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ABSTRACT: Objectives
This study was designed to assess the dose-response relationship between tissue, blood, vaginal and rectal compartment concentrations of tenofovir (TFV) and tenofovir diphosphate (TFVdp) and ex vivo rectal HIV suppression following oral tenofovir disoproxil fumarate (TDF) and rectal administration of TFV 1% vaginally-formulated gel.Design
Phase 1, randomized, two-site (US), double-blind, placebo-controlled study of sexually-abstinent males and females.Methods
Eighteen participants received a single 300 mg exposure of oral TDF and were then randomized 2?1 to receive a single then seven-daily rectal exposures of TFV 1% gel (40 mg TFV per 4 ml gel application) or hydroxyethyl-cellulose (HEC) placebo gel. Blood and rectal biopsies were collected for pharmacokinetic TDF and TFVdp analyses and ex vivo HIV-1 challenge.Results
There was a significant fit for the TFVdp dose-response model for rectal tissue (p?=?0.0004), CD4+MMC (p<0.0001), CD4-MMC (p<0.0001), and TotalMMC (p<0.0001) compartments with r2 ranging 0.36-0.64. Higher concentrations of TFVdp corresponded with lower p24, consistent with drug-mediated virus suppression. The single oral treatment failed to provide adequate compartment drug exposure to reach the EC50 of rectal tissue TFVdp predicted to be necessary to suppress HIV in rectal tissue. The EC50 for CD4+MMC was within the single topical treatment range, providing evidence that a 1% topical, vaginally-formulated TFV gel provided in-vivo doses predicted to provide for 50% efficacy in the ex vivo assay. The 7-daily topical TFV gel treatment provided TFVdp concentrations that reached EC90 biopsy efficacy for CD4-MMC, CD4+MMC and TotalMMC compartments.Conclusion
The TFVdp MMC compartment (CD4+, CD4- and Total) provided the best surrogate for biopsy infectibility and the 7-daily topical TFV gel treatment provided the strongest PK profile for HIV suppression. ClinicalTrials.gov NCT00984971.
SUBMITTER: Richardson-Harman N
PROVIDER: S-EPMC4211741 | biostudies-literature | 2014
REPOSITORIES: biostudies-literature
Richardson-Harman Nicola N Hendrix Craig W CW Bumpus Namandjé N NN Mauck Christine C Cranston Ross D RD Yang Kuo K Elliott Julie J Tanner Karen K McGowan Ian I Kashuba Angela A Anton Peter A PA
PloS one 20141028 10
<h4>Objectives</h4>This study was designed to assess the dose-response relationship between tissue, blood, vaginal and rectal compartment concentrations of tenofovir (TFV) and tenofovir diphosphate (TFVdp) and ex vivo rectal HIV suppression following oral tenofovir disoproxil fumarate (TDF) and rectal administration of TFV 1% vaginally-formulated gel.<h4>Design</h4>Phase 1, randomized, two-site (US), double-blind, placebo-controlled study of sexually-abstinent males and females.<h4>Methods</h4>E ...[more]