Among these, median (interquartile range) TFV-DP and HIV VL were 956 (407-1510) fmol/punch and 9840 (513-68,200) copies/mL, respectively. Five had quantifiable FTC-TP in DBS. Based on previously published data, a TFV-DP concentration of 956 fmol/punch would have an adjusted odds of virologic suppression of 32.8 versus TFV-DP <350 fmol/punch, making viremia of ∼10,000 copies/mL an unexpected outcome. Conclusion: Moderately high TFV-DP in DBS (700-1249 fmol/punch) in PLWH with high viremia suggest that antiretroviral drug resistance might be present.