The authors concluded that after twelve weeks of SOF/RBV treatment, TFV-DP concentrations in DBS were increased 6.8 fold despite not change in TFV plasma levels. Additional studies are needed to determine the clinical significance of this finding, and to determine if the causative agent was SOF versus RBV.
Tenofovir disoproxil fumarate vs sofosbuvir/ribavirin
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Study Design
Fifteen HIV infected males, treated with a tenofovir containing cART regimen, had plasma and dried blood spot (DBS) were obtained at baseline and at week twelve of treatment with sofosbuvir (SOF) and ribavirin (RBV), as well as twelve weeks following the end of treatment with SOF/RBV. Validated LC/MS-MS methods were used to quantify tenofovir (TFV) in plasma and tenofovir diphosphate (TVF-DP) in DBS.
Study Results
At entry, mean (+SD) TFV-DP in DBS was 1767.8 (± 543.1) fmol / punch. At week twelve of SOF/RBV treatment, TFV-DP concentrations were 6.8 fold higher versus entry (range 1.43-18.3, p=0.0043) with a mean (±SD) of 2237.55 (±814.3) fmol/punch. At entry, twelve weeks of therapy, and twelve weeks after the end of therapy with SOF/RBV, mean(±SD) TFV was 113.2 (±70.9), 109.9 (±62.9) and 110.5 (±87.1) ng/ml respectively. TFV-DP in DBS at week 12 did not differ in those that acheieved SVR versus those who replapsed.
References
MacBrayne CE, Marks KM, Fierer DS, S Naggie, Chung RT, Hollabaugh KM, et al. Increased tenofovir diphosphate concentrations in red blood cells, but not tenofovir in plasma with sofosbuvir and ribavirin. abstract o_19. 17th International Workshop On Clinical Pharmacology Of Hiv And Hepatitis Therapy. Washington DC, USA. ; 2016.
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